Apache Camel
USER GUIDE
Version 2.9.0
Copyright 2007-2011, Apache Software Foundation
Table of Contents
Table of Contents......................................................................... ii
Chapter 1
Introduction ...................................................................................1
Chapter 2
Quickstart .......................................................................................1
Chapter 3
Getting Started..............................................................................7
Chapter 4
Architecture ................................................................................ 17
Chapter 5
Enterprise Integration Patterns.............................................. 33
Chapter 6
Cook Book ................................................................................... 38
Chapter 7
Tutorials..................................................................................... 103
Chapter 8
Language Appendix.................................................................. 206
Chapter 9
DataFormat Appendix............................................................. 274
Chapter 10
Pattern Appendix..................................................................... 344
Chapter 11
Component Appendix ............................................................. 494
Index ................................................................................................0
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AP A C H E C A M E L
CHAPTER
1
°°°°
Introduction
Apache Camel ª is a powerful open source integration framework based on known Enterprise
Integration Patterns with powerful Bean Integration.
Camel lets you create the Enterprise Integration Patterns to implement routing and mediation
rules in either a Java based Domain Specific Language (or Fluent API), via Spring or Blueprint
based Xml Configuration files or via the Scala DSL. This means you get smart completion of
routing rules in your IDE whether in your Java, Scala or XML editor.
Apache Camel uses URIs so that it can easily work directly with any kind of Transport or
messaging model such as HTTP, ActiveMQ, JMS, JBI, SCA, MINA or CXF together with working
with pluggable Data Format options. Apache Camel is a small library which has minimal
dependencies for easy embedding in any Java application. Apache Camel lets you work with the
same API regardless which kind of Transport used, so learn the API once and you will be able
to interact with all the Components that is provided out-of-the-box.
Apache Camel has powerful Bean Binding and integrated seamless with popular frameworks
such as Spring, Blueprint and Guice.
Apache Camel has extensive Testing support allowing you to easily unit test your routes.
Apache Camel can be used as a routing and mediation engine for the following projects:
• Apache ServiceMix which is the most popular and powerful distributed open source
ESB and JBI container
• Apache ActiveMQ which is the most popular and powerful open source message
broker
• Apache CXF which is a smart web services suite (JAX-WS and JAX-RS)
• Apache Karaf which is a small OSGi based runtime which applications can be
deployed
• Apache MINA a networking framework
So don't get the hump, try Camel today!
CH APT ER 1 - IN T R O DUCT IO N
1
CHAPTER
2
°°°°
Quickstart
To start using Apache Camel quickly, you can read through some simple examples in this
chapter. For readers who would like a more thorough introduction, please skip ahead to
Chapter 3.
WALK THROUGH AN EXAMPLE CODE
This mini-guide takes you through the source code of a simple example.
Camel can be configured either by using Spring or directly in Java - which this example does.
This example is available in the examples\camel-example-jms-file directory of
the Camel distribution.
We start with creating a CamelContext - which is a container for Components, Routes etc:
CamelContext context = new DefaultCamelContext();
There is more than one way of adding a Component to the CamelContext. You can add
components implicitly - when we set up the routing - as we do here for the FileComponent:
context.addRoutes(new RouteBuilder() {
public void configure() {
from("test-jms:queue:test.queue").to("file://test");
}
});
or explicitly - as we do here when we add the JMS Component:
ConnectionFactory connectionFactory = new
ActiveMQConnectionFactory("vm://localhost?broker.persistent=false");
// Note we can explicit name the component
context.addComponent("test-jms",
JmsComponent.jmsComponentAutoAcknowledge(connectionFactory));
The above works with any JMS provider. If we know we are using ActiveMQ we can use an
even simpler form using the activeMQComponent() method while specifying the brokerURL
used to connect to ActiveMQ
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CH A PTE R 2 - Q U I CKS T A R T
camelContext.addComponent("activemq",
activeMQComponent("vm://localhost?broker.persistent=false"));
In normal use, an external system would be firing messages or events directly into Camel
through one if its Components but we are going to use the ProducerTemplate which is a really
easy way for testing your configuration:
ProducerTemplate template = context.createProducerTemplate();
Next you must start the camel context. If you are using Spring to configure the camel context
this is automatically done for you; though if you are using a pure Java approach then you just
need to call the start() method
camelContext.start();
This will start all of the configured routing rules.
So after starting the CamelContext, we can fire some objects into camel:
for (int i = 0; i < 10; i++) {
template.sendBody("test-jms:queue:test.queue", "Test Message: " + i);
}
WHAT HAPPENS?
From the ProducerTemplate - we send objects (in this case text) into the CamelContext to the
Component test-jms:queue:test.queue. These text objects will be converted automatically into
JMS Messages and posted to a JMS Queue named test.queue. When we set up the Route, we
configured the FileComponent to listen of the test.queue.
The File FileComponent will take messages off the Queue, and save them to a directory
named test. Every message will be saved in a file that corresponds to its destination and message
id.
Finally, we configured our own listener in the Route - to take notifications from the
FileComponent and print them out as text.
That's it!
If you have the time then use 5 more minutes to Walk through another example that
demonstrates the Spring DSL (XML based) routing.
CH APT ER 2 - Q UICK ST AR T
2
Camel 1.4.0 change
In Camel 1.4.0, CamelTemplate has been marked as @deprecated.
ProducerTemplate should be used instead and its created from the CamelContext
itself.
ProducerTemplate template = context.createProducerTemplate();
WALK THROUGH ANOTHER EXAMPLE
Introduction
We continue the walk from Walk through an Example. This time we take a closer look at the
routing and explains a few pointers so you wont walk into a bear trap, but can enjoy a walk
after hours to the local pub for a large beer
First we take a moment to look at the Enterprise Integration Patterns that is the base
pattern catalog for integrations. In particular we focus on the Pipes and Filters EIP pattern, that
is a central pattern. This is used for: route through a sequence of processing steps, each
performing a specific function - much like the Java Servlet Filters.
Pipes and filters
In this sample we want to process a message in a sequence of steps where each steps can
perform their specific function. In our example we have a JMS queue for receiving new orders.
When an order is received we need to process it in several steps:
▪ validate
▪ register
▪ send confirm email
This can be created in a route like this:
Where as the bean ref is a reference for a spring bean id, so we define our beans using
regular Spring XML as:
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CH A PTE R 2 - Q U I CKS T A R T
Pipeline is default
In the route above we specify pipeline but it can be omitted as its default, so
you can write the route as:
uri="jms:queue:order"/>
ref="validateOrder"/>
ref="registerOrder"/>
ref="sendConfirmEmail"/>
This is commonly used not to state the pipeline.
An example where the pipeline needs to be used, is when using a multicast and "one" of
the endpoints to send to (as a logical group) is a pipeline of other endpoints. For example.
The above sends the order (from jms:queue:order) to two locations at the same time,
our log component, and to the "pipeline" of beans which goes one to the other. If you
consider the opposite, sans the
you would see that multicast would not "flow" the message from one bean to the next, but
rather send the order to all 4 endpoints (1x log, 3x bean) in parallel, which is not (for this
CH APT ER 2 - Q UICK ST AR T
4
example) what we want. We need the message to flow to the validateOrder, then to the
registerOrder, then the sendConfirmEmail so adding the pipeline, provides this facility.
Our validator bean is a plain POJO that has no dependencies to Camel what so ever. So you
can implement this POJO as you like. Camel uses rather intelligent Bean Binding to invoke your
POJO with the payload of the received message. In this example we will not dig into this how
this happens. You should return to this topic later when you got some hands on experience
with Camel how it can easily bind routing using your existing POJO beans.
So what happens in the route above. Well when an order is received from the JMS queue
the message is routed like Pipes and Filters:
1. payload from the JMS is sent as input to the validateOrder bean
2. the output from validateOrder bean is sent as input to the registerOrder bean
3. the output from registerOrder bean is sent as input to the sendConfirmEmail bean
Using Camel Components
In the route lets imagine that the registration of the order has to be done by sending data to a
TCP socket that could be a big mainframe. As Camel has many Components we will use the
camel-mina component that supports TCP connectivity. So we change the route to:
What we now have in the route is a to type that can be used as a direct replacement for the
bean type. The steps is now:
1. payload from the JMS is sent as input to the validateOrder bean
2. the output from validateOrder bean is sent as text to the mainframe using TCP
3. the output from mainframe is sent back as input to the sendConfirmEmai bean
What to notice here is that the to is not the end of the route (the world
) in this
example it's used in the middle of the Pipes and Filters. In fact we can change the bean types to
to as well:
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CH A PTE R 2 - Q U I CKS T A R T
As the to is a generic type we must state in the uri scheme which component it is. So we must
write bean: for the Bean component that we are using.
Conclusion
This example was provided to demonstrate the Spring DSL (XML based) as opposed to the
pure Java DSL from the first example. And as well to point about that the to doesn't have to be
the last node in a route graph.
This example is also based on the in-only message exchange pattern. What you must
understand as well is the in-out message exchange pattern, where the caller expects a
response. We will look into this in another example.
See also
▪ Examples
▪ Tutorials
▪ User Guide
CH APT ER 2 - Q UICK ST AR T
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CHAPTER
3
°°°°
Getting Started with Apache
Camel
THE ENTERPRISE INTEGRATION PATTERNS (EIP) BOOK
The purpose of a "patterns" book is not to advocate new techniques that the authors have
invented, but rather to document existing best practices within a particular field. By doing this,
the authors of a patterns book hope to spread knowledge of best practices and promote a
vocabulary for discussing architectural designs.
One of the most famous patterns books is Design Patterns: Elements of Reusable Object-oriented
Software by Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides, commonly known as
the "Gang of Four" (GoF) book. Since the publication of Design Patterns, many other pattern
books, of varying quality, have been written. One famous patterns book is called Enterprise
Integration Patterns: Designing, Building, and Deploying Messaging Solutions by Gregor Hohpe and
Bobby Woolf. It is common for people to refer to this book by its initials EIP. As the subtitle of
EIP suggests, the book focuses on design patterns for asynchronous messaging systems. The
book discusses 65 patterns. Each pattern is given a textual name and most are also given a
graphical symbol, intended to be used in architectural diagrams.
THE CAMEL PROJECT
Camel (http://camel.apache.org) is an open-source, Java-based project that helps the user
implement many of the design patterns in the EIP book. Because Camel implements many of the
design patterns in the EIP book, it would be a good idea for people who work with Camel to
have the EIP book as a reference.
ONLINE DOCUMENTATION FOR CAMEL
The documentation is all under the Documentation category on the right-side menu of the
Camel website (also available in PDF form. Camel-related books are also available, in particular
the Camel in Action book, presently serving as the Camel bible--it has a free Chapter One
(pdf), which is highly recommended to read to get more familiar with Camel.
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A useful tip for navigating the online documentation
The breadcrumbs at the top of the online Camel documentation can help you navigate between
parent and child subsections.
For example, If you are on the "Languages" documentation page then the left-hand side of the
reddish bar contains the following links.
Apache Camel > Documentation > Architecture > Languages
As you might expect, clicking on "Apache Camel" takes you back to the home page of the
Apache Camel project, and clicking on "Documentation" takes you to the main documentation
page. You can interpret the "Architecture" and "Languages" buttons as indicating you are in the
"Languages" section of the "Architecture" chapter. Adding browser bookmarks to pages that
you frequently reference can also save time.
ONLINE JAVADOC DOCUMENTATION
The Apache Camel website provides Javadoc documentation. It is important to note that the
Javadoc documentation is spread over several independent Javadoc hierarchies rather than being
all contained in a single Javadoc hierarchy. In particular, there is one Javadoc hierarchy for the
core APIs of Camel, and a separate Javadoc hierarchy for each component technology supported
by Camel. For example, if you will be using Camel with ActiveMQ and FTP then you need to
look at the Javadoc hierarchies for the core API and Spring API.
CONCEPTS AND TERMINOLOGY FUNDAMENTAL TO CAMEL
In this section some of the concepts and terminology that are fundamental to Camel are
explained. This section is not meant as a complete Camel tutorial, but as a first step in that
direction.
Endpoint
The term endpoint is often used when talking about inter-process communication. For example,
in client-server communication, the client is one endpoint and the server is the other endpoint.
Depending on the context, an endpoint might refer to an address, such as a host:port pair for
TCP-based communication, or it might refer to a software entity that is contactable at that
address. For example, if somebody uses "www.example.com:80" as an example of an endpoint,
they might be referring to the actual port at that host name (that is, an address), or they might
be referring to the web server (that is, software contactable at that address). Often, the
distinction between the address and software contactable at that address is not an important
one.
Some middleware technologies make it possible for several software entities to be contactable
at the same physical address. For example, CORBA is an object-oriented, remote-procedure-
C H A P T E R 3 - G ET T IN G ST AR T ED W IT H APACH E CAM EL
8
call (RPC) middleware standard. If a CORBA server process contains several objects then a
client can communicate with any of these objects at the same physical address (host:port), but a
client communicates with a particular object via that object's logical address (called an IOR in
CORBA terminology), which consists of the physical address (host:port) plus an id that uniquely
identifies the object within its server process. (An IOR contains some additional information
that is not relevant to this present discussion.) When talking about CORBA, some people may
use the term "endpoint" to refer to a CORBA server's physical address, while other people may
use the term to refer to the logical address of a single CORBA object, and other people still
might use the term to refer to any of the following:
• The physical address (host:port) of the CORBA server process
• The logical address (host:port plus id) of a CORBA object.
• The CORBA server process (a relatively heavyweight software entity)
• A CORBA object (a lightweight software entity)
Because of this, you can see that the term endpoint is ambiguous in at least two ways. First, it is
ambiguous because it might refer to an address or to a software entity contactable at that
address. Second, it is ambiguous in the granularity of what it refers to: a heavyweight versus
lightweight software entity, or physical address versus logical address. It is useful to understand
that different people use the term endpoint in slightly different (and hence ambiguous) ways
because Camel's usage of this term might be different to whatever meaning you had previously
associated with the term.
Camel provides out-of-the-box support for endpoints implemented with many different
communication technologies. Here are some examples of the Camel-supported endpoint
technologies.
• A JMS queue.
• A web service.
• A file. A file may sound like an unlikely type of endpoint, until you realize that in some
systems one application might write information to a file and, later, another
application might read that file.
• An FTP server.
• An email address. A client can send a message to an email address, and a server can
read an incoming message from a mail server.
• A POJO (plain old Java object).
In a Camel-based application, you create (Camel wrappers around) some endpoints and
connect these endpoints with routes, which I will discuss later in Section 4.8 ("Routes,
RouteBuilders and Java DSL"). Camel defines a Java interface called Endpoint. Each Camelsupported endpoint has a class that implements this Endpoint interface. As I discussed in
Section 3.3 ("Online Javadoc documentation"), Camel provides a separate Javadoc hierarchy for
each communications technology supported by Camel. Because of this, you will find
documentation on, say, the JmsEndpoint class in the JMS Javadoc hierarchy, while
documentation for, say, the FtpEndpoint class is in the FTP Javadoc hierarchy.
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CamelContext
A CamelContext object represents the Camel runtime system. You typically have one
CamelContext object in an application. A typical application executes the following steps.
1. Create a CamelContext object.
2. Add endpoints Ð and possibly Components, which are discussed in Section 4.5
("Components") Ð to the CamelContext object.
3. Add routes to the CamelContext object to connect the endpoints.
4. Invoke the start() operation on the CamelContext object. This starts Camelinternal threads that are used to process the sending, receiving and processing of
messages in the endpoints.
5. Eventually invoke the stop() operation on the CamelContext object. Doing this
gracefully stops all the endpoints and Camel-internal threads.
Note that the CamelContext.start() operation does not block indefinitely. Rather, it
starts threads internal to each Component and Endpoint and then start() returns.
Conversely, CamelContext.stop() waits for all the threads internal to each Endpoint
and Component to terminate and then stop() returns.
If you neglect to call CamelContext.start() in your application then messages will not be
processed because internal threads will not have been created.
If you neglect to call CamelContext.stop() before terminating your application then the
application may terminate in an inconsistent state. If you neglect to call
CamelContext.stop() in a JUnit test then the test may fail due to messages not having
had a chance to be fully processed.
CamelTemplate
Camel used to have a class called CamelClient, but this was renamed to be
CamelTemplate to be similar to a naming convention used in some other open-source
projects, such as the TransactionTemplate and JmsTemplate classes in Spring.
The CamelTemplate class is a thin wrapper around the CamelContext class. It has
methods that send a Message or Exchange Ð both discussed in Section 4.6 ("Message and
Exchange")) Ð to an Endpoint Ð discussed in Section 4.1 ("Endpoint"). This provides a way to
enter messages into source endpoints, so that the messages will move along routes Ð discussed
in Section 4.8 ("Routes, RouteBuilders and Java DSL") Ð to destination endpoints.
The Meaning of URL, URI, URN and IRI
Some Camel methods take a parameter that is a URI string. Many people know that a URI is
"something like a URL" but do not properly understand the relationship between URI and URL,
or indeed its relationship with other acronyms such as IRI and URN.
Most people are familiar with URLs (uniform resource locators), such as "http://...", "ftp://...",
"mailto:...". Put simply, a URL specifies the location of a resource.
A URI (uniform resource identifier) is a URL or a URN. So, to fully understand what URI means,
C H A P T E R 3 - G ET T IN G ST AR T ED W IT H APACH E CAM EL
10
you need to first understand what is a URN.
URN is an acronym for uniform resource name. There are may "unique identifier" schemes in the
world, for example, ISBNs (globally unique for books), social security numbers (unique within a
country), customer numbers (unique within a company's customers database) and telephone
numbers. Each "unique identifier" scheme has its own notation. A URN is a wrapper for
different "unique identifier" schemes. The syntax of a URN is "urn::". A URN uniquely identifies a resource, such as a book, person or piece of equipment.
By itself, a URN does not specify the location of the resource. Instead, it is assumed that a
registry provides a mapping from a resource's URN to its location. The URN specification does
not state what form a registry takes, but it might be a database, a server application, a wall chart
or anything else that is convenient. Some hypothetical examples of URNs are
"urn:employee:08765245", "urn:customer:uk:3458:hul8" and
"urn:foo:0000-0000-9E59-0000-5E-2". The ("employee", "customer" and "foo"
in these examples) part of a URN implicitly defines how to parse and interpret the that follows it. An arbitrary URN is meaningless unless: (1) you know the semantics
implied by the , and (2) you have access to the registry appropriate for the
. A registry does not have to be public or globally accessible. For example,
"urn:employee:08765245" might be meaningful only within a specific company.
To date, URNs are not (yet) as popular as URLs. For this reason, URI is widely misused as a
synonym for URL.
IRI is an acronym for internationalized resource identifier. An IRI is simply an internationalized
version of a URI. In particular, a URI can contain letters and digits in the US-ASCII character
set, while a IRI can contain those same letters and digits, and also European accented characters,
Greek letters, Chinese ideograms and so on.
Components
Component is confusing terminology; EndpointFactory would have been more appropriate because
a Component is a factory for creating Endpoint instances. For example, if a Camel-based
application uses several JMS queues then the application will create one instance of the
JmsComponent class (which implements the Component interface), and then the application
invokes the createEndpoint() operation on this JmsComponent object several times.
Each invocation of JmsComponent.createEndpoint() creates an instance of the
JmsEndpoint class (which implements the Endpoint interface). Actually, application-level
code does not invoke Component.createEndpoint() directly. Instead, application-level
code normally invokes CamelContext.getEndpoint(); internally, the CamelContext
object finds the desired Component object (as I will discuss shortly) and then invokes
createEndpoint() on it.
Consider the following code.
myCamelContext.getEndpoint("pop3://john.smith@mailserv.example.com?password=myPassword");
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The parameter to getEndpoint() is a URI. The URI prefix (that is, the part before ":")
specifies the name of a component. Internally, the CamelContext object maintains a mapping
from names of components to Component objects. For the URI given in the above example,
the CamelContext object would probably map the pop3 prefix to an instance of the
MailComponent class. Then the CamelContext object invokes
createEndpoint("pop3://john.smith@mailserv.example.com?password=myPassword"
on that MailComponent object. The createEndpoint() operation splits the URI into its
component parts and uses these parts to create and configure an Endpoint object.
In the previous paragraph, I mentioned that a CamelContext object maintains a mapping
from component names to Component objects. This raises the question of how this map is
populated with named Component objects. There are two ways of populating the map. The
first way is for application-level code to invoke CamelContext.addComponent(String
componentName, Component component). The example below shows a single
MailComponent object being registered in the map under 3 different names.
Component mailComponent = new org.apache.camel.component.mail.MailComponent();
myCamelContext.addComponent("pop3", mailComponent);
myCamelContext.addComponent("imap", mailComponent);
myCamelContext.addComponent("smtp", mailComponent);
The second (and preferred) way to populate the map of named Component objects in the
CamelContext object is to let the CamelContext object perform lazy initialization. This
approach relies on developers following a convention when they write a class that implements
the Component interface. I illustrate the convention by an example. Let's assume you write a
class called com.example.myproject.FooComponent and you want Camel to
automatically recognize this by the name "foo". To do this, you have to write a properties file
called "META-INF/services/org/apache/camel/component/foo" (without a ".properties" file
extension) that has a single entry in it called class, the value of which is the fully-scoped name
of your class. This is shown below.
Listing 1. META-INF/services/org/apache/camel/component/foo
class=com.example.myproject.FooComponent
If you want Camel to also recognize the class by the name "bar" then you write another
properties file in the same directory called "bar" that has the same contents. Once you have
written the properties file(s), you create a jar file that contains the
com.example.myproject.FooComponent class and the properties file(s), and you add
this jar file to your CLASSPATH. Then, when application-level code invokes
createEndpoint("foo:...") on a CamelContext object, Camel will find the "foo""
properties file on the CLASSPATH, get the value of the class property from that properties
file, and use reflection APIs to create an instance of the specified class.
As I said in Section 4.1 ("Endpoint"), Camel provides out-of-the-box support for numerous
communication technologies. The out-of-the-box support consists of classes that implement the
C H A P T E R 3 - G ET T IN G ST AR T ED W IT H APACH E CAM EL
12
Component interface plus properties files that enable a CamelContext object to populate
its map of named Component objects.
Earlier in this section I gave the following example of calling
CamelContext.getEndpoint().
myCamelContext.getEndpoint("pop3://john.smith@mailserv.example.com?password=myPassword");
When I originally gave that example, I said that the parameter to getEndpoint() was a URI.
I said that because the online Camel documentation and the Camel source code both claim the
parameter is a URI. In reality, the parameter is restricted to being a URL. This is because when
Camel extracts the component name from the parameter, it looks for the first ":", which is a
simplistic algorithm. To understand why, recall from Section 4.4 ("The Meaning of URL, URI,
URN and IRI") that a URI can be a URL or a URN. Now consider the following calls to
getEndpoint.
myCamelContext.getEndpoint("pop3:...");
myCamelContext.getEndpoint("jms:...");
myCamelContext.getEndpoint("urn:foo:...");
myCamelContext.getEndpoint("urn:bar:...");
Camel identifies the components in the above example as "pop3", "jms", "urn" and "urn". It
would be more useful if the latter components were identified as "urn:foo" and "urn:bar" or,
alternatively, as "foo" and "bar" (that is, by skipping over the "urn:" prefix). So, in practice you
must identify an endpoint with a URL (a string of the form ":...") rather than with a
URN (a string of the form "urn::..."). This lack of proper support for URNs means the
you should consider the parameter to getEndpoint() as being a URL rather than (as
claimed) a URI.
Message and Exchange
The Message interface provides an abstraction for a single message, such as a request, reply
or exception message.
There are concrete classes that implement the Message interface for each Camel-supported
communications technology. For example, the JmsMessage class provides a JMS-specific
implementation of the Message interface. The public API of the Message interface provides
get- and set-style methods to access the message id, body and individual header fields of a
messge.
The Exchange interface provides an abstraction for an exchange of messages, that is, a
request message and its corresponding reply or exception message. In Camel terminology, the
request, reply and exception messages are called in, out and fault messages.
There are concrete classes that implement the Exchange interface for each Camel-supported
communications technology. For example, the JmsExchange class provides a JMS-specific
implementation of the Exchange interface. The public API of the Exchange interface is quite
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limited. This is intentional, and it is expected that each class that implements this interface will
provide its own technology-specific operations.
Application-level programmers rarely access the Exchange interface (or classes that
implement it) directly. However, many classes in Camel are generic types that are instantiated
on (a class that implements) Exchange. Because of this, the Exchange interface appears a
lot in the generic signatures of classes and methods.
Processor
The Processor interface represents a class that processes a message. The signature of this
interface is shown below.
Listing 2. Processor
package org.apache.camel;
public interface Processor {
void process(Exchange exchange) throws Exception;
}
Notice that the parameter to the process() method is an Exchange rather than a
Message. This provides flexibility. For example, an implementation of this method initially
might call exchange.getIn() to get the input message and process it. If an error occurs
during processing then the method can call exchange.setException().
An application-level developer might implement the Processor interface with a class that
executes some business logic. However, there are many classes in the Camel library that
implement the Processor interface in a way that provides support for a design pattern in the
EIP book. For example, ChoiceProcessor implements the message router pattern, that is, it
uses a cascading if-then-else statement to route a message from an input queue to one of
several output queues. Another example is the FilterProcessor class which discards
messages that do not satisfy a stated predicate (that is, condition).
Routes, RouteBuilders and Java DSL
A route is the step-by-step movement of a Message from an input queue, through arbitrary
types of decision making (such as filters and routers) to a destination queue (if any). Camel
provides two ways for an application developer to specify routes. One way is to specify route
information in an XML file. A discussion of that approach is outside the scope of this document.
The other way is through what Camel calls a Java DSL (domain-specific language).
Introduction to Java DSL
For many people, the term "domain-specific language" implies a compiler or interpreter that can
process an input file containing keywords and syntax specific to a particular domain. This is not
the approach taken by Camel. Camel documentation consistently uses the term "Java DSL"
C H A P T E R 3 - G ET T IN G ST AR T ED W IT H APACH E CAM EL
14
instead of "DSL", but this does not entirely avoid potential confusion. The Camel "Java DSL" is a
class library that can be used in a way that looks almost like a DSL, except that it has a bit of
Java syntactic baggage. You can see this in the example below. Comments afterwards explain
some of the constructs used in the example.
Listing 3. Example of Camel's "Java DSL"
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("queue:a").filter(header("foo").isEqualTo("bar")).to("queue:b");
from("queue:c").choice()
.when(header("foo").isEqualTo("bar")).to("queue:d")
.when(header("foo").isEqualTo("cheese")).to("queue:e")
.otherwise().to("queue:f");
}
};
CamelContext myCamelContext = new DefaultCamelContext();
myCamelContext.addRoutes(builder);
The first line in the above example creates an object which is an instance of an anonymous
subclass of RouteBuilder with the specified configure() method.
The CamelContext.addRoutes(RouterBuilder builder) method invokes
builder.setContext(this) Ð so the RouteBuilder object knows which
CamelContext object it is associated with Ð and then invokes builder.configure().
The body of configure() invokes methods such as from(), filter(), choice(),
when(), isEqualTo(), otherwise() and to().
The RouteBuilder.from(String uri) method invokes getEndpoint(uri) on the
CamelContext associated with the RouteBuilder object to get the specified Endpoint
and then puts a FromBuilder "wrapper" around this Endpoint. The
FromBuilder.filter(Predicate predicate) method creates a
FilterProcessor object for the Predicate (that is, condition) object built from the
header("foo").isEqualTo("bar") expression. In this way, these operations
incrementally build up a Route object (with a RouteBuilder wrapper around it) and add it
to the CamelContext object associated with the RouteBuilder.
Critique of Java DSL
The online Camel documentation compares Java DSL favourably against the alternative of
configuring routes and endpoints in a XML-based Spring configuration file. In particular, Java
DSL is less verbose than its XML counterpart. In addition, many integrated development
environments (IDEs) provide an auto-completion feature in their editors. This auto-completion
feature works with Java DSL, thereby making it easier for developers to write Java DSL.
However, there is another option that the Camel documentation neglects to consider: that of
writing a parser that can process DSL stored in, say, an external file. Currently, Camel does not
provide such a DSL parser, and I do not know if it is on the "to do" list of the Camel
15
CH A PTE R 3 - GE T T I NG S T A R T E D W I T H A PACH E CAM EL
maintainers. I think that a DSL parser would offer a significant benefit over the current Java
DSL. In particular, the DSL would have a syntactic definition that could be expressed in a
relatively short BNF form. The effort required by a Camel user to learn how to use DSL by
reading this BNF would almost certainly be significantly less than the effort currently required
to study the API of the RouterBuilder classes.
Continue Learning about Camel
Return to the main Getting Started page for additional introductory reference information.
C H A P T E R 3 - G ET T IN G ST AR T ED W IT H APACH E CAM EL
16
CHAPTER
4
°°°°
Architecture
Camel uses a Java based Routing Domain Specific Language (DSL) or an Xml Configuration to
configure routing and mediation rules which are added to a CamelContext to implement the
various Enterprise Integration Patterns.
At a high level Camel consists of a CamelContext which contains a collection of Component
instances. A Component is essentially a factory of Endpoint instances. You can explicitly
configure Component instances in Java code or an IoC container like Spring or Guice, or they
can be auto-discovered using URIs.
An Endpoint acts rather like a URI or URL in a web application or a Destination in a JMS
system; you can communicate with an endpoint; either sending messages to it or consuming
messages from it. You can then create a Producer or Consumer on an Endpoint to exchange
messages with it.
The DSL makes heavy use of pluggable Languages to create an Expression or Predicate to
make a truly powerful DSL which is extensible to the most suitable language depending on your
needs. The following languages are supported
• Bean Language for using Java for expressions
• Constant
• the unified EL from JSP and JSF
• Header
• JXPath
• Mvel
• OGNL
• Ref Language
• Property
• Scala DSL
• Scripting Languages such as
◦ BeanShell
◦ JavaScript
◦ Groovy
◦ Python
◦ PHP
◦ Ruby
• Simple
◦ File Language
• Spring Expression Language
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CH A PTE R 4 - AR C H I T E C T U R E
• SQL
• Tokenizer
• XPath
• XQuery
Most of these languages is also supported used as Annotation Based Expression Language.
For a full details of the individual languages see the Language Appendix
URIS
Camel makes extensive use of URIs to allow you to refer to endpoints which are lazily created
by a Component if you refer to them within Routes
Current Supported URIs
Component / ArtifactId / URI
Description
AHC / camel-ahc
ahc:hostname:[port]
To call external HTTP services
using Async Http Client
AMQP / camel-amqp
amqp:[topic:]destinationName
For Messaging with AMQP
protocol
APNS / camel-apns
apns:notify[?options]
Atom / camel-atom
atom:uri
For sending notifications to Apple
iOS devices
Working with Apache Abdera for
atom integration, such as
consuming an atom feed.
AWS-SDB / camel-aws
aws-sdb://domainName[?options]
For working with Amazon's
SimpleDB (SDB).
CH APT ER 4 - AR CH IT ECT UR E
18
AWS-SES / camel-aws
aws-ses://from[?options]
For working with Amazon's Simple
Email Service (SES).
AWS-SNS / camel-aws
aws-sns://topicname[?options]
For Messaging with Amazon's
Simple Notification Service (SNS).
AWS-SQS / camel-aws
aws-sqs://queuename[?options]
For Messaging with Amazon's
Simple Queue Service (SQS).
AWS-S3 / camel-aws
aws-s3://bucketname[?options]
Bean / camel-core
bean:beanName[?method=someMethod]
Bean Validation / camel-bean-validator
bean-validator:something
Browse / camel-core
browse:someName
Cache / camel-cache
cache://cachename[?options]
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CH A PTE R 4 - AR C H I T E C T U R E
For working with Amazon's Simple
Storage Service (S3).
Uses the Bean Binding to bind
message exchanges to beans in the
Registry. Is also used for exposing
and invoking POJO (Plain Old Java
Objects).
Validates the payload of a message
using the Java Validation API (JSR
303 and JAXP Validation) and its
reference implementation
Hibernate Validator
Provides a simple
BrowsableEndpoint which can be
useful for testing, visualisation tools
or debugging. The exchanges sent
to the endpoint are all available to
be browsed.
The cache component facilitates
creation of caching endpoints and
processors using EHCache as the
cache implementation.
Class / camel-core
class:className[?method=someMethod]
Cometd / camel-cometd
cometd://host:port/channelname
Context / camel-context
context:camelContextId:localEndpointName
Uses the Bean Binding to bind
message exchanges to beans in the
Registry. Is also used for exposing
and invoking POJO (Plain Old Java
Objects).
Used to deliver messages using the
jetty cometd implementation of the
bayeux protocol
Used to refer to endpoints within a
separate CamelContext to provide
a simple black box composition
approach so that routes can be
combined into a CamelContext
and then used as a black box
component inside other routes in
other CamelContexts
Crypto (Digital Signatures) / camel-crypto
crypto:sign:name[?options]
crypto:verify:name[?options]
Used to sign and verify exchanges
using the Signature Service of the
Java Cryptographic Extension.
CXF / camel-cxf
cxf:address[?serviceClass=...]
CXF Bean / camel-cxf
cxf:bean name
Working with Apache CXF for
web services integration
Proceess the exchange using a JAX
WS or JAX RS annotated bean
from the registry. Requires less
configuration than the above CXF
Component
CXFRS / camel-cxf
cxfrs:address[?resourcesClasses=...]
Working with Apache CXF for
REST services integration
CH APT ER 4 - AR CH IT ECT UR E
20
DataSet / camel-core
dataset:name
For load & soak testing the DataSet
provides a way to create huge
numbers of messages for sending
to Components or asserting that
they are consumed correctly
Direct / camel-core
direct:name
Synchronous call to another
endpoint
DNS / camel-dns
dns:operation
EJB / camel-ejb
ejb:ejbName[?method=someMethod]
To lookup domain information and
run DNS queries using DNSJava
Uses the Bean Binding to bind
message exchanges to EJBs. It
works like the Bean component
but just for accessing EJBs.
Supports EJB 3.0 onwards.
Event / camel-spring
event://default
spring-event://default
Working with Spring
ApplicationEvents
EventAdmin / camel-eventadmin
eventadmin:topic
Receiving OSGi EventAdmin events
Exec / camel-exec
exec://executable[?options]
File / camel-core
file://nameOfFileOrDirectory
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CH A PTE R 4 - AR C H I T E C T U R E
For executing system commands
Sending messages to a file or
polling a file or directory. Camel
1.x use this link File.
Flatpack / camel-flatpack
flatpack:[fixed|delim]:configFile
Processing fixed width or delimited
files or messages using the FlatPack
library
FreeMarker / camel-freemarker
freemarker:someTemplateResource
FTP / camel-ftp
ftp://host[:port]/fileName
Generates a response using a
FreeMarker template
Sending and receiving files over
FTP. Camel 1.x use this link
FTP.
FTPS / camel-ftp
ftps://host[:port]/fileName
GAuth / camel-gae
gauth://name[?options]
GHttp / camel-gae
ghttp://hostname[:port][/path][?options]
ghttp:///path[?options]
GLogin / camel-gae
glogin://hostname[:port][?options]
GTask / camel-gae
gtask://queue-name
Sending and receiving files over FTP
Secure (TLS and SSL).
Used by web applications to
implement an OAuth consumer.
See also Camel Components for
Google App Engine.
Provides connectivity to the URL
fetch service of Google App Engine
but can also be used to receive
messages from servlets. See also
Camel Components for Google
App Engine.
Used by Camel applications outside
Google App Engine (GAE) for
programmatic login to GAE
applications. See also Camel
Components for Google App
Engine.
Supports asynchronous message
processing on Google App Engine
by using the task queueing service
as message queue. See also Camel
Components for Google App
Engine.
CH APT ER 4 - AR CH IT ECT UR E
22
GMail / camel-gae
gmail://user@gmail.com[?options]
gmail://user@googlemail.com[?options]
Hazelcast / camel-hazelcast
hazelcast://[type]:cachename[?options]
Supports sending of emails via the
mail service of Google App Engine.
See also Camel Components for
Google App Engine.
Hazelcast is a data grid entirely
implemented in Java (single jar).
This component supports map,
multimap, seda, queue, set, atomic
number and simple cluster support.
HDFS / camel-hdfs
hdfs://path[?options]
HL7 / camel-hl7
mina:tcp://hostname[:port]
HTTP / camel-http
http://hostname[:port]
HTTP4 / camel-http4
http4://hostname[:port]
iBATIS / camel-ibatis
ibatis://statementName
For reading/writing from/to an
HDFS filesystem
For working with the HL7 MLLP
protocol and the HL7 model using
the HAPI library
For calling out to external HTTP
servers using Apache HTTP Client
3.x
For calling out to external HTTP
servers using Apache HTTP Client
4.x
Performs a query, poll, insert,
update or delete in a relational
database using Apache iBATIS
IMap / camel-mail
imap://hostname[:port]
Receiving email using IMap
IRC / camel-irc
irc:host[:port]/#room
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CH A PTE R 4 - AR C H I T E C T U R E
For IRC communication
JavaSpace / camel-javaspace
javaspace:jini://host?spaceName=mySpace?...
Sending and receiving messages
through JavaSpace
JBI / servicemix-camel
jbi:serviceName
For JBI integration such as working
with Apache ServiceMix
jclouds / jclouds
jclouds:[blobstore|computservice]:provider
JCR / camel-jcr
jcr://user:password@repository/path/to/node
For interacting with cloud compute
& blobstore service via jclouds
Storing a message in a JCR
compliant repository like Apache
Jackrabbit
JDBC / camel-jdbc
jdbc:dataSourceName?options
For performing JDBC queries and
operations
Jetty / camel-jetty
jetty:url
For exposing services over HTTP
JMS / camel-jms
jms:[topic:]destinationName
Working with JMS providers
JMX / camel-jmx
jmx://platform?options
JPA / camel-jpa
jpa://entityName
For working with JMX notification
listeners
For using a database as a queue via
the JPA specification for working
with OpenJPA, Hibernate or
TopLink
CH APT ER 4 - AR CH IT ECT UR E
24
JT/400 / camel-jt400
jt400://user:pwd@system/
For integrating with data queues on
an AS/400 (aka System i, IBM i, i5,
...) system
Kestrel / camel-kestrel
kestrel://[addresslist/]queuename[?options]
For producing to or consuming
from Kestrel queues
Krati / camel-krati
krati://[path to datastore/][?options]
For producing to or consuming to
Krati datastores
Language / camel-core
language://languageName[:script][?options]
LDAP / camel-ldap
ldap:host[:port]?base=...[&scope=]
Log / camel-core
log:loggingCategory[?level=ERROR]
Lucene / camel-lucene
lucene:searcherName:insert[?analyzer=]
lucene:searcherName:query[?analyzer=]
Executes Languages scripts
Performing searches on LDAP
servers ( must be one of
object|onelevel|subtree)
Uses Jakarta Commons Logging to
log the message exchange to some
underlying logging system like log4j
Uses Apache Lucene to perform
Java-based indexing and full text
based searches using advanced
analysis/tokenization capabilities
Mail / camel-mail
mail://user-info@host:port
Sending and receiving email
MINA / camel-mina
[tcp|udp|vm]:host[:port]
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CH A PTE R 4 - AR C H I T E C T U R E
Working with Apache MINA
Mock / camel-core
mock:name
For testing routes and mediation
rules using mocks
MSV / camel-msv
msv:someLocalOrRemoteResource
MyBatis / camel-mybatis
mybatis://statementName
Validates the payload of a message
using the MSV Library
Performs a query, poll, insert,
update or delete in a relational
database using MyBatis
Nagios / camel-nagios
nagios://host[:port]?options
Netty / camel-netty
netty:tcp//host[:port]?options
netty:udp//host[:port]?options
Sending passive checks to Nagios
using JSendNSCA
Working with TCP and UDP
protocols using Java NIO based
capabilities offered by the JBoss
Netty community project
Pax-Logging / camel-paxlogging
paxlogging:appender
Receiving Pax-Logging events in
OSGi
POP / camel-mail
pop3://user-info@host:port
Printer / camel-printer
lpr://host:port/path/to/printer[?options]
Receiving email using POP3 and
JavaMail
The printer component facilitates
creation of printer endpoints to
local, remote and wireless printers.
The endpoints provide the ability
to print camel directed payloads
when utilized on camel routes.
CH APT ER 4 - AR CH IT ECT UR E
26
Properties / camel-core
properties://key[?options]
Quartz / camel-quartz
quartz://groupName/timerName
The properties component
facilitates using property
placeholders directly in endpoint
uri definitions.
Provides a scheduled delivery of
messages using the Quartz
scheduler
Quickfix / camel-quickfix
quickfix-server:config file
quickfix-client:config-file
Implementation of the QuickFix for
Java engine which allow to send/
receive FIX messages
Ref / camel-core
ref:name
Restlet / camel-restlet
restlet:restletUrl[?options]
Component for lookup of existing
endpoints bound in the Registry.
Component for consuming and
producing Restful resources using
Restlet
RMI / camel-rmi
rmi://host[:port]
Working with RMI
RNC / camel-jing
rnc:/relativeOrAbsoluteUri
Validates the payload of a message
using RelaxNG Compact Syntax
RNG / camel-jing
rng:/relativeOrAbsoluteUri
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CH A PTE R 4 - AR C H I T E C T U R E
Validates the payload of a message
using RelaxNG
Routebox / camel-routebox
routebox:routeboxName[?options]
RSS / camel-rss
rss:uri
SEDA / camel-core
seda:name
SERVLET / camel-servlet
servlet:uri
SFTP / camel-ftp
sftp://host[:port]/fileName
Sip / camel-sip
sip://user@host[:port]?[options]
sips://user@host[:port]?[options]
Facilitates the creation of
specialized endpoints that offer
encapsulation and a strategy/map
based indirection service to a
collection of camel routes hosted
in an automatically created or user
injected camel context
Working with ROME for RSS
integration, such as consuming an
RSS feed.
Asynchronous call to another
endpoint in the same Camel
Context
For exposing services over HTTP
through the servlet which is
deployed into the Web container.
Sending and receiving files over
SFTP (FTP over SSH). Camel 1.x
use this link FTP.
Publish/Subscribe communication
capability using the Telecom SIP
protocol. RFC3903 - Session
Initiation Protocol (SIP) Extension
for Event
SMTP / camel-mail
smtp://user-info@host[:port]
SMPP / camel-smpp
smpp://user-info@host[:port]?options
Sending email using SMTP and
JavaMail
To send and receive SMS using
Short Messaging Service Center
using the JSMPP library
CH APT ER 4 - AR CH IT ECT UR E
28
SNMP / camel-snmp
snmp://host[:port]?options
Solr / camel-solr
solr://host[:port]/solr?[options]
Polling OID values and receiving
traps using SNMP via SNMP4J
library
Uses the Solrj client API to
interface with an Apache Lucene
Solr server
SpringIntegration / camel-spring-integration
spring-integration:defaultChannelName
Spring Web Services / camel-spring-ws
spring-ws:[mapping-type:]address[?options]
The bridge component of Camel
and Spring Integration
Client-side support for accessing
web services, and server-side
support for creating your own
contract-first web services using
Spring Web Services
SQL / camel-sql
sql:select * from table where id=#
Performing SQL queries using
JDBC
StAX / camel-stax
stax:contentHandlerClassName
Stream / camel-stream
stream:[in|out|err|file]
Process messages through a SAX
ContentHandler.
Read or write to an input/output/
error/file stream rather like unix
pipes
StringTemplate / camel-stringtemplate
string-template:someTemplateResource
Generates a response using a String
Template
TCP / camel-mina
mina:tcp://host:port
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CH A PTE R 4 - AR C H I T E C T U R E
Working with TCP protocols using
Apache MINA
Test / camel-spring
test:expectedMessagesEndpointUri
Creates a Mock endpoint which
expects to receive all the message
bodies that could be polled from
the given underlying endpoint
Timer / camel-core
timer://name
A timer endpoint
UDP / camel-mina
mina:udp://host:port
Validation / camel-core (camel-spring for Camel 2.8
or older)
validation:someLocalOrRemoteResource
Working with UDP protocols using
Apache MINA
Validates the payload of a message
using XML Schema and JAXP
Validation
Velocity / camel-velocity
velocity:someTemplateResource
Generates a response using an
Apache Velocity template
VM / camel-core
vm:name
Asynchronous call to another
endpoint in the same JVM
XMPP / camel-xmpp
xmpp://host:port/room
Working with XMPP and Jabber
XQuery / camel-saxon
xquery:someXQueryResource
XSLT / camel-core (camel-spring for Camel 2.8 or
older)
xslt:someTemplateResource
Generates a response using an
XQuery template
Generates a response using an
XSLT template
CH APT ER 4 - AR CH IT ECT UR E
30
Zookeeper / camel-zookeeper
Working with ZooKeeper
cluster(s)
zookeeper://host:port/path
URI's for external components
Other projects and companies have also created Camel components to integrate additional
functionality into Camel. These components may be provided under licenses that are not
compatible with the Apache License, use libraries that are not compatible, etc... These
components are not supported by the Camel team, but we provide links here to help users find
the additional functionality.
Component / ArtifactId / URI
License
Description
Apache
For JMS Messaging with Apache
ActiveMQ
Apache
Uses ActiveMQ's fast disk
journaling implementation to
store message bodies in a
rolling log file
GPL
For using a db4o datastore as a
queue via the db4o library
GPL
Working with the Esper Library
for Event Stream Processing
GPL
For using a database as a queue
via the Hibernate library
Apache
Integration with the
Normalized Message Router
BUS in ServiceMix 4.x
ActiveMQ / activemq-camel
activemq:[topic:]destinationName
ActiveMQ Journal / activemq-core
activemq.journal:directory-on-filesystem
Db4o / camel-db4o in camel-extra
db4o://className
Esper / camel-esper in camel-extra
esper:name
Hibernate / camel-hibernate in camel-extra
hibernate://entityName
NMR / servicemix-nmr
nmr://serviceName
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CH A PTE R 4 - AR C H I T E C T U R E
Scalate / scalate-camel
Apache
Uses the given Scalate template
to transform the message
GPL
For working with EDI parsing
using the Smooks library. This
component is deprecated as
Smooks now provides Camel
integration out of the box
scalate:templateName
Smooks / camel-smooks in camel-extra.
unmarshal(edi)
For a full details of the individual components see the Component Appendix
CH APT ER 4 - AR CH IT ECT UR E
32
CHAPTER
5
°°°°
Enterprise Integration Patterns
Camel supports most of the Enterprise Integration Patterns from the excellent book of the
same name by Gregor Hohpe and Bobby Woolf. Its a highly recommended book, particularly
for users of Camel.
PATTERN INDEX
There now follows a list of the Enterprise Integration Patterns from the book along with
examples of the various patterns using Apache Camel
Messaging Systems
33
Message
Channel
How does one application communicate with another using
messaging?
Message
How can two applications connected by a message channel
exchange a piece of information?
Pipes and
Filters
How can we perform complex processing on a message while
maintaining independence and flexibility?
Message
Router
How can you decouple individual processing steps so that
messages can be passed to different filters depending on a set of
conditions?
Message
Translator
How can systems using different data formats communicate with
each other using messaging?
Message
Endpoint
How does an application connect to a messaging channel to send
and receive messages?
CH A PTE R 5 - E N T E R P R I SE I NT E G R A T I ON P AT T ER N S
Messaging Channels
Point to
Point
Channel
How can the caller be sure that exactly one receiver will receive
the document or perform the call?
Publish
Subscribe
Channel
How can the sender broadcast an event to all interested
receivers?
Dead
Letter
Channel
What will the messaging system do with a message it cannot
deliver?
Guaranteed
Delivery
How can the sender make sure that a message will be delivered,
even if the messaging system fails?
Message
Bus
What is an architecture that enables separate applications to
work together, but in a de-coupled fashion such that applications
can be easily added or removed without affecting the others?
Message Construction
Event Message
How can messaging be used to transmit events from one
application to another?
Request Reply
When an application sends a message, how can it get a
response from the receiver?
Correlation
Identifier
How does a requestor that has received a reply know which
request this is the reply for?
Return
Address
How does a replier know where to send the reply?
Message Routing
Content
Based
Router
How do we handle a situation where the implementation of a
single logical function (e.g., inventory check) is spread across
multiple physical systems?
Message
Filter
How can a component avoid receiving uninteresting messages?
Dynamic
Router
How can you avoid the dependency of the router on all
possible destinations while maintaining its efficiency?
C H A P T E R 5 - EN T ER PR ISE IN T EGR AT IO N PAT T ER N S
34
Recipient
List
How do we route a message to a list of (static or dynamically)
specified recipients?
Splitter
How can we process a message if it contains multiple
elements, each of which may have to be processed in a
different way?
Aggregator
How do we combine the results of individual, but related
messages so that they can be processed as a whole?
Resequencer
How can we get a stream of related but out-of-sequence
messages back into the correct order?
Composed
Message
Processor
How can you maintain the overall message flow when
processing a message consisting of multiple elements, each of
which may require different processing?
ScatterGather
How do you maintain the overall message flow when a
message needs to be sent to multiple recipients, each of which
may send a reply?
Routing Slip
How do we route a message consecutively through a series of
processing steps when the sequence of steps is not known at
design-time and may vary for each message?
Throttler
How can I throttle messages to ensure that a specific endpoint
does not get overloaded, or we don't exceed an agreed SLA
with some external service?
Sampling
How can I sample one message out of many in a given period
to avoid downstream route does not get overloaded?
Delayer
How can I delay the sending of a message?
Load
Balancer
How can I balance load across a number of endpoints?
Multicast
How can I route a message to a number of endpoints at the
same time?
Loop
How can I repeat processing a message in a loop?
Message Transformation
Content
Enricher
35
How do we communicate with another system if the message
originator does not have all the required data items available?
CH A PTE R 5 - E N T E R P R I SE I NT E G R A T I ON P AT T ER N S
Content
Filter
How do you simplify dealing with a large message, when you are
interested only in a few data items?
Claim
Check
How can we reduce the data volume of message sent across the
system without sacrificing information content?
Normalizer
How do you process messages that are semantically equivalent,
but arrive in a different format?
Sort
How can I sort the body of a message?
Validate
How can I validate a message?
Messaging Endpoints
Messaging
Mapper
How do you move data between domain objects and the
messaging infrastructure while keeping the two independent of
each other?
Event Driven
Consumer
How can an application automatically consume messages as they
become available?
Polling
Consumer
How can an application consume a message when the
application is ready?
Competing
Consumers
How can a messaging client process multiple messages
concurrently?
Message
Dispatcher
How can multiple consumers on a single channel coordinate
their message processing?
Selective
Consumer
How can a message consumer select which messages it wishes
to receive?
Durable
Subscriber
How can a subscriber avoid missing messages while it's not
listening for them?
Idempotent
Consumer
How can a message receiver deal with duplicate messages?
Transactional
Client
How can a client control its transactions with the messaging
system?
Messaging
Gateway
How do you encapsulate access to the messaging system from
the rest of the application?
C H A P T E R 5 - EN T ER PR ISE IN T EGR AT IO N PAT T ER N S
36
How can an application design a service to be invoked both via
various messaging technologies and via non-messaging
techniques?
Service
Activator
System Management
Detour
How can you route a message through intermediate steps to
perform validation, testing or debugging functions?
Wire
Tap
How do you inspect messages that travel on a point-to-point
channel?
Log
How can I log processing a message?
For a full breakdown of each pattern see the Book Pattern Appendix
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CH A PTE R 5 - E N T E R P R I SE I NT E G R A T I ON P AT T ER N S
CookBook
This document describes various recipes for working with Camel
• Bean Integration describes how to work with beans and Camel in a loosely coupled
way so that your beans do not have to depend on any Camel APIs
◦ Annotation Based Expression Language binds expressions to method
parameters
◦ Bean Binding defines which methods are invoked and how the Message is
converted into the parameters of the method when it is invoked
◦ Bean Injection for injecting Camel related resources into your POJOs
◦ Parameter Binding Annotations for extracting various headers, properties
or payloads from a Message
◦ POJO Consuming for consuming and possibly routing messages from Camel
◦ POJO Producing for producing camel messages from your POJOs
◦ RecipientList Annotation for creating a Recipient List from a POJO method
◦ Using Exchange Pattern Annotations describes how pattern annotations can
be used to change the behaviour of method invocations
• Hiding Middleware describes how to avoid your business logic being coupled to any
particular middleware APIs allowing you to easily switch from in JVM SEDA to JMS,
ActiveMQ, Hibernate, JPA, JDBC, iBATIS or JavaSpace etc.
• Visualisation describes how to visualise your Enterprise Integration Patterns to help
you understand your routing rules
• Business Activity Monitoring (BAM) for monitoring business processes across systems
• Extract Transform Load (ETL) to load data into systems or databases
• Testing for testing distributed and asynchronous systems using a messaging approach
◦ Camel Test for creating test cases using a single Java class for all your
configuration and routing
◦ Spring Testing uses Spring Test together with either XML or Java Config to
dependency inject your test classes
◦ Guice uses Guice to dependency inject your test classes
• Templating is a great way to create service stubs to be able to test your system
without some back end system.
• Database for working with databases
• Parallel Processing and Ordering on how using parallel processing and SEDA or JMS
based load balancing can be achieved.
• Asynchronous Processing in Camel Routes.
• Implementing Virtual Topics on other JMS providers shows how to get the effect of
Virtual Topics and avoid issues with JMS durable topics
• Camel Transport for CXF describes how to put the Camel context into the CXF
transport layer.
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• Fine Grained Control Over a Channel describes how to deliver a sequence of
messages over a single channel and then stopping any more messages being sent over
that channel. Typically used for sending data over a socket and then closing the
socket.
• EventNotifier to log details about all sent Exchanges shows how to let Camels
EventNotifier log all sent to endpoint events and how long time it took.
• Loading routes from XML files into an existing CamelContext.
• Using MDC logging with Camel
• Running Camel standalone and have it keep running shows how to keep Camel
running when you run it standalone.
• Hazelcast Idempotent Repository Tutorial shows how to avoid to consume duplicated
messages in a clustered environment.
• How to use Camel as a HTTP proxy between a client and server shows how to use
Camel as a HTTP adapter/proxy between a client and HTTP service.
BEAN INTEGRATION
Camel supports the integration of beans and POJOs in a number of ways
Annotations
If a bean is defined in Spring XML or scanned using the Spring component scanning mechanism
and a is used or a CamelBeanPostProcessor then we process a
number of Camel annotations to do various things such as injecting resources or producing,
consuming or routing messages.
• POJO Consuming to consume and possibly route messages from Camel
• POJO Producing to make it easy to produce camel messages from your POJOs
• DynamicRouter Annotation for creating a Dynamic Router from a POJO method
• RecipientList Annotation for creating a Recipient List from a POJO method
• RoutingSlip Annotation for creating a Routing Slip for a POJO method
• Bean Injection to inject Camel related resources into your POJOs
• Using Exchange Pattern Annotations describes how the pattern annotations can be
used to change the behaviour of method invocations with Spring Remoting or POJO
Producing
Bean Component
The Bean component allows one to invoke a particular method. Alternately the Bean
component supports the creation of a proxy via ProxyHelper to a Java interface; which the
implementation just sends a message containing a BeanInvocation to some Camel endpoint.
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COO K BO O K
Spring Remoting
We support a Spring Remoting provider which uses Camel as the underlying transport
mechanism. The nice thing about this approach is we can use any of the Camel transport
Components to communicate between beans. It also means we can use Content Based Router
and the other Enterprise Integration Patterns in between the beans; in particular we can use
Message Translator to be able to convert what the on-the-wire messages look like in addition
to adding various headers and so forth.
Annotation Based Expression Language
You can also use any of the Languages supported in Camel to bind expressions to method
parameters when using Bean Integration. For example you can use any of these annotations:
Annotation
Description
@Bean
Inject a Bean expression
@BeanShell
Inject a BeanShell expression
@Constant
Inject a Constant expression
@EL
Inject an EL expression
@Groovy
Inject a Groovy expression
@Header
Inject a Header expression
@JavaScript
Inject a JavaScript expression
@MVEL
Inject a Mvel expression
@OGNL
Inject an OGNL expression
@PHP
Inject a PHP expression
@Python
Inject a Python expression
@Ruby
Inject a Ruby expression
@Simple
Inject an Simple expression
@XPath
Inject an XPath expression
@XQuery
Inject an XQuery expression
Example:
public class Foo {
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Bean binding
Whenever Camel invokes a bean method via one of the above methods (Bean
component, Spring Remoting or POJO Consuming) then the Bean Binding
mechanism is used to figure out what method to use (if it is not explicit) and how to
bind the Message to the parameters possibly using the Parameter Binding
Annotations or using a method name option.
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@XPath("/foo/bar/text()") String correlationID, @Body
String body) {
// process the inbound message here
}
}
Advanced example using @Bean
And an example of using the the @Bean binding annotation, where you can use a Pojo where
you can do whatever java code you like:
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@Bean("myCorrelationIdGenerator") String correlationID,
@Body String body) {
// process the inbound message here
}
}
And then we can have a spring bean with the id myCorrelationIdGenerator where we
can compute the id.
public class MyIdGenerator {
private UserManager userManager;
public String generate(@Header(name = "user") String user, @Body String payload)
throws Exception {
User user = userManager.lookupUser(user);
String userId = user.getPrimaryId();
String id = userId + generateHashCodeForPayload(payload);
return id;
}
}
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The Pojo MyIdGenerator has one public method that accepts two parameters. However we
have also annotated this one with the @Header and @Body annotation to help Camel know
what to bind here from the Message from the Exchange being processed.
Of course this could be simplified a lot if you for instance just have a simple id generator.
But we wanted to demonstrate that you can use the Bean Binding annotations anywhere.
public class MySimpleIdGenerator {
public static int generate()
// generate a unique id
return 123;
{
}
}
And finally we just need to remember to have our bean registered in the Spring Registry:
Example using Groovy
In this example we have an Exchange that has a User object stored in the in header. This User
object has methods to get some user information. We want to use Groovy to inject an
expression that extracts and concats the fullname of the user into the fullName parameter.
public void doSomething(@Groovy("$request.header['user'].firstName
$request.header['user'].familyName) String fullName, @Body String body) {
// process the inbound message here
}
Groovy supports GStrings that is like a template where we can insert $ placeholders that will
be evaluated by Groovy.
BEAN BINDING
Bean Binding in Camel defines both which methods are invoked and also how the Message is
converted into the parameters of the method when it is invoked.
Choosing the method to invoke
The binding of a Camel Message to a bean method call can occur in different ways, in the
following order of importance:
• if the message contains the header CamelBeanMethodName then that method
is invoked, converting the body to the type of the method's argument.
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◦ From Camel 2.8 onwards you can qualify parameter types to select
exactly which method to use among overloads with the same name (see
below for more details).
◦ From Camel 2.9 onwards you can specify parameter values directly in the
method option (see below for more details).
• you can explicitly specify the method name in the DSL or when using POJO
Consuming or POJO Producing
• if the bean has a method marked with the @Handler annotation, then that method
is selected
• if the bean can be converted to a Processor using the Type Converter mechanism,
then this is used to process the message. The ActiveMQ component uses this
mechanism to allow any JMS MessageListener to be invoked directly by Camel
without having to write any integration glue code. You can use the same mechanism
to integrate Camel into any other messaging/remoting frameworks.
• if the body of the message can be converted to a BeanInvocation (the default payload
used by the ProxyHelper) component - then that is used to invoke the method and
pass its arguments
• otherwise the type of the body is used to find a matching method; an error is thrown
if a single method cannot be chosen unambiguously.
• you can also use Exchange as the parameter itself, but then the return type must be
void.
• if the bean class is private (or package-private), interface methods will be preferred
(from Camel 2.9 onwards) since Camel can't invoke class methods on such beans
In cases where Camel cannot choose a method to invoke, an
AmbiguousMethodCallException is thrown.
By default the return value is set on the outbound message body.
Parameter binding
When a method has been chosen for invokation, Camel will bind to the parameters of the
method.
The following Camel-specific types are automatically bound:
▪ org.apache.camel.Exchange
▪ org.apache.camel.Message
▪ org.apache.camel.CamelContext
▪ org.apache.camel.TypeConverter
▪ org.apache.camel.spi.Registry
▪ java.lang.Exception
So, if you declare any of these types, they will be provided by Camel. Note that Exception
will bind to the caught exception of the Exchange - so it's often usable if you
employ a Pojo to handle, e.g., an onException route.
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What is most interesting is that Camel will also try to bind the body of the Exchange to the
first parameter of the method signature (albeit not of any of the types above). So if, for
instance, we declare a parameter as String body, then Camel will bind the IN body to this
type. Camel will also automatically convert to the type declared in the method signature.
Let's review some examples:
Below is a simple method with a body binding. Camel will bind the IN body to the body
parameter and convert it to a String.
public String doSomething(String body)
In the following sample we got one of the automatically-bound types as well - for instance, a
Registry that we can use to lookup beans.
public String doSomething(String body, Registry registry)
We can use Exchange as well:
public String doSomething(String body, Exchange exchange)
You can also have multiple types:
public String doSomething(String body, Exchange exchange, TypeConverter converter)
And imagine you use a Pojo to handle a given custom exception InvalidOrderException
- we can then bind that as well:
public String badOrder(String body, InvalidOrderException invalid)
Notice that we can bind to it even if we use a sub type of java.lang.Exception as Camel
still knows it's an exception and can bind the cause (if any exists).
So what about headers and other stuff? Well now it gets a bit tricky - so we can use
annotations to help us, or specify the binding in the method name option.
See the following sections for more detail.
Binding Annotations
You can use the Parameter Binding Annotations to customize how parameter values are
created from the Message
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Examples
For example, a Bean such as:
public class Bar {
public String doSomething(String body) {
// process the in body and return whatever you want
return "Bye World";
}
Or the Exchange example. Notice that the return type must be void when there is only a
single parameter:
public class Bar {
public void doSomething(Exchange exchange) {
// process the exchange
exchange.getIn().setBody("Bye World");
}
@Handler
You can mark a method in your bean with the @Handler annotation to indicate that this
method should be used for Bean Binding.
This has an advantage as you need not specify a method name in the Camel route, and
therefore do not run into problems after renaming the method in an IDE that can't find all its
references.
public class Bar {
@Handler
public String doSomething(String body) {
// process the in body and return whatever you want
return "Bye World";
}
Parameter binding using method option
Available as of Camel 2.9
Camel uses the following rules to determine if it's a parameter value in the method option
▪ The value is either true or false which denotes a boolean value
▪ The value is a numeric value such as 123 or 7
▪ The value is a String enclosed with either single or double quotes
▪ The value is null which denotes a null value
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▪ It can be evaluated using the Simple language, which means you can use, e.g., body,
header.foo and other Simple tokens. Notice the tokens must be enclosed with ${ }.
Any other value is consider to be a type declaration instead - see the next section about
specifying types for overloaded methods.
When invoking a Bean you can instruct Camel to invoke a specific method by providing the
method name:
.bean(OrderService.class, "doSomething")
Here we tell Camel to invoke the doSomething method - Camel handles the parameters'
binding. Now suppose the method has 2 parameters, and the 2nd parameter is a boolean where
we want to pass in a true value:
public void doSomething(String payload, boolean highPriority) {
...
}
This is now possible in Camel 2.9 onwards:
.bean(OrderService.class, "doSomething(*, true)")
In the example above, we defined the first parameter using the wild card symbol *, which tells
Camel to bind this parameter to any type, and let Camel figure this out. The 2nd parameter has
a fixed value of true. Instead of the wildcard symbol we can instruct Camel to use the
message body as shown:
.bean(OrderService.class, "doSomething(${body}, true)")
The syntax of the parameters is using the Simple expression language so we have to use ${ }
placeholders in the body to refer to the message body.
If you want to pass in a null value, then you can explicit define this in the method option as
shown below:
.to("bean:orderService?method=doSomething(null, true)")
Specifying null as a parameter value instructs Camel to force passing a null value.
Besides the message body, you can pass in the message headers as a java.util.Map:
.bean(OrderService.class, "doSomethingWithHeaders(${body}, ${headers})")
You can also pass in other fixed values besides booleans. For example, you can pass in a String
and an integer:
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.bean(MyBean.class, "echo('World', 5)")
In the example above, we invoke the echo method with two parameters. The first has the
content 'World' (without quotes), and the 2nd has the value of 5.
Camel will automatically convert these values to the parameters' types.
Having the power of the Simple language allows us to bind to message headers and other
values such as:
.bean(OrderService.class, "doSomething(${body}, ${header.high})")
You can also use the OGNL support of the Simple expression language. Now suppose the
message body is an object which has a method named asXml. To invoke the asXml method
we can do as follows:
.bean(OrderService.class, "doSomething(${body.asXml}, ${header.high})")
Instead of using .bean as shown in the examples above, you may want to use .to instead as
shown:
.to("bean:orderService?method=doSomething(${body.asXml}, ${header.high})")
Using type qualifiers to select among overloaded methods
Available as of Camel 2.8
If you have a Bean with overloaded methods, you can now specify parameter types in the
method name so Camel can match the method you intend to use.
Given the following bean:
Listing 4. MyBean
public static final class MyBean {
public String hello(String name) {
return "Hello " + name;
}
public String hello(String name, @Header("country") String country) {
return "Hello " + name + " you are from " + country;
}
public String times(String name, @Header("times") int times) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < times; i++) {
sb.append(name);
}
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return sb.toString();
}
public String times(byte[] data, @Header("times") int times) {
String s = new String(data);
StringBuilder sb = new StringBuilder();
for (int i = 0; i < times; i++) {
sb.append(s);
if (i < times - 1) {
sb.append(",");
}
}
return sb.toString();
}
public String times(String name, int times, char separator) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < times; i++) {
sb.append(name);
if (i < times - 1) {
sb.append(separator);
}
}
return sb.toString();
}
}
Then the MyBean has 2 overloaded methods with the names hello and times. So if we
want to use the method which has 2 parameters we can do as follows in the Camel route:
Listing 5. Invoke 2 parameter method
from("direct:start")
.bean(MyBean.class, "hello(String,String)")
.to("mock:result");
We can also use a * as wildcard so we can just say we want to execute the method with 2
parameters we do
Listing 6. Invoke 2 parameter method using wildcard
from("direct:start")
.bean(MyBean.class, "hello(*,*)")
.to("mock:result");
By default Camel will match the type name using the simple name, e.g. any leading package name
will be disregarded. However if you want to match using the FQN, then specify the FQN type
and Camel will leverage that. So if you have a com.foo.MyOrder and you want to match
against the FQN, and not the simple name "MyOrder", then follow this example:
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.bean(OrderService.class, "doSomething(com.foo.MyOrder)")
Bean Injection
We support the injection of various resources using @EndpointInject. This can be used to
inject
• Endpoint instances which can be used for testing when used with Mock endpoints; see
the Spring Testing for an example.
• ProducerTemplate instances for POJO Producing
• client side proxies for POJO Producing which is a simple approach to Spring
Remoting
Parameter Binding Annotations
Annotations can be used to define an Expression or to extract various headers, properties or
payloads from a Message when invoking a bean method (see Bean Integration for more detail of
how to invoke bean methods) together with being useful to help disambiguate which method to
invoke.
If no annotations are used then Camel assumes that a single parameter is the body of the
message. Camel will then use the Type Converter mechanism to convert from the expression
value to the actual type of the parameter.
The core annotations are as follows
49
Annotation
Meaning
Parameter
@Body
To bind to an inbound message body
Ê
@ExchangeException
To bind to an Exception set on the exchange
(Camel 2.0)
Ê
@Header
To bind to an inbound message header
String name
of the header
@Headers
To bind to the Map of the inbound message
headers
Ê
@OutHeaders
To bind to the Map of the outbound message
headers
Ê
@Property
To bind to a named property on the exchange
String name
of the
property
@Properties
To bind to the property map on the exchange
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Camel currently only supports either specifying parameter binding or type per
parameter in the method name option. You cannot specify both at the same time,
such as
doSomething(com.foo.MyOrder ${body}, boolean ${header.high})
This may change in the future.
camel-core
The annotations below are all part of camel-core and thus does not require
camel-spring or Spring. These annotations can be used with the Bean
component or when invoking beans in the DSL
@Handler
Camel 2.0: Not part as a type parameter but
stated in this table anyway to spread the good word
that we have this annotation in Camel now. See
more at Bean Binding.
Ê
The follow annotations @Headers, @OutHeaders and @Properties binds to the backing
java.util.Map so you can alter the content of these maps directly, for instance using the
put method to add a new entry. See the OrderService class at Exception Clause for such an
example.
Since Camel 2.0, you can use @Header("myHeader") and
@Property("myProperty") instead of @Header(name="myHeader") and
@Property(name="myProperty") as Camel 1.x does.
Example
In this example below we have a @Consume consumer (like message driven) that consumes
JMS messages from the activemq queue. We use the @Header and @Body parameter binding
annotations to bind from the JMSMessage to the method parameters.
public class Foo {
@Consume(uri = "activemq:my.queue")
public void doSomething(@Header("JMSCorrelationID") String correlationID, @Body
String body) {
// process the inbound message here
}
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}
In the above Camel will extract the value of Message.getJMSCorrelationID(), then using the
Type Converter to adapt the value to the type of the parameter if required - it will inject the
parameter value for the correlationID parameter. Then the payload of the message will be
converted to a String and injected into the body parameter.
You don't need to use the @Consume annotation; as you could use the Camel DSL to
route to the beans method
Using the DSL to invoke the bean method
Here is another example which does not use POJO Consuming annotations but instead uses
the DSL to route messages to the bean method
public class Foo {
public void doSomething(@Header("JMSCorrelationID") String correlationID, @Body
String body) {
// process the inbound message here
}
}
The routing DSL then looks like this
from("activemq:someQueue").
to("bean:myBean");
Here myBean would be looked up in the Registry (such as JNDI or the Spring
ApplicationContext), then the body of the message would be used to try figure out what
method to call.
If you want to be explicit you can use
from("activemq:someQueue").
to("bean:myBean?methodName=doSomething");
And here we have a nifty example for you to show some great power in Camel. You can mix
and match the annotations with the normal parameters, so we can have this example with
annotations and the Exchange also:
public void doSomething(@Header("user") String user, @Body String body, Exchange
exchange) {
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exchange.getIn().setBody(body + "MyBean");
}
Annotation Based Expression Language
You can also use any of the Languages supported in Camel to bind expressions to method
parameters when using Bean Integration. For example you can use any of these annotations:
Annotation
Description
@Bean
Inject a Bean expression
@BeanShell
Inject a BeanShell expression
@Constant
Inject a Constant expression
@EL
Inject an EL expression
@Groovy
Inject a Groovy expression
@Header
Inject a Header expression
@JavaScript
Inject a JavaScript expression
@MVEL
Inject a Mvel expression
@OGNL
Inject an OGNL expression
@PHP
Inject a PHP expression
@Python
Inject a Python expression
@Ruby
Inject a Ruby expression
@Simple
Inject an Simple expression
@XPath
Inject an XPath expression
@XQuery
Inject an XQuery expression
Example:
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@XPath("/foo/bar/text()") String correlationID, @Body
String body) {
// process the inbound message here
}
}
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Advanced example using @Bean
And an example of using the the @Bean binding annotation, where you can use a Pojo where
you can do whatever java code you like:
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@Bean("myCorrelationIdGenerator") String correlationID,
@Body String body) {
// process the inbound message here
}
}
And then we can have a spring bean with the id myCorrelationIdGenerator where we
can compute the id.
public class MyIdGenerator {
private UserManager userManager;
public String generate(@Header(name = "user") String user, @Body String payload)
throws Exception {
User user = userManager.lookupUser(user);
String userId = user.getPrimaryId();
String id = userId + generateHashCodeForPayload(payload);
return id;
}
}
The Pojo MyIdGenerator has one public method that accepts two parameters. However we
have also annotated this one with the @Header and @Body annotation to help Camel know
what to bind here from the Message from the Exchange being processed.
Of course this could be simplified a lot if you for instance just have a simple id generator.
But we wanted to demonstrate that you can use the Bean Binding annotations anywhere.
public class MySimpleIdGenerator {
public static int generate()
// generate a unique id
return 123;
{
}
}
And finally we just need to remember to have our bean registered in the Spring Registry:
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Example using Groovy
In this example we have an Exchange that has a User object stored in the in header. This User
object has methods to get some user information. We want to use Groovy to inject an
expression that extracts and concats the fullname of the user into the fullName parameter.
public void doSomething(@Groovy("$request.header['user'].firstName
$request.header['user'].familyName) String fullName, @Body String body) {
// process the inbound message here
}
Groovy supports GStrings that is like a template where we can insert $ placeholders that will
be evaluated by Groovy.
@MessageDriven or @Consume
To consume a message you use either the @MessageDriven annotation or from 1.5.0 the
@Consume annotation to mark a particular method of a bean as being a consumer method.
The uri of the annotation defines the Camel Endpoint to consume from.
e.g. lets invoke the onCheese() method with the String body of the inbound JMS message
from ActiveMQ on the cheese queue; this will use the Type Converter to convert the JMS
ObjectMessage or BytesMessage to a String - or just use a TextMessage from JMS
public class Foo {
@Consume(uri="activemq:cheese")
public void onCheese(String name) {
...
}
}
The Bean Binding is then used to convert the inbound Message to the parameter list used to
invoke the method .
What this does is basically create a route that looks kinda like this
from(uri).bean(theBean, "methodName");
Using context option to apply only a certain CamelContext
Available as of Camel 2.0
See the warning above.
You can use the context option to specify which CamelContext the consumer should
only apply for. For example:
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@MessageDriven is @deprecated
@MessageDriven is deprecated in Camel 1.x. You should use @Consume instead.
Its removed in Camel 2.0.
When using more than one CamelContext
When you use more than 1 CamelContext you might end up with each of them
creating a POJO Consuming.
In Camel 2.0 there is a new option on @Consume that allows you to specify
which CamelContext id/name you want it to apply for.
@Consume(uri="activemq:cheese", context="camel-1")
public void onCheese(String name) {
The consumer above will only be created for the CamelContext that have the context id =
camel-1. You set this id in the XML tag:
Using an explicit route
If you want to invoke a bean method from many different endpoints or within different complex
routes in different circumstances you can just use the normal routing DSL or the Spring XML
configuration file.
For example
from(uri).beanRef("myBean", "methodName");
which will then look up in the Registry and find the bean and invoke the given bean name. (You
can omit the method name and have Camel figure out the right method based on the method
annotations and body type).
Use the Bean endpoint
You can always use the bean endpoint
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from(uri).to("bean:myBean?method=methodName");
Which approach to use?
Using the @MessageDriven/@Consume annotations are simpler when you are creating a
simple route with a single well defined input URI.
However if you require more complex routes or the same bean method needs to be
invoked from many places then please use the routing DSL as shown above.
There are two different ways to send messages to any Camel Endpoint from a POJO
@EndpointInject
To allow sending of messages from POJOs you can use @EndpointInject() annotation. This will
inject either a ProducerTemplate or CamelTemplate so that the bean can send message
exchanges.
e.g. lets send a message to the foo.bar queue in ActiveMQ at some point
public class Foo {
@EndpointInject(uri="activemq:foo.bar")
ProducerTemplate producer;
public void doSomething() {
if (whatever) {
producer.sendBody("world!");
}
}
}
The downside of this is that your code is now dependent on a Camel API, the
ProducerTemplate. The next section describes how to remove this
Hiding the Camel APIs from your code using @Produce
We recommend Hiding Middleware APIs from your application code so the next option might
be more suitable.
You can add the @Produce annotation to an injection point (a field or property setter) using a
ProducerTemplate or using some interface you use in your business logic. e.g.
public interface MyListener {
String sayHello(String name);
}
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public class MyBean {
@Produce(uri = "activemq:foo")
protected MyListener producer;
public void doSomething() {
// lets send a message
String response = producer.sayHello("James");
}
}
Here Camel will automatically inject a smart client side proxy at the @Produce annotation - an
instance of the MyListener instance. When we invoke methods on this interface the method call
is turned into an object and using the Camel Spring Remoting mechanism it is sent to the
endpoint - in this case the ActiveMQ endpoint to queue foo; then the caller blocks for a
response.
If you want to make asynchronous message sends then use an @InOnly annotation on the
injection point.
@RECIPIENTLIST ANNOTATION
As of 1.5.0 we now support the use of @RecipientList on a bean method to easily create a
dynamic Recipient List using a Java method.
Simple Example using @Consume and @RecipientList
package com.acme.foo;
public class RouterBean {
@Consume(uri = "activemq:foo")
@RecipientList
public String[] route(String body) {
return new String[]{"activemq:bar", "activemq:whatnot"};
}
}
For example if the above bean is configured in Spring when using a
element as follows
then a route will be created consuming from the foo queue on the ActiveMQ component
which when a message is received the message will be forwarded to the endpoints defined by
the result of this method call - namely the bar and whatnot queues.
How it works
The return value of the @RecipientList method is converted to either a java.util.Collection /
java.util.Iterator or array of objects where each element is converted to an Endpoint or a String,
or if you are only going to route to a single endpoint then just return either an Endpoint object
or an object that can be converted to a String. So the following methods are all valid
@RecipientList
public String[] route(String body) { ... }
@RecipientList
public List route(String body) { ... }
@RecipientList
public Endpoint route(String body) { ... }
@RecipientList
public Endpoint[] route(String body) { ... }
@RecipientList
public Collection route(String body) { ... }
@RecipientList
public URI route(String body) { ... }
@RecipientList
public URI[] route(String body) { ... }
Then for each endpoint or URI the message is forwarded a separate copy to that endpoint.
You can then use whatever Java code you wish to figure out what endpoints to route to; for
example you can use the Bean Binding annotations to inject parts of the message body or
headers or use Expression values on the message.
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More Complex Example Using DSL
In this example we will use more complex Bean Binding, plus we will use a separate route to
invoke the Recipient List
public class RouterBean2 {
@RecipientList
public String route(@Header("customerID") String custID String body) {
if (custID == null) return null;
return "activemq:Customers.Orders." + custID;
}
}
public class MyRouteBuilder extends RouteBuilder {
protected void configure() {
from("activemq:Orders.Incoming").recipientList(bean("myRouterBean", "route"));
}
}
Notice how we are injecting some headers or expressions and using them to determine the
recipients using Recipient List EIP.
See the Bean Integration for more details.
USING EXCHANGE PATTERN ANNOTATIONS
When working with POJO Producing or Spring Remoting you invoke methods which typically
by default are InOut for Request Reply. That is there is an In message and an Out for the result.
Typically invoking this operation will be synchronous, the caller will block until the server
returns a result.
Camel has flexible Exchange Pattern support - so you can also support the Event Message
pattern to use InOnly for asynchronous or one way operations. These are often called 'fire and
forget' like sending a JMS message but not waiting for any response.
From 1.5 onwards Camel supports annotations for specifying the message exchange pattern
on regular Java methods, classes or interfaces.
Specifying InOnly methods
Typically the default InOut is what most folks want but you can customize to use InOnly using
an annotation.
public interface Foo {
Object someInOutMethod(String input);
String anotherInOutMethod(Cheese input);
@InOnly
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void someInOnlyMethod(Document input);
}
The above code shows three methods on an interface; the first two use the default InOut
mechanism but the someInOnlyMethod uses the InOnly annotation to specify it as being a
oneway method call.
Class level annotations
You can also use class level annotations to default all methods in an interface to some pattern
such as
@InOnly
public interface Foo {
void someInOnlyMethod(Document input);
void anotherInOnlyMethod(String input);
}
Annotations will also be detected on base classes or interfaces. So for example if you created a
client side proxy for
public class MyFoo implements Foo {
...
}
Then the methods inherited from Foo would be InOnly.
Overloading a class level annotation
You can overload a class level annotation on specific methods. A common use case for this is if
you have a class or interface with many InOnly methods but you want to just annote one or
two methods as InOut
@InOnly
public interface Foo {
void someInOnlyMethod(Document input);
void anotherInOnlyMethod(String input);
@InOut
String someInOutMethod(String input);
}
In the above Foo interface the someInOutMethod will be InOut
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Using your own annotations
You might want to create your own annotations to represent a group of different bits of
metadata; such as combining synchrony, concurrency and transaction behaviour.
So you could annotate your annotation with the @Pattern annotation to default the
exchange pattern you wish to use.
For example lets say we want to create our own annotation called @MyAsyncService
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
// lets add the message exchange pattern to it
@Pattern(ExchangePattern.InOnly)
// lets add some other annotations - maybe transaction behaviour?
public @interface MyAsyncService {
}
Now we can use this annotation and Camel will figure out the correct exchange pattern...
public interface Foo {
void someInOnlyMethod(Document input);
void anotherInOnlyMethod(String input);
@MyAsyncService
String someInOutMethod(String input);
}
When writing software these days, its important to try and decouple as much middleware code
from your business logic as possible.
This provides a number of benefits...
• you can choose the right middleware solution for your deployment and switch at any
time
• you don't have to spend a large amount of time learning the specifics of any particular
technology, whether its JMS or JavaSpace or Hibernate or JPA or iBATIS whatever
For example if you want to implement some kind of message passing, remoting, reliable load
balancing or asynchronous processing in your application we recommend you use Camel
annotations to bind your services and business logic to Camel Components which means you
can then easily switch between things like
• in JVM messaging with SEDA
• using JMS via ActiveMQ or other JMS providers for reliable load balancing, grid or
publish and subscribe
• for low volume, but easier administration since you're probably already using a
database you could use
◦ Hibernate or JPA to use an entity bean / table as a queue
◦ iBATIS to work with SQL
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◦ JDBC for raw SQL access
• use JavaSpace
How to decouple from middleware APIs
The best approach when using remoting is to use Spring Remoting which can then use any
messaging or remoting technology under the covers. When using Camel's implementation you
can then use any of the Camel Components along with any of the Enterprise Integration
Patterns.
Another approach is to bind Java beans to Camel endpoints via the Bean Integration. For
example using POJO Consuming and POJO Producing you can avoid using any Camel APIs to
decouple your code both from middleware APIs and Camel APIs!
VISUALISATION
Camel supports the visualisation of your Enterprise Integration Patterns using the GraphViz
DOT files which can either be rendered directly via a suitable GraphViz tool or turned into
HTML, PNG or SVG files via the Camel Maven Plugin.
Here is a typical example of the kind of thing we can generate
If you click on the actual generated htmlyou will see that you can navigate from an EIP node
to its pattern page, along with getting hover-over tool tips ec.
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How to generate
See Camel Dot Maven Goal or the other maven goals Camel Maven Plugin
For OS X users
If you are using OS X then you can open the DOT file using graphviz which will then
automatically re-render if it changes, so you end up with a real time graphical representation of
the topic and queue hierarchies!
Also if you want to edit the layout a little before adding it to a wiki to distribute to your
team, open the DOT file with OmniGraffle then just edit away
BUSINESS ACTIVITY MONITORING
The Camel BAM module provides a Business Activity Monitoring (BAM) framework for
testing business processes across multiple message exchanges on different Endpoint instances.
Consider, for example, a simple system in which you submit Purchase Orders into system A
and then receive Invoices from system B. You might want to test that, for a given Purchase
Order, you receive a matching Invoice from system B within a specific time period.
How Camel BAM Works
Camel BAM uses a Correlation Identifier on an input message to determine the Process Instance
to which it belongs. The process instance is an entity bean which can maintain state for each
Activity (where an activity typically maps to a single endpoint - such as the submission of
Purchase Orders or the receipt of Invoices).
You can then add rules to be triggered when a message is received on any activity - such as
to set time expectations or perform real time reconciliation of values across activities.
Simple Example
The following example shows how to perform some time based rules on a simple business
process of 2 activities - A and B - which correspond with Purchase Orders and Invoices in the
example above. If you would like to experiment with this scenario, you may edit this Test Case,
which defines the activities and rules, and then tests that they work.
return new ProcessBuilder(jpaTemplate, transactionTemplate) {
public void configure() throws Exception {
// let's define some activities, correlating on an XPath on the message bodies
ActivityBuilder a = activity("seda:a").name("a")
.correlate(xpath("/hello/@id"));
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ActivityBuilder b = activity("seda:b").name("b")
.correlate(xpath("/hello/@id"));
// now let's add some rules
b.starts().after(a.completes())
.expectWithin(seconds(1))
.errorIfOver(seconds(errorTimeout)).to("mock:overdue");
}
};
As you can see in the above example, we first define two activities, and then rules to specify
when we expect them to complete for a process instance and when an error condition should
be raised.p. The ProcessBuilder is a RouteBuilder and can be added to any CamelContext.
Complete Example
For a complete example please see the BAM Example, which is part of the standard Camel
Examples
Use Cases
In the world of finance, a common requirement is tracking trades. Often a trader will submit a
Front Office Trade which then flows through the Middle Office and Back Office through various
systems to settle the trade so that money is exchanged. You may wish to test that the front and
back office trades match up within a certain time period; if they don't match or a back office
trade does not arrive within a required amount of time, you might signal an alarm.
EXTRACT TRANSFORM LOAD (ETL)
The ETL (Extract, Transform, Load) is a mechanism for loading data into systems or databases
using some kind of Data Format from a variety of sources; often files then using Pipes and
Filters, Message Translator and possible other Enterprise Integration Patterns.
So you could query data from various Camel Components such as File, HTTP or JPA,
perform multiple patterns such as Splitter or Message Translator then send the messages to
some other Component.
To show how this all fits together, try the ETL Example
MOCK COMPONENT
Testing of distributed and asynchronous processing is notoriously difficult. The Mock, Test and
DataSet endpoints work great with the Camel Testing Framework to simplify your unit and
integration testing using Enterprise Integration Patterns and Camel's large range of Components
together with the powerful Bean Integration.
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The Mock component provides a powerful declarative testing mechanism, which is similar to
jMock in that it allows declarative expectations to be created on any Mock endpoint before a
test begins. Then the test is run, which typically fires messages to one or more endpoints, and
finally the expectations can be asserted in a test case to ensure the system worked as expected.
This allows you to test various things like:
• The correct number of messages are received on each endpoint,
• The correct payloads are received, in the right order,
• Messages arrive on an endpoint in order, using some Expression to create an order
testing function,
• Messages arrive match some kind of Predicate such as that specific headers have
certain values, or that parts of the messages match some predicate, such as by
evaluating an XPath or XQuery Expression.
Note that there is also the Test endpoint which is a Mock endpoint, but which uses a second
endpoint to provide the list of expected message bodies and automatically sets up the Mock
endpoint assertions. In other words, it's a Mock endpoint that automatically sets up its
assertions from some sample messages in a File or database, for example.
URI format
mock:someName[?options]
Where someName can be any string that uniquely identifies the endpoint.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
reportGroup
null
A size to use a throughput logger for reporting
Simple Example
Here's a simple example of Mock endpoint in use. First, the endpoint is resolved on the
context. Then we set an expectation, and then, after the test has run, we assert that our
expectations have been met.
MockEndpoint resultEndpoint = context.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.expectedMessageCount(2);
// send some messages
...
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Mock endpoints keep received Exchanges in memory indefinitely
Remember that Mock is designed for testing. When you add Mock endpoints to a
route, each Exchange sent to the endpoint will be stored (to allow for later
validation) in memory until explicitly reset or the JVM is restarted. If you are
sending high volume and/or large messages, this may cause excessive memory use. If
your goal is to test deployable routes inline, consider using NotifyBuilder or
AdviceWith in your tests instead of adding Mock endpoints to routes directly.
// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();
You typically always call the assertIsSatisfied() method to test that the expectations were met
after running a test.
Camel will by default wait 10 seconds when the assertIsSatisfied() is invoked. This
can be configured by setting the setResultWaitTime(millis) method.
When the assertion is satisfied then Camel will stop waiting and continue from the
assertIsSatisfied method. That means if a new message arrives on the mock endpoint,
just a bit later, that arrival will not affect the outcome of the assertion. Suppose you do want to
test that no new messages arrives after a period thereafter, then you can do that by setting the
setAssertPeriod method.
Using assertPeriod
Available as of Camel 2.7
When the assertion is satisfied then Camel will stop waiting and continue from the
assertIsSatisfied method. That means if a new message arrives on the mock endpoint,
just a bit later, that arrival will not affect the outcome of the assertion. Suppose you do want to
test that no new messages arrives after a period thereafter, then you can do that by setting the
setAssertPeriod method, for example:
MockEndpoint resultEndpoint = context.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.setAssertPeriod(5000);
resultEndpoint.expectedMessageCount(2);
// send some messages
...
// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();
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Setting expectations
You can see from the javadoc of MockEndpoint the various helper methods you can use to set
expectations. The main methods are as follows:
Method
Description
expectedMessageCount(int)
To define the expected message count on the endpoint.
expectedMinimumMessageCount(int)
To define the minimum number of expected messages on the endpoint.
expectedBodiesReceived(...)
To define the expected bodies that should be received (in order).
expectedHeaderReceived(...)
To define the expected header that should be received
expectsAscending(Expression)
To add an expectation that messages are received in order, using the given Expression to compare messages.
expectsDescending(Expression)
To add an expectation that messages are received in order, using the given Expression to compare messages.
expectsNoDuplicates(Expression)
To add an expectation that no duplicate messages are received; using an Expression to calculate a unique identifier for each message. This
could be something like the JMSMessageID if using JMS, or some unique reference number within the message.
Here's another example:
resultEndpoint.expectedBodiesReceived("firstMessageBody", "secondMessageBody",
"thirdMessageBody");
Adding expectations to specific messages
In addition, you can use the message(int messageIndex) method to add assertions about a
specific message that is received.
For example, to add expectations of the headers or body of the first message (using zerobased indexing like java.util.List), you can use the following code:
resultEndpoint.message(0).header("foo").isEqualTo("bar");
There are some examples of the Mock endpoint in use in the camel-core processor tests.
Mocking existing endpoints
Available as of Camel 2.7
Camel now allows you to automatic mock existing endpoints in your Camel routes.
Suppose you have the given route below:
Listing 7. Route
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:start").to("direct:foo").to("log:foo").to("mock:result");
from("direct:foo").transform(constant("Bye World"));
}
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How it works
Important: The endpoints are still in action, what happens is that a Mock
endpoint is injected and receives the message first, it then delegate the message to
the target endpoint. You can view this as a kind of intercept and delegate or
endpoint listener.
};
}
You can then use the adviceWith feature in Camel to mock all the endpoints in a given
route from your unit test, as shown below:
Listing 8. adviceWith mocking all endpoints
public void testAdvisedMockEndpoints() throws Exception {
// advice the first route using the inlined AdviceWith route builder
// which has extended capabilities than the regular route builder
context.getRouteDefinitions().get(0).adviceWith(context, new
AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
// mock all endpoints
mockEndpoints();
}
});
getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// all the endpoints was mocked
assertNotNull(context.hasEndpoint("mock:direct:start"));
assertNotNull(context.hasEndpoint("mock:direct:foo"));
assertNotNull(context.hasEndpoint("mock:log:foo"));
}
Notice that the mock endpoints is given the uri mock:, for example
mock:direct:foo. Camel logs at INFO level the endpoints being mocked:
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INFO
Adviced endpoint [direct://foo] with mock endpoint [mock:direct:foo]
Its also possible to only mock certain endpoints using a pattern. For example to mock all log
endpoints you do as shown:
Listing 9. adviceWith mocking only log endpoints using a pattern
public void testAdvisedMockEndpointsWithPattern() throws Exception {
// advice the first route using the inlined AdviceWith route builder
// which has extended capabilities than the regular route builder
context.getRouteDefinitions().get(0).adviceWith(context, new
AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
// mock only log endpoints
mockEndpoints("log*");
}
});
// now we can refer to log:foo as a mock and set our expectations
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// only the log:foo endpoint was mocked
assertNotNull(context.hasEndpoint("mock:log:foo"));
assertNull(context.hasEndpoint("mock:direct:start"));
assertNull(context.hasEndpoint("mock:direct:foo"));
}
The pattern supported can be a wildcard or a regular expression. See more details about this at
Intercept as its the same matching function used by Camel.
Mocking existing endpoints using the camel-test component
Instead of using the adviceWith to instruct Camel to mock endpoints, you can easily enable
this behavior when using the camel-test Test Kit.
The same route can be tested as follows. Notice that we return "*" from the
isMockEndpoints method, which tells Camel to mock all endpoints.
If you only want to mock all log endpoints you can return "log*" instead.
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Mocked endpoints are without parameters
Endpoints which are mocked will have their parameters stripped off. For example
the endpoint "log:foo?showAll=true" will be mocked to the following endpoint
"mock:log:foo". Notice the parameters has been removed.
Mind that mocking endpoints causes the messages to be copied when they arrive on
the mock.
That means Camel will use more memory. This may not be suitable when you send
in a lot of messages.
Listing 10. isMockEndpoints using camel-test kit
public class IsMockEndpointsJUnit4Test extends CamelTestSupport {
@Override
public String isMockEndpoints() {
// override this method and return the pattern for which endpoints to mock.
// use * to indicate all
return "*";
}
@Test
public void testMockAllEndpoints() throws Exception {
// notice we have automatic mocked all endpoints and the name of the endpoints
is "mock:uri"
getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// all the endpoints was mocked
assertNotNull(context.hasEndpoint("mock:direct:start"));
assertNotNull(context.hasEndpoint("mock:direct:foo"));
assertNotNull(context.hasEndpoint("mock:log:foo"));
}
@Override
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protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:start").to("direct:foo").to("log:foo").to("mock:result");
from("direct:foo").transform(constant("Bye World"));
}
};
}
}
Mocking existing endpoints with XML DSL
If you do not use the camel-test component for unit testing (as shown above) you can use a
different approach when using XML files for routes.
The solution is to create a new XML file used by the unit test and then include the intended
XML file which has the route you want to test.
Suppose we have the route in the camel-route.xml file:
Listing 11. camel-route.xml
Bye World
Then we create a new XML file as follows, where we include the camel-route.xml file and
define a spring bean with the class
org.apache.camel.impl.InterceptSendToMockEndpointStrategy which tells
Camel to mock all endpoints:
Listing 12. test-camel-route.xml
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Then in your unit test you load the new XML file (test-camel-route.xml) instead of
camel-route.xml.
To only mock all Log endpoints you can define the pattern in the constructor for the bean:
Testing with arrival times
Available as of Camel 2.7
The Mock endpoint stores the arrival time of the message as a property on the Exchange.
Date time = exchange.getProperty(Exchange.RECEIVED_TIMESTAMP, Date.class);
You can use this information to know when the message arrived on the mock. But it also
provides foundation to know the time interval between the previous and next message arrived
on the mock. You can use this to set expectations using the arrives DSL on the Mock
endpoint.
For example to say that the first message should arrive between 0-2 seconds before the
next you can do:
mock.message(0).arrives().noLaterThan(2).seconds().beforeNext();
You can also define this as that 2nd message (0 index based) should arrive no later than 0-2
seconds after the previous:
mock.message(1).arrives().noLaterThan(2).seconds().afterPrevious();
You can also use between to set a lower bound. For example suppose that it should be
between 1-4 seconds:
mock.message(1).arrives().between(1, 4).seconds().afterPrevious();
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You can also set the expectation on all messages, for example to say that the gap between them
should be at most 1 second:
mock.allMessages().arrives().noLaterThan(1).seconds().beforeNext();
See Also
•
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
Spring Testing
Testing
TESTING
Testing is a crucial activity in any piece of software development or integration. Typically Camel
Riders use various different technologies wired together in a variety of patterns with different
expression languages together with different forms of Bean Integration and Dependency
Injection so its very easy for things to go wrong!
. Testing is the crucial weapon to ensure
that things work as you would expect.
Camel is a Java library so you can easily wire up tests in whatever unit testing framework
you use (JUnit 3.x, 4.x or TestNG). However the Camel project has tried to make the testing
of Camel as easy and powerful as possible so we have introduced the following features.
Testing mechanisms
The following mechanisms are supported
Name
Description
Camel
Test
is a library letting you easily create Camel test cases using a single Java class for all
your configuration and routing without using Spring or Guice for Dependency
Injection which does not require an in depth knowledge of Spring+SpringTest or
Guice
Spring
Testing
uses Spring Test together with either XML or Java Config to dependency inject
your test classes
Guice
uses Guice to dependency inject your test classes
In all approaches the test classes look pretty much the same in that they all reuse the Camel
binding and injection annotations.
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time units
In the example above we use seconds as the time unit, but Camel offers
milliseconds, and minutes as well.
Camel Test Example
Here is the Camel Test example.
public class FilterTest extends CamelTestSupport {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@Test
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@Test
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
}
@Override
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
}
};
}
}
Notice how it derives from the Camel helper class CamelTestSupport but has no Spring or
Guice dependency injection configuration but instead overrides the createRouteBuilder()
method.
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Spring Test with XML Config Example
Here is the Spring Testing example using XML Config.
@ContextConfiguration
public class FilterTest extends AbstractJUnit38SpringContextTests {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@DirtiesContext
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@DirtiesContext
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
}
}
Notice that we use @DirtiesContext on the test methods to force Spring Testing to
automatically reload the CamelContext after each test method - this ensures that the tests
don't clash with each other (e.g. one test method sending to an endpoint that is then reused in
another test method).
Also notice the use of @ContextConfiguration to indicate that by default we should
look for the FilterTest-context.xml on the classpath to configure the test case which looks like
this
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$foo = 'bar'
Spring Test with Java Config Example
Here is the Spring Testing example using Java Config. For more information see Spring Java
Config.
@ContextConfiguration(
locations =
"org.apache.camel.spring.javaconfig.patterns.FilterTest$ContextConfig",
loader = JavaConfigContextLoader.class)
public class FilterTest extends AbstractJUnit4SpringContextTests {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@DirtiesContext
@Test
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@DirtiesContext
@Test
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
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}
@Configuration
public static class ContextConfig extends SingleRouteCamelConfiguration {
@Bean
public RouteBuilder route() {
return new RouteBuilder() {
public void configure() {
from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
}
};
}
}
}
This is similar to the XML Config example above except that there is no XML file and instead
the nested ContextConfig class does all of the configuration; so your entire test case is
contained in a single Java class. We currently have to reference by class name this class in the
@ContextConfiguration which is a bit ugly. Please vote for SJC-238 to address this and
make Spring Test work more cleanly with Spring JavaConfig.
Its totally optional but for the ContextConfig implementation we derive from
SingleRouteCamelConfiguration which is a helper Spring Java Config class which will
configure the CamelContext for us and then register the RouteBuilder we create.
Testing endpoints
Camel provides a number of endpoints which can make testing easier.
Name
Description
DataSet
For load & soak testing this endpoint provides a way to create huge numbers of
messages for sending to Components and asserting that they are consumed
correctly
Mock
For testing routes and mediation rules using mocks and allowing assertions to be
added to an endpoint
Test
Creates a Mock endpoint which expects to receive all the message bodies that
could be polled from the given underlying endpoint
The main endpoint is the Mock endpoint which allows expectations to be added to different
endpoints; you can then run your tests and assert that your expectations are met at the end.
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Stubbing out physical transport technologies
If you wish to test out a route but want to avoid actually using a real physical transport (for
example to unit test a transformation route rather than performing a full integration test) then
the following endpoints can be useful.
Name
Description
Direct
Direct invocation of the consumer from the producer so that single threaded
(non-SEDA) in VM invocation is performed which can be useful to mock out
physical transports
SEDA
Delivers messages asynchonously to consumers via a
java.util.concurrent.BlockingQueue which is good for testing asynchronous
transports
Testing existing routes
Camel provides some features to aid during testing of existing routes where you cannot or will
not use Mock etc. For example you may have a production ready route which you want to test
with some 3rd party API which sends messages into this route.
Name
Description
NotifyBuilder
Allows you to be notified when a certain condition has occurred. For
example when the route has completed 5 messages. You can build complex
expressions to match your criteria when to be notified.
AdviceWith
Allows you to advice or enhance an existing route using a RouteBuilder
style. For example you can add interceptors to intercept sending outgoing
messages to assert those messages are as expected.
CAMEL TEST
As a simple alternative to using Spring Testing or Guice the camel-test module was
introduced into the Camel 2.0 trunk so you can perform powerful Testing of your Enterprise
Integration Patterns easily.
Adding to your pom.xml
To get started using Camel Test you will need to add an entry to your pom.xml
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The camel-test JAR is using JUnit. There is an alternative camel-testng JAR
(Camel 2.8 onwards) using the TestNG test framework.
JUnit
org.apache.camelcamel-test${camel-version}test
TestNG
Available as of Camel 2.8
org.apache.camelcamel-testng${camel-version}test
You might also want to add slf4j and log4j to ensure nice logging messages (and maybe adding a
log4j.properties file into your src/test/resources directory).
org.slf4jslf4j-log4j12testlog4jlog4jtest
Writing your test
You firstly need to derive from the class CamelTestSupport and typically you will need to
override the createRouteBuilder() method to create routes to be tested.
Here is an example.
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public class FilterTest extends CamelTestSupport {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@Test
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@Test
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
}
@Override
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
}
};
}
}
Notice how you can use the various Camel binding and injection annotations to inject individual
Endpoint objects - particularly the Mock endpoints which are very useful for Testing. Also you
can inject producer objects such as ProducerTemplate or some application code interface for
sending messages or invoking services.
JNDI
Camel uses a Registry to allow you to configure Component or Endpoint instances or Beans
used in your routes. If you are not using Spring or OSGi then JNDI is used as the default
registry implementation.
So you will also need to create a jndi.properties file in your src/test/resources
directory so that there is a default registry available to initialise the CamelContext.
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Here is an example jndi.properties file
java.naming.factory.initial = org.apache.camel.util.jndi.CamelInitialContextFactory
Dynamically assigning ports
Available as of Camel 2.7
Tests that use port numbers will fail if that port is already on use.
AvailablePortFinder provides methods for finding unused port numbers at runtime.
// Get the next available port number starting from the default starting port of 1024
int port1 = AvailablePortFinder.getNextAvailable();
/*
* Get another port. Note that just getting a port number does not reserve it so
* we look starting one past the last port number we got.
*/
int port2 = AvailablePortFinder.getNextAvailable(port1 + 1);
Setup CamelContext once per class, or per every test method
Available as of Camel 2.8
The Camel Test kit will by default setup and shutdown CamelContext per every test
method in your test class. So for example if you have 3 test methods, then CamelContext is
started and shutdown after each test, that is 3 times.
You may want to do this once, to share the CamelContext between test methods, to speedup
unit testing. This requires to use JUnit 4! In your unit test method you have to extend the
org.apache.camel.test.junit4.CamelTestSupport or the
org.apache.camel.test.junit4.CamelSpringTestSupport test class and
override the isCreateCamelContextPerClass method and return true as shown in
the following example:
Listing 13. Setup CamelContext once per class
public class FilterCreateCamelContextPerClassTest extends CamelTestSupport {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@Override
public boolean isCreateCamelContextPerClass() {
// we override this method and return true, to tell Camel test-kit that
// it should only create CamelContext once (per class), so we will
// re-use the CamelContext between each test method in this class
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TestNG
This feature is also supported in camel-testng
Beware
When using this the CamelContext will keep state between tests, so have that in
mind. So if your unit tests start to fail for no apparent reason, it could be due this
fact. So use this feature with a bit of care.
return true;
}
@Test
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@Test
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
}
@Override
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
}
};
}
}
See Also
• Testing
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• Mock
• Test
SPRING TESTING
Testing is a crucial part of any development or integration work. The Spring Framework offers
a number of features that makes it easy to test while using Spring for Inversion of Control
which works with JUnit 3.x, JUnit 4.x or TestNG.
We can reuse Spring for IoC and the Camel Mock and Test endpoints to create
sophisticated integration tests that are easy to run and debug inside your IDE.
For example here is a simple unit test
import
import
import
import
import
org.apache.camel.CamelContext;
org.apache.camel.component.mock.MockEndpoint;
org.springframework.beans.factory.annotation.Autowired;
org.springframework.test.context.ContextConfiguration;
org.springframework.test.context.junit38.AbstractJUnit38SpringContextTests;
@ContextConfiguration
public class MyCamelTest extends AbstractJUnit38SpringContextTests {
@Autowired
protected CamelContext camelContext;
public void testMocksAreValid() throws Exception {
MockEndpoint.assertIsSatisfied(camelContext);
}
}
This test will load a Spring XML configuration file called MyCamelTest-context.xml from
the classpath in the same package structure as the MyCamelTest class and initialize it along with
any Camel routes we define inside it, then inject the CamelContext instance into our test case.
For instance, like this maven folder layout:
src/main/java/com/mycompany/MyCamelTest.class
src/main/resources/com/mycompany/MyCamelTest-context.xml
Spring Test with Java Config Example
You can completely avoid using an XML configuration file by using Spring Java Config.
Here is an example using Java Config.
@ContextConfiguration(
locations =
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"org.apache.camel.spring.javaconfig.patterns.FilterTest$ContextConfig",
loader = JavaConfigContextLoader.class)
public class FilterTest extends AbstractJUnit4SpringContextTests {
@EndpointInject(uri = "mock:result")
protected MockEndpoint resultEndpoint;
@Produce(uri = "direct:start")
protected ProducerTemplate template;
@DirtiesContext
@Test
public void testSendMatchingMessage() throws Exception {
String expectedBody = "";
resultEndpoint.expectedBodiesReceived(expectedBody);
template.sendBodyAndHeader(expectedBody, "foo", "bar");
resultEndpoint.assertIsSatisfied();
}
@DirtiesContext
@Test
public void testSendNotMatchingMessage() throws Exception {
resultEndpoint.expectedMessageCount(0);
template.sendBodyAndHeader("", "foo", "notMatchedHeaderValue");
resultEndpoint.assertIsSatisfied();
}
@Configuration
public static class ContextConfig extends SingleRouteCamelConfiguration {
@Bean
public RouteBuilder route() {
return new RouteBuilder() {
public void configure() {
from("direct:start").filter(header("foo").isEqualTo("bar")).to("mock:result");
}
};
}
}
}
This is similar to the XML Config example above except that there is no XML file and instead
the nested ContextConfig class does all of the configuration; so your entire test case is
contained in a single Java class. We currently have to reference by class name this class in the
@ContextConfiguration which is a bit ugly. Please vote for SJC-238 to address this and
make Spring Test work more cleanly with Spring JavaConfig.
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Adding more Mock expectations
If you wish to programmatically add any new assertions to your test you can easily do so with
the following. Notice how we use @EndpointInject to inject a Camel endpoint into our code
then the Mock API to add an expectation on a specific message.
@ContextConfiguration
public class MyCamelTest extends AbstractJUnit38SpringContextTests {
@Autowired
protected CamelContext camelContext;
@EndpointInject(uri = "mock:foo")
protected MockEndpoint foo;
public void testMocksAreValid() throws Exception {
// lets add more expectations
foo.message(0).header("bar").isEqualTo("ABC");
MockEndpoint.assertIsSatisfied(camelContext);
}
}
Further processing the received messages
Sometimes once a Mock endpoint has received some messages you want to then process them
further to add further assertions that your test case worked as you expect.
So you can then process the received message exchanges if you like...
@ContextConfiguration
public class MyCamelTest extends AbstractJUnit38SpringContextTests {
@Autowired
protected CamelContext camelContext;
@EndpointInject(uri = "mock:foo")
protected MockEndpoint foo;
public void testMocksAreValid() throws Exception {
// lets add more expectations...
MockEndpoint.assertIsSatisfied(camelContext);
// now lets do some further assertions
List list = foo.getReceivedExchanges();
for (Exchange exchange : list) {
Message in = exchange.getIn();
...
}
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}
}
Sending and receiving messages
It might be that the Enterprise Integration Patterns you have defined in either Spring XML or
using the Java DSL do all of the sending and receiving and you might just work with the Mock
endpoints as described above. However sometimes in a test case its useful to explicitly send or
receive messages directly.
To send or receive messages you should use the Bean Integration mechanism. For example
to send messages inject a ProducerTemplate using the @EndpointInject annotation then call the
various send methods on this object to send a message to an endpoint. To consume messages
use the @MessageDriven annotation on a method to have the method invoked when a message
is received.
public class Foo {
@EndpointInject(uri="activemq:foo.bar")
ProducerTemplate producer;
public void doSomething() {
// lets send a message!
producer.sendBody("world!");
}
// lets consume messages from the 'cheese' queue
@MessageDriven(uri="activemq:cheese")
public void onCheese(String name) {
...
}
}
See Also
•
•
•
•
a real example test case using Mock and Spring along with its Spring XML
Bean Integration
Mock endpoint
Test endpoint
CAMEL GUICE
As of 1.5 we now have support for Google Guice as a dependency injection framework. To use
it just be dependent on camel-guice.jar which also depends on the following jars.
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Dependency Injecting Camel with Guice
The GuiceCamelContext is designed to work nicely inside Guice. You then need to bind it
using some Guice Module.
The camel-guice library comes with a number of reusable Guice Modules you can use if you
wish - or you can bind the GuiceCamelContext yourself in your own module.
• CamelModule is the base module which binds the GuiceCamelContext but leaves it
up you to bind the RouteBuilder instances
• CamelModuleWithRouteTypes extends CamelModule so that in the constructor of
the module you specify the RouteBuilder classes or instances to use
• CamelModuleWithMatchingRoutes extends CamelModule so that all bound
RouteBuilder instances will be injected into the CamelContext or you can supply an
optional Matcher to find RouteBuilder instances matching some kind of predicate.
So you can specify the exact RouteBuilder instances you want
Injector injector = Guice.createInjector(new
CamelModuleWithRouteTypes(MyRouteBuilder.class, AnotherRouteBuilder.class));
// if required you can lookup the CamelContext
CamelContext camelContext = injector.getInstance(CamelContext.class);
Or inject them all
Injector injector = Guice.createInjector(new CamelModuleWithRouteTypes());
// if required you can lookup the CamelContext
CamelContext camelContext = injector.getInstance(CamelContext.class);
You can then use Guice in the usual way to inject the route instances or any other dependent
objects.
Bootstrapping with JNDI
A common pattern used in J2EE is to bootstrap your application or root objects by looking
them up in JNDI. This has long been the approach when working with JMS for example looking up the JMS ConnectionFactory in JNDI for example.
You can follow a similar pattern with Guice using the GuiceyFruit JNDI Provider which lets
you bootstrap Guice from a jndi.properties file which can include the Guice Modules to
create along with environment specific properties you can inject into your modules and objects.
If the jndi.properties is conflict with other component, you can specify the jndi
properties file name in the Guice Main with option -j or -jndiProperties with the properties file
location to let Guice Main to load right jndi properties file.
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Configuring Component, Endpoint or RouteBuilder instances
You can use Guice to dependency inject whatever objects you need to create, be it an
Endpoint, Component, RouteBuilder or arbitrary bean used within a route.
The easiest way to do this is to create your own Guice Module class which extends one of
the above module classes and add a provider method for each object you wish to create. A
provider method is annotated with @Provides as follows
public class MyModule extends CamelModuleWithMatchingRoutes {
@Provides
@JndiBind("jms")
JmsComponent jms(@Named("activemq.brokerURL") String brokerUrl) {
return JmsComponent.jmsComponent(new ActiveMQConnectionFactory(brokerUrl));
}
}
You can optionally annotate the method with @JndiBind to bind the object to JNDI at some
name if the object is a component, endpoint or bean you wish to refer to by name in your
routes.
You can inject any environment specific properties (such as URLs, machine names,
usernames/passwords and so forth) from the jndi.properties file easily using the @Named
annotation as shown above. This allows most of your configuration to be in Java code which is
typesafe and easily refactorable - then leaving some properties to be environment specific (the
jndi.properties file) which you can then change based on development, testing, production etc.
Creating multiple RouteBuilder instances per type
It is sometimes useful to create multiple instances of a particular RouteBuilder with different
configurations.
To do this just create multiple provider methods for each configuration; or create a single
provider method that returns a collection of RouteBuilder instances.
For example
import org.apache.camel.guice.CamelModuleWithMatchingRoutes;
import com.google.common.collect.Lists;
public class MyModule extends CamelModuleWithMatchingRoutes {
@Provides
@JndiBind("foo")
Collection foo(@Named("fooUrl") String fooUrl) {
return Lists.newArrayList(new MyRouteBuilder(fooUrl), new
MyRouteBuilder("activemq:CheeseQueue"));
}
}
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See Also
• there are a number of Examples you can look at to see Guice and Camel being used
such as Guice JMS Example
• Guice Maven Plugin for running your Guice based routes via Maven
TEMPLATING
When you are testing distributed systems its a very common requirement to have to stub out
certain external systems with some stub so that you can test other parts of the system until a
specific system is available or written etc.
A great way to do this is using some kind of Template system to generate responses to
requests generating a dynamic message using a mostly-static body.
There are a number of templating components included in the Camel distribution you could
use
• FreeMarker
• StringTemplate
• Velocity
• XQuery
• XSLT
or the following external Camel components
• Scalate
Example
Here's a simple example showing how we can respond to InOut requests on the My.Queue
queue on ActiveMQ with a template generated response. The reply would be sent back to the
JMSReplyTo Destination.
from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm");
If you want to use InOnly and consume the message and send it to another destination you
could use
from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm").
to("activemq:Another.Queue");
See Also
• Mock for details of mock endpoint testing (as opposed to template based stubs).
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DATABASE
Camel can work with databases in a number of different ways. This document tries to outline
the most common approaches.
Database endpoints
Camel provides a number of different endpoints for working with databases
• JPA for working with hibernate, openjpa or toplink. When consuming from the
endpoints entity beans are read (and deleted/updated to mark as processed) then
when producing to the endpoints they are written to the database (via insert/update).
• iBATIS similar to the above but using Apache iBATIS
• JDBC similar though using explicit SQL
Database pattern implementations
Various patterns can work with databases as follows
• Idempotent Consumer
• Aggregator
• BAM for business activity monitoring
PARALLEL PROCESSING AND ORDERING
It is a common requirement to want to use parallel processing of messages for throughput and
load balancing, while at the same time process certain kinds of messages in order.
How to achieve parallel processing
You can send messages to a number of Camel Components to achieve parallel processing and
load balancing such as
• SEDA for in-JVM load balancing across a thread pool
• ActiveMQ or JMS for distributed load balancing and parallel processing
• JPA for using the database as a poor mans message broker
When processing messages concurrently, you should consider ordering and concurrency issues.
These are described below
Concurrency issues
Note that there is no concurrency or locking issue when using ActiveMQ, JMS or SEDA by
design; they are designed for highly concurrent use. However there are possible concurrency
issues in the Processor of the messages i.e. what the processor does with the message?
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For example if a processor of a message transfers money from one account to another
account; you probably want to use a database with pessimistic locking to ensure that operation
takes place atomically.
Ordering issues
As soon as you send multiple messages to different threads or processes you will end up with
an unknown ordering across the entire message stream as each thread is going to process
messages concurrently.
For many use cases the order of messages is not too important. However for some
applications this can be crucial. e.g. if a customer submits a purchase order version 1, then
amends it and sends version 2; you don't want to process the first version last (so that you
loose the update). Your Processor might be clever enough to ignore old messages. If not you
need to preserve order.
Recommendations
This topic is large and diverse with lots of different requirements; but from a high level here are
our recommendations on parallel processing, ordering and concurrency
• for distributed locking, use a database by default, they are very good at it
• to preserve ordering across a JMS queue consider using Exclusive Consumers in the
ActiveMQ component
• even better are Message Groups which allows you to preserve ordering across
messages while still offering parallelisation via the JMSXGrouopID header to
determine what can be parallelized
• if you receive messages out of order you could use the Resequencer to put them
back together again
A good rule of thumb to help reduce ordering problems is to make sure each single can be
processed as an atomic unit in parallel (either without concurrency issues or using say, database
locking); or if it can't, use a Message Group to relate the messages together which need to be
processed in order by a single thread.
Using Message Groups with Camel
To use a Message Group with Camel you just need to add a header to the output JMS message
based on some kind of Correlation Identifier to correlate messages which should be processed
in order by a single thread - so that things which don't correlate together can be processed
concurrently.
For example the following code shows how to create a message group using an XPath
expression taking an invoice's product code as the Correlation Identifier
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from("activemq:a").setHeader("JMSXGroupID", xpath("/invoice/
productCode")).to("activemq:b");
You can of course use the Xml Configuration if you prefer
ASYNCHRONOUS PROCESSING
Overview
Camel supports a more complex asynchronous processing model. The asynchronous
processors implement the AsyncProcessor interface which is derived from the more
synchronous Processor interface. There are advantages and disadvantages when using
asynchronous processing when compared to using the standard synchronous processing model.
Advantages:
• Processing routes that are composed fully of asynchronous processors do not use up
threads waiting for processors to complete on blocking calls. This can increase the
scalability of your system by reducing the number of threads needed to process the
same workload.
• Processing routes can be broken up into SEDA processing stages where different
thread pools can process the different stages. This means that your routes can be
processed concurrently.
Disadvantages:
• Implementing asynchronous processors is more complex than implementing the
synchronous versions.
When to Use
We recommend that processors and components be implemented the more simple
synchronous APIs unless you identify a performance of scalability requirement that dictates
otherwise. A Processor whose process() method blocks for a long time would be good
candidates for being converted into an asynchronous processor.
Interface Details
public interface AsyncProcessor extends Processor {
boolean process(Exchange exchange, AsyncCallback callback);
}
The AsyncProcessor defines a single process() method which is very similar to it's
synchronous Processor.process() brethren. Here are the differences:
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Supported versions
The information on this page applies for the Camel 1.x and Camel 2.4 onwards. In
Camel 1.x the asynchronous processing is only implemented for JBI where as in
Camel 2.4 onwards we have implemented it in many other areas. See more at
Asynchronous Routing Engine.
• A non-null AsyncCallback MUST be supplied which will be notified when the
exchange processing is completed.
• It MUST not throw any exceptions that occurred while processing the exchange.
Any such exceptions must be stored on the exchange's Exception property.
• It MUST know if it will complete the processing synchronously or asynchronously.
The method will return true if it does complete synchronously, otherwise it returns
false.
• When the processor has completed processing the exchange, it must call the
callback.done(boolean sync) method. The sync parameter MUST match
the value returned by the process() method.
Implementing Processors that Use the AsyncProcessor API
All processors, even synchronous processors that do not implement the AsyncProcessor
interface, can be coerced to implement the AsyncProcessor interface. This is usually done when
you are implementing a Camel component consumer that supports asynchronous completion of
the exchanges that it is pushing through the Camel routes. Consumers are provided a
Processor object when created. All Processor object can be coerced to a AsyncProcessor using
the following API:
Processor processor = ...
AsyncProcessor asyncProcessor = AsyncProcessorTypeConverter.convert(processor);
For a route to be fully asynchronous and reap the benefits to lower Thread usage, it must start
with the consumer implementation making use of the asynchronous processing API. If it called
the synchronous process() method instead, the consumer's thread would be forced to be
blocked and in use for the duration that it takes to process the exchange.
It is important to take note that just because you call the asynchronous API, it does not
mean that the processing will take place asynchronously. It only allows the possibility that it can
be done without tying up the caller's thread. If the processing happens asynchronously is
dependent on the configuration of the Camel route.
Normally, the the process call is passed in an inline inner AsyncCallback class instance which
can reference the exchange object that was declared final. This allows it to finish up any post
processing that is needed when the called processor is done processing the exchange. See
below for an example.
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final Exchange exchange = ...
AsyncProcessor asyncProcessor = ...
asyncProcessor.process(exchange, new AsyncCallback() {
public void done(boolean sync) {
if (exchange.isFailed()) {
... // do failure processing.. perhaps rollback etc.
} else {
... // processing completed successfully, finish up
// perhaps commit etc.
}
}
});
Asynchronous Route Sequence Scenarios
Now that we have understood the interface contract of the AsyncProcessor, and have seen
how to make use of it when calling processors, lets looks a what the thread model/sequence
scenarios will look like for some sample routes.
The Jetty component's consumers support async processing by using continuations. Suffice
to say it can take a http request and pass it to a camel route for async processing. If the
processing is indeed async, it uses Jetty continuation so that the http request is 'parked' and the
thread is released. Once the camel route finishes processing the request, the jetty component
uses the AsyncCallback to tell Jetty to 'un-park' the request. Jetty un-parks the request, the http
response returned using the result of the exchange processing.
Notice that the jetty continuations feature is only used "If the processing is indeed async".
This is why AsyncProcessor.process() implementations MUST accurately report if request is
completed synchronously or not.
The jhc component's producer allows you to make HTTP requests and implement the
AsyncProcessor interface. A route that uses both the jetty asynchronous consumer and the jhc
asynchronous producer will be a fully asynchronous route and has some nice attributes that can
be seen if we take a look at a sequence diagram of the processing route. For the route:
from("jetty:http://localhost:8080/service").to("jhc:http://localhost/service-impl");
The sequence diagram would look something like this:
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The diagram simplifies things by making it looks like processors implement the
AsyncCallback interface when in reality the AsyncCallback interfaces are inline inner classes, but
it illustrates the processing flow and shows how 2 separate threads are used to complete the
processing of the original http request. The first thread is synchronous up until processing hits
the jhc producer which issues the http request. It then reports that the exchange processing
will complete async since it will use a NIO to complete getting the response back. Once the jhc
component has received a full response it uses AsyncCallback.done() method to notify
the caller. These callback notifications continue up until it reaches the original jetty consumer
which then un-parks the http request and completes it by providing the response.
Mixing Synchronous and Asynchronous Processors
It is totally possible and reasonable to mix the use of synchronous and asynchronous
processors/components. The pipeline processor is the backbone of a Camel processing route. It
glues all the processing steps together. It is implemented as an AsyncProcessor and supports
interleaving synchronous and asynchronous processors as the processing steps in the pipeline.
Lets say we have 2 custom processors, MyValidator and MyTransformation, both of which
are synchronous processors. Lets say we want to load file from the data/in directory validate
them with the MyValidator() processor, Transform them into JPA java objects using
MyTransformation and then insert them into the database using the JPA component. Lets say
that the transformation process takes quite a bit of time and we want to allocate 20 threads to
do parallel transformations of the input files. The solution is to make use of the thread
processor. The thread is AsyncProcessor that forces subsequent processing in asynchronous
thread from a thread pool.
The route might look like:
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from("file:data/in").process(new MyValidator()).threads(20).process(new
MyTransformation()).to("jpa:PurchaseOrder");
The sequence diagram would look something like this:
You would actually have multiple threads executing the 2nd part of the thread sequence.
Staying synchronous in an AsyncProcessor
Generally speaking you get better throughput processing when you process things
synchronously. This is due to the fact that starting up an asynchronous thread and doing a
context switch to it adds a little bit of of overhead. So it is generally encouraged that
AsyncProcessors do as much work as they can synchronously. When they get to a step that
would block for a long time, at that point they should return from the process call and let the
caller know that it will be completing the call asynchronously.
IMPLEMENTING VIRTUAL TOPICS ON OTHER JMS
PROVIDERS
ActiveMQ supports Virtual Topics since durable topic subscriptions kinda suck (see this page
for more detail) mostly since they don't support Competing Consumers.
Most folks want Queue semantics when consuming messages; so that you can support
Competing Consumers for load balancing along with things like Message Groups and Exclusive
Consumers to preserve ordering or partition the queue across consumers.
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However if you are using another JMS provider you can implement Virtual Topics by
switching to ActiveMQ
or you can use the following Camel pattern.
First here's the ActiveMQ approach.
• send to activemq:topic:VirtualTopic.Orders
• for consumer A consume from activemq:Consumer.A.VirtualTopic.Orders
When using another message broker use the following pattern
• send to jms:Orders
• add this route with a to() for each logical durable topic subscriber
from("jms:Orders").to("jms:Consumer.A", "jms:Consumer.B", ...);
• for consumer A consume from jms:Consumer.A
WHAT'S THE CAMEL TRANSPORT FOR CXF
In CXF you offer or consume a webservice by defining it«s address. The first part of the
address specifies the protocol to use. For example address="http://localhost:90000" in an
endpoint configuration means your service will be offered using the http protocol on port 9000
of localhost. When you integrate Camel Tranport into CXF you get a new transport "camel".
So you can specify address="camel://direct:MyEndpointName" to bind the CXF service address
to a camel direct endpoint.
Technically speaking Camel transport for CXF is a component which implements the CXF
transport API with the Camel core library. This allows you to use camel«s routing engine and
integration patterns support smoothly together with your CXF services.
INTEGRATE CAMEL INTO CXF TRANSPORT LAYER
To include the Camel Tranport into your CXF bus you use the CamelTransportFactory. You
can do this in Java as well as in Spring.
Setting up the Camel Transport in Spring
You can use the following snippet in your applicationcontext if you want to configure anything
special. If you only want to activate the camel transport you do not have to do anything in your
application context. As soon as you include the camel-cxf jar in your app cxf will scan the jar
and load a CamelTransportFactory for you.
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http://cxf.apache.org/transports/camel
Integrating the Camel Transport in a programmatic way
Camel transport provides a setContext method that you could use to set the Camel context
into the transport factory. If you want this factory take effect, you need to register the factory
into the CXF bus. Here is a full example for you.
import
import
import
import
...
org.apache.cxf.Bus;
org.apache.cxf.BusFactory;
org.apache.cxf.transport.ConduitInitiatorManager;
org.apache.cxf.transport.DestinationFactoryManager;
BusFactory bf = BusFactory.newInstance();
Bus bus = bf.createBus();
CamelTransportFactory camelTransportFactory = new CamelTransportFactory();
camelTransportFactory.setCamelContext(context)
// register the conduit initiator
ConduitInitiatorManager cim = bus.getExtension(ConduitInitiatorManager.class);
cim.registerConduitInitiator(CamelTransportFactory.TRANSPORT_ID,
camelTransportFactory);
// register the destination factory
DestinationFactoryManager dfm = bus.getExtension(DestinationFactoryManager.class);
dfm.registerDestinationFactory(CamelTransportFactory.TRANSPORT_ID,
camelTransportFactory);
// set or bus as the default bus for cxf
BusFactory.setDefaultBus(bus);
CONFIGURE THE DESTINATION AND CONDUIT
Namespace
The elements used to configure an Camel transport endpoint are defined in the namespace
http://cxf.apache.org/transports/camel. It is commonly referred to using the
prefix camel. In order to use the Camel transport configuration elements you will need to add
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the lines shown below to the beans element of your endpoint's configuration file. In addition,
you will need to add the configuration elements' namespace to the xsi:schemaLocation
attribute.
Listing 14. Adding the Configuration Namespace
The destination element
You configure an Camel transport server endpoint using the camel:destination element
and its children. The camel:destination element takes a single attribute, name, the
specifies the WSDL port element that corresponds to the endpoint. The value for the name
attribute takes the form portQName.camel-destination. The example below shows the
camel:destination element that would be used to add configuration for an endpoint that
was specified by the WSDL fragment
...
The camel:destination element has a number of child elements that specify configuration
information. They are described below.
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Element
Description
camelspring:camelContext
You can specify the camel context in the camel destination
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camel:camelContextRef
The camel context id which you want inject into the camel
destination
The conduit element
You configure an Camel transport client using the camel:conduit element and its children.
The camel:conduit element takes a single attribute, name, that specifies the WSDL port
element that corresponds to the endpoint. The value for the name attribute takes the form
portQName.camel-conduit. For example, the code below shows the camel:conduit
element that would be used to add configuration for an endpoint that was specified by the
WSDL fragment conduit_context
...
...
The camel:conduit element has a number of child elements that specify configuration
information. They are described below.
Element
Description
camelspring:camelContext
You can specify the camel context in the camel conduit
camel:camelContextRef
The camel context id which you want inject into the
camel conduit
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EXAMPLE USING CAMEL AS A LOAD BALANCER FOR CXF
This example show how to use the camel load balance feature in CXF, and you need load the
configuration file in CXF and publish the endpoints on the address "camel://direct:EndpointA"
and "camel://direct:EndpointB"
dest_context
COMPLETE HOWTO AND EXAMPLE FOR ATTACHING
CAMEL TO CXF
Better JMS Transport for CXF Webservice using Apache CamelÊ
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INTRODUCTION
When sending an Exchange to an Endpoint you can either use a Route or a ProducerTemplate.
This works fine in many scenarios. However you may need to guarantee that an exchange is
delivered to the same endpoint that you delivered a previous exchange on. For example in the
case of delivering a batch of exchanges to a MINA socket you may need to ensure that they are
all delivered through the same socket connection. Furthermore once the batch of exchanges
have been delivered the protocol requirements may be such that you are responsible for
closing the socket.
USING A PRODUCER
To achieve fine grained control over sending exchanges you will need to program directly to a
Producer. Your code will look similar to:
CamelContext camelContext = ...
// Obtain an endpoint and create the producer we will be using.
Endpoint endpoint = camelContext.getEndpoint("someuri:etc");
Producer producer = endpoint.createProducer();
producer.start();
try {
// For each message to send...
Object requestMessage = ...
Exchange exchangeToSend = producer.createExchange();
exchangeToSend().setBody(requestMessage);
producer.process(exchangeToSend);
...
} finally {
// Tidy the producer up.
producer.stop();
}
In the case of using Apache MINA the producer.stop() invocation will cause the socket to be
closed.
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Tutorials
There now follows the documentation on camel tutorials
• OAuth Tutorial
This tutorial demonstrates how to implement OAuth for a web application with
Camel's gauth component. The sample application of this tutorial is also online at
http://gauthcloud.appspot.com/
• Tutorial for Camel on Google App Engine
This tutorial demonstrates the usage of the Camel Components for Google App
Engine. The sample application of this tutorial is also online at
http://camelcloud.appspot.com/
• Tutorial on Spring Remoting with JMS
This tutorial is focused on different techniques with Camel for Client-Server
communication.
• Report Incident - This tutorial introduces Camel steadily and is based on a real life
integration problem
This is a very long tutorial beginning from the start; its for entry level to Camel. Its
based on a real life integration, showing how Camel can be introduced in an existing
solution. We do this in baby steps. The tutorial is currently work in progress, so
check it out from time to time. The tutorial explains some of the inner building blocks
Camel uses under the covers. This is good knowledge to have when you start using
Camel on a higher abstract level where it can do wonders in a few lines of routing
DSL.
• Using Camel with ServiceMix a tutorial on using Camel inside Apache ServiceMix.
• Better JMS Transport for CXF Webservice using Apache Camel Describes how to
use the Camel Transport for CXF to attach a CXF Webservice to a JMS Queue
• Tutorial how to use good old Axis 1.4 with Camel
This tutorial shows that Camel does work with the good old frameworks such as
AXIS that is/was widely used for WebService.
• Tutorial on using Camel in a Web Application
This tutorial gives an overview of how to use Camel inside Tomcat, Jetty or any other
servlet engine
• Tutorial on Camel 1.4 for Integration
Another real-life scenario. The company sells widgets, with a somewhat unique
business process (their customers periodically report what they've purchased in order
to get billed). However every customer uses a different data format and protocol.
This tutorial goes through the process of integrating (and testing!) several customers
and their electronic reporting of the widgets they've bought, along with the company's
response.
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• Tutorial how to build a Service Oriented Architecture using Camel with OSGI Updated 20/11/2009
The tutorial has been designed in two parts. The first part introduces basic concept to
create a simple SOA solution using Camel and OSGI and deploy it in a OSGI Server
like Apache Felix Karaf and Spring DM Server while the second extends the
ReportIncident tutorial part 4 to show How we can separate the different layers
(domain, service, ...) of an application and deploy them in separate bundles. The Web
Application has also be modified in order to communicate to the OSGI bundles.
• Several of the vendors on the Commercial Camel Offerings page also offer various
tutorials, webinars, examples, etc.... that may be useful.
• Examples
While not actual tutorials you might find working through the source of the various
Examples useful.
TUTORIAL ON SPRING REMOTING WITH JMS
Ê
PREFACE
This tutorial aims to guide the reader through the stages of creating a project which uses Camel
to facilitate the routing of messages from a JMS queue to a Spring service. The route works in a
synchronous fashion returning a response to the client.
• Tutorial on Spring Remoting with JMS
• Preface
• Prerequisites
• Distribution
• About
• Create the Camel Project
• Update the POM with Dependencies
• Writing the Server
• Create the Spring Service
• Define the Camel Routes
• Configure Spring
• Run the Server
• Writing The Clients
• Client Using The ProducerTemplate
• Client Using Spring Remoting
• Client Using Message Endpoint EIP Pattern
• Run the Clients
• Using the Camel Maven Plugin
• Using Camel JMX
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Thanks
This tutorial was kindly donated to Apache Camel by Martin Gilday.
• See Also
PREREQUISITES
This tutorial uses Maven to setup the Camel project and for dependencies for artifacts.
DISTRIBUTION
This sample is distributed with the Camel distribution as examples/camel-examplespring-jms.
ABOUT
This tutorial is a simple example that demonstrates more the fact how well Camel is seamless
integrated with Spring to leverage the best of both worlds. This sample is client server solution
using JMS messaging as the transport. The sample has two flavors of servers and also for clients
demonstrating different techniques for easy communication.
The Server is a JMS message broker that routes incoming messages to a business service that
does computations on the received message and returns a response.
The EIP patterns used in this sample are:
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Pattern
Description
Message
Channel
We need a channel so the Clients can communicate with the server.
Message
The information is exchanged using the Camel Message interface.
Message
Translator
This is where Camel shines as the message exchange between the Server and
the Clients are text based strings with numbers. However our business service
uses int for numbers. So Camel can do the message translation automatically.
Message
Endpoint
It should be easy to send messages to the Server from the the clients. This is
archived with Camels powerful Endpoint pattern that even can be more
powerful combined with Spring remoting. The tutorial have clients using each
kind of technique for this.
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Point to
Point
Channel
We using JMS queues so there are only one receive of the message exchange
Event
Driven
Consumer
Yes the JMS broker is of course event driven and only reacts when the client
sends a message to the server.
We use the following Camel components:
Component
Description
ActiveMQ
We use Apache ActiveMQ as the JMS broker on the Server side
Bean
We use the bean binding to easily route the messages to our business
service. This is a very powerful component in Camel.
File
In the AOP enabled Server we store audit trails as files.
JMS
Used for the JMS messaging
CREATE THE CAMEL PROJECT
mvn archetype:create -DgroupId=org.example -DartifactId=CamelWithJmsAndSpring
Update the POM with Dependencies
First we need to have dependencies for the core Camel jars, its spring, jms components and
finally ActiveMQ as the message broker.
org.apache.camelcamel-coreorg.apache.camelcamel-jmsorg.apache.camelcamel-springorg.apache.activemqactivemq-camel
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For the purposes of the tutorial a single Maven project will be used for both the
client and server. Ideally you would break your application down into the
appropriate components.
As we use spring xml configuration for the ActiveMQ JMS broker we need this dependency:
org.apache.xbeanxbean-spring
WRITING THE SERVER
Create the Spring Service
For this example the Spring service (= our business service) on the server will be a simple
multiplier which trebles in the received value.
public interface Multiplier {
/**
* Multiplies the given number by a pre-defined constant.
*
* @param originalNumber The number to be multiplied
* @return The result of the multiplication
*/
int multiply(int originalNumber);
}
And the implementation of this service is:
@Service(value = "multiplier")
public class Treble implements Multiplier {
public int multiply(final int originalNumber) {
return originalNumber * 3;
}
}
Notice that this class has been annotated with the @Service spring annotation. This ensures
that this class is registered as a bean in the registry with the given name multiplier.
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Define the Camel Routes
public class ServerRoutes extends RouteBuilder {
@Override
public void configure() throws Exception {
// route from the numbers queue to our business that is a spring bean
registered with the id=multiplier
// Camel will introspect the multiplier bean and find the best candidate of
the method to invoke.
// You can add annotations etc to help Camel find the method to invoke.
// As our multiplier bean only have one method its easy for Camel to find the
method to use.
from("jms:queue:numbers").to("multiplier");
// Camel has several ways to configure the same routing, we have defined some
of them here below
// as above but with the bean: prefix
//from("jms:queue:numbers").to("bean:multiplier");
// beanRef is using explicit bean bindings to lookup the multiplier bean and
invoke the multiply method
//from("jms:queue:numbers").beanRef("multiplier", "multiply");
// the same as above but expressed as a URI configuration
//from("jms:queue:numbers").to("bean:multiplier?methodName=multiply");
}
}
This defines a Camel route from the JMS queue named numbers to the Spring bean named
multiplier. Camel will create a consumer to the JMS queue which forwards all received
messages onto the the Spring bean, using the method named multiply.
Configure Spring
The Spring config file is placed under META-INF/spring as this is the default location used
by the Camel Maven Plugin, which we will later use to run our server.
First we need to do the standard scheme declarations in the top. In the camel-server.xml we
are using spring beans as the default bean: namespace and springs context:. For configuring
ActiveMQ we use broker: and for Camel we of course have camel:. Notice that we don't
use version numbers for the camel-spring schema. At runtime the schema is resolved in the
Camel bundle. If we use a specific version number such as 1.4 then its IDE friendly as it would
be able to import it and provide smart completion etc. See Xml Reference for further details.
We use Spring annotations for doing IoC dependencies and its component-scan features comes
to the rescue as it scans for spring annotations in the given package name:
Camel will of course not be less than Spring in this regard so it supports a similar feature for
scanning of Routes. This is configured as shown below.
Notice that we also have enabled the JMXAgent so we will be able to introspect the Camel
Server with a JMX Console.
org.apache.camel.example.server
The ActiveMQ JMS broker is also configured in this xml file. We set it up to listen on TCP port
61610.
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As this examples uses JMS then Camel needs a JMS component that is connected with the
ActiveMQ broker. This is configured as shown below:
Notice: The JMS component is configured in standard Spring beans, but the gem is that the
bean id can be referenced from Camel routes - meaning we can do routing using the JMS
Component by just using jms: prefix in the route URI. What happens is that Camel will find in
the Spring Registry for a bean with the id="jms". Since the bean id can have arbitrary name you
could have named it id="jmsbroker" and then referenced to it in the routing as
from="jmsbroker:queue:numbers).to("multiplier");
We use the vm protocol to connect to the ActiveMQ server as its embedded in this
application.
componentscan
Defines the package to be scanned for Spring stereotype annotations, in this
case, to load the "multiplier" bean
camelcontext
Defines the package to be scanned for Camel routes. Will find the
ServerRoutes class and create the routes contained within it
jms bean
Creates the Camel JMS component
Run the Server
The Server is started using the org.apache.camel.spring.Main class that can start
camel-spring application out-of-the-box. The Server can be started in several flavors:
▪ as a standard java main application - just start the
org.apache.camel.spring.Main class
▪ using maven jave:exec
▪ using camel:run
In this sample as there are two servers (with and without AOP) we have prepared some
profiles in maven to start the Server of your choice.
The server is started with:
mvn compile exec:java -PCamelServer
WRITING THE CLIENTS
This sample has three clients demonstrating different Camel techniques for communication
▪ CamelClient using the ProducerTemplate for Spring template style coding
▪ CamelRemoting using Spring Remoting
▪ CamelEndpoint using the Message Endpoint EIP pattern using a neutral Camel API
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Client Using The ProducerTemplate
We will initially create a client by directly using ProducerTemplate. We will later create a
client which uses Spring remoting to hide the fact that messaging is being used.
The client will not use the Camel Maven Plugin so the Spring XML has been placed in src/main/
resources to not conflict with the server configs.
camelContext
The Camel context is defined but does not contain any routes
template
The ProducerTemplate is used to place messages onto the JMS queue
jms bean
This initialises the Camel JMS component, allowing us to place messages
onto the queue
And the CamelClient source code:
public static void main(final String[] args) throws Exception {
System.out.println("Notice this client requires that the CamelServer is already
running!");
ApplicationContext context = new
ClassPathXmlApplicationContext("camel-client.xml");
// get the camel template for Spring template style sending of messages (=
producer)
ProducerTemplate camelTemplate = context.getBean("camelTemplate",
ProducerTemplate.class);
System.out.println("Invoking the multiply with 22");
// as opposed to the CamelClientRemoting example we need to define the service URI
in this java code
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int response = (Integer)camelTemplate.sendBody("jms:queue:numbers",
ExchangePattern.InOut, 22);
System.out.println("... the result is: " + response);
System.exit(0);
}
The ProducerTemplate is retrieved from a Spring ApplicationContext and used to
manually place a message on the "numbers" JMS queue. The requestBody method will use
the exchange pattern InOut, which states that the call should be synchronous, and that the
caller expects a response.
Before running the client be sure that both the ActiveMQ broker and the CamelServer
are running.
Client Using Spring Remoting
Spring Remoting "eases the development of remote-enabled services". It does this by allowing
you to invoke remote services through your regular Java interface, masking that a remote
service is being called.
The snippet above only illustrates the different and how Camel easily can setup and use Spring
Remoting in one line configurations.
The proxy will create a proxy service bean for you to use to make the remote invocations.
The serviceInterface property details which Java interface is to be implemented by the
proxy. serviceUrl defines where messages sent to this proxy bean will be directed. Here we
define the JMS endpoint with the "numbers" queue we used when working with Camel template
directly. The value of the id property is the name that will be the given to the bean when it is
exposed through the Spring ApplicationContext. We will use this name to retrieve the
service in our client. I have named the bean multiplierProxy simply to highlight that it is not the
same multiplier bean as is being used by CamelServer. They are in completely independent
contexts and have no knowledge of each other. As you are trying to mask the fact that
remoting is being used in a real application you would generally not include proxy in the name.
And the Java client source code:
public static void main(final String[] args) {
System.out.println("Notice this client requires that the CamelServer is already
running!");
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ApplicationContext context = new
ClassPathXmlApplicationContext("camel-client-remoting.xml");
// just get the proxy to the service and we as the client can use the "proxy" as
it was
// a local object we are invoking. Camel will under the covers do the remote
communication
// to the remote ActiveMQ server and fetch the response.
Multiplier multiplier = context.getBean("multiplierProxy", Multiplier.class);
System.out.println("Invoking the multiply with 33");
int response = multiplier.multiply(33);
System.out.println("... the result is: " + response);
System.exit(0);
}
Again, the client is similar to the original client, but with some important differences.
1. The Spring context is created with the new camel-client-remoting.xml
2. We retrieve the proxy bean instead of a ProducerTemplate. In a non-trivial
example you would have the bean injected as in the standard Spring manner.
3. The multiply method is then called directly. In the client we are now working to an
interface. There is no mention of Camel or JMS inside our Java code.
Client Using Message Endpoint EIP Pattern
This client uses the Message Endpoint EIP pattern to hide the complexity to communicate to
the Server. The Client uses the same simple API to get hold of the endpoint, create an
exchange that holds the message, set the payload and create a producer that does the send and
receive. All done using the same neutral Camel API for all the components in Camel. So if the
communication was socket TCP based you just get hold of a different endpoint and all the java
code stays the same. That is really powerful.
Okay enough talk, show me the code!
public static void main(final String[] args) throws Exception {
System.out.println("Notice this client requires that the CamelServer is already
running!");
ApplicationContext context = new
ClassPathXmlApplicationContext("camel-client.xml");
CamelContext camel = context.getBean("camel-client", CamelContext.class);
// get the endpoint from the camel context
Endpoint endpoint = camel.getEndpoint("jms:queue:numbers");
// create the exchange used for the communication
// we use the in out pattern for a synchronized exchange where we expect a response
Exchange exchange = endpoint.createExchange(ExchangePattern.InOut);
// set the input on the in body
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TU TO RI A L S
// must you correct type to match the expected type of an Integer object
exchange.getIn().setBody(11);
// to send the exchange we need an producer to do it for us
Producer producer = endpoint.createProducer();
// start the producer so it can operate
producer.start();
// let the producer process the exchange where it does all the work in this
oneline of code
System.out.println("Invoking the multiply with 11");
producer.process(exchange);
// get the response from the out body and cast it to an integer
int response = exchange.getOut().getBody(Integer.class);
System.out.println("... the result is: " + response);
// stop and exit the client
producer.stop();
System.exit(0);
}
Switching to a different component is just a matter of using the correct endpoint. So if we had
defined a TCP endpoint as: "mina:tcp://localhost:61610" then its just a matter of
getting hold of this endpoint instead of the JMS and all the rest of the java code is exactly the
same.
Run the Clients
The Clients is started using their main class respectively.
▪ as a standard java main application - just start their main class
▪ using maven jave:exec
In this sample we start the clients using maven:
mvn compile exec:java -PCamelClient
mvn compile exec:java -PCamelClientRemoting
mvn compile exec:java -PCamelClientEndpoint
Also see the Maven pom.xml file how the profiles for the clients is defined.
USING THE CAMEL MAVEN PLUGIN
The Camel Maven Plugin allows you to run your Camel routes directly from Maven. This
negates the need to create a host application, as we did with Camel server, simply to start up
the container. This can be very useful during development to get Camel routes running quickly.
Listing 17. pom.xml
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org.apache.camelcamel-maven-plugin
All that is required is a new plugin definition in your Maven POM. As we have already placed
our Camel config in the default location (camel-server.xml has been placed in META-INF/
spring/) we do not need to tell the plugin where the route definitions are located. Simply run
mvn camel:run.
USING CAMEL JMX
Camel has extensive support for JMX and allows us to inspect the Camel Server at runtime. As
we have enabled the JMXAgent in our tutorial we can fire up the jconsole and connect to the
following service URI: service:jmx:rmi:///jndi/rmi://localhost:1099/
jmxrmi/camel. Notice that Camel will log at INFO level the JMX Connector URI:
...
DefaultInstrumentationAgent
INFO JMX connector thread started on
service:jmx:rmi:///jndi/rmi://claus-acer:1099/jmxrmi/camel
...
In the screenshot below we can see the route and its performance metrics:
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SEE ALSO
• Spring Remoting with JMS Example on Amin Abbaspour's Weblog
TUTORIAL - CAMEL-EXAMPLE-REPORTINCIDENT
INTRODUCTION
Creating this tutorial was inspired by a real life use-case I discussed over the phone with a
colleague. He was working at a client whom uses a heavy-weight integration platform from a
very large vendor. He was in talks with developer shops to implement a new integration on this
platform. His trouble was the shop tripled the price when they realized the platform of choice.
So I was wondering how we could do this integration with Camel. Can it be done, without
tripling the cost
.
This tutorial is written during the development of the integration. I have decided to start off
with a sample that isn't Camel's but standard Java and then plugin Camel as we goes. Just as
when people needed to learn Spring you could consume it piece by piece, the same goes with
Camel.
The target reader is person whom hasn't experience or just started using Camel.
MOTIVATION FOR THIS TUTORIAL
I wrote this tutorial motivated as Camel lacked an example application that was based on the
web application deployment model. The entire world hasn't moved to pure OSGi deployments
yet.
THE USE-CASE
The goal is to allow staff to report incidents into a central administration. For that they use
client software where they report the incident and submit it to the central administration. As
this is an integration in a transition phase the administration should get these incidents by email
whereas they are manually added to the database. The client software should gather the
incident and submit the information to the integration platform that in term will transform the
report into an email and send it to the central administrator for manual processing.
The figure below illustrates this process. The end users reports the incidents using the client
applications. The incident is sent to the central integration platform as webservice. The
integration platform will process the incident and send an OK acknowledgment back to the
client. Then the integration will transform the message to an email and send it to the
administration mail server. The users in the administration will receive the emails and take it
from there.
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In EIP patterns
We distill the use case as EIP patterns:
PARTS
This tutorial is divided into sections and parts:
Section A: Existing Solution, how to slowly use Camel
Part 1 - This first part explain how to setup the project and get a webservice exposed using
Apache CXF. In fact we don't touch Camel yet.
Part 2 - Now we are ready to introduce Camel piece by piece (without using Spring or any
XML configuration file) and create the full feature integration. This part will introduce different
Camel's concepts and How we can build our solution using them like :
▪ CamelContext
▪ Endpoint, Exchange & Producer
▪ Components : Log, File
Part 3 - Continued from part 2 where we implement that last part of the solution with the
event driven consumer and how to send the email through the Mail component.
Section B: The Camel Solution
Part 4 - We now turn into the path of Camel where it excels - the routing.
Part 5 - Is about how embed Camel with Spring and using CXF endpoints directly in Camel
LINKS
▪ Introduction
▪ Part 1
▪ Part 2
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Using Axis 2
See this blog entry by Sagara demonstrating how to use Apache Axis 2 instead of
Apache CXF as the web service framework.
▪ Part 3
▪ Part 4
▪ Part 5
PART 1
PREREQUISITES
This tutorial uses the following frameworks:
• Maven 2.0.9
• Apache Camel 1.4.0
• Apache CXF 2.1.1
• Spring 2.5.5
Note: The sample project can be downloaded, see the resources section.
INITIAL PROJECT SETUP
We want the integration to be a standard .war application that can be deployed in any web
container such as Tomcat, Jetty or even heavy weight application servers such as WebLogic or
WebSphere. There fore we start off with the standard Maven webapp project that is created
with the following long archetype command:
mvn archetype:create -DgroupId=org.apache.camel
-DartifactId=camel-example-reportincident -DarchetypeArtifactId=maven-archetype-webapp
Notice that the groupId etc. doens't have to be org.apache.camel it can be
com.mycompany.whatever. But I have used these package names as the example is an official
part of the Camel distribution.
Then we have the basic maven folder layout. We start out with the webservice part where
we want to use Apache CXF for the webservice stuff. So we add this to the pom.xml
2.1.1
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org.apache.cxfcxf-rt-core${cxf-version}org.apache.cxfcxf-rt-frontend-jaxws${cxf-version}org.apache.cxfcxf-rt-transports-http${cxf-version}
DEVELOPING THE WEBSERVICE
As we want to develop webservice with the contract first approach we create our .wsdl file. As
this is a example we have simplified the model of the incident to only include 8 fields. In real life
the model would be a bit more complex, but not to much.
We put the wsdl file in the folder src/main/webapp/WEB-INF/wsdl and name the
file report_incident.wsdl.
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CXF wsdl2java
Then we integration the CXF wsdl2java generator in the pom.xml so we have CXF generate
the needed POJO classes for our webservice contract.
However at first we must configure maven to live in the modern world of Java 1.5 so we must
add this to the pom.xml
org.apache.maven.pluginsmaven-compiler-plugin1.51.5
And then we can add the CXF wsdl2java code generator that will hook into the compile goal so
its automatic run all the time:
org.apache.cxfcxf-codegen-plugin${cxf-version}generate-sourcesgenerate-sources${basedir}/target/
generated/src/main/java${basedir}/src/main/webapp/WEB-INF/wsdl/report_incident.wsdl
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wsdl2java
You are now setup and should be able to compile the project. So running the mvn compile
should run the CXF wsdl2java and generate the source code in the folder &{basedir}/
target/generated/src/main/java that we specified in the pom.xml above. Since its in
the target/generated/src/main/java maven will pick it up and include it in the build
process.
Configuration of the web.xml
Next up is to configure the web.xml to be ready to use CXF so we can expose the webservice.
As Spring is the center of the universe, or at least is a very important framework in today's Java
land we start with the listener that kick-starts Spring. This is the usual piece of code:
org.springframework.web.context.ContextLoaderListener
And then we have the CXF part where we define the CXF servlet and its URI mappings to
which we have chosen that all our webservices should be in the path /webservices/
CXFServletorg.apache.cxf.transport.servlet.CXFServlet1CXFServlet/webservices/*
Then the last piece of the puzzle is to configure CXF, this is done in a spring XML that we link
to fron the web.xml by the standard Spring contextConfigLocation property in the
web.xml
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contextConfigLocationclasspath:cxf-config.xml
We have named our CXF configuration file cxf-config.xml and its located in the root of
the classpath. In Maven land that is we can have the cxf-config.xml file in the src/
main/resources folder. We could also have the file located in the WEB-INF folder for
instance /WEB-INF/cxf-config.xml.
Getting rid of the old jsp world
The maven archetype that created the basic folder structure also created a sample .jsp file
index.jsp. This file src/main/webapp/index.jsp should be deleted.
Configuration of CXF
The cxf-config.xml is as follows:
The configuration is standard CXF and is documented at the Apache CXF website.
The 3 import elements is needed by CXF and they must be in the file.
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Noticed that we have a spring bean reportIncidentEndpoint that is the implementation
of the webservice endpoint we let CXF expose.
Its linked from the jaxws element with the implementator attribute as we use the # mark to
identify its a reference to a spring bean. We could have stated the classname directly as
implementor="org.apache.camel.example.reportincident.ReportIncidentEndpoint
but then we lose the ability to let the ReportIncidentEndpoint be configured by spring.
The address attribute defines the relative part of the URL of the exposed webservice.
wsdlLocation is an optional parameter but for persons like me that likes contract-first we
want to expose our own .wsdl contracts and not the auto generated by the frameworks, so
with this attribute we can link to the real .wsdl file. The last stuff is needed by CXF as you could
have several services so it needs to know which this one is. Configuring these is quite easy as all
the information is in the wsdl already.
Implementing the ReportIncidentEndpoint
Phew after all these meta files its time for some java code so we should code the implementor
of the webservice. So we fire up mvn compile to let CXF generate the POJO classes for our
webservice and we are ready to fire up a Java editor.
You can use mvn idea:idea or mvn eclipse:eclipse to create project files for
these editors so you can load the project. However IDEA has been smarter lately and can load
a pom.xml directly.
As we want to quickly see our webservice we implement just a quick and dirty as it can get.
At first beware that since its jaxws and Java 1.5 we get annotations for the money, but they
reside on the interface so we can remove them from our implementations so its a nice plain
POJO again:
package org.apache.camel.example.reportincident;
/**
* The webservice we have implemented.
*/
public class ReportIncidentEndpointImpl implements ReportIncidentEndpoint {
public OutputReportIncident reportIncident(InputReportIncident parameters) {
System.out.println("Hello ReportIncidentEndpointImpl is called from " +
parameters.getGivenName());
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
}
We just output the person that invokes this webservice and returns a OK response. This class
should be in the maven source root folder src/main/java under the package name
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org.apache.camel.example.reportincident. Beware that the maven archetype
tool didn't create the src/main/java folder, so you should create it manually.
To test if we are home free we run mvn clean compile.
Running our webservice
Now that the code compiles we would like to run it in a web container, so we add jetty to our
pom.xml so we can run mvn jetty:run:
...
6.1.1
...
org.mortbay.jettymaven-jetty-plugin${jetty-version}
Notice: We use Jetty v6.1.1 as never versions has troubles on my laptop. Feel free to try a
newer version on your system, but v6.1.1 works flawless.
So to see if everything is in order we fire up jetty with mvn jetty:run and if everything
is okay you should be able to access http://localhost:8080.
Jetty is smart that it will list the correct URI on the page to our web application, so just click on
the link. This is smart as you don't have to remember the exact web context URI for your
application - just fire up the default page and Jetty will help you.
So where is the damn webservice then? Well as we did configure the web.xml to instruct
the CXF servlet to accept the pattern /webservices/* we should hit this URL to get the
attention of CXF: http://localhost:8080/camel-example-reportincident/
webservices.
Ê
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TU TO RI A L S
Hitting the webservice
Now we have the webservice running in a standard .war application in a standard web container
such as Jetty we would like to invoke the webservice and see if we get our code executed.
Unfortunately this isn't the easiest task in the world - its not so easy as a REST URL, so we
need tools for this. So we fire up our trusty webservice tool SoapUI and let it be the one to fire
the webservice request and see the response.
Using SoapUI we sent a request to our webservice and we got the expected OK response
and the console outputs the System.out so we are ready to code.
Ê
Remote Debugging
Okay a little sidestep but wouldn't it be cool to be able to debug your code when its fired up
under Jetty? As Jetty is started from maven, we need to instruct maven to use debug mode.
Se we set the MAVEN_OPTS environment to start in debug mode and listen on port 5005.
MAVEN_OPTS=-Xmx512m -XX:MaxPermSize=128m -Xdebug
-Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005
Then you need to restart Jetty so its stopped with ctrl + c. Remember to start a new shell to
pickup the new environment settings. And start jetty again.
Then we can from our IDE attach a remote debugger and debug as we want.
First we configure IDEA to attach to a remote debugger on port 5005:
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Ê
Then we set a breakpoint in our code ReportIncidentEndpoint and hit the SoapUI
once again and we are breaked at the breakpoint where we can inspect the parameters:
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Ê
Adding a unit test
Oh so much hard work just to hit a webservice, why can't we just use an unit test to invoke
our webservice? Yes of course we can do this, and that's the next step.
First we create the folder structure src/test/java and src/test/resources. We
then create the unit test in the src/test/java folder.
package org.apache.camel.example.reportincident;
import junit.framework.TestCase;
/**
* Plain JUnit test of our webservice.
*/
public class ReportIncidentEndpointTest extends TestCase {
}
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Here we have a plain old JUnit class. As we want to test webservices we need to start and
expose our webservice in the unit test before we can test it. And JAXWS has pretty decent
methods to help us here, the code is simple as:
import javax.xml.ws.Endpoint;
...
private static String ADDRESS = "http://localhost:9090/unittest";
protected void startServer() throws Exception {
// We need to start a server that exposes or webservice during the unit testing
// We use jaxws to do this pretty simple
ReportIncidentEndpointImpl server = new ReportIncidentEndpointImpl();
Endpoint.publish(ADDRESS, server);
}
The Endpoint class is the javax.xml.ws.Endpoint that under the covers looks for a
provider and in our case its CXF - so its CXF that does the heavy lifting of exposing out
webservice on the given URL address. Since our class ReportIncidentEndpointImpl implements
the interface ReportIncidentEndpoint that is decorated with all the jaxws annotations it
got all the information it need to expose the webservice. Below is the CXF wsdl2java generated
interface:
/*
*
*/
package org.apache.camel.example.reportincident;
import
import
import
import
import
import
import
javax.jws.WebMethod;
javax.jws.WebParam;
javax.jws.WebResult;
javax.jws.WebService;
javax.jws.soap.SOAPBinding;
javax.jws.soap.SOAPBinding.ParameterStyle;
javax.xml.bind.annotation.XmlSeeAlso;
/**
* This class was generated by Apache CXF 2.1.1
* Wed Jul 16 12:40:31 CEST 2008
* Generated source version: 2.1.1
*
*/
/*
*
*/
@WebService(targetNamespace = "http://reportincident.example.camel.apache.org", name =
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"ReportIncidentEndpoint")
@XmlSeeAlso({ObjectFactory.class})
@SOAPBinding(parameterStyle = SOAPBinding.ParameterStyle.BARE)
public interface ReportIncidentEndpoint {
/*
*
*/
@SOAPBinding(parameterStyle = SOAPBinding.ParameterStyle.BARE)
@WebResult(name = "outputReportIncident", targetNamespace =
"http://reportincident.example.camel.apache.org", partName = "parameters")
@WebMethod(operationName = "ReportIncident", action =
"http://reportincident.example.camel.apache.org/ReportIncident")
public OutputReportIncident reportIncident(
@WebParam(partName = "parameters", name = "inputReportIncident",
targetNamespace = "http://reportincident.example.camel.apache.org")
InputReportIncident parameters
);
}
Next up is to create a webservice client so we can invoke our webservice. For this we actually
use the CXF framework directly as its a bit more easier to create a client using this framework
than using the JAXWS style. We could have done the same for the server part, and you should
do this if you need more power and access more advanced features.
import org.apache.cxf.jaxws.JaxWsProxyFactoryBean;
...
protected ReportIncidentEndpoint createCXFClient() {
// we use CXF to create a client for us as its easier than JAXWS and works
JaxWsProxyFactoryBean factory = new JaxWsProxyFactoryBean();
factory.setServiceClass(ReportIncidentEndpoint.class);
factory.setAddress(ADDRESS);
return (ReportIncidentEndpoint) factory.create();
}
So now we are ready for creating a unit test. We have the server and the client. So we just
create a plain simple unit test method as the usual junit style:
public void testRendportIncident() throws Exception {
startServer();
ReportIncidentEndpoint client = createCXFClient();
InputReportIncident input = new InputReportIncident();
input.setIncidentId("123");
input.setIncidentDate("2008-07-16");
input.setGivenName("Claus");
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input.setFamilyName("Ibsen");
input.setSummary("bla bla");
input.setDetails("more bla bla");
input.setEmail("davsclaus@apache.org");
input.setPhone("+45 2962 7576");
OutputReportIncident out = client.reportIncident(input);
assertEquals("Response code is wrong", "OK", out.getCode());
}
Now we are nearly there. But if you run the unit test with mvn test then it will fail. Why!!!
Well its because that CXF needs is missing some dependencies during unit testing. In fact it
needs the web container, so we need to add this to our pom.xml.
org.apache.cxfcxf-rt-transports-http-jetty${cxf-version}test
Well what is that, CXF also uses Jetty for unit test - well its just shows how agile, embedable
and popular Jetty is.
So lets run our junit test with, and it reports:
mvn test
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] BUILD SUCCESSFUL
Yep thats it for now. We have a basic project setup.
END OF PART 1
Thanks for being patient and reading all this more or less standard Maven, Spring, JAXWS and
Apache CXF stuff. Its stuff that is well covered on the net, but I wanted a full fledged tutorial on
a maven project setup that is web service ready with Apache CXF. We will use this as a base
for the next part where we demonstrate how Camel can be digested slowly and piece by piece
just as it was back in the times when was introduced and was learning the Spring framework
that we take for granted today.
RESOURCES
• Apache CXF user guide
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Name
Size
Creator
Creation
Date
Comment
ZIP Archive
tutorial_reportincident_partone.zi...
14
kB
Claus
Ibsen
Jul 17,
2008
23:34
Ê
Ê
◦ Properti
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LINKS
▪
▪
▪
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▪
▪
Introduction
Part 1
Part 2
Part 3
Part 4
Part 5
PART 2
ADDING CAMEL
In this part we will introduce Camel so we start by adding Camel to our pom.xml:
...
1.4.0org.apache.camelcamel-core${camel-version}
That's it, only one dependency for now.
Now we turn towards our webservice endpoint implementation where we want to let Camel
have a go at the input we receive. As Camel is very non invasive its basically a .jar file then we
can just grap Camel but creating a new instance of DefaultCamelContext that is the
hearth of Camel its context.
CamelContext camel = new DefaultCamelContext();
In fact we create a constructor in our webservice and add this code:
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Synchronize IDE
If you continue from part 1, remember to update your editor project settings since
we have introduce new .jar files. For instance IDEA has a feature to synchronize
with Maven projects.
private CamelContext camel;
public ReportIncidentEndpointImpl() throws Exception {
// create the camel context that is the "heart" of Camel
camel = new DefaultCamelContext();
// add the log component
camel.addComponent("log", new LogComponent());
// start Camel
camel.start();
}
LOGGING THE "HELLO WORLD"
Here at first we want Camel to log the givenName and familyName parameters we
receive, so we add the LogComponent with the key log. And we must start Camel before
its ready to act.
Then we change the code in the method that is invoked by Apache CXF when a webservice
request arrives. We get the name and let Camel have a go at it in the new method we create
sendToCamel:
public OutputReportIncident reportIncident(InputReportIncident parameters) {
String name = parameters.getGivenName() + " " + parameters.getFamilyName();
// let Camel do something with the name
sendToCamelLog(name);
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
Next is the Camel code. At first it looks like there are many code lines to do a simple task of
logging the name - yes it is. But later you will in fact realize this is one of Camels true power. Its
concise API. Hint: The same code can be used for any component in Camel.
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Component Documentation
The Log and File components is documented as well, just click on the links. Just
return to this documentation later when you must use these components for real.
private void sendToCamelLog(String name) {
try {
// get the log component
Component component = camel.getComponent("log");
//
//
//
//
create an endpoint and configure it.
Notice the URI parameters this is a common pratice in Camel to configure
endpoints based on URI.
com.mycompany.part2 = the log category used. Will log at INFO level as
default
Endpoint endpoint = component.createEndpoint("log:com.mycompany.part2");
// create an Exchange that we want to send to the endpoint
Exchange exchange = endpoint.createExchange();
// set the in message payload (=body) with the name parameter
exchange.getIn().setBody(name);
// now we want to send the exchange to this endpoint and we then need a
producer
// for this, so we create and start the producer.
Producer producer = endpoint.createProducer();
producer.start();
// process the exchange will send the exchange to the log component, that
will process
// the exchange and yes log the payload
producer.process(exchange);
// stop the producer, we want to be nice and cleanup
producer.stop();
} catch (Exception e) {
// we ignore any exceptions and just rethrow as runtime
throw new RuntimeException(e);
}
}
Okay there are code comments in the code block above that should explain what is happening.
We run the code by invoking our unit test with maven mvn test, and we should get this log
line:
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INFO: Exchange[BodyType:String, Body:Claus Ibsen]
WRITE TO FILE - EASY WITH THE SAME CODE STYLE
Okay that isn't to impressive, Camel can log
Well I promised that the above code style can
be used for any component, so let's store the payload in a file. We do this by adding the file
component to the Camel context
// add the file component
camel.addComponent("file", new FileComponent());
And then we let camel write the payload to the file after we have logged, by creating a new
method sendToCamelFile. We want to store the payload in filename with the incident id so
we need this parameter also:
// let Camel do something with the name
sendToCamelLog(name);
sendToCamelFile(parameters.getIncidentId(), name);
And then the code that is 99% identical. We have change the URI configuration when we create
the endpoint as we pass in configuration parameters to the file component.
And then we need to set the output filename and this is done by adding a special header to the
exchange. That's the only difference:
private void sendToCamelFile(String incidentId, String name) {
try {
// get the file component
Component component = camel.getComponent("file");
// create an endpoint and configure it.
// Notice the URI parameters this is a common pratice in Camel to configure
// endpoints based on URI.
// file://target instructs the base folder to output the files. We put in
the target folder
// then its actumatically cleaned by mvn clean
Endpoint endpoint = component.createEndpoint("file://target");
// create an Exchange that we want to send to the endpoint
Exchange exchange = endpoint.createExchange();
// set the in message payload (=body) with the name parameter
exchange.getIn().setBody(name);
// now a special header is set to instruct the file component what the
output filename
// should be
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exchange.getIn().setHeader(FileComponent.HEADER_FILE_NAME, "incident-" +
incidentId + ".txt");
// now we want to send the exchange to this endpoint and we then need a
producer
// for this, so we create and start the producer.
Producer producer = endpoint.createProducer();
producer.start();
// process the exchange will send the exchange to the file component, that
will process
// the exchange and yes write the payload to the given filename
producer.process(exchange);
// stop the producer, we want to be nice and cleanup
producer.stop();
} catch (Exception e) {
// we ignore any exceptions and just rethrow as runtime
throw new RuntimeException(e);
}
}
After running our unit test again with mvn test we have a output file in the target folder:
D:\demo\part-two>type target\incident-123.txt
Claus Ibsen
FULLY JAVA BASED CONFIGURATION OF ENDPOINTS
In the file example above the configuration was URI based. What if you want 100% java setter
based style, well this is of course also possible. We just need to cast to the component specific
endpoint and then we have all the setters available:
// create the file endpoint, we cast to FileEndpoint because then we can do
// 100% java settter based configuration instead of the URI sting based
// must pass in an empty string, or part of the URI configuration if
wanted
FileEndpoint endpoint = (FileEndpoint)component.createEndpoint("");
endpoint.setFile(new File("target/subfolder"));
endpoint.setAutoCreate(true);
That's it. Now we have used the setters to configure the FileEndpoint that it should store
the file in the folder target/subfolder. Of course Camel now stores the file in the subfolder.
D:\demo\part-two>type target\subfolder\incident-123.txt
Claus Ibsen
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LESSONS LEARNED
Okay I wanted to demonstrate how you can be in 100% control of the configuration and usage
of Camel based on plain Java code with no hidden magic or special XML or other configuration
files. Just add the camel-core.jar and you are ready to go.
You must have noticed that the code for sending a message to a given endpoint is the same
for both the log and file, in fact any Camel endpoint. You as the client shouldn't bother with
component specific code such as file stuff for file components, jms stuff for JMS messaging etc.
This is what the Message Endpoint EIP pattern is all about and Camel solves this very very nice a key pattern in Camel.
REDUCING CODE LINES
Now that you have been introduced to Camel and one of its masterpiece patterns solved
elegantly with the Message Endpoint its time to give productive and show a solution in fewer
code lines, in fact we can get it down to 5, 4, 3, 2 .. yes only 1 line of code.
The key is the ProducerTemplate that is a Spring'ish xxxTemplate based producer.
Meaning that it has methods to send messages to any Camel endpoints. First of all we need to
get hold of such a template and this is done from the CamelContext
private ProducerTemplate template;
public ReportIncidentEndpointImpl() throws Exception {
...
// get the ProducerTemplate thst is a Spring'ish xxxTemplate based producer
for very
// easy sending exchanges to Camel.
template = camel.createProducerTemplate();
// start Camel
camel.start();
}
Now we can use template for sending payloads to any endpoint in Camel. So all the logging
gabble can be reduced to:
template.sendBody("log:com.mycompany.part2.easy", name);
And the same goes for the file, but we must also send the header to instruct what the output
filename should be:
String filename = "easy-incident-" + incidentId + ".txt";
template.sendBodyAndHeader("file://target/subfolder", name,
FileComponent.HEADER_FILE_NAME, filename);
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REDUCING EVEN MORE CODE LINES
Well we got the Camel code down to 1-2 lines for sending the message to the component that
does all the heavy work of wring the message to a file etc. But we still got 5 lines to initialize
Camel.
camel = new DefaultCamelContext();
camel.addComponent("log", new LogComponent());
camel.addComponent("file", new FileComponent());
template = camel.createProducerTemplate();
camel.start();
This can also be reduced. All the standard components in Camel is auto discovered on-the-fly
so we can remove these code lines and we are down to 3 lines.
Okay back to the 3 code lines:
camel = new DefaultCamelContext();
template = camel.createProducerTemplate();
camel.start();
Later will we see how we can reduce this to ... in fact 0 java code lines. But the 3 lines will do
for now.
MESSAGE TRANSLATION
Okay lets head back to the over goal of the integration. Looking at the EIP diagrams at the
introduction page we need to be able to translate the incoming webservice to an email. Doing
so we need to create the email body. When doing the message translation we could put up our
sleeves and do it manually in pure java with a StringBuilder such as:
private String createMailBody(InputReportIncident parameters) {
StringBuilder sb = new StringBuilder();
sb.append("Incident ").append(parameters.getIncidentId());
sb.append(" has been reported on the ").append(parameters.getIncidentDate());
sb.append(" by ").append(parameters.getGivenName());
sb.append(" ").append(parameters.getFamilyName());
// and the rest of the mail body with more appends to the string builder
return sb.toString();
}
But as always it is a hardcoded template for the mail body and the code gets kinda ugly if the
mail message has to be a bit more advanced. But of course it just works out-of-the-box with
just classes already in the JDK.
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Component auto discovery
When an endpoint is requested with a scheme that Camel hasn't seen before it will
try to look for it in the classpath. It will do so by looking for special Camel
component marker files that reside in the folder META-INF/services/org/
apache/camel/component. If there are files in this folder it will read them as
the filename is the scheme part of the URL. For instance the log component is
defined in this file META-INF/services/org/apache/component/log
and its content is:
class=org.apache.camel.component.log.LogComponent
The class property defines the component implementation.
Tip: End-users can create their 3rd party components using the same technique and have
them been auto discovered on-the-fly.
Lets use a template language instead such as Apache Velocity. As Camel have a component
for Velocity integration we will use this component. Looking at the Component List overview
we can see that camel-velocity component uses the artifactId camel-velocity so therefore
we need to add this to the pom.xml
org.apache.camelcamel-velocity${camel-version}
And now we have a Spring conflict as Apache CXF is dependent on Spring 2.0.8 and camelvelocity is dependent on Spring 2.5.5. To remedy this we could wrestle with the pom.xml
with excludes settings in the dependencies or just bring in another dependency camelspring:
org.apache.camelcamel-spring${camel-version}
In fact camel-spring is such a vital part of Camel that you will end up using it in nearly all
situations - we will look into how well Camel is seamless integration with Spring in part 3. For
now its just another dependency.
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We create the mail body with the Velocity template and create the file src/main/
resources/MailBody.vm. The content in the MailBody.vm file is:
Incident $body.incidentId has been reported on the $body.incidentDate by
$body.givenName $body.familyName.
The person can be contact by:
- email: $body.email
- phone: $body.phone
Summary: $body.summary
Details:
$body.details
This is an auto generated email. You can not reply.
Letting Camel creating the mail body and storing it as a file is as easy as the following 3 code
lines:
private void generateEmailBodyAndStoreAsFile(InputReportIncident parameters) {
// generate the mail body using velocity template
// notice that we just pass in our POJO (= InputReportIncident) that we
// got from Apache CXF to Velocity.
Object response = template.sendBody("velocity:MailBody.vm", parameters);
// Note: the response is a String and can be cast to String if needed
// store the mail in a file
String filename = "mail-incident-" + parameters.getIncidentId() + ".txt";
template.sendBodyAndHeader("file://target/subfolder", response,
FileComponent.HEADER_FILE_NAME, filename);
}
What is impressive is that we can just pass in our POJO object we got from Apache CXF to
Velocity and it will be able to generate the mail body with this object in its context. Thus we
don't need to prepare anything before we let Velocity loose and generate our mail body.
Notice that the template method returns a object with out response. This object contains
the mail body as a String object. We can cast to String if needed.
If we run our unit test with mvn test we can in fact see that Camel has produced the file
and we can type its content:
D:\demo\part-two>type target\subfolder\mail-incident-123.txt
Incident 123 has been reported on the 2008-07-16 by Claus Ibsen.
The person can be contact by:
- email: davsclaus@apache.org
- phone: +45 2962 7576
Summary: bla bla
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Details:
more bla bla
This is an auto generated email. You can not reply.
FIRST PART OF THE SOLUTION
What we have seen here is actually what it takes to build the first part of the integration flow.
Receiving a request from a webservice, transform it to a mail body and store it to a file, and
return an OK response to the webservice. All possible within 10 lines of code. So lets wrap it
up here is what it takes:
/**
* The webservice we have implemented.
*/
public class ReportIncidentEndpointImpl implements ReportIncidentEndpoint {
private CamelContext camel;
private ProducerTemplate template;
public ReportIncidentEndpointImpl() throws Exception {
// create the camel context that is the "heart" of Camel
camel = new DefaultCamelContext();
// get the ProducerTemplate thst is a Spring'ish xxxTemplate based producer
for very
// easy sending exchanges to Camel.
template = camel.createProducerTemplate();
// start Camel
camel.start();
}
public OutputReportIncident reportIncident(InputReportIncident parameters) {
// transform the request into a mail body
Object mailBody = template.sendBody("velocity:MailBody.vm", parameters);
// store the mail body in a file
String filename = "mail-incident-" + parameters.getIncidentId() + ".txt";
template.sendBodyAndHeader("file://target/subfolder", mailBody,
FileComponent.HEADER_FILE_NAME, filename);
// return an OK reply
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
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}
Okay I missed by one, its in fact only 9 lines of java code and 2 fields.
END OF PART 2
I know this is a bit different introduction to Camel to how you can start using it in your
projects just as a plain java .jar framework that isn't invasive at all. I took you through the
coding parts that requires 6 - 10 lines to send a message to an endpoint, buts it's important to
show the Message Endpoint EIP pattern in action and how its implemented in Camel. Yes of
course Camel also has to one liners that you can use, and will use in your projects for sending
messages to endpoints. This part has been about good old plain java, nothing fancy with Spring,
XML files, auto discovery, OGSi or other new technologies. I wanted to demonstrate the basic
building blocks in Camel and how its setup in pure god old fashioned Java. There are plenty of
eye catcher examples with one liners that does more than you can imagine - we will come
there in the later parts.
Okay part 3 is about building the last pieces of the solution and now it gets interesting since
we have to wrestle with the event driven consumer.
Brew a cup of coffee, tug the kids and kiss the wife, for now we will have us some fun with the
Camel. See you in part 3.
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Part 1
Part 2
Part 3
Part 4
Part 5
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PART 3
RECAP
Lets just recap on the solution we have now:
public class ReportIncidentEndpointImpl implements ReportIncidentEndpoint {
private CamelContext camel;
private ProducerTemplate template;
public ReportIncidentEndpointImpl() throws Exception {
// create the camel context that is the "heart" of Camel
camel = new DefaultCamelContext();
// get the ProducerTemplate thst is a Spring'ish xxxTemplate based producer
for very
// easy sending exchanges to Camel.
template = camel.createProducerTemplate();
// start Camel
camel.start();
}
/**
* This is the last solution displayed that is the most simple
*/
public OutputReportIncident reportIncident(InputReportIncident parameters) {
// transform the request into a mail body
Object mailBody = template.sendBody("velocity:MailBody.vm", parameters);
// store the mail body in a file
String filename = "mail-incident-" + parameters.getIncidentId() + ".txt";
template.sendBodyAndHeader("file://target/subfolder", mailBody,
FileComponent.HEADER_FILE_NAME, filename);
// return an OK reply
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
}
This completes the first part of the solution: receiving the message using webservice, transform
it to a mail body and store it as a text file.
What is missing is the last part that polls the text files and send them as emails. Here is where
some fun starts, as this requires usage of the Event Driven Consumer EIP pattern to react when
new files arrives. So lets see how we can do this in Camel. There is a saying: Many roads lead to
Rome, and that is also true for Camel - there are many ways to do it in Camel.
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ADDING THE EVENT DRIVEN CONSUMER
We want to add the consumer to our integration that listen for new files, we do this by
creating a private method where the consumer code lives. We must register our consumer in
Camel before its started so we need to add, and there fore we call the method
addMailSenderConsumer in the constructor below:
public ReportIncidentEndpointImpl() throws Exception {
// create the camel context that is the "heart" of Camel
camel = new DefaultCamelContext();
// get the ProducerTemplate thst is a Spring'ish xxxTemplate based producer
for very
// easy sending exchanges to Camel.
template = camel.createProducerTemplate();
// add the event driven consumer that will listen for mail files and process
them
addMailSendConsumer();
// start Camel
camel.start();
}
The consumer needs to be consuming from an endpoint so we grab the endpoint from Camel
we want to consume. It's file://target/subfolder. Don't be fooled this endpoint
doesn't have to 100% identical to the producer, i.e. the endpoint we used in the previous part
to create and store the files. We could change the URL to include some options, and to make it
more clear that it's possible we setup a delay value to 10 seconds, and the first poll starts after
2 seconds. This is done by adding
?consumer.delay=10000&consumer.initialDelay=2000 to the URL.
When we have the endpoint we can create the consumer (just as in part 1 where we created a
producer}. Creating the consumer requires a Processor where we implement the java code
what should happen when a message arrives. To get the mail body as a String object we can use
the getBody method where we can provide the type we want in return.
Sending the email is still left to be implemented, we will do this later. And finally we must
remember to start the consumer otherwise its not active and won't listen for new files.
private void addMailSendConsumer() throws Exception {
// Grab the endpoint where we should consume. Option - the first poll starts
after 2 seconds
Endpoint endpint = camel.getEndpoint("file://target/
subfolder?consumer.initialDelay=2000");
// create the event
// the Processor is
// (think it as the
Consumer consumer =
driven consumer
the code what should happen when there is an event
onMessage method)
endpint.createConsumer(new Processor() {
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URL Configuration
The URL configuration in Camel endpoints is just like regular URL we know from
the Internet. You use ? and & to set the options.
Camel Type Converter
Why don't we just cast it as we always do in Java? Well the biggest advantage when
you provide the type as a parameter you tell Camel what type you want and Camel
can automatically convert it for you, using its flexible Type Converter mechanism.
This is a great advantage, and you should try to use this instead of regular type
casting.
public void process(Exchange exchange) throws Exception {
// get the mail body as a String
String mailBody = exchange.getIn().getBody(String.class);
// okay now we are read to send it as an email
System.out.println("Sending email..." + mailBody);
}
});
// star the consumer, it will listen for files
consumer.start();
}
Before we test it we need to be aware that our unit test is only catering for the first part of the
solution, receiving the message with webservice, transforming it using Velocity and then storing
it as a file - it doesn't test the Event Driven Consumer we just added. As we are eager to see it
in action, we just do a common trick adding some sleep in our unit test, that gives our Event
Driven Consumer time to react and print to System.out. We will later refine the test:
public void testRendportIncident() throws Exception {
...
OutputReportIncident out = client.reportIncident(input);
assertEquals("Response code is wrong", "OK", out.getCode());
// give the event driven consumer time to react
Thread.sleep(10 * 1000);
}
We run the test with mvn clean test and have eyes fixed on the console output.
During all the output in the console, we see that our consumer has been triggered, as we want.
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2008-07-19 12:09:24,140 [mponent@1f12c4e] DEBUG FileProcessStrategySupport - Locking
the file: target\subfolder\mail-incident-123.txt ...
Sending email...Incident 123 has been reported on the 2008-07-16 by Claus Ibsen.
The person can be contact by:
- email: davsclaus@apache.org
- phone: +45 2962 7576
Summary: bla bla
Details:
more bla bla
This is an auto generated email. You can not reply.
2008-07-19 12:09:24,156 [mponent@1f12c4e] DEBUG FileConsumer - Done processing file:
target\subfolder\mail-incident-123.txt. Status is: OK
SENDING THE EMAIL
Sending the email requires access to a SMTP mail server, but the implementation code is very
simple:
private void sendEmail(String body) {
// send the email to your mail server
String url =
"smtp://someone@localhost?password=secret&to=incident@mycompany.com";
template.sendBodyAndHeader(url, body, "subject", "New incident reported");
}
And just invoke the method from our consumer:
// okay now we are read to send it as an email
System.out.println("Sending email...");
sendEmail(mailBody);
System.out.println("Email sent");
UNIT TESTING MAIL
For unit testing the consumer part we will use a mock mail framework, so we add this to our
pom.xml:
org.jvnet.mock-javamailmock-javamail
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1.7test
Then we prepare our integration to run with or without the consumer enabled. We do this to
separate the route into the two parts:
▪ receive the webservice, transform and save mail file and return OK as repose
▪ the consumer that listen for mail files and send them as emails
So we change the constructor code a bit:
public ReportIncidentEndpointImpl() throws Exception {
init(true);
}
public ReportIncidentEndpointImpl(boolean enableConsumer) throws Exception {
init(enableConsumer);
}
private void init(boolean enableConsumer) throws Exception {
// create the camel context that is the "heart" of Camel
camel = new DefaultCamelContext();
// get the ProducerTemplate thst is a Spring'ish xxxTemplate based producer
for very
// easy sending exchanges to Camel.
template = camel.createProducerTemplate();
// add the event driven consumer that will listen for mail files and process
them
if (enableConsumer) {
addMailSendConsumer();
}
// start Camel
camel.start();
}
Then remember to change the ReportIncidentEndpointTest to pass in false in the
ReportIncidentEndpointImpl constructor.
And as always run mvn clean test to be sure that the latest code changes works.
ADDING NEW UNIT TEST
We are now ready to add a new unit test that tests the consumer part so we create a new test
class that has the following code structure:
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/**
* Plain JUnit test of our consumer.
*/
public class ReportIncidentConsumerTest extends TestCase {
private ReportIncidentEndpointImpl endpoint;
public void testConsumer() throws Exception {
// we run this unit test with the consumer, hence the true parameter
endpoint = new ReportIncidentEndpointImpl(true);
}
}
As we want to test the consumer that it can listen for files, read the file content and send it as
an email to our mailbox we will test it by asserting that we receive 1 mail in our mailbox and
that the mail is the one we expect. To do so we need to grab the mailbox with the mockmail
API. This is done as simple as:
public void testConsumer() throws Exception {
// we run this unit test with the consumer, hence the true parameter
endpoint = new ReportIncidentEndpointImpl(true);
// get the mailbox
Mailbox box = Mailbox.get("incident@mycompany.com");
assertEquals("Should not have mails", 0, box.size());
How do we trigger the consumer? Well by creating a file in the folder it listen for. So we could
use plain java.io.File API to create the file, but wait isn't there an smarter solution? ... yes Camel
of course. Camel can do amazing stuff in one liner codes with its ProducerTemplate, so we
need to get a hold of this baby. We expose this template in our ReportIncidentEndpointImpl
but adding this getter:
protected ProducerTemplate getTemplate() {
return template;
}
Then we can use the template to create the file in one code line:
// drop a file in the folder that the consumer listen
// here is a trick to reuse Camel! so we get the producer template and just
// fire a message that will create the file for us
endpoint.getTemplate().sendBodyAndHeader("file://target/
subfolder?append=false", "Hello World",
FileComponent.HEADER_FILE_NAME, "mail-incident-test.txt");
Then we just need to wait a little for the consumer to kick in and do its work and then we
should assert that we got the new mail. Easy as just:
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// let the consumer have time to run
Thread.sleep(3 * 1000);
// get the mock mailbox and check if we got mail ;)
assertEquals("Should have got 1 mail", 1, box.size());
assertEquals("Subject wrong", "New incident reported",
box.get(0).getSubject());
assertEquals("Mail body wrong", "Hello World", box.get(0).getContent());
}
The final class for the unit test is:
/**
* Plain JUnit test of our consumer.
*/
public class ReportIncidentConsumerTest extends TestCase {
private ReportIncidentEndpointImpl endpoint;
public void testConsumer() throws Exception {
// we run this unit test with the consumer, hence the true parameter
endpoint = new ReportIncidentEndpointImpl(true);
// get the mailbox
Mailbox box = Mailbox.get("incident@mycompany.com");
assertEquals("Should not have mails", 0, box.size());
// drop a file in the folder that the consumer listen
// here is a trick to reuse Camel! so we get the producer template and just
// fire a message that will create the file for us
endpoint.getTemplate().sendBodyAndHeader("file://target/
subfolder?append=false", "Hello World",
FileComponent.HEADER_FILE_NAME, "mail-incident-test.txt");
// let the consumer have time to run
Thread.sleep(3 * 1000);
// get the mock mailbox and check if we got mail ;)
assertEquals("Should have got 1 mail", 1, box.size());
assertEquals("Subject wrong", "New incident reported",
box.get(0).getSubject());
assertEquals("Mail body wrong", "Hello World", box.get(0).getContent());
}
}
END OF PART 3
Okay we have reached the end of part 3. For now we have only scratched the surface of what
Camel is and what it can do. We have introduced Camel into our integration piece by piece and
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slowly added more and more along the way. And the most important is: you as the
developer never lost control. We hit a sweet spot in the webservice implementation
where we could write our java code. Adding Camel to the mix is just to use it as a regular java
code, nothing magic. We were in control of the flow, we decided when it was time to translate
the input to a mail body, we decided when the content should be written to a file. This is very
important to not lose control, that the bigger and heavier frameworks tend to do. No names
mentioned, but boy do developers from time to time dislike these elephants. And Camel is no
elephant.
I suggest you download the samples from part 1 to 3 and try them out. It is great basic
knowledge to have in mind when we look at some of the features where Camel really excel the routing domain language.
From part 1 to 3 we touched concepts such as::
▪ Endpoint
▪ URI configuration
▪ Consumer
▪ Producer
▪ Event Driven Consumer
▪ Component
▪ CamelContext
▪ ProducerTemplate
▪ Processor
▪ Type Converter
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Jul 20,
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PART 4
INTRODUCTION
This section is about regular Camel. The examples presented here in this section is much more
in common of all the examples we have in the Camel documentation.
ROUTING
Camel is particular strong as a light-weight and agile routing and mediation framework. In
this part we will introduce the routing concept and how we can introduce this into our
solution.
Looking back at the figure from the Introduction page we want to implement this routing.
Camel has support for expressing this routing logic using Java as a DSL (Domain Specific
Language). In fact Camel also has DSL for XML and Scala. In this part we use the Java DSL as its
the most powerful and all developers know Java. Later we will introduce the XML version that
is very well integrated with Spring.
Before we jump into it, we want to state that this tutorial is about Developers not
loosing control. In my humble experience one of the key fears of developers is that they are
forced into a tool/framework where they loose control and/or power, and the possible is now
impossible. So in this part we stay clear with this vision and our starting point is as follows:
▪ We have generated the webservice source code using the CXF wsdl2java generator
and we have our ReportIncidentEndpointImpl.java file where we as a Developer feels
home and have the power.
So the starting point is:
/**
* The webservice we have implemented.
*/
public class ReportIncidentEndpointImpl implements ReportIncidentEndpoint {
/**
* This is the last solution displayed that is the most simple
*/
public OutputReportIncident reportIncident(InputReportIncident parameters) {
// WE ARE HERE !!!
return null;
}
}
Yes we have a simple plain Java class where we have the implementation of the webservice. The
cursor is blinking at the WE ARE HERE block and this is where we feel home. More or less any
Java Developers have implemented webservices using a stack such as: Apache AXIS, Apache
CXF or some other quite popular framework. They all allow the developer to be in control and
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If you have been reading the previous 3 parts then, this quote applies:
you must unlearn what you have learned
Master Yoda, Star Wars IV
So we start all over again!
implement the code logic as plain Java code. Camel of course doesn't enforce this to be any
different. Okay the boss told us to implement the solution from the figure in the Introduction
page and we are now ready to code.
RouteBuilder
RouteBuilder is the hearth in Camel of the Java DSL routing. This class does all the heavy
lifting of supporting EIP verbs for end-users to express the routing. It does take a little while to
get settled and used to, but when you have worked with it for a while you will enjoy its power
and realize it is in fact a little language inside Java itself. Camel is the only integration
framework we are aware of that has Java DSL, all the others are usually only XML based.
As an end-user you usually use the RouteBuilder as of follows:
▪ create your own Route class that extends RouteBuilder
▪ implement your routing DSL in the configure method
So we create a new class ReportIncidentRoutes and implement the first part of the routing:
import org.apache.camel.builder.RouteBuilder;
public class ReportIncidentRoutes extends RouteBuilder {
public void configure() throws Exception {
// direct:start is a internal queue to kick-start the routing in our example
// we use this as the starting point where you can send messages to
direct:start
from("direct:start")
// to is the destination we send the message to our velocity endpoint
// where we transform the mail body
.to("velocity:MailBody.vm");
}
}
What to notice here is the configure method. Here is where all the action is. Here we have
the Java DSL langauge, that is expressed using the fluent builder syntax that is also known
from Hibernate when you build the dynamic queries etc. What you do is that you can stack
methods separating with the dot.
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In the example above we have a very common routing, that can be distilled from pseudo
verbs to actual code with:
▪ from A to B
▪ From Endpoint A To Endpoint B
▪ from("endpointA").to("endpointB")
▪ from("direct:start").to("velocity:MailBody.vm");
from("direct:start") is the consumer that is kick-starting our routing flow. It will wait for
messages to arrive on the direct queue and then dispatch the message.
to("velocity:MailBody.vm") is the producer that will receive a message and let Velocity
generate the mail body response.
So what we have implemented so far with our ReportIncidentRoutes RouteBuilder is this
part of the picture:
Adding the RouteBuilder
Now we have our RouteBuilder we need to add/connect it to our CamelContext that is the
hearth of Camel. So turning back to our webservice implementation class
ReportIncidentEndpointImpl we add this constructor to the code, to create the CamelContext
and add the routes from our route builder and finally to start it.
private CamelContext context;
public ReportIncidentEndpointImpl() throws Exception {
// create the context
context = new DefaultCamelContext();
// append the routes to the context
context.addRoutes(new ReportIncidentRoutes());
// at the end start the camel context
context.start();
}
Okay how do you use the routes then? Well its just as before we use a ProducerTemplate to
send messages to Endpoints, so we just send to the direct:start endpoint and it will take it
from there.
So we implement the logic in our webservice operation:
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/**
* This is the last solution displayed that is the most simple
*/
public OutputReportIncident reportIncident(InputReportIncident parameters) {
Object mailBody = context.createProducerTemplate().sendBody("direct:start",
parameters);
System.out.println("Body:" + mailBody);
// return an OK reply
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
Notice that we get the producer template using the createProducerTemplate method on
the CamelContext. Then we send the input parameters to the direct:start endpoint and it
will route it to the velocity endpoint that will generate the mail body. Since we use direct as
the consumer endpoint (=from) and its a synchronous exchange we will get the response
back from the route. And the response is of course the output from the velocity endpoint.
We have now completed this part of the picture:
UNIT TESTING
Now is the time we would like to unit test what we got now. So we call for camel and its great
test kit. For this to work we need to add it to the pom.xml
org.apache.camelcamel-core1.4.0testtest-jar
After adding it to the pom.xml you should refresh your Java Editor so it pickups the new jar.
Then we are ready to create out unit test class.
We create this unit test skeleton, where we extend this class ContextTestSupport
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About creating ProducerTemplate
In the example above we create a new ProducerTemplate when the
reportIncident method is invoked. However in reality you should only create
the template once and re-use it. See this FAQ entry.
package org.apache.camel.example.reportincident;
import org.apache.camel.ContextTestSupport;
import org.apache.camel.builder.RouteBuilder;
/**
* Unit test of our routes
*/
public class ReportIncidentRoutesTest extends ContextTestSupport {
}
ContextTestSupport is a supporting unit test class for much easier unit testing with
Apache Camel. The class is extending JUnit TestCase itself so you get all its glory. What we
need to do now is to somehow tell this unit test class that it should use our route builder as
this is the one we gonna test. So we do this by implementing the createRouteBuilder
method.
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new ReportIncidentRoutes();
}
That is easy just return an instance of our route builder and this unit test will use our routes.
We then code our unit test method that sends a message to the route and assert that its
transformed to the mail body using the Velocity template.
public void testTransformMailBody() throws Exception {
// create a dummy input with some input data
InputReportIncident parameters = createInput();
// send the message (using the sendBody method that takes a parameters as the
input body)
// to "direct:start" that kick-starts the route
// the response is returned as the out object, and its also the body of the
response
Object out = context.createProducerTemplate().sendBody("direct:start",
parameters);
// convert the response to a string using camel converters. However we could
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It is quite common in Camel itself to unit test using routes defined as an anonymous
inner class, such as illustrated below:
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
// TODO: Add your routes here, such as:
from("jms:queue:inbox").to("file://target/out");
}
};
}
The same technique is of course also possible for end-users of Camel to create parts of your
routes and test them separately in many test classes.
However in this tutorial we test the real route that is to be used for production, so we just
return an instance of the real one.
also have casted it to
// a string directly but using the type converters ensure that Camel can
convert it if it wasn't a string
// in the first place. The type converters in Camel is really powerful and you
will later learn to
// appreciate them and wonder why its not build in Java out-of-the-box
String body = context.getTypeConverter().convertTo(String.class, out);
// do some simple assertions of the mail body
assertTrue(body.startsWith("Incident 123 has been reported on the 2008-07-16
by Claus Ibsen."));
}
/**
* Creates a dummy request to be used for input
*/
protected InputReportIncident createInput() {
InputReportIncident input = new InputReportIncident();
input.setIncidentId("123");
input.setIncidentDate("2008-07-16");
input.setGivenName("Claus");
input.setFamilyName("Ibsen");
input.setSummary("bla bla");
input.setDetails("more bla bla");
input.setEmail("davsclaus@apache.org");
input.setPhone("+45 2962 7576");
return input;
}
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ADDING THE FILE BACKUP
The next piece of puzzle that is missing is to store the mail body as a backup file. So we turn
back to our route and the EIP patterns. We use the Pipes and Filters pattern here to chain the
routing as:
public void configure() throws Exception {
from("direct:start")
.to("velocity:MailBody.vm")
// using pipes-and-filters we send the output from the previous to the next
.to("file://target/subfolder");
}
Notice that we just add a 2nd .to on the newline. Camel will default use the Pipes and Filters
pattern here when there are multi endpoints chained liked this. We could have used the
pipeline verb to let out stand out that its the Pipes and Filters pattern such as:
from("direct:start")
// using pipes-and-filters we send the output from the previous to the next
.pipeline("velocity:MailBody.vm", "file://target/subfolder");
But most people are using the multi .to style instead.
We re-run out unit test and verifies that it still passes:
Running org.apache.camel.example.reportincident.ReportIncidentRoutesTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.157 sec
But hey we have added the file producer endpoint and thus a file should also be created as the
backup file. If we look in the target/subfolder we can see that something happened.
On my humble laptop it created this folder: target\subfolder\ID-claus-acer. So the file
producer create a sub folder named ID-claus-acer what is this? Well Camel auto
generates an unique filename based on the unique message id if not given instructions to use a
fixed filename. In fact it creates another sub folder and name the file as: target\subfolder\IDclaus-acer\3750-1219148558921\1-0 where 1-0 is the file with the mail body. What we want is
to use our own filename instead of this auto generated filename. This is archived by adding a
header to the message with the filename to use. So we need to add this to our route and
compute the filename based on the message content.
Setting the filename
For starters we show the simple solution and build from there. We start by setting a constant
filename, just to verify that we are on the right path, to instruct the file producer what filename
to use. The file producer uses a special header FileComponent.HEADER_FILE_NAME to
set the filename.
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What we do is to send the header when we "kick-start" the routing as the header will be
propagated from the direct queue to the file producer. What we need to do is to use the
ProducerTemplate.sendBodyAndHeader method that takes both a body and a
header. So we change out webservice code to include the filename also:
public OutputReportIncident reportIncident(InputReportIncident parameters) {
// create the producer template to use for sending messages
ProducerTemplate producer = context.createProducerTemplate();
// send the body and the filename defined with the special header key
Object mailBody = producer.sendBodyAndHeader("direct:start", parameters,
FileComponent.HEADER_FILE_NAME, "incident.txt");
System.out.println("Body:" + mailBody);
// return an OK reply
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
However we could also have used the route builder itself to configure the constant filename as
shown below:
public void configure() throws Exception {
from("direct:start")
.to("velocity:MailBody.vm")
// set the filename to a constant before the file producer receives the
message
.setHeader(FileComponent.HEADER_FILE_NAME, constant("incident.txt"))
.to("file://target/subfolder");
}
But Camel can be smarter and we want to dynamic set the filename based on some of the input
parameters, how can we do this?
Well the obvious solution is to compute and set the filename from the webservice
implementation, but then the webservice implementation has such logic and we want this
decoupled, so we could create our own POJO bean that has a method to compute the
filename. We could then instruct the routing to invoke this method to get the computed
filename. This is a string feature in Camel, its Bean binding. So lets show how this can be done:
Using Bean Language to compute the filename
First we create our plain java class that computes the filename, and it has 100% no
dependencies to Camel what so ever.
/**
* Plain java class to be used for filename generation based on the reported incident
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*/
public class FilenameGenerator {
public String generateFilename(InputReportIncident input) {
// compute the filename
return "incident-" + input.getIncidentId() + ".txt";
}
}
The class is very simple and we could easily create unit tests for it to verify that it works as
expected. So what we want now is to let Camel invoke this class and its generateFilename with
the input parameters and use the output as the filename. Pheeeww is this really possible out-ofthe-box in Camel? Yes it is. So lets get on with the show. We have the code that computes the
filename, we just need to call it from our route using the Bean Language:
public void configure() throws Exception {
from("direct:start")
// set the filename using the bean language and call the FilenameGenerator
class.
// the 2nd null parameter is optional methodname, to be used to avoid
ambiguity.
// if not provided Camel will try to figure out the best method to invoke,
as we
// only have one method this is very simple
.setHeader(FileComponent.HEADER_FILE_NAME,
BeanLanguage.bean(FilenameGenerator.class, null))
.to("velocity:MailBody.vm")
.to("file://target/subfolder");
}
Notice that we use the bean language where we supply the class with our bean to invoke.
Camel will instantiate an instance of the class and invoke the suited method. For completeness
and ease of code readability we add the method name as the 2nd parameter
.setHeader(FileComponent.HEADER_FILE_NAME,
BeanLanguage.bean(FilenameGenerator.class, "generateFilename"))
Then other developers can understand what the parameter is, instead of null.
Now we have a nice solution, but as a sidetrack I want to demonstrate the Camel has other
languages out-of-the-box, and that scripting language is a first class citizen in Camel where it etc.
can be used in content based routing. However we want it to be used for the filename
generation.
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Using a script language to set the filename
We could do as in the previous parts where we send the computed filename as a message
header when we "kick-start" the route. But we want to learn new stuff so we look for a
different solution using some of Camels many Languages. As OGNL is a favorite language of
mine (used by WebWork) so we pick this baby for a Camel ride. For starters we must add it
to our pom.xml:
org.apache.camelcamel-ognl${camel-version}
And remember to refresh your editor so you got the new .jars.
We want to construct the filename based on this syntax: mail-incident-#ID#.txt
where #ID# is the incident id from the input parameters. As OGNL is a language that can
invoke methods on bean we can invoke the getIncidentId() on the message body and
then concat it with the fixed pre and postfix strings.
In OGNL glory this is done as:
"'mail-incident-' + request.body.incidentId + '.txt'"
where request.body.incidentId computes to:
▪ request is the IN message. See the OGNL for other predefined objects
available
▪ body is the body of the in message
▪ incidentId will invoke the getIncidentId() method on the body.
The rest is just more or less regular plain code where we can concat
strings.
Now we got the expression to dynamic compute the filename on the fly we need to set it on
our route so we turn back to our route, where we can add the OGNL expression:
public void configure() throws Exception {
from("direct:start")
// we need to set the filename and uses OGNL for this
.setHeader(FileComponent.HEADER_FILE_NAME,
OgnlExpression.ognl("'mail-incident-' + request.body.incidentId + '.txt'"))
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// using pipes-and-filters we send the output from the previous
to the next
.pipeline("velocity:MailBody.vm", "file://target/subfolder");
}
And since we are on Java 1.5 we can use the static import of ognl so we have:
import static org.apache.camel.language.ognl.OgnlExpression.ognl;
...
.setHeader(FileComponent.HEADER_FILE_NAME, ognl("'mail-incident-' +
request.body.incidentId + '.txt'"))
Notice the import static also applies for all the other languages, such as the Bean Language
we used previously.
Whatever worked for you we have now implemented the backup of the data files:
SENDING THE EMAIL
What we need to do before the solution is completed is to actually send the email with the mail
body we generated and stored as a file. In the previous part we did this with a File consumer,
that we manually added to the CamelContext. We can do this quite easily with the routing.
import org.apache.camel.builder.RouteBuilder;
public class ReportIncidentRoutes extends RouteBuilder {
public void configure() throws Exception {
// first part from the webservice -> file backup
from("direct:start")
.setHeader(FileComponent.HEADER_FILE_NAME, bean(FilenameGenerator.class,
"generateFilename"))
.to("velocity:MailBody.vm")
.to("file://target/subfolder");
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// second part from the file backup -> send email
from("file://target/subfolder")
// set the subject of the email
.setHeader("subject", constant("new incident reported"))
// send the email
.to("smtp://someone@localhost?password=secret&to=incident@mycompany.com");
}
}
The last 3 lines of code does all this. It adds a file consumer from("file://target/
subfolder"), sets the mail subject, and finally send it as an email.
The DSL is really powerful where you can express your routing integration logic.
So we completed the last piece in the picture puzzle with just 3 lines of code.
We have now completed the integration:
CONCLUSION
We have just briefly touched the routing in Camel and shown how to implement them using
the fluent builder syntax in Java. There is much more to the routing in Camel than shown
here, but we are learning step by step. We continue in part 5. See you there.
RESOURCES
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Name
Size
Creator
Creation
Date
Comment
ZIP
Archive
partfour.zip
11
kB
Claus
Ibsen
Aug 25,
2008
07:24
Ê
Ê
◦ Properties
◦ Remove
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LINKS
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Introduction
Part 1
Part 2
Part 3
Part 4
Part 5
BETTER JMS TRANSPORT FOR CXF WEBSERVICE USING
APACHE CAMEL
Configuring JMS in Apache CXF before Version 2.1.3 is possible but not really easy or nice. This
article shows how to use Apache Camel to provide a better JMS Transport for CXF.
Update: Since CXF 2.1.3 there is a new way of configuring JMS (Using the
JMSConfigFeature). It makes JMS config for CXF as easy as with Camel. Using Camel for JMS is
still a good idea if you want to use the rich feature of Camel for routing and other Integration
Scenarios that CXF does not support.
You can find the original announcement for this Tutorial and some additional info on
Christian Schneider«s Blog
So how to connect Apache Camel and CXF
The best way to connect Camel and CXF is using the Camel transport for CXF. This is a camel
module that registers with cxf as a new transport. It is quite easy to configure.
http://cxf.apache.org/transports/camel
This bean registers with CXF and provides a new transport prefix camel:// that can be used in
CXF address configurations. The bean references a bean cxf which will be already present in
your config. The other refrenceis a camel context. We will later define this bean to provide the
routing config.
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TU TO RI A L S
How is JMS configured in Camel
In camel you need two things to configure JMS. A ConnectionFactory and a JMSComponent. As
ConnectionFactory you can simply set up the normal Factory your JMS provider offers or bind
a JNDI ConnectionFactory. In this example we use the ConnectionFactory provided by
ActiveMQ.
Then we set up the JMSComponent. It offers a new transport prefix to camel that we simply
call jms. If we need several JMSComponents we can differentiate them by their name.
You can find more details about the JMSComponent at the Camel Wiki. For example you find
the complete configuration options and a JNDI sample there.
Setting up the CXF client
We will configure a simple CXF webservice client. It will use stub code generated from a wsdl.
The webservice client will be configured to use JMS directly. You can also use a direct: Endpoint
and do the routing to JMS in the Camel Context.
We explicitly configure serviceName and endpointName so they are not read from the wsdl.
The names we use are arbitrary and have no further function but we set them to look nice. The
serviceclass points to the service interface that was generated from the wsdl. Now the
important thing is address. Here we tell cxf to use the camel transport, use the JmsComponent
who registered the prefix "jms" and use the queue "CustomerService".
Setting up the CamelContext
As we do not need additional routing an empty CamelContext bean will suffice.
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Running the Example
• Download the example project here
• Follow the readme.txt
Conclusion
As you have seen in this example you can use Camel to connect services to JMS easily while
being able to also use the rich integration features of Apache Camel.
TUTORIAL USING AXIS 1.4 WITH APACHE CAMEL
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Tutorial using Axis 1.4 with Apache Camel
Prerequisites
Distribution
Introduction
Setting up the project to run Axis
Maven 2
wsdl
Configuring Axis
Running the Example
Integrating Spring
Using Spring
Integrating Camel
CamelContext
Store a file backup
Running the example
Unit Testing
Smarter Unit Testing with Spring
Unit Test calling WebService
Annotations
The End
See Also
Prerequisites
This tutorial uses Maven 2 to setup the Camel project and for dependencies for artifacts.
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Removed from distribution
This example has been removed from Camel 2.9 onwards. Apache Axis 1.4 is a
very old and unsupported framework. We encourage users to use CXF instead of
Axis.
Distribution
This sample is distributed with the Camel 1.5 distribution as examples/camel-exampleaxis.
Introduction
Apache Axis is/was widely used as a webservice framework. So in line with some of the other
tutorials to demonstrate how Camel is not an invasive framework but is flexible and integrates
well with existing solution.
We have an existing solution that exposes a webservice using Axis 1.4 deployed as web
applications. This is a common solution. We use contract first so we have Axis generated
source code from an existing wsdl file. Then we show how we introduce Spring and Camel to
integrate with Axis.
This tutorial uses the following frameworks:
• Maven 2.0.9
• Apache Camel 1.5.0
• Apache Axis 1.4
• Spring 2.5.5
Setting up the project to run Axis
This first part is about getting the project up to speed with Axis. We are not touching Camel or
Spring at this time.
Maven 2
Axis dependencies is available for maven 2 so we configure our pom.xml as:
org.apache.axisaxis1.4org.apache.axis
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166
axis-jaxrpc1.4org.apache.axisaxis-saaj1.4axisaxis-wsdl4j1.5.1commons-discoverycommons-discovery0.4log4jlog4j1.2.14
Then we need to configure maven to use Java 1.5 and the Axis maven plugin that generates the
source code based on the wsdl file:
org.apache.maven.pluginsmaven-compiler-plugin1.51.5org.codehaus.mojoaxistools-maven-pluginsrc/main/resources/com.mycompany.myschemafalsetruefalse
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TU TO RI A L S
wsdl2java
wsdl
We use the same .wsdl file as the Tutorial-Example-ReportIncident and copy it to src/main/
webapp/WEB-INF/wsdl
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TU TO RI A L S
Configuring Axis
Okay we are now setup for the contract first development and can generate the source file. For
now we are still only using standard Axis and not Spring nor Camel. We still need to setup Axis
as a web application so we configure the web.xml in src/main/webapp/WEB-INF/
web.xml as:
axisorg.apache.axis.transport.http.AxisServletaxis/services/*
The web.xml just registers Axis servlet that is handling the incoming web requests to its servlet
mapping. We still need to configure Axis itself and this is done using its special configuration file
server-config.wsdd. We nearly get this file for free if we let Axis generate the source
code so we run the maven goal:
mvn axistools:wsdl2java
The tool will generate the source code based on the wsdl and save the files to the following
folder:
.\target\generated-sources\axistools\wsdl2java\org\apache\camel\example\reportincident
deploy.wsdd
InputReportIncident.java
OutputReportIncident.java
ReportIncidentBindingImpl.java
ReportIncidentBindingStub.java
ReportIncidentService_PortType.java
ReportIncidentService_Service.java
ReportIncidentService_ServiceLocator.java
undeploy.wsdd
This is standard Axis and so far no Camel or Spring has been touched. To implement our
webservice we will add our code, so we create a new class
AxisReportIncidentService that implements the port type interface where we can
implement our code logic what happens when the webservice is invoked.
package org.apache.camel.example.axis;
import org.apache.camel.example.reportincident.InputReportIncident;
import org.apache.camel.example.reportincident.OutputReportIncident;
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import org.apache.camel.example.reportincident.ReportIncidentService_PortType;
import java.rmi.RemoteException;
/**
* Axis webservice
*/
public class AxisReportIncidentService implements ReportIncidentService_PortType {
public OutputReportIncident reportIncident(InputReportIncident parameters) throws
RemoteException {
System.out.println("Hello AxisReportIncidentService is called from " +
parameters.getGivenName());
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
}
Now we need to configure Axis itself and this is done using its server-config.wsdd file.
We nearly get this for for free from the auto generated code, we copy the stuff from
deploy.wsdd and made a few modifications:
The globalConfiguration and transport is not in the deploy.wsdd file so you gotta write
that yourself. The service is a 100% copy from deploy.wsdd. Axis has more configuration to it
than shown here, but then you should check the Axis documentation.
What we need to do now is important, as we need to modify the above configuration to use
our webservice class than the default one, so we change the classname parameter to our class
AxisReportIncidentService:
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Running the Example
Now we are ready to run our example for the first time, so we use Jetty as the quick web
container using its maven command:
mvn jetty:run
Then we can hit the web browser and enter this URL: http://localhost:8080/
camel-example-axis/services and you should see the famous Axis start page with the
text And now... Some Services.
Clicking on the .wsdl link shows the wsdl file, but what. It's an auto generated one and not
our original .wsdl file. So we need to fix this ASAP and this is done by configuring Axis in the
server-config.wsdd file:
/WEB-INF/wsdl/report_incident.wsdl
...
We do this by adding the wsdlFile tag in the service element where we can point to the real
.wsdl file.
Integrating Spring
First we need to add its dependencies to the pom.xml.
org.springframeworkspring-web2.5.5
Spring is integrated just as it would like to, we add its listener to the web.xml and a context
parameter to be able to configure precisely what spring xml files to use:
contextConfigLocation
classpath:axis-example-context.xml
org.springframework.web.context.ContextLoaderListener
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TU TO RI A L S
Next is to add a plain spring XML file named axis-example-context.xml in the src/main/
resources folder.
The spring XML file is currently empty. We hit jetty again with mvn jetty:run just to make
sure Spring was setup correctly.
Using Spring
We would like to be able to get hold of the Spring ApplicationContext from our webservice so
we can get access to the glory spring, but how do we do this? And our webservice class
AxisReportIncidentService is created and managed by Axis we want to let Spring do this. So we
have two problems.
We solve these problems by creating a delegate class that Axis creates, and this delegate
class gets hold on Spring and then gets our real webservice as a spring bean and invoke the
service.
First we create a new class that is 100% independent from Axis and just a plain POJO. This is
our real service.
package org.apache.camel.example.axis;
import org.apache.camel.example.reportincident.InputReportIncident;
import org.apache.camel.example.reportincident.OutputReportIncident;
/**
* Our real service that is not tied to Axis
*/
public class ReportIncidentService {
public OutputReportIncident reportIncident(InputReportIncident parameters) {
System.out.println("Hello ReportIncidentService is called from " +
parameters.getGivenName());
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
}
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So now we need to get from AxisReportIncidentService to this one ReportIncidentService using
Spring. Well first of all we add our real service to spring XML configuration file so Spring can
handle its lifecycle:
And then we need to modify AxisReportIncidentService to use Spring to lookup the spring bean
id="incidentservice" and delegate the call. We do this by extending the spring class
org.springframework.remoting.jaxrpc.ServletEndpointSupport so the
refactored code is:
package org.apache.camel.example.axis;
import
import
import
import
org.apache.camel.example.reportincident.InputReportIncident;
org.apache.camel.example.reportincident.OutputReportIncident;
org.apache.camel.example.reportincident.ReportIncidentService_PortType;
org.springframework.remoting.jaxrpc.ServletEndpointSupport;
import java.rmi.RemoteException;
/**
* Axis webservice
*/
public class AxisReportIncidentService extends ServletEndpointSupport implements
ReportIncidentService_PortType {
public OutputReportIncident reportIncident(InputReportIncident parameters) throws
RemoteException {
// get hold of the spring bean from the application context
ReportIncidentService service = (ReportIncidentService)
getApplicationContext().getBean("incidentservice");
// delegate to the real service
return service.reportIncident(parameters);
}
}
To see if everything is okay we run mvn jetty:run.
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TU TO RI A L S
In the code above we get hold of our service at each request by looking up in the application
context. However Spring also supports an init method where we can do this once. So we
change the code to:
public class AxisReportIncidentService extends ServletEndpointSupport implements
ReportIncidentService_PortType {
private ReportIncidentService service;
@Override
protected void onInit() throws ServiceException {
// get hold of the spring bean from the application context
service = (ReportIncidentService)
getApplicationContext().getBean("incidentservice");
}
public OutputReportIncident reportIncident(InputReportIncident parameters) throws
RemoteException {
// delegate to the real service
return service.reportIncident(parameters);
}
}
So now we have integrated Axis with Spring and we are ready for Camel.
Integrating Camel
Again the first step is to add the dependencies to the maven pom.xml file:
org.apache.camelcamel-core1.5.0org.apache.camelcamel-spring1.5.0
Now that we have integrated with Spring then we easily integrate with Camel as Camel works
well with Spring.
We choose to integrate Camel in the Spring XML file so we add the camel namespace and the
schema location:
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Camel does not require Spring
Camel does not require Spring, we could easily have used Camel without Spring,
but most users prefer to use Spring also.
xmlns:camel="http://activemq.apache.org/camel/schema/spring"
http://activemq.apache.org/camel/schema/spring http://activemq.apache.org/camel/schema/
spring/camel-spring.xsd"
CamelContext
CamelContext is the heart of Camel its where all the routes, endpoints, components, etc. is
registered. So we setup a CamelContext and the spring XML files looks like:
Store a file backup
We want to store the web service request as a file before we return a response. To do this we
want to send the file content as a message to an endpoint that produces the file. So we need to
do two steps:
▪ configure the file backup endpoint
▪ send the message to the endpoint
The endpoint is configured in spring XML so we just add it as:
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TU TO RI A L S
In the CamelContext we have defined our endpoint with the id backup and configured it use
the URL notation that we know from the internet. Its a file scheme that accepts a context
and some options. The contest is target and its the folder to store the file. The option is just
as the internet with ? and & for subsequent options. We configure it to not append, meaning
than any existing file will be overwritten. See the File component for options and how to use
the camel file endpoint.
Next up is to be able to send a message to this endpoint. The easiest way is to use a
ProducerTemplate. A ProducerTemplate is inspired by Spring template pattern with for
instance JmsTemplate or JdbcTemplate in mind. The template that all the grunt work and
exposes a simple interface to the end-user where he/she can set the payload to send. Then the
template will do proper resource handling and all related issues in that regard. But how do we
get hold of such a template? Well the CamelContext is able to provide one. This is done by
configuring the template on the camel context in the spring XML as:
Then we can expose a ProducerTemplate property on our service with a setter in the Java
code as:
public class ReportIncidentService {
private ProducerTemplate template;
public void setTemplate(ProducerTemplate template) {
this.template = template;
}
And then let Spring handle the dependency inject as below:
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Now we are ready to use the producer template in our service to send the payload to the
endpoint. The template has many sendXXX methods for this purpose. But before we send
the payload to the file endpoint we must also specify what filename to store the file as. This is
done by sending meta data with the payload. In Camel metadata is sent as headers. Headers is
just a plain Map. So if we needed to send several metadata then we
could construct an ordinary HashMap and put the values in there. But as we just need to send
one header with the filename Camel has a convenient send method sendBodyAndHeader so
we choose this one.
public OutputReportIncident reportIncident(InputReportIncident parameters) {
System.out.println("Hello ReportIncidentService is called from " +
parameters.getGivenName());
String data = parameters.getDetails();
// store the data as a file
String filename = parameters.getIncidentId() + ".txt";
// send the data to the endpoint and the header contains what filename it
should be stored as
template.sendBodyAndHeader("backup", data, "org.apache.camel.file.name",
filename);
OutputReportIncident out = new OutputReportIncident();
out.setCode("OK");
return out;
}
The template in the code above uses 4 parameters:
▪ the endpoint name, in this case the id referring to the endpoint defined in Spring XML
in the camelContext element.
▪ the payload, can be any kind of object
▪ the key for the header, in this case a Camel keyword to set the filename
▪ and the value for the header
Running the example
We start our integration with maven using mvn jetty:run. Then we open a browser and
hit http://localhost:8080. Jetty is so smart that it display a frontpage with links to the
deployed application so just hit the link and you get our application. Now we hit append
/services to the URL to access the Axis frontpage. The URL should be
http://localhost:8080/camel-example-axis/services.
You can then test it using a web service test tools such as SoapUI.
Hitting the service will output to the console
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2008-09-06 15:01:41.718::INFO: Started SelectChannelConnector @ 0.0.0.0:8080
[INFO] Started Jetty Server
Hello ReportIncidentService is called from Ibsen
And there should be a file in the target subfolder.
dir target /b
123.txt
Unit Testing
We would like to be able to unit test our ReportIncidentService class. So we add junit to
the maven dependency:
junitjunit3.8.2test
And then we create a plain junit testcase for our service class.
package org.apache.camel.example.axis;
import junit.framework.TestCase;
import org.apache.camel.example.reportincident.InputReportIncident;
import org.apache.camel.example.reportincident.OutputReportIncident;
/**
* Unit test of service
*/
public class ReportIncidentServiceTest extends TestCase {
public void testIncident() {
ReportIncidentService service = new ReportIncidentService();
InputReportIncident input = createDummyIncident();
OutputReportIncident output = service.reportIncident(input);
assertEquals("OK", output.getCode());
}
protected InputReportIncident createDummyIncident() {
InputReportIncident input = new InputReportIncident();
input.setEmail("davsclaus@apache.org");
input.setIncidentId("12345678");
input.setIncidentDate("2008-07-13");
input.setPhone("+45 2962 7576");
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input.setSummary("Failed operation");
input.setDetails("The wrong foot was operated.");
input.setFamilyName("Ibsen");
input.setGivenName("Claus");
return input;
}
}
Then we can run the test with maven using: mvn test. But we will get a failure:
Running org.apache.camel.example.axis.ReportIncidentServiceTest
Hello ReportIncidentService is called from Claus
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.235 sec <<< FAILURE!
Results :
Tests in error:
testIncident(org.apache.camel.example.axis.ReportIncidentServiceTest)
Tests run: 1, Failures: 0, Errors: 1, Skipped: 0
What is the problem? Well our service uses a CamelProducer (the template) to send a message
to the file endpoint so the message will be stored in a file. What we need is to get hold of such
a producer and inject it on our service, by calling the setter.
Since Camel is very light weight and embedable we are able to create a CamelContext and
add the endpoint in our unit test code directly. We do this to show how this is possible:
private CamelContext context;
@Override
protected void setUp() throws Exception {
super.setUp();
// CamelContext is just created like this
context = new DefaultCamelContext();
// then we can create our endpoint and set the options
FileEndpoint endpoint = new FileEndpoint();
// the endpoint must have the camel context set also
endpoint.setCamelContext(context);
// our output folder
endpoint.setFile(new File("target"));
// and the option not to append
endpoint.setAppend(false);
// then we add the endpoint just in java code just as the spring XML, we
register it with the "backup" id.
context.addSingletonEndpoint("backup", endpoint);
// finally we need to start the context so Camel is ready to rock
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context.start();
}
@Override
protected void tearDown() throws Exception {
super.tearDown();
// and we are nice boys so we stop it to allow resources to clean up
context.stop();
}
So now we are ready to set the ProducerTemplate on our service, and we get a hold of that
baby from the CamelContext as:
public void testIncident() {
ReportIncidentService service = new ReportIncidentService();
// get a producer template from the camel context
ProducerTemplate template = context.createProducerTemplate();
// inject it on our service using the setter
service.setTemplate(template);
InputReportIncident input = createDummyIncident();
OutputReportIncident output = service.reportIncident(input);
assertEquals("OK", output.getCode());
}
And this time when we run the unit test its a success:
Results :
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
We would like to test that the file exists so we add these two lines to our test method:
// should generate a file also
File file = new File("target/" + input.getIncidentId() + ".txt");
assertTrue("File should exists", file.exists());
Smarter Unit Testing with Spring
The unit test above requires us to assemble the Camel pieces manually in java code. What if we
would like our unit test to use our spring configuration file axis-example-context.xml
where we already have setup the endpoint. And of course we would like to test using this
configuration file as this is the real file we will use. Well hey presto the xml file is a spring
ApplicationContext file and spring is able to load it, so we go the spring path for unit testing.
First we add the spring-test jar to our maven dependency:
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org.springframeworkspring-testtest
And then we refactor our unit test to be a standard spring unit class. What we need to do is to
extend AbstractJUnit38SpringContextTests instead of TestCase in our unit test.
Since Spring 2.5 embraces annotations we will use one as well to instruct what our xml
configuration file is located:
@ContextConfiguration(locations = "classpath:axis-example-context.xml")
public class ReportIncidentServiceTest extends AbstractJUnit38SpringContextTests {
What we must remember to add is the classpath: prefix as our xml file is located in src/
main/resources. If we omit the prefix then Spring will by default try to locate the xml file
in the current package and that is org.apache.camel.example.axis. If the xml file is located
outside the classpath you can use file: prefix instead. So with these two modifications we can
get rid of all the setup and teardown code we had before and now we will test our real
configuration.
The last change is to get hold of the producer template and now we can just refer to the
bean id it has in the spring xml file:
So we get hold of it by just getting it from the spring ApplicationContext as all spring users is
used to do:
// get a producer template from the the spring context
ProducerTemplate template = (ProducerTemplate)
applicationContext.getBean("camelTemplate");
// inject it on our service using the setter
service.setTemplate(template);
Now our unit test is much better, and a real power of Camel is that is fits nicely with Spring
and you can use standard Spring'ish unit test to test your Camel applications as well.
Unit Test calling WebService
What if you would like to execute a unit test where you send a webservice request to the
AxisReportIncidentService how do we unit test this one? Well first of all the code is
merely just a delegate to our real service that we have just tested, but nevertheless its a good
question and we would like to know how. Well the answer is that we can exploit that fact that
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Jetty is also a slim web container that can be embedded anywhere just as Camel can. So we add
this to our pom.xml:
org.mortbay.jettyjetty${jetty-version}test
Then we can create a new class AxisReportIncidentServiceTest to unit test with Jetty.
The code to setup Jetty is shown below with code comments:
public class AxisReportIncidentServiceTest extends TestCase {
private Server server;
private void startJetty() throws Exception {
// create an embedded Jetty server
server = new Server();
// add a listener on port 8080 on localhost (127.0.0.1)
Connector connector = new SelectChannelConnector();
connector.setPort(8080);
connector.setHost("127.0.0.1");
server.addConnector(connector);
// add our web context path
WebAppContext wac = new WebAppContext();
wac.setContextPath("/unittest");
// set the location of the exploded webapp where WEB-INF is located
// this is a nice feature of Jetty where we can point to src/main/webapp
wac.setWar("./src/main/webapp");
server.setHandler(wac);
// then start Jetty
server.setStopAtShutdown(true);
server.start();
}
@Override
protected void setUp() throws Exception {
super.setUp();
startJetty();
}
@Override
protected void tearDown() throws Exception {
super.tearDown();
server.stop();
}
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}
Now we just need to send the incident as a webservice request using Axis. So we add the
following code:
public void testReportIncidentWithAxis() throws Exception {
// the url to the axis webservice exposed by jetty
URL url = new URL("http://localhost:8080/unittest/services/
ReportIncidentPort");
// Axis stuff to get the port where we can send the webservice request
ReportIncidentService_ServiceLocator locator = new
ReportIncidentService_ServiceLocator();
ReportIncidentService_PortType port = locator.getReportIncidentPort(url);
// create input to send
InputReportIncident input = createDummyIncident();
// send the webservice and get the response
OutputReportIncident output = port.reportIncident(input);
assertEquals("OK", output.getCode());
// should generate a file also
File file = new File("target/" + input.getIncidentId() + ".txt");
assertTrue("File should exists", file.exists());
}
protected InputReportIncident createDummyIncident() {
InputReportIncident input = new InputReportIncident();
input.setEmail("davsclaus@apache.org");
input.setIncidentId("12345678");
input.setIncidentDate("2008-07-13");
input.setPhone("+45 2962 7576");
input.setSummary("Failed operation");
input.setDetails("The wrong foot was operated.");
input.setFamilyName("Ibsen");
input.setGivenName("Claus");
return input;
}
And now we have an unittest that sends a webservice request using good old Axis.
Annotations
Both Camel and Spring has annotations that can be used to configure and wire trivial settings
more elegantly. Camel has the endpoint annotation @EndpointInjected that is just what
we need. With this annotation we can inject the endpoint into our service. The annotation
takes either a name or uri parameter. The name is the bean id in the Registry. The uri is the
URI configuration for the endpoint. Using this you can actually inject an endpoint that you have
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not defined in the camel context. As we have defined our endpoint with the id backup we use
the name parameter.
@EndpointInject(name = "backup")
private ProducerTemplate template;
Camel is smart as @EndpointInjected supports different kinds of object types. We like
the ProducerTemplate so we just keep it as it is.
Since we use annotations on the field directly we do not need to set the property in the spring
xml file so we change our service bean:
Running the unit test with mvn test reveals that it works nicely.
And since we use the @EndpointInjected that refers to the endpoint with the id
backup directly we can loose the template tag in the xml, so its shorter:
And the final touch we can do is that since the endpoint is injected with concrete endpoint to
use we can remove the "backup" name parameter when we send the message. So we change
from:
// send the data to the endpoint and the header contains what filename it
should be stored as
template.sendBodyAndHeader("backup", data, "org.apache.camel.file.name",
filename);
To without the name:
// send the data to the endpoint and the header contains what filename it
should be stored as
template.sendBodyAndHeader(data, "org.apache.camel.file.name", filename);
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Then we avoid to duplicate the name and if we rename the endpoint name then we don't forget
to change it in the code also.
The End
This tutorial hasn't really touched the one of the key concept of Camel as a powerful routing
and mediation framework. But we wanted to demonstrate its flexibility and that it integrates
well with even older frameworks such as Apache Axis 1.4.
Check out the other tutorials on Camel and the other examples.
Note that the code shown here also applies to Camel 1.4 so actually you can get started
right away with the released version of Camel. As this time of writing Camel 1.5 is work in
progress.
See Also
▪ Tutorials
▪ Examples
TUTORIAL ON USING CAMEL IN A WEB APPLICATION
Camel has been designed to work great with the Spring framework; so if you are already a
Spring user you can think of Camel as just a framework for adding to your Spring XML files.
So you can follow the usual Spring approach to working with web applications; namely to
add the standard Spring hook to load a /WEB-INF/applicationContext.xml file. In that
file you can include your usual Camel XML configuration.
Step1: Edit your web.xml
To enable spring add a context loader listener to your /WEB-INF/web.xml file
org.springframework.web.context.ContextLoaderListener
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This will cause Spring to boot up and look for the /WEB-INF/applicationContext.xml
file.
Step 2: Create a /WEB-INF/applicationContext.xml file
Now you just need to create your Spring XML file and add your camel routes or configuration.
For example
Then boot up your web application and you're good to go!
Hints and Tips
If you use Maven to build your application your directory tree will look like this...
src/main/webapp/WEB-INF
web.xml
applicationContext.xml
You should update your Maven pom.xml to enable WAR packaging/naming like this...
...
war
...
[desired WAR file name]
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...
To enable more rapid development we highly recommend the jetty:run maven plugin.
Please refer to the help for more information on using jetty:run - but briefly if you add the
following to your pom.xml
org.mortbay.jettymaven-jetty-plugin/10
Then you can run your web application as follows
mvn jetty:run
Then Jetty will also monitor your target/classes directory and your src/main/webapp directory
so that if you modify your spring XML, your web.xml or your java code the web application will
be restarted, re-creating your Camel routes.
If your unit tests take a while to run, you could miss them out when running your web
application via
mvn -Dtest=false jetty:run
TUTORIAL BUSINESS PARTNERS
BACKGROUND AND INTRODUCTION
Business Background
So there's a company, which we'll call Acme. Acme sells widgets, in a fairly unusual way. Their
customers are responsible for telling Acme what they purchased. The customer enters into
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Under Construction
This tutorial is a work in progress.
their own systems (ERP or whatever) which widgets they bought from Acme. Then at some
point, their systems emit a record of the sale which needs to go to Acme so Acme can bill them
for it. Obviously, everyone wants this to be as automated as possible, so there needs to be
integration between the customer's system and Acme.
Sadly, Acme's sales people are, technically speaking, doormats. They tell all their prospects,
"you can send us the data in whatever format, using whatever protocols, whatever. You just
can't change once it's up and running."
The result is pretty much what you'd expect. Taking a random sample of 3 customers:
• Customer 1: XML over FTP
• Customer 2: CSV over HTTP
• Customer 3: Excel via e-mail
Now on the Acme side, all this has to be converted to a canonical XML format and submitted
to the Acme accounting system via JMS. Then the Acme accounting system does its stuff and
sends an XML reply via JMS, with a summary of what it processed (e.g. 3 line items accepted,
line item #2 in error, total invoice $123.45). Finally, that data needs to be formatted into an email, and sent to a contact at the customer in question ("Dear Joyce, we received an invoice on
1/2/08. We accepted 3 line items totaling $123.45, though there was an error with line items
#2 [invalid quantity ordered]. Thank you for your business. Love, Acme.").
So it turns out Camel can handle all this:
• Listen for HTTP, e-mail, and FTP files
• Grab attachments from the e-mail messages
• Convert XML, XLS, and CSV files to a canonical XML format
• read and write JMS messages
• route based on company ID
• format e-mails using Velocity templates
• send outgoing e-mail messages
Tutorial Background
This tutorial will cover all that, plus setting up tests along the way.
Before starting, you should be familiar with:
• Camel concepts including the CamelContext, Routes, Components and Endpoints,
and Enterprise Integration Patterns
• Configuring Camel with the XML or Java DSL
You'll learn:
• How to set up a Maven build for a Camel project
• How to transform XML, CSV, and Excel data into a standard XML format with Camel
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◦ How to write POJOs (Plain Old Java Objects), Velocity templates, and XSLT
stylesheets that are invoked by Camel routes for message transformation
• How to configure simple and complex Routes in Camel, using either the XML or the
Java DSL format
• How to set up unit tests that load a Camel configuration and test Camel routes
• How to use Camel's Data Formats to automatically convert data between Java objects
and XML, CSV files, etc.
• How to send and receive e-mail from Camel
• How to send and receive JMS messages from Camel
• How to use Enterprise Integration Patterns including Message Router and Pipes and
Filters
◦ How to use various languages to express content-based routing rules in
Camel
• How to deal with Camel messages, headers, and attachments
You may choose to treat this as a hands-on tutorial, and work through building the code and
configuration files yourself. Each of the sections gives detailed descriptions of the steps that
need to be taken to get the components and routes working in Camel, and takes you through
tests to make sure they are working as expected.
But each section also links to working copies of the source and configuration files, so if you
don't want the hands-on approach, you can simply review and/or download the finished files.
High-Level Diagram
Here's more or less what the integration process looks like.
First, the input from the customers to Acme:
And then, the output from Acme to the customers:
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Tutorial Tasks
To get through this scenario, we're going to break it down into smaller pieces, implement and
test those, and then try to assemble the big scenario and test that.
Here's what we'll try to accomplish:
1. Create a Maven build for the project
2. Get sample files for the customer Excel, CSV, and XML input
3. Get a sample file for the canonical XML format that Acme's accounting system uses
4. Create an XSD for the canonical XML format
5. Create JAXB POJOs corresponding to the canonical XSD
6. Create an XSLT stylesheet to convert the Customer 1 (XML over FTP) messages to
the canonical format
7. Create a unit test to ensure that a simple Camel route invoking the XSLT stylesheet
works
8. Create a POJO that converts a List> to the above JAXB POJOs
◦ Note that Camel can automatically convert CSV input to a List of Lists of
Strings representing the rows and columns of the CSV, so we'll use this
POJO to handle Customer 2 (CSV over HTTP)
9. Create a unit test to ensure that a simple Camel route invoking the CSV processing
works
10. Create a POJO that converts a Customer 3 Excel file to the above JAXB POJOs
(using POI to read Excel)
11. Create a unit test to ensure that a simple Camel route invoking the Excel processing
works
12. Create a POJO that reads an input message, takes an attachment off the message, and
replaces the body of the message with the attachment
◦ This is assuming for Customer 3 (Excel over e-mail) that the e-mail contains
a single Excel file as an attachment, and the actual e-mail body is throwaway
13. Build a set of Camel routes to handle the entire input (Customer -> Acme) side of
the scenario.
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14. Build unit tests for the Camel input.
15. TODO: Tasks for the output (Acme -> Customer) side of the scenario
LET'S GET STARTED!
Step 1: Initial Maven build
We'll use Maven for this project as there will eventually be quite a few dependencies and it's
nice to have Maven handle them for us. You should have a current version of Maven (e.g. 2.0.9)
installed.
You can start with a pretty empty project directory and a Maven POM file, or use a simple
JAR archetype to create one.
Here's a sample POM. We've added a dependency on camel-core, and set the compile
version to 1.5 (so we can use annotations):
Listing 18. pom.xml
4.0.0org.apache.camel.tutorialbusiness-partners1.0-SNAPSHOTCamel Business Partners Tutorialcamel-coreorg.apache.camel1.4.0org.apache.maven.pluginsmaven-compiler-plugin1.51.5
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Step 2: Get Sample Files
You can make up your own if you like, but here are the "off the shelf" ones. You can save
yourself some time by downloading these to src/test/resources in your Maven project.
• Customer 1 (XML): input-customer1.xml
• Customer 2 (CSV): input-customer2.csv
• Customer 3 (Excel): input-customer3.xls
• Canonical Acme XML Request: canonical-acme-request.xml
• Canonical Acme XML Response: TODO
If you look at these files, you'll see that the different input formats use different field names and/
or ordering, because of course the sales guys were totally OK with that. Sigh.
Step 3: XSD and JAXB Beans for the Canonical XML Format
Here's the sample of the canonical XML file:
29/12/2008134A widget310.456/5/2008218.82
If you're ambitions, you can write your own XSD (XML Schema) for files that look like this, and
save it to src/main/xsd.
Solution: If not, you can download mine, and save that to save it to src/main/xsd.
Generating JAXB Beans
Down the road we'll want to deal with the XML as Java POJOs. We'll take a moment now to
set up those XML binding POJOs. So we'll update the Maven POM to generate JAXB beans
from the XSD file.
We need a dependency:
camel-jaxborg.apache.camel
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1.4.0
And a plugin configured:
org.codehaus.mojojaxb2-maven-pluginxjc
That should do it (it automatically looks for XML Schemas in src/main/xsd to generate
beans for). Run mvn install and it should emit the beans into target/generatedsources/jaxb. Your IDE should see them there, though you may need to update the
project to reflect the new settings in the Maven POM.
Step 4: Initial Work on Customer 1 Input (XML over FTP)
To get a start on Customer 1, we'll create an XSLT template to convert the Customer 1
sample file into the canonical XML format, write a small Camel route to test it, and build that
into a unit test. If we get through this, we can be pretty sure that the XSLT template is valid and
can be run safely in Camel.
Create an XSLT template
Start with the Customer 1 sample input. You want to create an XSLT template to generate
XML like the canonical XML sample above Ð an invoice element with line-item
elements (one per item in the original XML document). If you're especially clever, you can
populate the current date and order total elements too.
Solution: My sample XSLT template isn't that smart, but it'll get you going if you don't
want to write one of your own.
Create a unit test
Here's where we get to some meaty Camel work. We need to:
• Set up a unit test
• That loads a Camel configuration
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• That has a route invoking our XSLT
• Where the test sends a message to the route
• And ensures that some XML comes out the end of the route
The easiest way to do this is to set up a Spring context that defines the Camel stuff, and then
use a base unit test class from Spring that knows how to load a Spring context to run tests
against. So, the procedure is:
Set Up a Skeletal Camel/Spring Unit Test
1. Add dependencies on Camel-Spring, and the Spring test JAR (which will automatically
bring in JUnit 3.8.x) to your POM:
camel-springorg.apache.camel1.4.0spring-testorg.springframework2.5.5test
2. Create a new unit test class in src/test/java/your-package-here, perhaps
called XMLInputTest.java
3. Make the test extend Spring's AbstractJUnit38SpringContextTests class, so it can load
a Spring context for the test
4. Create a Spring context configuration file in src/test/resources, perhaps
called XMLInputTest-context.xml
5. In the unit test class, use the class-level @ContextConfiguration annotation to
indicate that a Spring context should be loaded
◦ By default, this looks for a Context configuration file called
TestClassName-context.xml in a subdirectory corresponding to the
package of the test class. For instance, if your test class was
org.apache.camel.tutorial.XMLInputTest, it would look for
org/apache/camel/tutorial/XMLInputTest-context.xml
◦ To override this default, use the locations attribute on the
@ContextConfiguration annotation to provide specific context file
locations (starting each path with a / if you don't want it to be relative to
the package directory). My solution does this so I can put the context file
directly in src/test/resources instead of in a package directory
under there.
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6. Add a CamelContext instance variable to the test class, with the @Autowired
annotation. That way Spring will automatically pull the CamelContext out of the
Spring context and inject it into our test class.
7. Add a ProducerTemplate instance variable and a setUp method that instantiates it
from the CamelContext. We'll use the ProducerTemplate later to send messages to
the route.
protected ProducerTemplate template;
protected void setUp() throws Exception {
super.setUp();
template = camelContext.createProducerTemplate();
}
8. Put in an empty test method just for the moment (so when we run this we can see
that "1 test succeeded")
9. Add the Spring element (including the Camel Namespace) with an empty
element to the Spring context, like this:
Test it by running mvn install and make sure there are no build errors. So far it doesn't test
much; just that your project and test and source files are all organized correctly, and the one
empty test method completes successfully.
Solution: Your test class might look something like this:
• src/test/java/org/apache/camel/tutorial/XMLInputTest.java
• src/test/resources/XMLInputTest-context.xml (same as just above)
Flesh Out the Unit Test
So now we're going to write a Camel route that applies the XSLT to the sample Customer 1
input file, and makes sure that some XML output comes out:
1. Save the input-customer1.xml file to src/test/resources
2. Save your XSLT file (created in the previous step) to src/main/resources
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3. Write a Camel Route, either right in the Spring XML, or using the Java DSL (in
another class under src/test/java somewhere). This route should use the Pipes
and Filters integration pattern to:
1. Start from the endpoint direct:start (which lets the test conveniently pass
messages into the route)
2. Call the endpoint xslt:YourXSLTFile.xsl (to transform the message with the
specified XSLT template)
3. Send the result to the endpoint mock:finish (which lets the test verify the
route output)
4. Add a test method to the unit test class that:
1. Get a reference to the Mock endpoint mock:finish using code like this:
MockEndpoint finish = MockEndpoint.resolve(camelContext,
"mock:finish");
2. Set the expectedMessageCount on that endpoint to 1
3. Get a reference to the Customer 1 input file, using code like this:
InputStream in =
XMLInputTest.class.getResourceAsStream("/input-partner1.xml");
assertNotNull(in);
4. Send that InputStream as a message to the direct:start endpoint,
using code like this:
template.sendBody("direct:start", in);
Note that we can send the sample file body in several formats (File,
InputStream, String, etc.) but in this case an InputStream is pretty
convenient.
5. Ensure that the message made it through the route to the final endpoint, by
testing all configured Mock endpoints like this:
MockEndpoint.assertIsSatisfied(camelContext);
6. If you like, inspect the final message body using some code like
finish.getExchanges().get(0).getIn().getBody().
▪ If you do this, you'll need to know what format that body is Ð
String, byte array, InputStream, etc.
5. Run your test with mvn install and make sure the build completes successfully.
Solution: Your finished test might look something like this:
• src/test/java/org/apache/camel/tutorial/XMLInputTest.java
• For XML Configuration:
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◦ src/test/resources/XMLInputTest-context.xml
• Or, for Java DSL Configuration:
◦ src/test/resources/XMLInputTest-dsl-context.xml
◦ src/test/java/org/apache/camel/tutorial/routes/XMLInputTestRoute.java
Step 5: Initial Work on Customer 2 Input (CSV over HTTP)
To get a start on Customer 2, we'll create a POJO to convert the Customer 2 sample CSV data
into the JAXB POJOs representing the canonical XML format, write a small Camel route to test
it, and build that into a unit test. If we get through this, we can be pretty sure that the CSV
conversion and JAXB handling is valid and can be run safely in Camel.
Create a CSV-handling POJO
To begin with, CSV is a known data format in Camel. Camel can convert a CSV file to a List
(representing rows in the CSV) of Lists (representing cells in the row) of Strings (the data for
each cell). That means our POJO can just assume the data coming in is of type
List>, and we can declare a method with that as the argument.
Looking at the JAXB code in target/generated-sources/jaxb, it looks like an
Invoice object represents the whole document, with a nested list of LineItemType objects
for the line items. Therefore our POJO method will return an Invoice (a document in the
canonical XML format).
So to implement the CSV-to-JAXB POJO, we need to do something like this:
1. Create a new class under src/main/java, perhaps called CSVConverterBean.
2. Add a method, with one argument of type List> and the return
type Invoice
◦ You may annotate the argument with @Body to specifically designate it as
the body of the incoming message
3. In the method, the logic should look roughly like this:
1. Create a new Invoice, using the method on the generated
ObjectFactory class
2. Loop through all the rows in the incoming CSV (the outer List)
3. Skip the first row, which contains headers (column names)
4. For the other rows:
1. Create a new LineItemType (using the ObjectFactory
again)
2. Pick out all the cell values (the Strings in the inner List) and put
them into the correct fields of the LineItemType
▪ Not all of the values will actually go into the line item in
this example
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Test Base Class
Once your test class is working, you might want to extract things like the
@Autowired CamelContext, the ProducerTemplate, and the setUp method to a
custom base class that you extend with your other tests.
▪ You may hardcode the column ordering based on the
sample data file, or else try to read it dynamically from
the headers in the first line
▪ Note that you'll need to use a JAXB
DatatypeFactory to create the
XMLGregorianCalendar values that JAXB uses for
the date fields in the XML Ð which probably means
using a SimpleDateFormat to parse the date and
setting that date on a GregorianCalendar
3. Add the line item to the invoice
5. Populate the partner ID, date of receipt, and order total on the Invoice
6. Throw any exceptions out of the method, so Camel knows something went
wrong
7. Return the finished Invoice
Solution: Here's an example of what the CSVConverterBean might look like.
Create a unit test
Start with a simple test class and test Spring context like last time, perhaps based on the name
CSVInputTest:
Listing 19. CSVInputTest.java
/**
* A test class the ensure we can convert Partner 2 CSV input files to the
* canonical XML output format, using JAXB POJOs.
*/
@ContextConfiguration(locations = "/CSVInputTest-context.xml")
public class CSVInputTest extends AbstractJUnit38SpringContextTests {
@Autowired
protected CamelContext camelContext;
protected ProducerTemplate template;
protected void setUp() throws Exception {
super.setUp();
template = camelContext.createProducerTemplate();
}
public void testCSVConversion() {
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200
// TODO
}
}
Listing 20. CSVInputTest-context.xml
Now the meaty part is to flesh out the test class and write the Camel routes.
1. Update the Maven POM to include CSV Data Format support:
camel-csvorg.apache.camel1.4.0
2. Write the routes (right in the Spring XML context, or using the Java DSL) for the
CSV conversion process, again using the Pipes and Filters pattern:
1. Start from the endpoint direct:CSVstart (which lets the test conveniently
pass messages into the route). We'll name this differently than the starting
point for the previous test, in case you use the Java DSL and put all your
routes in the same package (which would mean that each test would load
the DSL routes for several tests.)
2. This time, there's a little preparation to be done. Camel doesn't know that
the initial input is a CSV, so it won't be able to convert it to the expected
List> without a little hint. For that, we need an
unmarshal transformation in the route. The unmarshal method (in the
DSL) or element (in the XML) takes a child indicating the format to
unmarshal; in this case that should be csv.
3. Next invoke the POJO to transform the message with a
bean:CSVConverter endpoint
4. As before, send the result to the endpoint mock:finish (which lets the test
verify the route output)
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TU TO RI A L S
5. Finally, we need a Spring element in the Spring context XML file
(but outside the element) to define the Spring bean
that our route invokes. This Spring bean should have a name attribute that
matches the name used in the bean endpoint (CSVConverter in the
example above), and a class attribute that points to the CSV-to-JAXB
POJO class you wrote above (such as,
org.apache.camel.tutorial.CSVConverterBean). When
Spring is in the picture, any bean endpoints look up Spring beans with the
specified name.
3. Write a test method in the test class, which should look very similar to the previous
test class:
1. Get the MockEndpoint for the final endpoint, and tell it to expect one
message
2. Load the Partner 2 sample CSV file from the ClassPath, and send it as the
body of a message to the starting endpoint
3. Verify that the final MockEndpoint is satisfied (that is, it received one
message) and examine the message body if you like
▪ Note that we didn't marshal the JAXB POJOs to XML in this test,
so the final message should contain an Invoice as the body. You
could write a simple line of code to get the Exchange (and
Message) from the MockEndpoint to confirm that.
4. Run this new test with mvn install and make sure it passes and the build completes
successfully.
Solution: Your finished test might look something like this:
• src/test/java/org/apache/camel/tutorial/CSVInputTest.java
• For XML Configuration:
◦ src/test/resources/CSVInputTest-context.xml
• Or, for Java DSL Configuration:
◦ src/test/resources/CSVInputTest-dsl-context.xml
◦ src/test/java/org/apache/camel/tutorial/routes/CSVInputTestRoute.java
Step 6: Initial Work on Customer 3 Input (Excel over e-mail)
To get a start on Customer 3, we'll create a POJO to convert the Customer 3 sample Excel
data into the JAXB POJOs representing the canonical XML format, write a small Camel route
to test it, and build that into a unit test. If we get through this, we can be pretty sure that the
Excel conversion and JAXB handling is valid and can be run safely in Camel.
Create an Excel-handling POJO
Camel does not have a data format handler for Excel by default. We have two options Ð create
an Excel DataFormat (so Camel can convert Excel spreadsheets to something like the CSV
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202
List> automatically), or create a POJO that can translate Excel data
manually. For now, the second approach is easier (if we go the DataFormat route, we need
code to both read and write Excel files, whereas otherwise read-only will do).
So, we need a POJO with a method that takes something like an InputStream or
byte[] as an argument, and returns in Invoice as before. The process should look
something like this:
1. Update the Maven POM to include POI support:
poiorg.apache.poi3.1-FINAL
2. Create a new class under src/main/java, perhaps called
ExcelConverterBean.
3. Add a method, with one argument of type InputStream and the return type
Invoice
◦ You may annotate the argument with @Body to specifically designate it as
the body of the incoming message
4. In the method, the logic should look roughly like this:
1. Create a new Invoice, using the method on the generated
ObjectFactory class
2. Create a new HSSFWorkbook from the InputStream, and get the first
sheet from it
3. Loop through all the rows in the sheet
4. Skip the first row, which contains headers (column names)
5. For the other rows:
1. Create a new LineItemType (using the ObjectFactory
again)
2. Pick out all the cell values and put them into the correct fields of
the LineItemType (you'll need some data type conversion
logic)
▪ Not all of the values will actually go into the line item in
this example
▪ You may hardcode the column ordering based on the
sample data file, or else try to read it dynamically from
the headers in the first line
▪ Note that you'll need to use a JAXB
DatatypeFactory to create the
XMLGregorianCalendar values that JAXB uses for
the date fields in the XML Ð which probably means
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TU TO RI A L S
setting the date from a date cell on a
GregorianCalendar
3. Add the line item to the invoice
6. Populate the partner ID, date of receipt, and order total on the Invoice
7. Throw any exceptions out of the method, so Camel knows something went
wrong
8. Return the finished Invoice
Solution: Here's an example of what the ExcelConverterBean might look like.
Create a unit test
The unit tests should be pretty familiar now. The test class and context for the Excel bean
should be quite similar to the CSV bean.
1. Create the basic test class and corresponding Spring Context XML configuration file
2. The XML config should look a lot like the CSV test, except:
◦ Remember to use a different start endpoint name if you're using the Java
DSL and not use separate packages per test
◦ You don't need the unmarshal step since the Excel POJO takes the raw
InputStream from the source endpoint
◦ You'll declare a and endpoint for the Excel bean prepared above
instead of the CSV bean
3. The test class should look a lot like the CSV test, except use the right input file name
and start endpoint name.
Solution: Your finished test might look something like this:
• src/test/java/org/apache/camel/tutorial/ExcelInputTest.java
• For XML Configuration:
◦ src/test/resources/ExcelInputTest-context.xml
• Or, for Java DSL Configuration:
◦ src/test/resources/ExcelInputTest-dsl-context.xml
◦ src/test/java/org/apache/camel/tutorial/routes/ExcelInputTestRoute.java
Step 7: Put this all together into Camel routes for the Customer Input
With all the data type conversions working, the next step is to write the real routes that listen
for HTTP, FTP, or e-mail input, and write the final XML output to an ActiveMQ queue. Along
the way these routes will use the data conversions we've developed above.
So we'll create 3 routes to start with, as shown in the diagram back at the beginning:
1. Accept XML orders over FTP from Customer 1 (we'll assume the FTP server dumps
files in a local directory on the Camel machine)
2. Accept CSV orders over HTTP from Customer 2
3. Accept Excel orders via e-mail from Customer 3 (we'll assume the messages are sent
to an account we can access via IMAP)
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204
Logging
You may notice that your tests emit a lot less output all of a sudden. The
dependency on POI brought in Log4J and configured commons-logging to use it, so
now we need a log4j.properties file to configure log output. You can use the
attached one (snarfed from ActiveMQ) or write your own; either way save it to
src/main/resources to ensure you continue to see log output.
...
Step 8: Create a unit test for the Customer Input Routes
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TU TO RI A L S
Languages Supported Appendix
To support flexible and powerful Enterprise Integration Patterns Camel supports various
Languages to create an Expression or Predicate within either the Routing Domain Specific
Language or the Xml Configuration. The following languages are supported
BEAN LANGUAGE
The purpose of the Bean Language is to be able to implement an Expression or Predicate using
a simple method on a bean.
So the idea is you specify a bean name which will then be resolved in the Registry such as
the Spring ApplicationContext then a method is invoked to evaluate the Expression or
Predicate.
If no method name is provided then one is attempted to be chosen using the rules for Bean
Binding; using the type of the message body and using any annotations on the bean methods.
The Bean Binding rules are used to bind the Message Exchange to the method parameters;
so you can annotate the bean to extract headers or other expressions such as XPath or
XQuery from the message.
Using Bean Expressions from the Java DSL
from("activemq:topic:OrdersTopic").
filter().method("myBean", "isGoldCustomer").
to("activemq:BigSpendersQueue");
Using Bean Expressions from XML
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Writing the expression bean
The bean in the above examples is just any old Java Bean with a method called
isGoldCustomer() that returns some object that is easily converted to a boolean value in this
case, as its used as a predicate.
So we could implement it like this...
public class MyBean {
public boolean isGoldCustomer(Exchange exchange) {
...
}
}
We can also use the Bean Integration annotations. For example you could do...
public boolean isGoldCustomer(String body) {...}
or
public boolean isGoldCustomer(@Header(name = "foo") Integer fooHeader) {...}
So you can bind parameters of the method to the Exchange, the Message or individual headers,
properties, the body or other expressions.
Non registry beans
As of Camel 1.5 the Bean Language also supports invoking beans that isn't registered in the
Registry. This is usable for quickly to invoke a bean from Java DSL where you don't need to
register the bean in the Registry such as the Spring ApplicationContext.
Camel can instantiate the bean and invoke the method if given a class or invoke an already
existing instance. This is illustrated from the example below:
NOTE This bean DSL is supported since Camel 2.0-M2
from("activemq:topic:OrdersTopic").
filter().expression(BeanLanguage(MyBean.class, "isGoldCustomer")).
to("activemq:BigSpendersQueue");
The 2nd parameter isGoldCustomer is an optional parameter to explicit set the method
name to invoke. If not provided Camel will try to invoke the best suited method. If case of
ambiguity Camel will thrown an Exception. In these situations the 2nd parameter can solve this
problem. Also the code is more readable if the method name is provided. The 1st parameter
can also be an existing instance of a Bean such as:
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L A N G U A G E S S U P P OR T E D A P P E ND I X
private MyBean my;
from("activemq:topic:OrdersTopic").
filter().expression(BeanLanguage.bean(my, "isGoldCustomer")).
to("activemq:BigSpendersQueue");
In Camel 2.2 onwards you can avoid the BeanLanguage and have it just as:
private MyBean my;
from("activemq:topic:OrdersTopic").
filter().expression(bean(my, "isGoldCustomer")).
to("activemq:BigSpendersQueue");
Which also can be done in a bit shorter and nice way:
private MyBean my;
from("activemq:topic:OrdersTopic").
filter().method(my, "isGoldCustomer").
to("activemq:BigSpendersQueue");
Other examples
We have some test cases you can look at if it'll help
• MethodFilterTest is a JUnit test case showing the Java DSL use of the bean expression
being used in a filter
• aggregator.xml is a Spring XML test case for the Aggregator which uses a bean
method call to test for the completion of the aggregation.
Dependencies
The Bean language is part of camel-core.
CONSTANT EXPRESSION LANGUAGE
The Constant Expression Language is really just a way to specify constant strings as a type of
expression.
Available as of Camel 1.5
Example usage
The setHeader element of the Spring DSL can utilize a constant expression like:
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the value
in this case, the Message coming from the seda:a Endpoint will have 'theHeader' header set to
the constant value 'the value'.
And the same example using Java DSL:
from("seda:a").setHeader("theHeader", constant("the value")).to("mock:b");
Dependencies
The Constant language is part of camel-core.
EL
Camel supports the unified JSP and JSF Expression Language via the JUEL to allow an Expression
or Predicate to be used in the DSL or Xml Configuration.
For example you could use EL inside a Message Filter in XML
${in.headers.foo == 'bar'}
You could also use slightly different syntax, e.g. if the header name is not a valid identifier:
${in.headers['My Header'] == 'bar'}
You could use EL to create an Predicate in a Message Filter or as an Expression for a Recipient
List
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Variables
Variable
Type
Description
exchange
Exchange
the Exchange object
in
Message
the exchange.in message
out
Message
the exchange.out message
Samples
You can use EL dot notation to invoke operations. If you for instance have a body that contains
a POJO that has a getFamiliyName method then you can construct the syntax as follows:
"$in.body.familyName"
Dependencies
To use EL in your camel routes you need to add the a dependency on camel-juel which
implements the EL language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-juel1.6.1
Otherwise you'll also need to include JUEL.
HEADER EXPRESSION LANGUAGE
The Header Expression Language allows you to extract values of named headers.
Available as of Camel 1.5
Example usage
The recipientList element of the Spring DSL can utilize a header expression like:
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myHeader
In this case, the list of recipients are contained in the header 'myHeader'.
And the same example in Java DSL:
from("direct:a").recipientList(header("myHeader"));
And with a slightly different syntax where you use the builder to the fullest (i.e. avoid using
parameters but using stacked operations, notice that header is not a parameter but a stacked
method call)
from("direct:a").recipientList().header("myHeader");
Dependencies
The Header language is part of camel-core.
JXPATH
Camel supports JXPath to allow XPath expressions to be used on beans in an Expression or
Predicate to be used in the DSL or Xml Configuration. For example you could use JXPath to
create an Predicate in a Message Filter or as an Expression for a Recipient List.
From 1.3 of Camel onwards you can use XPath expressions directly using smart completion
in your IDE as follows
from("queue:foo").filter().
jxpath("/in/body/foo").
to("queue:bar")
Variables
211
Variable
Type
Description
this
Exchange
the Exchange object
in
Message
the exchange.in message
out
Message
the exchange.out message
L A N G U A G E S S U P P OR T E D A P P E ND I X
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use JXPath
expressions as follows
in/body/name = 'James'
Examples
Here is a simple example using a JXPath expression as a predicate in a Message Filter
from("direct:start").
filter().jxpath("in/body/name='James'").
to("mock:result");
JXPATH INJECTION
You can use Bean Integration to invoke a method on a bean and use various languages such as
JXPath to extract a value from the message and bind it to a method parameter.
For example
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@JXPath("in/body/foo") String correlationID, @Body String
body) {
// process the inbound message here
}
}
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Dependencies
To use JXpath in your camel routes you need to add the a dependency on camel-jxpath
which implements the JXpath language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-jxpath1.4.0
Otherwise, you'll also need Commons JXPath.
MVEL
Avialable in Camel 2.0
Camel allows Mvel to be used as an Expression or Predicate the DSL or Xml Configuration.
You could use Mvel to create an Predicate in a Message Filter or as an Expression for a
Recipient List
You can use Mvel dot notation to invoke operations. If you for instance have a body that
contains a POJO that has a getFamiliyName method then you can construct the syntax as
follows:
"request.body.familyName"
// or
"getRequest().getBody().getFamilyName()"
Variables
213
Variable
Type
Description
this
Exchange
the Exchange is the root object
exchange
Exchange
the Exchange object
exception
Throwable
the Exchange exception (if any)
exchangeId
String
the exchange id
fault
Message
the Fault message (if any)
request
Message
the exchange.in message
response
Message
the exchange.out message (if any)
L A N G U A G E S S U P P OR T E D A P P E ND I X
properties
Map
the exchange properties
property(name)
Object
the property by the given name
property(name, type)
Type
the property by the given name as the given type
Samples
For example you could use Mvel inside a Message Filter in XML
request.headers.foo == 'bar'
And the sample using Java DSL:
from("seda:foo").filter().mvel("request.headers.foo == 'bar'").to("seda:bar");
Dependencies
To use Mvel in your camel routes you need to add the a dependency on camel-mvel which
implements the Mvel language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-mvel2.0.0
Otherwise, you'll also need MVEL
OGNL
Camel allows OGNL to be used as an Expression or Predicate the DSL or Xml Configuration.
You could use OGNL to create an Predicate in a Message Filter or as an Expression for a
Recipient List
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You can use OGNL dot notation to invoke operations. If you for instance have a body that
contains a POJO that has a getFamiliyName method then you can construct the syntax as
follows:
"request.body.familyName"
// or
"getRequest().getBody().getFamilyName()"
Variables
Variable
Type
Description
this
Exchange
the Exchange is the root object
exchange
Exchange
the Exchange object
exception
Throwable
the Exchange exception (if any)
exchangeId
String
the exchange id
fault
Message
the Fault message (if any)
request
Message
the exchange.in message
response
Message
the exchange.out message (if any)
properties
Map
the exchange properties
property(name)
Object
the property by the given name
property(name, type)
Type
the property by the given name as the given type
Samples
For example you could use OGNL inside a Message Filter in XML
request.headers.foo == 'bar'
And the sample using Java DSL:
from("seda:foo").filter().ognl("request.headers.foo == 'bar'").to("seda:bar");
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Dependencies
To use OGNL in your camel routes you need to add the a dependency on camel-ognl which
implements the OGNL language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-ognl1.4.0
Otherwise, you'll also need OGNL
PROPERTY EXPRESSION LANGUAGE
The Property Expression Language allows you to extract values of named exchange properties.
Available as of Camel 2.0
Example usage
The recipientList element of the Spring DSL can utilize a property expression like:
myProperty
In this case, the list of recipients are contained in the property 'myProperty'.
And the same example in Java DSL:
from("direct:a").recipientList(property("myProperty"));
And with a slightly different syntax where you use the builder to the fullest (i.e. avoid using
parameters but using stacked operations, notice that property is not a parameter but a stacked
method call)
from("direct:a").recipientList().property("myProperty");
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Dependencies
The Property language is part of camel-core.
SCRIPTING LANGUAGES
Camel supports a number of scripting languages which can be used to create an Expression or
Predicate via the standard JSR 223 which is a standard part of Java 6.
The following scripting languages are integrated into the DSL:
Language
DSL keyword
EL
el
Groovy
groovy
JavaScript
javaScript
JoSQL
sql
JXPath
jxpath
MVEL
mvel
OGNL
ognl
PHP
php
Python
python
Ruby
ruby
XPath
xpath
XQuery
xquery
However any JSR 223 scripting language can be used using the generic DSL methods.
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
217
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
L A N G U A G E S S U P P OR T E D A P P E ND I X
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
properties
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
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This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
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assertMockEndpointsSatisfied();
}
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-scriptx.x.x
SEE ALSO
• Languages
• DSL
• Xml Configuration
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BEANSHELL
Camel supports BeanShell among other Scripting Languages to allow an Expression or Predicate
to be used in the DSL or Xml Configuration.
To use a BeanShell expression use the following Java code:
...choice()
.when(script("beanshell", "request.getHeaders().get(\"foo\").equals(\"bar\")"))
.to("...")
Or the something like this in your Spring XML:
request.getHeaders().get("Foo") == null
...
You could follow the examples above to create an Predicate in a Message Filter or as an
Expression for a Recipient List
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
221
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
L A N G U A G E S S U P P OR T E D A P P E ND I X
BeanShell Issues
You must use BeanShell 2.0b5 or greater. Note that as of 2.0b5 BeanShell cannot
compile scripts, which causes Camel releases before 2.6 to fail when configured
with BeanShell expressions.
properties
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
LAN GUAGES SUPPO R T ED APPEN DIX
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from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
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arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
assertMockEndpointsSatisfied();
}
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-scriptx.x.x
JAVASCRIPT
Camel supports JavaScript/ECMAScript among other Scripting Languages to allow an Expression
or Predicate to be used in the DSL or Xml Configuration.
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To use a JavaScript expression use the following Java code
... javaScript("someJavaScriptExpression") ...
For example you could use the javaScript function to create an Predicate in a Message Filter
or as an Expression for a Recipient List
Example
In the sample below we use JavaScript to create a Predicate use in the route path, to route
exchanges from admin users to a special queue.
from("direct:start")
.choice()
.when().javaScript("request.headers.get('user') ==
'admin'").to("seda:adminQueue")
.otherwise()
.to("seda:regularQueue");
And a Spring DSL sample as well:
request.headers.get('user') == 'admin'
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
225
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
L A N G U A G E S S U P P OR T E D A P P E ND I X
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
properties
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
LAN GUAGES SUPPO R T ED APPEN DIX
226
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
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L A N G U A G E S S U P P OR T E D A P P E ND I X
assertMockEndpointsSatisfied();
}
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-scriptx.x.x
GROOVY
Camel supports Groovy among other Scripting Languages to allow an Expression or Predicate
to be used in the DSL or Xml Configuration.
To use a Groovy expression use the following Java code
... groovy("someGroovyExpression") ...
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228
For example you could use the groovy function to create an Predicate in a Message Filter or
as an Expression for a Recipient List
Example
// lets route if a line item is over $100
from("queue:foo").filter(groovy("request.lineItems.any { i -> i.value > 100
}")).to("queue:bar")
And the Spring DSL:
request.lineItems.any { i -> i.value > 100 }
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
229
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
L A N G U A G E S S U P P OR T E D A P P E ND I X
properties
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
LAN GUAGES SUPPO R T ED APPEN DIX
230
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
assertMockEndpointsSatisfied();
}
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Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-scriptx.x.x
PYTHON
Camel supports Python among other Scripting Languages to allow an Expression or Predicate
to be used in the DSL or Xml Configuration.
To use a Python expression use the following Java code
... python("somePythonExpression") ...
For example you could use the python function to create an Predicate in a Message Filter or
as an Expression for a Recipient List
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232
Example
In the sample below we use Python to create a Predicate use in the route path, to route
exchanges from admin users to a special queue.
from("direct:start")
.choice()
.when().python("request.headers['user'] == 'admin'").to("seda:adminQueue")
.otherwise()
.to("seda:regularQueue");
And a Spring DSL sample as well:
request.headers['user'] == 'admin'
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
233
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
L A N G U A G E S S U P P OR T E D A P P E ND I X
properties
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
LAN GUAGES SUPPO R T ED APPEN DIX
234
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
assertMockEndpointsSatisfied();
}
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L A N G U A G E S S U P P OR T E D A P P E ND I X
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-scriptx.x.x
PHP
Camel supports PHP among other Scripting Languages to allow an Expression or Predicate to
be used in the DSL or Xml Configuration.
To use a PHP expression use the following Java code
... php("somePHPExpression") ...
For example you could use the php function to create an Predicate in a Message Filter or as an
Expression for a Recipient List
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ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
properties
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
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L A N G U A G E S S U P P OR T E D A P P E ND I X
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
LAN GUAGES SUPPO R T ED APPEN DIX
238
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
assertMockEndpointsSatisfied();
}
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
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L A N G U A G E S S U P P OR T E D A P P E ND I X
org.apache.camelcamel-scriptx.x.x
RUBY
Camel supports Ruby among other Scripting Languages to allow an Expression or Predicate to
be used in the DSL or Xml Configuration.
To use a Ruby expression use the following Java code
... ruby("someRubyExpression") ...
For example you could use the ruby function to create an Predicate in a Message Filter or as
an Expression for a Recipient List
Example
In the sample below we use Ruby to create a Predicate use in the route path, to route
exchanges from admin users to a special queue.
from("direct:start")
.choice()
.when().ruby("$request.headers['user'] == 'admin'").to("seda:adminQueue")
.otherwise()
.to("seda:regularQueue");
And a Spring DSL sample as well:
$request.headers['user'] == 'admin'
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240
ScriptContext
The JSR-223 scripting languages ScriptContext is pre configured with the following attributes all
set at ENGINE_SCOPE:
Attribute
Type
Value
context
org.apache.camel.CamelContext
The Camel
Context
exchange
org.apache.camel.Exchange
The
current
Exchange
request
org.apache.camel.Message
The IN
message
response
org.apache.camel.Message
The OUT
message
org.apache.camel.builder.script.PropertiesFunction
Camel
2.9:
Function
with a
resolve
method to
make it
easier to
use
Camels
Properties
component
from
scripts. See
further
below for
example.
properties
Attributes
You can add your own attributes with the attribute(name, value) DSL method, such
as:
In the sample below we add an attribute user that is an object we already have instantiated
as myUser. This object has a getFirstName() method that we want to set as header on the
message. We use the groovy language to concat the first and last name into a single string that
is returned.
241
L A N G U A G E S S U P P OR T E D A P P E ND I X
from("direct:in").setHeader("name").groovy("'$user.firstName
$user.lastName'").attribute("user", myUser).to("seda:users");
Any scripting language
Camel can run any JSR-223 scripting languages using the script DSL method such as:
from("direct:in").setHeader("firstName").script("jaskel",
"user.firstName").attribute("user", myUser).to("seda:users");
This is a bit different using the Spring DSL where you use the expression element that
doesn't support setting attributes (yet):
user.firstName
You can also use predicates e.g. in a Filter:
request.getHeaders().get("Foo").equals("Bar")
See Scripting Languages for the list of languages with explicit DSL support.
Some languages without specific DSL support but known to work with these generic
methods include:
Language
Implementation
language="..." value
BeanShell
BeanShell 2.0b5
beanshell or bsh
Additional arguments to ScriptingEngine
Available as of Camel 2.8
You can provide additional arguments to the ScriptingEngine using a header on the
Camel message with the key CamelScriptArguments.
See this example:
LAN GUAGES SUPPO R T ED APPEN DIX
242
public void testArgumentsExample() throws Exception {
if (!ScriptTestHelper.canRunTestOnThisPlatform()) {
return;
}
getMockEndpoint("mock:result").expectedMessageCount(0);
getMockEndpoint("mock:unmatched").expectedMessageCount(1);
// additional arguments to ScriptEngine
Map arguments = new HashMap();
arguments.put("foo", "bar");
arguments.put("baz", 7);
// those additional arguments is provided as a header on the Camel Message
template.sendBodyAndHeader("direct:start", "hello", ScriptBuilder.ARGUMENTS,
arguments);
assertMockEndpointsSatisfied();
}
Using properties function
Available as of Camel 2.9
If you need to use the Properties component from a script to lookup property placeholders,
then its a bit cumbersome to do so.
For example to set a header name myHeader with a value from a property placeholder, which
key is provided in a header named "foo".
.setHeader("myHeader").groovy("context.resolvePropertyPlaceholders('{{' +
request.headers.get('foo') + '}}')")
From Camel 2.9 onwards you can now use the properties function and the same example is
simpler:
.setHeader("myHeader").groovy("properties.resolve(request.headers.get('foo'))")
Dependencies
To use scripting languages in your camel routes you need to add the a dependency on camelscript which integrates the JSR-223 scripting engine.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
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L A N G U A G E S S U P P OR T E D A P P E ND I X
org.apache.camelcamel-scriptx.x.x
SIMPLE EXPRESSION LANGUAGE
The Simple Expression Language was a really simple language you can use, but has since grown
more powerful. Its primarily intended for being a really small and simple language for evaluating
Expression and Predicate without requiring any new dependencies or knowledge of XPath; so
its ideal for testing in camel-core. Its ideal to cover 95% of the common use cases when you
need a little bit of expression based script in your Camel routes.
However for much more complex use cases you are generally recommended to choose a
more expressive and powerful language such as:
• JavaScript
• EL
• OGNL
• Mvel
• Groovy
• one of the supported Scripting Languages
The simple language uses ${body} placeholders for complex expressions where the
expression contains constant literals. The ${ } placeholders can be omitted if the expression is
only the token itself.
To get the body of the in message: "body", or "in.body" or "${body}".
A complex expression must use ${ } placeholders, such as: "Hello
${in.header.name} how are you?".
You can have multiple functions in the same expression: "Hello ${in.header.name}
this is ${in.header.me} speaking".
However you can not nest functions in Camel 2.8.x or older (i.e. having another ${ }
placeholder in an existing, is not allowed).
From Camel 2.9 onwards you can nest functions.
Variables
Variable
Type
Description
exchangeId
String
Camel 2.3: the exchange id
id
String
the input message id
body
Object
the input body
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Alternative syntax
From Camel 2.5 onwards you can also use the alternative syntax which uses
$simple{ } as placeholders.
This can be used in situations to avoid clashes when using for example Spring
property placeholder together with Camel.
Configuring result type
From Camel 2.8 onwards you can configure the result type of the Simple
expression. For example to set the type as a java.lang.Boolean or a
java.lang.Integer etc.
File language is now merged with Simple language
From Camel 2.2 onwards, the File Language is now merged with Simple language
which means you can use all the file syntax directly within the simple language.
Simple Language Changes in Camel 2.9 onwards
The Simple language have been improved from Camel 2.9 onwards to use a better
syntax parser, which can do index precise error messages, so you know exactly
what is wrong and where the problem is. For example if you have made a typo in
one of the operators, then previously the parser would not be able to detect this,
and cause the evaluation to be true. There is a few changes in the syntax which are
no longer backwards compatible. When using Simple language as a Predicate then
the literal text must be enclosed in either single or double quotes. For example:
"${body} == 'Camel'". Notice how we have single quotes around the literal.
The old style of using "body" and "header.foo" to refer to the message body
and header is @deprecated, and its encouraged to always use ${ } tokens for the
built-in functions.
The range operator now requires the range to be in single quote as well as shown:
"${header.zip} between '30000..39999'".
245
in.body
Object
the input body
body.OGNL
Object
Camel 2.3: the input body invoked using a Camel
OGNL expression.
L A N G U A G E S S U P P OR T E D A P P E ND I X
in.body.OGNL
Object
Camel 2.3: the input body invoked using a Camel
OGNL expression.
bodyAs(type)
Type
Camel 2.3: Converts the body to the given type
determined by its classname. The converted body can
be null.
mandatoryBodyAs(type)
Type
Camel 2.5: Converts the body to the given type
determined by its classname, and expects the body to
be not null.
out.body
Object
the output body
header.foo
Object
refer to the input foo header
headers.foo
Object
refer to the input foo header
in.header.foo
Object
refer to the input foo header
in.headers.foo
Object
refer to the input foo header
header.foo[bar]
Object
Camel 2.3: regard input foo header as a map and
perform lookup on the map with bar as key
in.header.foo[bar]
Object
Camel 2.3: regard input foo header as a map and
perform lookup on the map with bar as key
in.headers.foo[bar]
Object
Camel 2.3: regard input foo header as a map and
perform lookup on the map with bar as key
header.foo.OGNL
Object
Camel 2.3: refer to the input foo header and invoke
its value using a Camel OGNL expression.
in.header.foo.OGNL
Object
Camel 2.3: refer to the input foo header and invoke
its value using a Camel OGNL expression.
in.headers.foo.OGNL
Object
Camel 2.3: refer to the input foo header and invoke
its value using a Camel OGNL expression.
out.header.foo
Object
refer to the out header foo
out.headers.foo
Object
refer to the out header foo
headerAs(key,type)
Type
Camel 2.5: Converts the header to the given type
determined by its classname
headers
Map
Camel 2.9: refer to the input headers
in.headers
Map
Camel 2.9: refer to the input headers
property.foo
Object
refer to the foo property on the exchange
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property.foo.OGNL
Object
Camel 2.8: refer to the foo property on the exchange
and invoke its value using a Camel OGNL expression.
sys.foo
String
refer to the system property
sysenv.foo
String
Camel 2.3: refer to the system environment
exception
Object
Camel 2.4: Refer to the exception object on the
exchange, is null if no exception set on exchange. Will
fallback and grab caught exceptions
(Exchange.EXCEPTION_CAUGHT) if the Exchange
has any.
exception.OGNL
Object
Camel 2.4: Refer to the exchange exception invoked
using a Camel OGNL expression object
String
Camel 2.0. Refer to the exception.message on the
exchange, is null if no exception set on exchange. Will
fallback and grab caught exceptions
(Exchange.EXCEPTION_CAUGHT) if the Exchange
has any.
String
Camel 2.6. Refer to the exception.stracktrace on the
exchange, is null if no exception set on exchange. Will
fallback and grab caught exceptions
(Exchange.EXCEPTION_CAUGHT) if the Exchange
has any.
String
Camel 1.5. Date formatting using the
java.text.SimpleDataFormat patterns.
Supported commands are: now for current timestamp,
in.header.xxx or header.xxx to use the Date
object in the IN header with the key xxx.
out.header.xxx to use the Date object in the OUT
header with the key xxx.
Object
Camel 1.5. Invoking a bean expression using the Bean
language. Specifying a method name you must use dot as
separator. In Camel 2.0 we also support the
?method=methodname syntax that is used by the Bean
component.
properties:locations:key
String
Camel 2.3: Lookup a property with the given key. The
locations option is optional. See more at Using
PropertyPlaceholder.
threadName
String
Camel 2.3: Returns the name of the current thread.
Can be used for logging purpose.
exception.message
exception.stacktrace
date:command:pattern
bean:bean expression
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ref:xxx
Object
Camel 2.6: To lookup a bean from the Registry with
the given id.
OGNL expression support
Available as of Camel 2.3
The Simple and Bean language now supports a Camel OGNL notation for invoking beans in
a chain like fashion.
Suppose the Message IN body contains a POJO which has a getAddress() method.
Then you can use Camel OGNL notation to access the address object:
simple("${body.address}")
simple("${body.address.street}")
simple("${body.address.zip}")
Camel understands the shorthand names for getters, but you can invoke any method or use the
real name such as:
simple("${body.address}")
simple("${body.getAddress.getStreet}")
simple("${body.address.getZip}")
simple("${body.doSomething}")
You can also use the null safe operator (?.) to avoid NPE if for example the body does NOT
have an address
simple("${body?.address?.street}")
Its also possible to index in Map or List types, so you can do:
simple("${body[foo].name}")
To assume the body is Map based and lookup the value with foo as key, and invoke the
getName method on that value.
You can access the Map or List objects directly using their key name (with or without
dots) :
simple("${body[foo]}")
simple("${body[this.is.foo]}")
Suppose there was no value with the key foo then you can use the null safe operator to avoid
the NPE as shown:
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simple("${body[foo]?.name}")
You can also access List types, for example to get lines from the address you can do:
simple("${body.address.lines[0]}")
simple("${body.address.lines[1]}")
simple("${body.address.lines[2]}")
There is a special last keyword which can be used to get the last value from a list.
simple("${body.address.lines[last]}")
And to get the 2nd last you can subtract a number, so we can use last-1 to indicate this:
simple("${body.address.lines[last-1]}")
And the 3rd last is of course:
simple("${body.address.lines[last-2]}")
And yes you can combine this with the operator support as shown below:
simple("${body.address.zip} > 1000")
Operator support
Available as of Camel 2.0
We added a basic set of operators supported in the simple language in Camel 2.0. The parser is
limited to only support a single operator.
To enable it the left value must be enclosed in ${ }. The syntax is:
${leftValue} OP rightValue
Where the rightValue can be a String literal enclosed in ' ', null, a constant value or
another expression enclosed in ${ }.
Camel will automatically type convert the rightValue type to the leftValue type, so its able to eg.
convert a string into a numeric so you can use > comparison for numeric values.
The following operators are supported:
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Operator
Description
==
equals
L A N G U A G E S S U P P OR T E D A P P E ND I X
Important
There must be spaces around the operator.
>
greater than
>=
greater than or equals
<
less than
<=
less than or equals
!=
not equals
contains
For testing if contains in a string based value
not
contains
For testing if not contains in a string based value
regex
For matching against a given regular expression pattern defined as a String
value
not regex
For not matching against a given regular expression pattern defined as a String
value
in
For matching if in a set of values, each element must be separated by comma.
not in
For matching if not in a set of values, each element must be separated by
comma.
is
For matching if the left hand side type is an instanceof the value.
not is
For matching if the left hand side type is not an instanceof the value.
range
For matching if the left hand side is within a range of values defined as
numbers: from..to. From Camel 2.9 onwards the range values must be
enclosed in single quotes.
not range
For matching if the left hand side is not within a range of values defined as
numbers: from..to. From Camel 2.9 onwards the range values must be
enclosed in single quotes.
And the following unary operators can be used:
Operator
Description
++
Camel 2.9: To increment a number by one.
--
Camel 2.9: To decrement a number by one.
And the following logical operators can be used to group expressions:
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Operator
Description
and
deprecated use && instead. The logical and operator is used to group two
expressions.
or
deprecated use || instead. The logical or operator is used to group two
expressions.
&&
Camel 2.9: The logical and operator is used to group two expressions.
||
Camel 2.9: The logical or operator is used to group two expressions.
The syntax for AND is:
${leftValue} OP rightValue and ${leftValue} OP rightValue
And the syntax for OR is:
${leftValue} OP rightValue or ${leftValue} OP rightValue
Some examples:
simple("${in.header.foo} == 'foo'")
// here Camel will type convert '100' into the type of in.header.bar and if its an
Integer '100' will also be converter to an Integer
simple("${in.header.bar} == '100'")
simple("${in.header.bar} == 100")
// 100 will be converter to the type of in.header.bar so we can do > comparison
simple("${in.header.bar} > 100")
// testing for null
simple("${in.header.baz} == null")
// testing for not null
simple("${in.header.baz} != null")
And a bit more advanced example where the right value is another expression
simple("${in.header.date} == ${date:now:yyyyMMdd}")
simple("${in.header.type} == ${bean:orderService?method=getOrderType}")
And an example with contains, testing if the title contains the word Camel
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Using and,or operators
In Camel 2.4 or older the and or or can only be used once in a simple
language expression. From Camel 2.5 onwards you can use these operators
multiple times.
Comparing with different types
When you compare with different types such as String and int, then you have to
take a bit care. Camel will use the type from the left hand side as 1st priority. And
fallback to the right hand side type if both values couldn't be compared based on
that type.
This means you can flip the values to enforce a specific type. Suppose the bar value
above is a String. Then you can flip the equation:
simple("100 < ${in.header.bar}")
which then ensures the int type is used as 1st priority.
This may change in the future if the Camel team improves the binary comparison
operations to prefer numeric types over String based. It's most often the String type which
causes problem when comparing with numbers.
simple("${in.header.title} contains 'Camel'")
And an example with regex, testing if the number header is a 4 digit value:
simple("${in.header.number} regex '\\d{4}'")
And finally an example if the header equals any of the values in the list. Each element must be
separated by comma, and no space around.
This also works for numbers etc, as Camel will convert each element into the type of the left
hand side.
simple("${in.header.type} in 'gold,silver'")
And for all the last 3 we also support the negate test using not:
simple("${in.header.type} not in 'gold,silver'")
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And you can test if the type is a certain instance, eg for instance a String
simple("${in.header.type} is 'java.lang.String'")
We have added a shorthand for all java.lang types so you can write it as:
simple("${in.header.type} is 'String'")
Ranges are also supported. The range interval requires numbers and both from and end are
inclusive. For instance to test whether a value is between 100 and 199:
simple("${in.header.number} range 100..199")
Notice we use .. in the range without spaces. Its based on the same syntax as Groovy.
From Camel 2.9 onwards the range value must be in single quotes
simple("${in.header.number} range '100..199'")
Using and / or
If you have two expressions you can combine them with the and or or operator.
For instance:
simple("${in.header.title} contains 'Camel' and ${in.header.type'} == 'gold'")
And of course the or is also supported. The sample would be:
simple("${in.header.title} contains 'Camel' or ${in.header.type'} == 'gold'")
Notice: Currently and or or can only be used once in a simple language expression. This
might change in the future.
So you cannot do:
simple("${in.header.title} contains 'Camel' and ${in.header.type'} == 'gold' and
${in.header.number} range 100..200")
Samples
In the Spring XML sample below we filter based on a header value:
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Can be used in Spring XML
As the Spring XML does not have all the power as the Java DSL with all its various
builder methods, you have to resort to use some other languages
for testing with simple operators. Now you can do this with the simple language. In
the sample below we want to test if the header is a widget order:
${in.header.type} == 'widget'
Camel 2.9 onwards
Use && or || from Camel 2.9 onwards.
in.header.foo
The Simple language can be used for the predicate test above in the Message Filter pattern,
where we test if the in message has a foo header (a header with the key foo exists). If the
expression evaluates to true then the message is routed to the mock:foo endpoint,
otherwise its lost in the deep blue sea
The same example in Java DSL:
.
from("seda:orders")
.filter().simple("${in.header.foo}").to("seda:fooOrders");
You can also use the simple language for simple text concatenations such as:
from("direct:hello").transform().simple("Hello ${in.header.user} how are
you?").to("mock:reply");
Notice that we must use ${ } placeholders in the expression now to allow Camel to parse it
correctly.
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And this sample uses the date command to output current date.
from("direct:hello").transform().simple("The today is ${date:now:yyyyMMdd} and its
a great day.").to("mock:reply");
And in the sample below we invoke the bean language to invoke a method on a bean to be
included in the returned string:
from("direct:order").transform().simple("OrderId:
${bean:orderIdGenerator}").to("mock:reply");
Where orderIdGenerator is the id of the bean registered in the Registry. If using Spring
then its the Spring bean id.
If we want to declare which method to invoke on the order id generator bean we must
prepend .method name such as below where we invoke the generateId method.
from("direct:order").transform().simple("OrderId:
${bean:orderIdGenerator.generateId}").to("mock:reply");
And in Camel 2.0 we can use the ?method=methodname option that we are familiar with
the Bean component itself:
from("direct:order").transform().simple("OrderId:
${bean:orderIdGenerator?method=generateId}").to("mock:reply");
And from Camel 2.3 onwards you can also convert the body to a given type, for example to
ensure its a String you can do:
Hello ${bodyAs(String)} how are you?
There are a few types which have a shorthand notation, so we can use String instead of
java.lang.String. These are: byte[], String, Integer, Long. All other types
must use their FQN name, e.g. org.w3c.dom.Document.
Its also possible to lookup a value from a header Map in Camel 2.3 onwards:
The gold value is ${header.type[gold]}
In the code above we lookup the header with name type and regard it as a java.util.Map
and we then lookup with the key gold and return the value.
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If the header is not convertible to Map an exception is thrown. If the header with name type
does not exist null is returned.
From Camel 2.9 onwards you can nest functions, such as shown below:
${properties:${header.someKey}}
Setting result type
Available as of Camel 2.8
You can now provide a result type to the Simple expression, which means the result of the
evaluation will be converted to the desired type. This is most useable to define types such as
booleans, integers, etc.
For example to set a header as a boolean type you can do:
.setHeader("cool", simple("true", Boolean.class))
And in XML DSL
true
Changing function start and end tokens
Available as of Camel 2.9
You can configure the function start and end tokens - ${ } using the methods
changeFunctionStartToken and changeFunctionEndToken on
SimpleLanguage, using Java code. From Spring XML you can define a tag with the
new changed tokens in the constructor as shown below:
In the example above we use [ ] as the changed tokens.
Notice by changing the start/end tokens you change those in all the Camel applications
which share the same camel-core on their classpath.
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For example in an OSGi server this may affect many applications, where as a Web Application
as a WAR file it only affects the Web Application.
Dependencies
The Simple language is part of camel-core.
FILE EXPRESSION LANGUAGE
Available as of Camel 1.5
The File Expression Language is an extension to the Simple language, adding file related
capabilities. These capabilities are related to common use cases working with file path and
names. The goal is to allow expressions to be used with the File and FTP components for
setting dynamic file patterns for both consumer and producer.
Syntax
This language is an extension to the Simple language so the Simple syntax applies also. So the
table below only lists the additional.
As opposed to Simple language File Language also supports Constant expressions so you can
enter a fixed filename.
All the file tokens use the same expression name as the method on the java.io.File
object, for instance file:absolute refers to the java.io.File.getAbsolute()
method. Notice that not all expressions are supported by the current Exchange. For instance
the FTP component supports some of the options, where as the File component supports all of
them.
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Expression
Type
File
Consumer
File
Producer
FTP
Consumer
FTP
Producer
Description
file:name
String
yes
no
yes
no
refers to the file name (is relative to the
starting directory, see note below)
file:name.ext
String
yes
no
yes
no
Camel 2.3: refers to the file extension
only
file:name.noext
String
yes
no
yes
no
refers to the file name with no extension
(is relative to the starting directory, see
note below)
file:onlyname
String
yes
no
yes
no
Camel 2.0: refers to the file name only
with no leading paths.
file:onlyname.noext
String
yes
no
yes
no
Camel 2.0: refers to the file name only
with no extension and with no leading
paths.
file:ext
String
yes
no
yes
no
Camel 1.6.1/Camel 2.0: refers to the
file extension only
file:parent
String
yes
no
yes
no
refers to the file parent
file:path
String
yes
no
yes
no
refers to the file path
file:absolute
Boolean
yes
no
no
no
Camel 2.0: refers to whether the file is
regarded as absolute or relative
file:absolute.path
String
yes
no
no
no
refers to the absolute file path
file:length
Long
yes
no
yes
no
refers to the file length returned as a Long
type
L A N G U A G E S S U P P OR T E D A P P E ND I X
File language is now merged with Simple language
From Camel 2.2 onwards, the file language is now merged with Simple language
which means you can use all the file syntax directly within the simple language.
file:size
Long
yes
no
yes
no
Camel 2.5: refers to the file length
returned as a Long type
file:modified
Date
yes
no
yes
no
Camel 2.0: refers to the file last modified
returned as a Date type
yes
for date formatting using the
java.text.SimepleDataFormat
patterns. Is an extension to the Simple
language. Additional command is: file
(consumers only) for the last modified
timestamp of the file. Notice: all the
commands from the Simple language can
also be used.
date:command:pattern
String
yes
yes
yes
File token example
Relative paths
We have a java.io.File handle for the file hello.txt in the following relative
directory: .\filelanguage\test. And we configure our endpoint to use this starting
directory .\filelanguage. The file tokens will return as:
Expression
Returns
file:name
test\hello.txt
file:name.ext
txt
file:name.noext
test\hello
file:onlyname
hello.txt
file:onlyname.noext
hello
file:ext
txt
file:parent
filelanguage\test
file:path
filelanguage\test\hello.txt
file:absolute
false
file:absolute.path
\workspace\camel\camel-core\target\filelanguage\test\hello.txt
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Absolute paths
We have a java.io.File handle for the file hello.txt in the following absolute
directory: \workspace\camel\camel-core\target\filelanguage\test. And
we configure out endpoint to use the absolute starting directory
\workspace\camel\camel-core\target\filelanguage. The file tokens will
return as:
Expression
Returns
file:name
test\hello.txt
file:name.ext
txt
file:name.noext
test\hello
file:onlyname
hello.txt
file:onlyname.noext
hello
file:ext
txt
file:parent
\workspace\camel\camel-core\target\filelanguage\test
file:path
\workspace\camel\camel-core\target\filelanguage\test\hello.txt
file:absolute
true
file:absolute.path
\workspace\camel\camel-core\target\filelanguage\test\hello.txt
Samples
You can enter a fixed Constant expression such as myfile.txt:
fileName="myfile.txt"
Lets assume we use the file consumer to read files and want to move the read files to backup
folder with the current date as a sub folder. This can be archieved using an expression like:
fileName="backup/${date:now:yyyyMMdd}/${file:name.noext}.bak"
relative folder names are also supported so suppose the backup folder should be a sibling folder
then you can append .. as:
fileName="../backup/${date:now:yyyyMMdd}/${file:name.noext}.bak"
As this is an extension to the Simple language we have access to all the goodies from this
language also, so in this use case we want to use the in.header.type as a parameter in the
dynamic expression:
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fileName="../backup/${date:now:yyyyMMdd}/type-${in.header.type}/
backup-of-${file:name.noext}.bak"
If you have a custom Date you want to use in the expression then Camel supports retrieving
dates from the message header.
fileName="orders/
order-${in.header.customerId}-${date:in.header.orderDate:yyyyMMdd}.xml"
And finally we can also use a bean expression to invoke a POJO class that generates some
String output (or convertible to String) to be used:
fileName="uniquefile-${bean:myguidgenerator.generateid}.txt"
And of course all this can be combined in one expression where you can use the File Language,
Simple and the Bean language in one combined expression. This is pretty powerful for those
common file path patterns.
Using Spring PropertyPlaceholderConfigurer together with the File
component
In Camel you can use the File Language directly from the Simple language which makes a
Content Based Router easier to do in Spring XML, where we can route based on file
extensions as shown below:
${file:ext} == 'txt'${file:ext} == 'xml'
If you use the fileName option on the File endpoint to set a dynamic filename using the File
Language then make sure you
use the alternative syntax (available from Camel 2.5 onwards) to avoid clashing with Springs
PropertyPlaceholderConfigurer.
Listing 21. bundle-context.xml
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Listing 22. bundle-context.cfg
fromEndpoint=activemq:queue:test
toEndpoint=file://fileRoute/out?fileName=test-$simple{date:now:yyyyMMdd}.txt
Notice how we use the $simple{ } syntax in the toEndpoint above.
If you don't do this, there is a clash and Spring will throw an exception like
org.springframework.beans.factory.BeanDefinitionStoreException:
Invalid bean definition with name 'sampleRoute' defined in class path resource
[bundle-context.xml]:
Could not resolve placeholder 'date:now:yyyyMMdd'
Dependencies
The File language is part of camel-core.
SQL
The SQL support is added by JoSQL and is primarily used for performing SQL queries on inmemory objects. If you prefer to perform actual database queries then check out the JPA
component.
To use SQL in your camel routes you need to add the a dependency on camel-josql
which implements the SQL language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-josql2.5.0
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Camel supports SQL to allow an Expression or Predicate to be used in the DSL or Xml
Configuration. For example you could use SQL to create an Predicate in a Message Filter or as
an Expression for a Recipient List.
from("queue:foo").setBody().sql("select * from MyType").to("queue:bar")
And the spring DSL:
select * from MyType
Variables
Variable
Type
Description
exchange
Exchange
the Exchange object
in
Message
the exchange.in message
out
Message
the exchange.out message
the property
key
Object
the Exchange properties
the header key
Object
the exchange.in headers
the variable key
Object
if any additional variables is added using setVariables
method
XPATH
Camel supports XPath to allow an Expression or Predicate to be used in the DSL or Xml
Configuration. For example you could use XPath to create an Predicate in a Message Filter or
as an Expression for a Recipient List.
from("queue:foo").
filter().xpath("//foo")).
to("queue:bar")
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from("queue:foo").
choice().xpath("//foo")).to("queue:bar").
otherwise().to("queue:others");
Namespaces
In 1.3 onwards you can easily use namespaces with XPath expressions using the Namespaces
helper class.
Namespaces ns = new Namespaces("c", "http://acme.com/cheese");
from("direct:start").filter().
xpath("/c:person[@name='James']", ns).
to("mock:result");
Variables
Variables in XPath is defined in different namespaces. The default namespace is
http://camel.apache.org/schema/spring.
Namespace URI
Local
part
Type
Description
http://camel.apache.org/xml/in/
in
Message
the exchange.in
message
http://camel.apache.org/xml/out/
out
Message
the exchange.out
message
http://camel.apache.org/xml/functions/
functions
Object
Camel 2.5: Additional
functions
http://camel.apache.org/xml/variables/
environment-variables
env
Object
OS environment
variables
http://camel.apache.org/xml/variables/
system-properties
system
Object
Java System properties
http://camel.apache.org/xml/variables/
exchange-property
Ê
Object
the exchange property
Camel will resolve variables according to either:
▪ namespace given
▪ no namespace given
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Namespace given
If the namespace is given then Camel is instructed exactly what to return. However when
resolving either in or out Camel will try to resolve a header with the given local part first, and
return it. If the local part has the value body then the body is returned instead.
No namespace given
If there is no namespace given then Camel resolves only based on the local part. Camel will try
to resolve a variable in the following steps:
▪ from variables that has been set using the variable(name, value) fluent
builder
▪ from message.in.header if there is a header with the given key
▪ from exchange.properties if there is a property with the given key
Functions
Camel adds the following XPath functions that can be used to access the exchange:
Function
Argument
Type
Description
in:body
none
Object
Will return the in message body.
in:header
the header
name
Object
Will return the in message header.
out:body
none
Object
Will return the out message body.
out:header
the header
name
Object
Will return the out message header.
function:properties
key for
property
String
Camel 2.5: To lookup a property using the
Properties component (property
placeholders).
function:simple
simple
expression
Object
Camel 2.5: To evaluate a Simple
expression.
Notice: function:properties and function:simple is not supported when the
return type is a NodeSet, such as when using with a Splitter EIP.
Here's an example showing some of these functions in use.
from("direct:start").choice()
.when().xpath("in:header('foo') = 'bar'").to("mock:x")
.when().xpath("in:body() = ''").to("mock:y")
.otherwise().to("mock:z");
And the new functions introduced in Camel 2.5:
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// setup properties component
PropertiesComponent properties = new PropertiesComponent();
properties.setLocation("classpath:org/apache/camel/builder/xml/myprop.properties");
context.addComponent("properties", properties);
// myprop.properties contains the following properties
// foo=Camel
// bar=Kong
from("direct:in").choice()
// $type is a variable for the header with key type
// here we use the properties function to lookup foo from the properties files
// which at runtime will be evaluted to 'Camel'
.when().xpath("$type = function:properties('foo')")
.to("mock:camel")
// here we use the simple language to evaluate the expression
// which at runtime will be evaluated to 'Donkey Kong'
.when().xpath("//name = function:simple('Donkey ${properties:bar}')")
.to("mock:donkey")
.otherwise()
.to("mock:other")
.end();
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use XPath
expressions as follows
/foo:person[@name='James']
Notice how we can reuse the namespace prefixes, foo in this case, in the XPath expression for
easier namespace based XPath expressions!
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See also this discussion on the mailinglist about using your own namespaces with xpath
Setting result type
The XPath expression will return a result type using native XML objects such as
org.w3c.dom.NodeList. But many times you want a result type to be a String. To do this
you have to instruct the XPath which result type to use.
In Java DSL:
xpath("/foo:person/@id", String.class)
In Spring DSL you use the resultType attribute to provide a fully qualified classname:
/foo:person/@id
In @XPath:
Available as of Camel 2.1
@XPath(value = "concat('foo-',//order/name/)", resultType = String.class) String name)
Where we use the xpath function concat to prefix the order name with foo-. In this case we
have to specify that we want a String as result type so the concat function works.
Examples
Here is a simple example using an XPath expression as a predicate in a Message Filter
from("direct:start").
filter().xpath("/person[@name='James']").
to("mock:result");
If you have a standard set of namespaces you wish to work with and wish to share them across
many different XPath expressions you can use the NamespaceBuilder as shown in this example
// lets define the namespaces we'll need in our filters
Namespaces ns = new Namespaces("c", "http://acme.com/cheese")
.add("xsd", "http://www.w3.org/2001/XMLSchema");
// now lets create an xpath based Message Filter
from("direct:start").
filter(ns.xpath("/c:person[@name='James']")).
to("mock:result");
In this sample we have a choice construct. The first choice evaulates if the message has a header
key type that has the value Camel.
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The 2nd choice evaluates if the message body has a name tag which values is Kong.
If neither is true the message is routed in the otherwise block:
from("direct:in").choice()
// using $headerName is special notation in Camel to get the header key
.when().xpath("$type = 'Camel'")
.to("mock:camel")
// here we test for the body name tag
.when().xpath("//name = 'Kong'")
.to("mock:donkey")
.otherwise()
.to("mock:other")
.end();
And the spring XML equivalent of the route:
$type = 'Camel'//name = 'Kong'
XPATH INJECTION
You can use Bean Integration to invoke a method on a bean and use various languages such as
XPath to extract a value from the message and bind it to a method parameter.
The default XPath annotation has SOAP and XML namespaces available. If you want to use
your own namespace URIs in an XPath expression you can use your own copy of the XPath
annotation to create whatever namespace prefixes you want to use.
import
import
import
import
267
java.lang.annotation.ElementType;
java.lang.annotation.Retention;
java.lang.annotation.RetentionPolicy;
java.lang.annotation.Target;
L A N G U A G E S S U P P OR T E D A P P E ND I X
import org.w3c.dom.NodeList;
import org.apache.camel.component.bean.XPathAnnotationExpressionFactory;
import org.apache.camel.language.LanguageAnnotation;
import org.apache.camel.language.NamespacePrefix;
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER})
@LanguageAnnotation(language = "xpath", factory =
XPathAnnotationExpressionFactory.class)
public @interface MyXPath {
String value();
// You can add the namespaces as the default value of the annotation
NamespacePrefix[] namespaces() default {
@NamespacePrefix(prefix = "n1", uri = "http://example.org/ns1"),
@NamespacePrefix(prefix = "n2", uri = "http://example.org/ns2")};
Class resultType() default NodeList.class;
}
i.e. cut and paste upper code to your own project in a different package and/or annotation
name then add whatever namespace prefix/uris you want in scope when you use your
annotation on a method parameter. Then when you use your annotation on a method
parameter all the namespaces you want will be available for use in your XPath expression.
NOTE this feature is supported from Camel 1.6.1.
For example
public class Foo {
@MessageDriven(uri = "activemq:my.queue")
public void doSomething(@MyXPath("/ns1:foo/ns2:bar/text()") String correlationID,
@Body String body) {
// process the inbound message here
}
}
Using XPathBuilder without an Exchange
Available as of Camel 2.3
You can now use the org.apache.camel.builder.XPathBuilder without the
need for an Exchange. This comes handy if you want to use it as a helper to do custom xpath
evaluations.
It requires that you pass in a CamelContext since a lot of the moving parts inside the
XPathBuilder requires access to the Camel Type Converter and hence why CamelContext is
needed.
For example you can do something like this:
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boolean matches = XPathBuilder.xpath("/foo/bar/@xyz").matches(context, ""));
This will match the given predicate.
You can also evaluate for example as shown in the following three examples:
String name = XPathBuilder.xpath("foo/bar").evaluate(context,
"cheese", String.class);
Integer number = XPathBuilder.xpath("foo/bar").evaluate(context,
"123", Integer.class);
Boolean bool = XPathBuilder.xpath("foo/bar").evaluate(context,
"true", Boolean.class);
Evaluating with a String result is a common requirement and thus you can do it a bit simpler:
String name = XPathBuilder.xpath("foo/bar").evaluate(context,
"cheese");
Using Saxon with XPathBuilder
Available as of Camel 2.3
You need to add camel-saxon as dependency to your project.
Its now easier to use Saxon with the XPathBuilder which can be done in several ways as
shown below.
Where as the latter ones are the easiest ones.
Using a factory
// create a Saxon factory
XPathFactory fac = new net.sf.saxon.xpath.XPathFactoryImpl();
// create a builder to evaluate the xpath using the saxon factory
XPathBuilder builder = XPathBuilder.xpath("tokenize(/foo/bar, '_')[2]").factory(fac);
// evaluate as a String result
String result = builder.evaluate(context, "abc_def_ghi");
assertEquals("def", result);
Using ObjectModel
// create a builder to evaluate the xpath using saxon based on its object model uri
XPathBuilder builder = XPathBuilder.xpath("tokenize(/foo/bar,
'_')[2]").objectModel("http://saxon.sf.net/jaxp/xpath/om");
// evaluate as a String result
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String result = builder.evaluate(context, "abc_def_ghi");
assertEquals("def", result);
The easy one
// create a builder to evaluate the xpath using saxon
XPathBuilder builder = XPathBuilder.xpath("tokenize(/foo/bar, '_')[2]").saxon();
// evaluate as a String result
String result = builder.evaluate(context, "abc_def_ghi");
assertEquals("def", result);
Setting a custom XPathFactory using System Property
Available as of Camel 2.3
Camel now supports reading the JVM system property
javax.xml.xpath.XPathFactory that can be used to set a custom XPathFactory to
use.
This unit test shows how this can be done to use Saxon instead:
// set system property with the XPath factory to use which is Saxon
System.setProperty(XPathFactory.DEFAULT_PROPERTY_NAME + ":" + "http://saxon.sf.net/
jaxp/xpath/om", "net.sf.saxon.xpath.XPathFactoryImpl");
// create a builder to evaluate the xpath using saxon
XPathBuilder builder = XPathBuilder.xpath("tokenize(/foo/bar, '_')[2]");
// evaluate as a String result
String result = builder.evaluate(context, "abc_def_ghi");
assertEquals("def", result);
Camel will log at INFO level if it uses a non default XPathFactory such as:
XPathBuilder INFO Using system property
javax.xml.xpath.XPathFactory:http://saxon.sf.net/jaxp/xpath/om with value:
net.sf.saxon.xpath.XPathFactoryImpl when creating XPathFactory
Dependencies
The XPath language is part of camel-core.
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XQUERY
Camel supports XQuery to allow an Expression or Predicate to be used in the DSL or Xml
Configuration. For example you could use XQuery to create an Predicate in a Message Filter or
as an Expression for a Recipient List.
Options
Name
Default Value
Description
allowStAX
false
Camel 2.8.3/2.9: Whether to allow using StAX as the javax.xml.transform.Source.
Examples
from("queue:foo").filter().
xquery("//foo").
to("queue:bar")
You can also use functions inside your query, in which case you need an explicit type
conversion (or you will get a org.w3c.dom.DOMException: HIERARCHY_REQUEST_ERR) by
passing the Class as a second argument to the xquery() method.
from("direct:start").
recipientList().xquery("concat('mock:foo.', /person/@city)", String.class);
Variables
The IN message body will be set as the contextItem. Besides this these Variables is also
added as parameters:
271
Variable
Type
Description
Support
version
exchange
Exchange
The current Exchange
Ê
in.body
Object
The In message's body
>= 1.6.1
out.body
Object
The OUT message's body (if any)
>= 1.6.1
in.headers.*
Object
You can access the value of exchange.in.headers
with key foo by using the variable which name is
in.headers.foo
>=1.6.1
out.headers.*
Object
You can access the value of exchange.out.headers
with key foo by using the variable which name is
out.headers.foo variable
>=1.6.1
L A N G U A G E S S U P P OR T E D A P P E ND I X
key name
Object
Any exchange.properties and exchange.in.headers
(exchange.in.headers support was removed since
camel 1.6.1) and any additional parameters set
using setParameters(Map). These parameters
is added with they own key name, for instance if
there is an IN header with the key name foo then
its added as foo.
Ê
Using XML configuration
If you prefer to configure your routes in your Spring XML file then you can use XPath
expressions as follows
/foo:person[@name='James']
Notice how we can reuse the namespace prefixes, foo in this case, in the XPath expression for
easier namespace based XQuery expressions!
When you use functions in your XQuery expression you need an explicit type conversion
which is done in the xml configuration via the @type attribute:
concat('mock:foo.', /person/@city)
Using XQuery as an endpoint
Sometimes an XQuery expression can be quite large; it can essentally be used for Templating.
So you may want to use an XQuery Endpoint so you can route using XQuery templates.
The following example shows how to take a message of an ActiveMQ queue (MyQueue) and
transform it using XQuery and send it to MQSeries.
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Examples
Here is a simple example using an XQuery expression as a predicate in a Message Filter
from("direct:start").filter().xquery("/person[@name='James']").to("mock:result");
This example uses XQuery with namespaces as a predicate in a Message Filter
Namespaces ns = new Namespaces("c", "http://acme.com/cheese");
from("direct:start").
filter().xquery("/c:person[@name='James']", ns).
to("mock:result");
Learning XQuery
XQuery is a very powerful language for querying, searching, sorting and returning XML. For
help learning XQuery try these tutorials
• Mike Kay's XQuery Primer
• the W3Schools XQuery Tutorial
You might also find the XQuery function reference useful
Dependencies
To use XQuery in your camel routes you need to add the a dependency on camel-saxon
which implements the XQuery language.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-saxon1.4.0
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Data Format Appendix
DATA FORMAT
Camel supports a pluggable DataFormat to allow messages to be marshalled to and from binary
or text formats to support a kind of Message Translator.
The following data formats are currently supported:
• Standard JVM object marshalling
◦ Serialization
◦ String
• Object marshalling
◦ JSON
◦ Protobuf
• Object/XML marshalling
◦ Castor
◦ JAXB
◦ XmlBeans
◦ XStream
◦ JiBX
• Object/XML/Webservice marshalling
◦ SOAP
• Flat data structure marshalling
◦ Bindy
◦ CSV
◦ EDI
◦ Flatpack DataFormat
• Domain specific marshalling
◦ HL7 DataFormat
• Compression
◦ GZip data format
◦ Zip DataFormat
• Security
◦ Crypto
◦ PGP
◦ XMLSecurity DataFormat
• Misc.
◦ Custom DataFormat - to use your own custom implementation
◦ TidyMarkup
◦ Syslog
And related is the following Type Converters:
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▪ Dozer Type Conversion
Unmarshalling
If you receive a message from one of the Camel Components such as File, HTTP or JMS you
often want to unmarshal the payload into some bean so that you can process it using some
Bean Integration or perform Predicate evaluation and so forth. To do this use the unmarshal
word in the DSL in Java or the Xml Configuration.
For example
DataFormat jaxb = new JaxbDataFormat("com.acme.model");
from("activemq:My.Queue").
unmarshal(jaxb).
to("mqseries:Another.Queue");
The above uses a named DataFormat of jaxb which is configured with a number of Java package
names. You can if you prefer use a named reference to a data format which can then be defined
in your Registry such as via your Spring XML file.
You can also use the DSL itself to define the data format as you use it. For example the
following uses Java serialization to unmarshal a binary file then send it as an ObjectMessage to
ActiveMQ
from("file://foo/bar").
unmarshal().serialization().
to("activemq:Some.Queue");
Marshalling
Marshalling is the opposite of unmarshalling, where a bean is marshalled into some binary or
textual format for transmission over some transport via a Camel Component. Marshalling is
used in the same way as unmarshalling above; in the DSL you can use a DataFormat instance,
you can configure the DataFormat dynamically using the DSL or you can refer to a named
instance of the format in the Registry.
The following example unmarshals via serialization then marshals using a named JAXB data
format to perform a kind of Message Translator
from("file://foo/bar").
unmarshal().serialization().
marshal("jaxb").
to("activemq:Some.Queue");
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Using Spring XML
This example shows how to configure the data type just once and reuse it on multiple routes
You can also define reusable data formats as Spring beans
SERIALIZATION
Serialization is a Data Format which uses the standard Java Serialization mechanism to
unmarshal a binary payload into Java objects or to marshal Java objects into a binary blob.
For example the following uses Java serialization to unmarshal a binary file then send it as an
ObjectMessage to ActiveMQ
from("file://foo/bar").
unmarshal().serialization().
to("activemq:Some.Queue");
Dependencies
This data format is provided in camel-core so no additional dependencies is needed.
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JAXB
JAXB is a Data Format which uses the JAXB2 XML marshalling standard which is included in
Java 6 to unmarshal an XML payload into Java objects or to marshal Java objects into an XML
payload.
Using the Java DSL
For example the following uses a named DataFormat of jaxb which is configured with a number
of Java package names to initialize the JAXBContext.
DataFormat jaxb = new JaxbDataFormat("com.acme.model");
from("activemq:My.Queue").
unmarshal(jaxb).
to("mqseries:Another.Queue");
You can if you prefer use a named reference to a data format which can then be defined in your
Registry such as via your Spring XML file. e.g.
from("activemq:My.Queue").
unmarshal("myJaxbDataType").
to("mqseries:Another.Queue");
Using Spring XML
The following example shows how to use JAXB to unmarshal using Spring configuring the jaxb
data type
This example shows how to configure the data type just once and reuse it on multiple routes.
For Camel versions below 1.5.0 you have to set the element directly in
.
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Partial marshalling/unmarshalling
This feature is new to Camel 2.2.0.
JAXB 2 supports marshalling and unmarshalling XML tree fragments. By default JAXB looks for
@XmlRootElement annotation on given class to operate on whole XML tree. This is useful
but not always - sometimes generated code does not have @XmlRootElement annotation,
sometimes you need unmarshall only part of tree.
In that case you can use partial unmarshalling. To enable this behaviours you need set property
partClass. Camel will pass this class to JAXB's unmarshaler.
For marshalling you have to add partNamespace attribute with QName of destination
namespace. Example of Spring DSL you can find above.
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Multiple context paths
It is possible to use this data format with more than one context path. You can
specify context path using : as separator, for example
com.mycompany:com.mycompany2. Note that this is handled by JAXB
implementation and might change if you use different vendor than RI.
Fragment
This feature is new to Camel 2.8.0.
JaxbDataFormat has new property fragment which can set the the
Marshaller.JAXB_FRAGMENT encoding property on the JAXB Marshaller. If you don't
want the JAXB Marshaller to generate the XML declaration, you can set this option to be true.
The default value of this property is fales.
Ignoring the NonXML Character
This feature is new to Camel 2.2.0.
JaxbDataFromat supports to ignore the NonXML Character, you just need to set the
filterNonXmlChars property to be true, JaxbDataFormat will replace the NonXML character
with " " when it is marshaling or unmarshaling the message. You can also do it by setting the
Exchange property Exchange.FILTER_NON_XML_CHARS.
Ê
JDK 1.5
JDK 1.6+
Filtering in use
StAX API and implementation
No
Filtering not in use
StAX API only
No
This feature has been tested with Woodstox 3.2.9 and Sun JDK 1.6 StAX implementation.
Working with the ObjectFactory
If you use XJC to create the java class from the schema, you will get an ObjectFactory for you
JAXB context. Since the ObjectFactory uses JAXBElement to hold the reference of the schema
and element instance value, from Camel 1.5.1 jaxbDataformat will ignore the JAXBElement by
default and you will get the element instance value instead of the JAXBElement object form the
unmarshaled message body.
If you want to get the JAXBElement object form the unmarshaled message body, you need to
set the JaxbDataFormat object's ignoreJAXBElement property to be false.
Setting encoding
In Camel 1.6.1 and newer you can set the encoding option to use when marshalling. Its the
Marshaller.JAXB_ENCODING encoding property on the JAXB Marshaller.
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You can setup which encoding to use when you declare the JAXB data format. You can also
provide the encoding in the Exchange property Exchange.CHARSET_NAME. This property
will overrule the encoding set on the JAXB data format.
In this Spring DSL we have defined to use iso-8859-1 as the encoding:
Dependencies
To use JAXB in your camel routes you need to add the a dependency on camel-jaxb which
implements this data format.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-jaxb1.6.0
XMLBEANS
XmlBeans is a Data Format which uses the XmlBeans library to unmarshal an XML payload into
Java objects or to marshal Java objects into an XML payload.
from("activemq:My.Queue").
unmarshal().xmlBeans().
to("mqseries:Another.Queue");
Dependencies
To use XmlBeans in your camel routes you need to add the dependency on camelxmlbeans which implements this data format.
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If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-xmlbeans2.8.0
XSTREAM
XStream is a Data Format which uses the XStream library to marshal and unmarshal Java
objects to and from XML.
// lets turn Object messages into XML then send to MQSeries
from("activemq:My.Queue").
marshal().xstream().
to("mqseries:Another.Queue");
XMLInputFactory and XMLOutputFactory
The XStream library uses the javax.xml.stream.XMLInputFactory and
javax.xml.stream.XMLOutputFactory, you can control which implementation of this
factory should be used.
The Factory is discovered using this algorithm:
1. Use the javax.xml.stream.XMLInputFactory ,
javax.xml.stream.XMLOutputFactory system property.
2. Use the lib/xml.stream.properties file in the JRE_HOME directory.
3. Use the Services API, if available, to determine the classname by looking in the META-INF/
services/javax.xml.stream.XMLInputFactory, META-INF/services/
javax.xml.stream.XMLOutputFactory files in jars available to the JRE.
4. Use the platform default XMLInputFactory,XMLOutputFactory instance.
How to set the XML encoding in Xstream DataFormat?
From Camel 1.6.3 or Camel 2.2.0, you can set the encoding of XML in Xstream DataFormat by
setting the Exchange's property with the key Exchange.CHARSET_NAME, or setting the
encoding property on Xstream from DSL or Spring config.
from("activemq:My.Queue").
marshal().xstream("UTF-8").
to("mqseries:Another.Queue");
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Dependencies
To use XStream in your camel routes you need to add the a dependency on camel-xstream
which implements this data format.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-xstream1.5.0
CSV
The CSV Data Format uses Apache Commons CSV to handle CSV payloads (Comma Separated
Values) such as those exported/imported by Excel.
Options
Option
Type
Description
config
CSVConfig
Can be used to set a custom CSVConfig object.
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CSVStrategy
Camel uses by default
CSVStrategy.DEFAULT_STRATEGY.
autogenColumns
boolean
Camel 1.6.1/2.0: Is default true. By default, columns
are autogenerated in the resulting CSV. Subsequent
messages use the previously created columns with new
fields being added at the end of the line.
delimiter
String
Camel 2.4: Is default ,. Can be used to configure the
delimiter, if it's not the comma.
strategy
Marshalling a Map to CSV
The component allows you to marshal a Java Map (or any other message type that can be
converted in a Map) into a CSV payload.
An example: if you send a message with this map...
Map body = new HashMap();
body.put("foo", "abc");
body.put("bar", 123);
... through this route ...
from("direct:start").
marshal().csv().
to("mock:result");
... you will end up with a String containing this CSV message
abc,123
Sending the Map below through this route will result in a CSV message that looks like
foo,bar
Unmarshalling a CSV message into a Java List
Unmarshalling will transform a CSV messsage into a Java List with CSV file lines (containing
another List with all the field values).
An example: we have a CSV file with names of persons, their IQ and their current activity.
Jack Dalton, 115, mad at Averell
Joe Dalton, 105, calming Joe
William Dalton, 105, keeping Joe from killing Averell
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Averell Dalton, 80, playing with Rantanplan
Lucky Luke, 120, capturing the Daltons
We can now use the CSV component to unmarshal this file:
from("file:src/test/resources/?fileName=daltons.csv&noop=true").
unmarshal().csv().
to("mock:daltons");
The resulting message will contain a List> like...
List> data = (List>) exchange.getIn().getBody();
for (List line : data) {
LOG.debug(String.format("%s has an IQ of %s and is currently %s",
line.get(0), line.get(1), line.get(2)));
}
Marshalling a List tag
make sure you put the endpoint you want to filter (, etc.) before
the closing tag or the filter will not be applied (in 2.8+, omitting this will
result in an error)
Using This Pattern
If you would like to use this EIP Pattern then please read the Getting Started, you may also find
the Architecture useful particularly the description of Endpoint and URIs. Then you could try
out some of the Examples first before trying this pattern out.
DYNAMIC ROUTER
The Dynamic Router from the EIP patterns allows you to route messages while avoiding the
dependency of the router on all possible destinations while maintaining its efficiency.
In Camel 2.5 we introduced a dynamicRouter in the DSL which is like a dynamic
Routing Slip which evaluates the slip on-the-fly.
Options
Name
Default
Value
Description
uriDelimiter
,
Delimiter used if the Expression returned multiple endpoints.
ignoreInvalidEndpoints
false
If an endpoint uri could not be resolved, should it be ignored. Otherwise Camel will thrown an exception stating the
endpoint uri is not valid.
Dynamic Router in Camel 2.5 onwards
From Camel 2.5 the Dynamic Router will set a property (Exchange.SLIP_ENDPOINT) on the
Exchange which contains the current endpoint as it advanced though the slip. This allows you to
know how far we have processed in the slip. (It's a slip because the Dynamic Router
implementation is based on top of Routing Slip).
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Beware
You must ensure the expression used for the dynamicRouter such as a bean,
will return null to indicate the end. Otherwise the dynamicRouter will keep
repeating endlessly.
Java DSL
In Java DSL you can use the dynamicRouter as shown below:
from("direct:start")
// use a bean as the dynamic router
.dynamicRouter(bean(DynamicRouterTest.class, "slip"));
Which will leverage a Bean to compute the slip on-the-fly, which could be implemented as
follows:
/**
* Use this method to compute dynamic where we should route next.
*
* @param body the message body
* @return endpoints to go, or null to indicate the end
*/
public String slip(String body) {
bodies.add(body);
invoked++;
if (invoked == 1) {
return "mock:a";
} else if (invoked == 2) {
return "mock:b,mock:c";
} else if (invoked == 3) {
return "direct:foo";
} else if (invoked == 4) {
return "mock:result";
}
// no more so return null
return null;
}
Mind that this example is only for show and tell. The current implementation is not thread safe.
You would have to store the state on the Exchange, to ensure thread safety.
Spring XML
The same example in Spring XML would be:
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Bye World
@DynamicRouter annotation
You can also use the @DynamicRouter annotation, for example the Camel 2.4 example
below could be written as follows. The route method would then be invoked repeatedly as
the message is processed dynamically. The idea is to return the next endpoint uri where to go.
Return null to indicate the end. You can return multiple endpoints if you like, just as the
Routing Slip, where each endpoint is separated by a delimiter.
public class MyDynamicRouter {
@Consume(uri = "activemq:foo")
@DynamicRouter
public String route(@XPath("/customer/id") String customerId, @Header("Location")
String location, Document body) {
// query a database to find the best match of the endpoint based on the input
parameteres
// return the next endpoint uri, where to go. Return null to indicate the end.
}
}
Dynamic Router in Camel 2.4 or older
The simplest way to implement this is to use the RecipientList Annotation on a Bean method to
determine where to route the message.
public class MyDynamicRouter {
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@Consume(uri = "activemq:foo")
@RecipientList
public List route(@XPath("/customer/id") String customerId,
@Header("Location") String location, Document body) {
// query a database to find the best match of the endpoint based on the input
parameteres
...
}
}
In the above we can use the Parameter Binding Annotations to bind different parts of the
Message to method parameters or use an Expression such as using XPath or XQuery.
The method can be invoked in a number of ways as described in the Bean Integration such
as
• POJO Producing
• Spring Remoting
• Bean component
Using This Pattern
If you would like to use this EIP Pattern then please read the Getting Started, you may also find
the Architecture useful particularly the description of Endpoint and URIs. Then you could try
out some of the Examples first before trying this pattern out.
Recipient List
The Recipient List from the EIP patterns allows you to route messages to a number of
dynamically specified recipients.
The recipients will receive a copy of the same Exchange and Camel will execute them
sequentially.
Options
Name
Default
Value
Description
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delimiter
,
Delimiter used if the Expression returned multiple endpoints.
strategyRef
Ê
Refers to an AggregationStrategy to be used to assemble the replies from the recipients, into a single outgoing message
from the Recipient List. By default Camel will use the last reply as the outgoing message.
parallelProcessing
false
Camel 2.2: If enables then sending messages to the recipients occurs concurrently. Note the caller thread will still wait
until all messages has been fully processed, before it continues. Its only the sending and processing the replies from the
recipients which happens concurrently.
executorServiceRef
Ê
Camel 2.2: Refers to a custom Thread Pool to be used for parallel processing. Notice if you set this option, then parallel
processing is automatic implied, and you do not have to enable that option as well.
stopOnException
false
Camel 2.2: Whether or not to stop continue processing immediately when an exception occurred. If disable, then Camel
will send the message to all recipients regardless if one of them failed. You can deal with exceptions in the
AggregationStrategy class where you have full control how to handle that.
ignoreInvalidEndpoints
false
Camel 2.3: If an endpoint uri could not be resolved, should it be ignored. Otherwise Camel will thrown an exception
stating the endpoint uri is not valid.
streaming
false
Camel 2.5: If enabled then Camel will process replies out-of-order, eg in the order they come back. If disabled, Camel will
process replies in the same order as the Expression specified.
timeout
Ê
Camel 2.5: Sets a total timeout specified in millis. If the Recipient List hasn't been able to send and process all replies
within the given timeframe, then the timeout triggers and the Recipient List breaks out and continues. Notice if you provide
a TimeoutAwareAggregationStrategy then the timeout method is invoked before breaking out.
onPrepareRef
Ê
Camel 2.8: Refers to a custom Processor to prepare the copy of the Exchange each recipient will receive. This allows you
to do any custom logic, such as deep-cloning the message payload if that's needed etc.
shareUnitOfWork
false
Camel 2.8: Whether the unit of work should be shared. See the same option on Splitter for more details.
Static Recipient List
The following example shows how to route a request from an input queue:a endpoint to a
static list of destinations
Using Annotations
You can use the RecipientList Annotation on a POJO to create a Dynamic Recipient List. For
more details see the Bean Integration.
Using the Fluent Builders
RouteBuilder builder = new RouteBuilder() {
public void configure() {
errorHandler(deadLetterChannel("mock:error"));
from("seda:a")
.multicast().to("seda:b", "seda:c", "seda:d");
}
};
Using the Spring XML Extensions
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Dynamic Recipient List
Usually one of the main reasons for using the Recipient List pattern is that the list of recipients
is dynamic and calculated at runtime. The following example demonstrates how to create a
dynamic recipient list using an Expression (which in this case it extracts a named header value
dynamically) to calculate the list of endpoints which are either of type Endpoint or are
converted to a String and then resolved using the endpoint URIs.
Using the Fluent Builders
RouteBuilder builder = new RouteBuilder() {
public void configure() {
errorHandler(deadLetterChannel("mock:error"));
from("seda:a")
.recipientList(header("foo"));
}
};
The above assumes that the header contains a list of endpoint URIs. The following takes a single
string header and tokenizes it
from("direct:a").recipientList(
header("recipientListHeader").tokenize(","));
Iteratable value
The dynamic list of recipients that are defined in the header must be iteratable such as:
▪ java.util.Collection
▪ java.util.Iterator
▪ arrays
▪ org.w3c.dom.NodeList
▪ Camel 1.6.0: a single String with values separated with comma
▪ any other type will be regarded as a single value
Using the Spring XML Extensions
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$foo
For further examples of this pattern in use you could look at one of the junit test case
Using delimiter in Spring XML
Available as of Camel 1.6.0
In Spring DSL you can set the delimiter attribute for setting a delimiter to be used if the
header value is a single String with multiple separated endpoints. By default Camel uses comma
as delimiter, but this option lets you specify a customer delimiter to use instead.
myHeader
So if myHeader contains a String with the value "activemq:queue:foo,
activemq:topic:hello , log:bar" then Camel will split the String using the
delimiter given in the XML that was comma, resulting into 3 endpoints to send to. You can use
spaces between the endpoints as Camel will trim the value when it lookup the endpoint to send
to.
Note: In Java DSL you use the tokenizer to archive the same. The route above in Java
DSL:
from("direct:a").recipientList(header("myHeader").tokenize(","));
In Camel 2.1 its a bit easier as you can pass in the delimiter as 2nd parameter:
from("direct:a").recipientList(header("myHeader"), "#");
Sending to multiple recipients in parallel
Available as of Camel 2.2
The Recipient List now supports parallelProcessing that for example Splitter also
supports. You can use it to use a thread pool to have concurrent tasks sending the Exchange to
multiple recipients concurrently.
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from("direct:a").recipientList(header("myHeader")).parallelProcessing();
And in Spring XML its an attribute on the recipient list tag.
myHeader
Stop continuing in case one recipient failed
Available as of Camel 2.2
The Recipient List now supports stopOnException that for example Splitter also
supports. You can use it to stop sending to any further recipients in case any recipient failed.
from("direct:a").recipientList(header("myHeader")).stopOnException();
And in Spring XML its an attribute on the recipient list tag.
myHeader
Note: You can combine parallelProcessing and stopOnException and have them
both true.
Ignore invalid endpoints
Available as of Camel 2.3
The Recipient List now supports ignoreInvalidEndpoints which the Routing Slip
also supports. You can use it to skip endpoints which is invalid.
from("direct:a").recipientList(header("myHeader")).ignoreInvalidEndpoints();
And in Spring XML its an attribute on the recipient list tag.
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myHeader
Then lets say the myHeader contains the following two endpoints direct:foo,xxx:bar.
The first endpoint is valid and works. However the 2nd is invalid and will just be ignored. Camel
logs at INFO level about, so you can see why the endpoint was invalid.
Using custom AggregationStrategy
Available as of Camel 2.2
You can now use you own AggregationStrategy with the Recipient List. However its
not that often you need that. What its good for is that in case you are using Request Reply
messaging then the replies from the recipient can be aggregated. By default Camel uses
UseLatestAggregationStrategy which just keeps that last received reply. What if you
must remember all the bodies that all the recipients send back, then you can use your own
custom aggregator that keeps those. Its the same principle as with the Aggregator EIP so check
it out for details.
from("direct:a")
.recipientList(header("myHeader")).aggregationStrategy(new
MyOwnAggregationStrategy())
.to("direct:b");
And in Spring XML its an attribute on the recipient list tag.
myHeader
Using custom thread pool
Available as of Camel 2.2
A thread pool is only used for parallelProcessing. You supply your own custom
thread pool via the ExecutorServiceStrategy (see Camel's Threading Model), the same
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way you would do it for the aggregationStrategy. By default Camel uses a thread pool
with 10 threads (subject to change in a future version).
Using method call as recipient list
You can use a Bean to provide the recipients, for example:
from("activemq:queue:test").recipientList().method(MessageRouter.class, "routeTo");
And then MessageRouter:
public class MessageRouter {
public String routeTo() {
String queueName = "activemq:queue:test2";
return queueName;
}
}
When you use a Bean then do not also use the @RecipientList annotation as this will in
fact add yet another recipient list, so you end up having two. Do not do like this.
public class MessageRouter {
@RecipientList
public String routeTo() {
String queueName = "activemq:queue:test2";
return queueName;
}
}
Well you should only do like that above (using @RecipientList) if you route just route to a
Bean which you then want to act as a recipient list.
So the original route can be changed to:
from("activemq:queue:test").bean(MessageRouter.class, "routeTo");
Which then would invoke the routeTo method and detect its annotated with
@RecipientList and then act accordingly as if it was a recipient list EIP.
Using timeout
Available as of Camel 2.5
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If you use parallelProcessing then you can configure a total timeout value in millis.
Camel will then process the messages in parallel until the timeout is hit. This allows you to
continue processing if one message is slow. For example you can set a timeout value of 20 sec.
For example in the unit test below you can see we multicast the message to 3 destinations.
We have a timeout of 2 seconds, which means only the last two messages can be completed
within the timeframe. This means we will only aggregate the last two which yields a result
aggregation which outputs "BC".
from("direct:start")
.multicast(new AggregationStrategy() {
public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
if (oldExchange == null) {
return newExchange;
}
String body = oldExchange.getIn().getBody(String.class);
oldExchange.getIn().setBody(body +
newExchange.getIn().getBody(String.class));
return oldExchange;
}
})
.parallelProcessing().timeout(250).to("direct:a", "direct:b", "direct:c")
// use end to indicate end of multicast route
.end()
.to("mock:result");
from("direct:a").delay(1000).to("mock:A").setBody(constant("A"));
from("direct:b").to("mock:B").setBody(constant("B"));
from("direct:c").to("mock:C").setBody(constant("C"));
By default if a timeout occurs the AggregationStrategy is not invoked. However you can
implement a specialized version
public interface TimeoutAwareAggregationStrategy extends AggregationStrategy {
/**
* A timeout occurred
*
* @param oldExchange the oldest exchange (is null on first aggregation
as we only have the new exchange)
* @param index
the index
* @param total
the total
* @param timeout
the timeout value in millis
*/
void timeout(Exchange oldExchange, int index, int total, long timeout);
This allows you to deal with the timeout in the AggregationStrategy if you really need
to.
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Timeout in other EIPs
This timeout feature is also supported by Splitter and both multicast and
recipientList.
Timeout is total
The timeout is total, which means that after X time, Camel will aggregate the
messages which has completed within the timeframe. The remainders will be
cancelled. Camel will also only invoke the timeout method in the
TimeoutAwareAggregationStrategy once, for the first index which caused
the timeout.
Using onPrepare to execute custom logic when preparing messages
Available as of Camel 2.8
See details at Multicast
Using This Pattern
If you would like to use this EIP Pattern then please read the Getting Started, you may also find
the Architecture useful particularly the description of Endpoint and URIs. Then you could try
out some of the Examples first before trying this pattern out.
Splitter
The Splitter from the EIP patterns allows you split a message into a number of pieces and
process them individually
As of Camel 2.0, you need to specify a Splitter as split(). In earlier versions of Camel,
you need to use splitter().
Options
Name
Default
Value
Description
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strategyRef
Ê
Refers to an AggregationStrategy to be used to assemble the replies from the sub-messages, into a single outgoing message from
the Splitter. See the defaults described below in What the Splitter returns.
parallelProcessing
false
If enables then processing the sub-messages occurs concurrently. Note the caller thread will still wait until all sub-messages has
been fully processed, before it continues.
executorServiceRef
Ê
Refers to a custom Thread Pool to be used for parallel processing. Notice if you set this option, then parallel processing is
automatic implied, and you do not have to enable that option as well.
stopOnException
false
Camel 2.2: Whether or not to stop continue processing immediately when an exception occurred. If disable, then Camel
continue splitting and process the sub-messages regardless if one of them failed. You can deal with exceptions in the
AggregationStrategy class where you have full control how to handle that.
streaming
false
If enabled then Camel will split in a streaming fashion, which means it will split the input message in chunks. This reduces the
memory overhead. For example if you split big messages its recommended to enable streaming. If streaming is enabled then the
sub-message replies will be aggregated out-of-order, eg in the order they come back. If disabled, Camel will process sub-message
replies in the same order as they where splitted.
timeout
Ê
Camel 2.5: Sets a total timeout specified in millis. If the Recipient List hasn't been able to split and process all replies within the
given timeframe, then the timeout triggers and the Splitter breaks out and continues. Notice if you provide a
TimeoutAwareAggregationStrategy then the timeout method is invoked before breaking out.
onPrepareRef
Ê
Camel 2.8: Refers to a custom Processor to prepare the sub-message of the Exchange, before its processed. This allows you to
do any custom logic, such as deep-cloning the message payload if that's needed etc.
shareUnitOfWork
false
Camel 2.8: Whether the unit of work should be shared. See further below for more details.
Exchange properties
The following properties is set on each Exchange that are split:
header
type
description
CamelSplitIndex
int
Camel 2.0: A split counter that increases for each
Exchange being split. The counter starts from 0.
CamelSplitSize
int
Camel 2.0: The total number of Exchanges that was
splitted. This header is not applied for stream based
splitting. From Camel 2.9 onwards this header is
also set in stream based splitting, but only on the
completed Exchange.
CamelSplitComplete
boolean
Camel 2.4: Whether or not this Exchange is the
last.
Examples
The following example shows how to take a request from the queue:a endpoint the split it
into pieces using an Expression, then forward each piece to queue:b
Using the Fluent Builders
RouteBuilder builder = new RouteBuilder() {
public void configure() {
errorHandler(deadLetterChannel("mock:error"));
from("seda:a")
.split(body(String.class).tokenize("\n"))
.to("seda:b");
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}
};
The splitter can use any Expression language so you could use any of the Languages Supported
such as XPath, XQuery, SQL or one of the Scripting Languages to perform the split. e.g.
from("activemq:my.queue").split(xpath("//foo/
bar")).convertBodyTo(String.class).to("file://some/directory")
Using the Spring XML Extensions
/invoice/lineItems
For further examples of this pattern in use you could look at one of the junit test case
Using Tokenizer from Spring XML Extensions*
Avaiaible as of Camel 2.0
You can use the tokenizer expression in the Spring DSL to split bodies or headers using a
token. This is a common use-case, so we provided a special tokenizer tag for this.
In the sample below we split the body using a @ as separator. You can of course use comma or
space or even a regex pattern, also set regex=true.
Splitting the body in Spring XML is a bit harder as you need to use the Simple language to
dictate this
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${body}
What the Splitter returns
Camel 2.2 or older:
The Splitter will by default return the last splitted message.
Camel 2.3 and newer
The Splitter will by default return the original input message.
For all versions
You can override this by suppling your own strategy as an AggregationStrategy. There is
a sample on this page (Split aggregate request/reply sample). Notice its the same strategy as the
Aggregator supports. This Splitter can be viewed as having a build in light weight Aggregator.
Parallel execution of distinct 'parts'
If you want to execute all parts in parallel you can use special notation of split() with two
arguments, where the second one is a boolean flag if processing should be parallel. e.g.
XPathBuilder xPathBuilder = new XPathBuilder("//foo/bar");
from("activemq:my.queue").split(xPathBuilder, true).to("activemq:my.parts");
In Camel 2.0 the boolean option has been refactored into a builder method
parallelProcessing so its easier to understand what the route does when we use a
method instead of true|false.
XPathBuilder xPathBuilder = new XPathBuilder("//foo/bar");
from("activemq:my.queue").split(xPathBuilder).parallelProcessing().to("activemq:my.parts");
Stream based
You can split streams by enabling the streaming mode using the streaming builder method.
from("direct:streaming").split(body().tokenize(",")).streaming().to("activemq:my.parts");
You can also supply your custom splitter to use with streaming like this:
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Splitting big XML payloads
The XPath engine in Java and saxon will load the entire XML content into memory.
And thus they are not well suited for very big XML payloads.
Instead you can use a custom Expression which will iterate the XML payload in a
streamed fashion. From Camel 2.9 onwards you can use the Tokenizer language
which supports this when you supply the start and end tokens.
import static org.apache.camel.builder.ExpressionBuilder.beanExpression;
from("direct:streaming")
.split(beanExpression(new MyCustomIteratorFactory(), "iterator"))
.streaming().to("activemq:my.parts")
Streaming big XML payloads using Tokenizer language
Available as of Camel 2.9
If you have a big XML payload, from a file source, and want to split it in streaming mode, then
you can use the Tokenizer language with start/end tokens to do this with low memory
footprint.
For example you may have a XML payload structured as follows
...
Now to split this big file using XPath would cause the entire content to be loaded into memory.
So instead we can use the Tokenizer language to do this as follows:
from("file:inbox")
.split().tokenizeXML("order").streaming()
.to("activemq:queue:order");
In XML DSL the route would be as follows:
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StAX component
The Camel StAX component can also be used to split big XML files in a streaming
mode. See more details at StAX.
Notice the tokenizeXML method which will split the file using the tag name of the child
node, which mean it will grab the content between the and tags (incl.
the tokens). So for example a splitted message would be as follows:
If you want to inherit namespaces from a root/parent tag, then you can do this as well by
providing the name of the root/parent tag:
And in Java DSL its as follows:
from("file:inbox")
.split().tokenizeXML("order", "orders").streaming()
.to("activemq:queue:order");
Specifying a custom aggregation strategy
Available as of Camel 2.0
This is specified similar to the Aggregator.
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Specifying a custom ThreadPoolExecutor
You can customize the underlying ThreadPoolExecutor used in the parallel splitter. In the Java
DSL try something like this:
XPathBuilder xPathBuilder = new XPathBuilder("//foo/bar");
ExecutorService pool = ...
from("activemq:my.queue")
.split(xPathBuilder).parallelProcessing().executorService(pool)
.to("activemq:my.parts");
Using a Pojo to do the splitting
As the Splitter can use any Expression to do the actual splitting we leverage this fact and use a
method expression to invoke a Bean to get the splitted parts.
The Bean should return a value that is iterable such as: java.util.Collection,
java.util.Iterator or an array.
In the route we define the Expression as a method call to invoke our Bean that we have
registered with the id mySplitterBean in the Registry.
from("direct:body")
// here we use a POJO bean mySplitterBean to do the split of the payload
.split().method("mySplitterBean", "splitBody")
.to("mock:result");
from("direct:message")
// here we use a POJO bean mySplitterBean to do the split of the message
// with a certain header value
.split().method("mySplitterBean", "splitMessage")
.to("mock:result");
And the logic for our Bean is as simple as. Notice we use Camel Bean Binding to pass in the
message body as a String object.
public class MySplitterBean {
/**
* The split body method returns something that is iteratable such as a
java.util.List.
*
* @param body the payload of the incoming message
* @return a list containing each part splitted
*/
public List splitBody(String body) {
// since this is based on an unit test you can of cause
// use different logic for splitting as Camel have out
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// of the box support for splitting a String based on comma
// but this is for show and tell, since this is java code
// you have the full power how you like to split your messages
List answer = new ArrayList();
String[] parts = body.split(",");
for (String part : parts) {
answer.add(part);
}
return answer;
}
/**
* The split message method returns something that is iteratable such as a
java.util.List.
*
* @param header the header of the incoming message with the name user
* @param body the payload of the incoming message
* @return a list containing each part splitted
*/
public List splitMessage(@Header(value = "user") String header, @Body
String body) {
// we can leverage the Parameter Binding Annotations
// http://camel.apache.org/parameter-binding-annotations.html
// to access the message header and body at same time,
// then create the message that we want, splitter will
// take care rest of them.
// *NOTE* this feature requires Camel version >= 1.6.1
List answer = new ArrayList();
String[] parts = header.split(",");
for (String part : parts) {
DefaultMessage message = new DefaultMessage();
message.setHeader("user", part);
message.setBody(body);
answer.add(message);
}
return answer;
}
}
Split aggregate request/reply sample
This sample shows how you can split an Exchange, process each splitted message, aggregate and
return a combined response to the original caller using request/reply.
The route below illustrates this and how the split supports a aggregationStrategy to
hold the in progress processed messages:
// this routes starts from the direct:start endpoint
// the body is then splitted based on @ separator
// the splitter in Camel supports InOut as well and for that we need
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// to be able to aggregate what response we need to send back, so we provide our
// own strategy with the class MyOrderStrategy.
from("direct:start")
.split(body().tokenize("@"), new MyOrderStrategy())
// each splitted message is then send to this bean where we can process it
.to("bean:MyOrderService?method=handleOrder")
// this is important to end the splitter route as we do not want to do more
routing
// on each splitted message
.end()
// after we have splitted and handled each message we want to send a single
combined
// response back to the original caller, so we let this bean build it for us
// this bean will receive the result of the aggregate strategy: MyOrderStrategy
.to("bean:MyOrderService?method=buildCombinedResponse")
And the OrderService bean is as follows:
public static class MyOrderService {
private static int counter;
/**
* We just handle the order by returning a id line for the order
*/
public String handleOrder(String line) {
LOG.debug("HandleOrder: " + line);
return "(id=" + ++counter + ",item=" + line + ")";
}
/**
* We use the same bean for building the combined response to send
* back to the original caller
*/
public String buildCombinedResponse(String line) {
LOG.debug("BuildCombinedResponse: " + line);
return "Response[" + line + "]";
}
}
And our custom aggregationStrategy that is responsible for holding the in progress
aggregated message that after the splitter is ended will be sent to the
buildCombinedResponse method for final processing before the combined response can
be returned to the waiting caller.
/**
* This is our own order aggregation strategy where we can control
* how each splitted message should be combined. As we do not want to
* loos any message we copy from the new to the old to preserve the
* order lines as long we process them
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*/
public static class MyOrderStrategy implements AggregationStrategy {
public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
// put order together in old exchange by adding the order from new exchange
if (oldExchange == null) {
// the first time we aggregate we only have the new exchange,
// so we just return it
return newExchange;
}
String orders = oldExchange.getIn().getBody(String.class);
String newLine = newExchange.getIn().getBody(String.class);
LOG.debug("Aggregate old orders: " + orders);
LOG.debug("Aggregate new order: " + newLine);
// put orders together separating by semi colon
orders = orders + ";" + newLine;
// put combined order back on old to preserve it
oldExchange.getIn().setBody(orders);
// return old as this is the one that has all the orders gathered until now
return oldExchange;
}
}
So lets run the sample and see how it works.
We send an Exchange to the direct:start endpoint containing a IN body with the String
value: A@B@C. The flow is:
HandleOrder: A
HandleOrder: B
Aggregate old orders: (id=1,item=A)
Aggregate new order: (id=2,item=B)
HandleOrder: C
Aggregate old orders: (id=1,item=A);(id=2,item=B)
Aggregate new order: (id=3,item=C)
BuildCombinedResponse: (id=1,item=A);(id=2,item=B);(id=3,item=C)
Response to caller: Response[(id=1,item=A);(id=2,item=B);(id=3,item=C)]
Stop processing in case of exception
Available as of Camel 2.1
The Splitter will by default continue to process the entire Exchange even in case of one of
the splitted message will thrown an exception during routing.
For example if you have an Exchange with 1000 rows that you split and route each sub
message. During processing of these sub messages an exception is thrown at the 17th. What
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Camel does by default is to process the remainder 983 messages. You have the chance to
remedy or handle this in the AggregationStrategy.
But sometimes you just want Camel to stop and let the exception be propagated back, and
let the Camel error handler handle it. You can do this in Camel 2.1 by specifying that it should
stop in case of an exception occurred. This is done by the stopOnException option as
shown below:
from("direct:start")
.split(body().tokenize(",")).stopOnException()
.process(new MyProcessor())
.to("mock:split");
And using XML DSL you specify it as follows:
Using onPrepare to execute custom logic when preparing messages
Available as of Camel 2.8
See details at Multicast
Sharing unit of work
Available as of Camel 2.8
The Splitter will by default not share unit of work between the parent exchange and each
splitted exchange. This means each sub exchange has its own individual unit of work.
For example you may have an use case, where you want to split a big message. And you
want to regard that process as an atomic isolated operation that either is a success or failure. In
case of a failure you want that big message to be moved into a dead letter queue. To support
this use case, you would have to share the unit of work on the Splitter.
Here is an example in Java DSL
errorHandler(deadLetterChannel("mock:dead").useOriginalMessage()
.maximumRedeliveries(3).redeliveryDelay(0));
from("direct:start")
.to("mock:a")
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// share unit of work in the splitter, which tells Camel to propagate failures from
// processing the splitted messages back to the result of the splitter, which
allows
// it to act as a combined unit of work
.split(body().tokenize(",")).shareUnitOfWork()
.to("mock:b")
.to("direct:line")
.end()
.to("mock:result");
from("direct:line")
.to("log:line")
.process(new MyProcessor())
.to("mock:line");
Now in this example what would happen is that in case there is a problem processing each sub
message, the error handler will kick in (yes error handling still applies for the sub messages).
But what doesn't happen is that if a sub message fails all redelivery attempts (its exhausted),
then its not moved into that dead letter queue. The reason is that we have shared the unit of
work, so the sub message will report the error on the shared unit of work. When the Splitter
is done, it checks the state of the shared unit of work and checks if any errors occurred. And if
an error occurred it will set the exception on the Exchange and mark it for rollback. The error
handler will yet again kick in, as the Exchange has been marked as rollback and it had an
exception as well. No redelivery attempts is performed (as it was marked for rollback) and the
Exchange will be moved into the dead letter queue.
Using this from XML DSL is just as easy as you just have to set the shareUnitOfWork
attribute to true:
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Using This Pattern
If you would like to use this EIP Pattern then please read the Getting Started, you may also find
the Architecture useful particularly the description of Endpoint and URIs. Then you could try
out some of the Examples first before trying this pattern out.
Aggregator
This applies for Camel version 2.3 or newer. If you use an older version then
use this Aggregator link instead.
The Aggregator from the EIP patterns allows you to combine a number of messages
together into a single message.
A correlation Expression is used to determine the messages which should be aggregated
together. If you want to aggregate all messages into a single message, just use a constant
expression. An AggregationStrategy is used to combine all the message exchanges for a single
correlation key into a single message exchange.
Aggregator options
The aggregator supports the following options:
Option
Default
Description
correlationExpression
Ê
Mandatory Expression which evaluates the correlation key to use for aggregation. The Exchange which has the same
correlation key is aggregated together. If the correlation key could not be evaluated an Exception is thrown. You can
disable this by using the ignoreBadCorrelationKeys option.
aggregationStrategy
Ê
Mandatory AggregationStrategy which is used to merge the incoming Exchange with the existing already merged
exchanges. At first call the oldExchange parameter is null. On subsequent invocations the oldExchange
contains the merged exchanges and newExchange is of course the new incoming Exchange.
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Implementation of shared unit of work in Camel 2.x
The Camel team had to introduce a SubUnitOfWork to keep API compatible
with the current UnitOfWork in Camel 2.x code base. So in reality the unit of
work is not shared as a single object instance. Instead SubUnitOfWork is
attached to their parent, and issues callback to the parent about their status
(commit or rollback). This may be refactored in Camel 3.0 where larger API
changes can be done.
395
strategyRef
Ê
A reference to lookup the AggregationStrategy in the Registry.
completionSize
Ê
Number of messages aggregated before the aggregation is complete. This option can be set as either a fixed value or
using an Expression which allows you to evaluate a size dynamically - will use Integer as result. If both are set Camel
will fallback to use the fixed value if the Expression result was null or 0.
completionTimeout
Ê
Time in millis that an aggregated exchange should be inactive before its complete. This option can be set as either a fixed
value or using an Expression which allows you to evaluate a timeout dynamically - will use Long as result. If both are set
Camel will fallback to use the fixed value if the Expression result was null or 0. You cannot use this option together
with completionInterval, only one of the two can be used.
completionInterval
Ê
A repeating period in millis by which the aggregator will complete all current aggregated exchanges. Camel has a
background task which is triggered every period. You cannot use this option together with completionTimeout, only one
of them can be used.
completionPredicate
Ê
A Predicate to indicate when an aggregated exchange is complete.
completionFromBatchConsumer
false
This option is if the exchanges are coming from a Batch Consumer. Then when enabled the Aggregator2 will use the
batch size determined by the Batch Consumer in the message header CamelBatchSize. See more details at Batch
Consumer. This can be used to aggregate all files consumed from a File endpoint in that given poll.
forceCompletionOnStop
false
Camel 2.9 Indicates to complete all current aggregated exchanges when the context is stopped
eagerCheckCompletion
false
Whether or not to eager check for completion when a new incoming Exchange has been received. This option
influences the behavior of the completionPredicate option as the Exchange being passed in changes accordingly.
When false the Exchange passed in the Predicate is the aggregated Exchange which means any information you may
store on the aggregated Exchange from the AggregationStrategy is available for the Predicate. When true the
Exchange passed in the Predicate is the incoming Exchange, which means you can access data from the incoming
Exchange.
groupExchanges
false
If enabled then Camel will group all aggregated Exchanges into a single combined
org.apache.camel.impl.GroupedExchange holder class that holds all the aggregated Exchanges. And as a
result only one Exchange is being sent out from the aggregator. Can be used to combine many incoming Exchanges into
a single output Exchange without coding a custom AggregationStrategy yourself.
ignoreInvalidCorrelationKeys
false
Whether or not to ignore correlation keys which could not be evaluated to a value. By default Camel will throw an
Exception, but you can enable this option and ignore the situation instead.
closeCorrelationKeyOnCompletion
Ê
Whether or not too late Exchanges should be accepted or not. You can enable this to indicate that if a correlation key
has already been completed, then any new exchanges with the same correlation key be denied. Camel will then throw a
closedCorrelationKeyException exception. When using this option you pass in a integer which is a
number for a LRUCache which keeps that last X number of closed correlation keys. You can pass in 0 or a negative
value to indicate a unbounded cache. By passing in a number you are ensured that cache won't grow too big if you use a
log of different correlation keys.
discardOnCompletionTimeout
false
Camel 2.5: Whether or not exchanges which complete due to a timeout should be discarded. If enabled then when a
timeout occurs the aggregated message will not be sent out but dropped (discarded).
aggregationRepository
Ê
Allows you to plugin you own implementation of org.apache.camel.spi.AggregationRepository which
keeps track of the current inflight aggregated exchanges. Camel uses by default a memory based implementation.
aggregationRepositoryRef
Ê
Reference to lookup a aggregationRepository in the Registry.
parallelProcessing
false
When aggregated are completed they are being send out of the aggregator. This option indicates whether or not Camel
should use a thread pool with multiple threads for concurrency. If no custom thread pool has been specified then Camel
creates a default pool with 10 concurrent threads.
executorService
Ê
If using parallelProcessing you can specify a custom thread pool to be used. In fact also if you are not using
parallelProcessing this custom thread pool is used to send out aggregated exchanges as well.
executorServiceRef
Ê
Reference to lookup a executorService in the Registry
timeoutCheckerExecutorService
Ê
Camel 2.9: If using either of the completionTimeout, completionTimeoutExpression, or
completionInterval options a background thread is created to check for the completion for every aggregator. Set
this option to provide a custom thread pool to be used rather than creating a new thread for every aggregator.
timeoutCheckerExecutorServiceRef
Ê
Camel 2.9: Reference to lookup a timeoutCheckerExecutorService in the Registry
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Exchange Properties
The following properties are set on each aggregated Exchange:
header
type
description
CamelAggregatedSize
int
The total number of Exchanges aggregated into this combined Exchange.
CamelAggregatedCompletedBy
String
Indicator how the aggregation was completed as a value of either: predicate, size, consumer, timeout or
interval.
About AggregationStrategy
The AggregationStrategy is used for aggregating the old (lookup by its correlation id)
and the new exchanges together into a single exchange. Possible implementations include
performing some kind of combining or delta processing, such as adding line items together into
an invoice or just using the newest exchange and removing old exchanges such as for state
tracking or market data prices; where old values are of little use.
Notice the aggregation strategy is a mandatory option and must be provided to the
aggregator.
Here are a few example AggregationStrategy implementations that should help you create
your own custom strategy.
//simply combines Exchange String body values using '+' as a delimiter
class StringAggregationStrategy implements AggregationStrategy {
public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
if (oldExchange == null) {
return newExchange;
}
String oldBody = oldExchange.getIn().getBody(String.class);
String newBody = newExchange.getIn().getBody(String.class);
oldExchange.getIn().setBody(oldBody + "+" + newBody);
return oldExchange;
}
}
//simply combines Exchange body values into an ArrayList
Using the context component
Then in another CamelContext we can then refer to this "accounts black box" by just sending
to accounts:purchaseOrder and consuming from accounts:invoice.
If you prefer to be more verbose and explicit you could use
context:accounts:purchaseOrder or even
context:accounts:direct://purchaseOrder if you prefer. But using logical endpoint
URIs is preferred as it hides the implementation detail and provides a simple logical naming
scheme.
For example if we wish to then expose this accounts black box on some middleware
(outside of the black box) we can do things like...
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Naming endpoints
A context component instance can have many public input and output endpoints that can be
accessed from outside it's CamelContext. When there are many it is recommended that you
use logical names for them to hide the middleware as shown above.
However when there is only one input, output or error/dead letter endpoint in a
component we recommend using the common posix shell names in, out and err
CRYPTO COMPONENT FOR DIGITAL SIGNATURES
Available as of Camel 2.3
Using Camel cryptographic endpoints and Java's Cryptographic extension it is easy to create
Digital Signatures for Exchanges. Camel provides a pair of flexible endpoints which get used in
concert to create a signature for an exchange in one part of the exchange's workflow and then
verify the signature in a later part of the workflow.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-cryptox.x.x
Introduction
Digital signatures make use Asymmetric Cryptographic techniques to sign messages. From a
(very) high level, the algorithms use pairs of complimentary keys with the special property that
data encrypted with one key can only be decrypted with the other. One, the private key, is
closely guarded and used to 'sign' the message while the other, public key, is shared around to
anyone interested in verifying your messages. Messages are signed by encrypting a digest of the
message with the private key. This encrypted digest is transmitted along with the message. On
the other side the verifier recalculates the message digest and uses the public key to decrypt
the the digest in the signature. If both digest match the verifier knows only the holder of the
private key could have created the signature.
Camel uses the Signature service from the Java Cryptographic Extension to do all the heavy
cryptographic lifting required to create exchange signatures. The following are some excellent
sources for explaining the mechanics of Cryptography, Message digests and Digital Signatures
and how to leverage them with the JCE.
▪ Bruce Schneier's Applied Cryptography
▪ Beginning Cryptography with Java by David Hook
▪ The ever insightful, Wikipedia Digital_signatures
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URI format
As mentioned Camel provides a pair of crypto endpoints to create and verify signatures
crypto:sign:name[?options]
crypto:verify:name[?options]
• crypto:sign creates the signature and stores it in the Header keyed by the
constant Exchange.SIGNATURE, i.e. "CamelDigitalSignature".
• crypto:verify will read in the contents of this header and do the verification
calculation.
In order to correctly function, sign and verify need to share a pair of keys, sign requiring a
PrivateKey and verify a PublicKey (or a Certificate containing one). Using the JCE
is is very simple to generate these key pairs but it is usually most secure to use a KeyStore to
house and share your keys. The DSL is very flexible about how keys are supplied and provides a
number of mechanisms.
Note a crypto:sign endpoint is typically defined in one route and the complimentary
crypto:verify in another, though for simplicity in the examples they appear one after the
other. It goes without saying that both sign and verify should be configured identically.
Options
Name
Type
Default
Description
algorithm
String
DSA
The name of the JCE Signature algorithm that will be used.
alias
String
null
An alias name that will be used to select a key from the keystore.
bufferSize
Integer
2048
the size of the buffer used in the signature process.
certificate
Certificate
null
A Certificate used to verify the signature of the exchange's payload. Either this or a Public Key is required.
keystore
KeyStore
null
A reference to a JCE Keystore that stores keys and certificates used to sign and verify.
provider
String
null
The name of the JCE Security Provider that should be used.
privateKey
PrivatKey
null
The private key used to sign the exchange's payload.
publicKey
PublicKey
null
The public key used to verify the signature of the exchange's payload.
secureRandom
secureRandom
null
A reference to a SecureRandom object that wil lbe used to initialize the Signature service.
password
char[]
null
The password for the keystore.
Using
1) Raw keys
The most basic way to way to sign an verify an exchange is with a KeyPair as follows.
from("direct:keypair").to("crypto:sign://basic?privateKey=#myPrivateKey",
"crypto:verify://basic?publicKey=#myPublicKey", "mock:result");
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The same can be achieved with the Spring XML Extensions using references to keys
2) KeyStores and Aliases.
The JCE provides a very versatile KeyStore for housing pairs of PrivateKeys and Certificates
keeping them encrypted and password protected. They can be retrieved from it by applying an
alias to the retrieval apis. There are a number of ways to get keys and Certificates into a
keystore most often this is done with the external 'keytool' application. This is a good example
of using keytool to create a KeyStore with a self signed Cert and Private key.
The examples use a Keystore with a key and cert aliased by 'bob'. The password for the
keystore and the key is 'letmein'
The following shows how to use a Keystore via the Fluent builders, it also shows how to
load and initialize the keystore.
from("direct:keystore").to("crypto:sign://keystore?keystore=#keystore&alias=bob&password=letmein",
"crypto:verify://keystore?keystore=#keystore&alias=bob", "mock:result");
Again in Spring a ref is used to lookup an actual keystore instance.
3) Changing JCE Provider and Algorithm
Changing the Signature algorithm or the Security provider is a simple matter of specifying their
names. You will need to also use Keys that are compatible with the algorithm you choose.
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
keyGen.initialize(512, new SecureRandom());
keyPair = keyGen.generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
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PublicKey publicKey = keyPair.getPublic();
// we can set the keys explicitly on the endpoint instances.
context.getEndpoint("crypto:sign://rsa?algorithm=MD5withRSA",
DigitalSignatureEndpoint.class).setPrivateKey(privateKey);
context.getEndpoint("crypto:verify://rsa?algorithm=MD5withRSA",
DigitalSignatureEndpoint.class).setPublicKey(publicKey);
from("direct:algorithm").to("crypto:sign://rsa?algorithm=MD5withRSA",
"crypto:verify://rsa?algorithm=MD5withRSA", "mock:result");
from("direct:provider").to("crypto:sign://provider?privateKey=#myPrivateKey&provider=SUN",
"crypto:verify://provider?publicKey=#myPublicKey&provider=SUN", "mock:result");
or
4) Changing the Signature Mesasge Header
It may be desirable to change the message header used to store the signature. A different
header name can be specified in the route definition as follows
from("direct:signature-header").to("crypto:sign://another?privateKey=#myPrivateKey&signatureHeader=Ano
"crypto:verify://another?publicKey=#myPublicKey&signatureHeader=AnotherDigitalSignature",
"mock:result");
or
5) Changing the buffersize
In case you need to update the size of the buffer...
from("direct:buffersize").to("crypto:sign://buffer?privateKey=#myPrivateKey&buffersize=1024",
"crypto:verify://buffer?publicKey=#myPublicKey&buffersize=1024", "mock:result");
or
6) Supplying Keys dynamically.
When using a Recipient list or similar EIP the recipient of an exchange can vary dynamically.
Using the same key across all recipients may neither be feasible or desirable. It would be useful
to be able to specify the signature keys dynamically on a per exchange basis. The exchange
could then be dynamically enriched with the key of its target recipient prior to signing. To
facilitate this the signature mechanisms allow for keys to be supplied dynamically via the
message headers below
• Exchange.SIGNATURE_PRIVATE_KEY, "CamelSignaturePrivateKey"
• Exchange.SIGNATURE_PUBLIC_KEY_OR_CERT,
"CamelSignaturePublicKeyOrCert"
from("direct:headerkey-sign").to("crypto:sign://alias");
from("direct:headerkey-verify").to("crypto:verify://alias", "mock:result");
or
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Better again would be to dynamically supply a keystore alias. Again the alias can be supplied in a
message header
• Exchange.KEYSTORE_ALIAS, "CamelSignatureKeyStoreAlias"
from("direct:alias-sign").to("crypto:sign://alias?keystore=#keystore");
from("direct:alias-verify").to("crypto:verify://alias?keystore=#keystore",
"mock:result");
or
The header would be set as follows
Exchange unsigned = getMandatoryEndpoint("direct:alias-sign").createExchange();
unsigned.getIn().setBody(payload);
unsigned.getIn().setHeader(DigitalSignatureConstants.KEYSTORE_ALIAS, "bob");
unsigned.getIn().setHeader(DigitalSignatureConstants.KEYSTORE_PASSWORD,
"letmein".toCharArray());
template.send("direct:alias-sign", unsigned);
Exchange signed = getMandatoryEndpoint("direct:alias-sign").createExchange();
signed.getIn().copyFrom(unsigned.getOut());
signed.getIn().setHeader(KEYSTORE_ALIAS, "bob");
template.send("direct:alias-verify", signed);
See Also
• Configuring Camel
• Component
• Endpoint
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• Getting Started
• Crypto Crypto is also available as a Data Format
CXF COMPONENT
The cxf: component provides integration with Apache CXF for connecting to JAX-WS services
hosted in CXF.
• CXF Component
• URI format
• Options
• The descriptions of the dataformats
• How to enable CXF's LoggingOutInterceptor in MESSAGE mode
• Description of relayHeaders option
• Available in Release 1.6.1 and after (only in POJO mode)
• Changes since Release 2.0
• Configure the CXF endpoints with Spring
• Configuring the CXF Endpoints with Apache Aries Blueprint.
• How to make the camel-cxf component use log4j instead of java.util.logging
• How to let camel-cxf response message with xml start document
• How to consume a message from a camel-cxf endpoint in POJO data format
• How to prepare the message for the camel-cxf endpoint in POJO data format
• How to deal with the message for a camel-cxf endpoint in PAYLOAD data format
• How to get and set SOAP headers in POJO mode
• How to get and set SOAP headers in PAYLOAD mode
• SOAP headers are not available in MESSAGE mode
• How to throw a SOAP Fault from Camel
• How to propagate a camel-cxf endpoint's request and response context
• Attachment Support
• Streaming Support in PAYLOAD mode
• See Also
Maven users will need to add the following dependency to their pom.xml for this component:
org.apache.camelcamel-cxfx.x.x
URI format
cxf:bean:cxfEndpoint[?options]
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When using CXF as a consumer, the CXF Bean Component allows you to factor
out how message payloads are received from their processing as a RESTful or SOAP
web service. This has the potential of using a multitude of transports to consume
web services. The bean component's configuration is also simpler and provides the
fastest method to implement web services using Camel and CXF.
CXF dependencies
If you want to learn about CXF dependencies you can checkout the WHICH-JARS
text file.
Where cxfEndpoint represents a bean ID that references a bean in the Spring bean registry.
With this URI format, most of the endpoint details are specified in the bean definition.
cxf://someAddress[?options]
Where someAddress specifies the CXF endpoint's address. With this URI format, most of
the endpoint details are specified using options.
For either style above, you can append options to the URI as follows:
cxf:bean:cxfEndpoint?wsdlURL=wsdl/hello_world.wsdl&dataFormat=PAYLOAD
Options
Name
Required
wsdlURL
No
Description
The location of the WSDL. It is obtained from endpoint address by default.
Example: file://local/wsdl/hello.wsdl or wsdl/hello.wsdl
serviceClass
Yes
The name of the SEI (Service Endpoint Interface) class. This class can have, but does not require, JSR181
annotations.
Since 2.0, this option is only required by POJO mode. If the wsdlURL option is provided, serviceClass is not
required for PAYLOAD and MESSAGE mode. When wsdlURL option is used without serviceClass, the serviceName
and portName (endpointName for Spring configuration) options MUST be provided. It is possible to use #
notation to reference a serviceClass object instance from the registry. E.g. serviceClass=#beanName.
Since 2.8, it is possible to omit both wsdlURL and serviceClass options for PAYLOAD and MESSAGE mode.
When they are omitted, arbitrary XML elements can be put in CxfPayload's body in PAYLOAD mode to facilitate
CXF Dispatch Mode.
Please be advised that the referenced object cannot be a Proxy (Spring AOP Proxy is OK) as it relies on
Object.getClass().getName() method for non Spring AOP Proxy.
Example: org.apache.camel.Hello
serviceClassInstance
No
Use either serviceClass or serviceClassInstance.
Deprecated in 2.x. In 1.6.x serviceClassInstance works like serviceClass=#beanName, which
looks up a serviceObject instance from the registry.
Example: serviceClassInstance=beanName
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The service name this service is implementing, it maps to the wsdl:service@name.
serviceName
No
Required for camel-cxf consumer since camel-2.2.0 or if more than one serviceName is present in WSDL.
Example: {http:?//org.apache.camel}ServiceName
The port name this service is implementing, it maps to the wsdl:port@name.
portName
No
Required for camel-cxf consumer since camel-2.2.0 or if more than one portName is present under
serviceName.
Example: {http:?//org.apache.camel}PortName
The data type messages supported by the CXF endpoint.
dataFormat
No
Default: POJO
Example: POJO, PAYLOAD, MESSAGE
Available since 1.6.1. Please see the Description of relayHeaders option section for this option in 2.0.
Should a CXF endpoint relay headers along the route. Currently only available when dataFormat=POJO
relayHeaders
No
Default: true
Example: true, false
Which kind of operation that CXF endpoint producer will invoke
wrapped
wrappedStyle
No
No
Default: false
Example: true, false
New in 2.5.0 The WSDL style that describes how parameters are represented in the SOAP body. If the value is
false, CXF will chose the document-literal unwrapped style, If the value is true, CXF will chose the document-literal
wrapped style
Default: Null
Example: true, false
Will set the default bus when CXF endpoint create a bus by itself
setDefaultBus
No
bus
No
Default: false
Example: true, false
New in 2.0.0. A default bus created by CXF Bus Factory. Use # notation to reference a bus object from the registry.
The referenced object must be an instance of org.apache.cxf.Bus.
Example: bus=#busName
cxfBinding
No
New in 2.0. Use # notation to reference a CXF binding object from the registry. The referenced object must be an
instance of org.apache.camel.component.cxf.CxfBinding (use an instance of
org.apache.camel.component.cxf.DefaultCxfBinding).
Example: cxfBinding=#bindingName
headerFilterStrategy
No
New in 2.0. Use # notation to reference a header filter strategy object from the registry. The referenced object
must be an instance of org.apache.camel.spi.HeaderFilterStrategy (use an instance of
org.apache.camel.component.cxf.CxfHeaderFilterStrategy).
Example: headerFilterStrategy=#strategyName
New in 2.3. This option enables CXF Logging Feature which writes inbound and outbound SOAP messages to log.
loggingFeatureEnabled
No
Default: false
Example: loggingFeatureEnabled=true
New in 2.4, this option will set the default operationName that will be used by the CxfProducer which invokes the
remote service.
defaultOperationName
No
Default: null
Example: defaultOperationName=greetMe
New in 2.4. This option will set the default operationNamespace that will be used by the CxfProducer which
invokes the remote service.
defaultOperationNamespace
No
Default: null
Example: defaultOperationNamespace=http://apache.org/hello_world_soap_http
New in 2.5. This option will let cxf endpoint decide to use sync or async API to do the underlying work. The default
value is false which means camel-cxf endpoint will try to use async API by default.
synchronous
No
Default: false
Example: synchronous=true
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New in 2.5. This option can override the endpointUrl that published from the WSDL which can be accessed with
service address url plus ?wsdl.
publishedEndpointUrl
No
Default: null
Example: publshedEndpointUrl=http://example.com/service
properties.XXX
No
Camel 2.8: Allows to set custom properties to CXF in the endpoint uri. For example setting
properties.mtom-enabled=true to enable MTOM.
allowStreaming
No
New in 2.8.2. This option controls whether the CXF component, when running in PAYLOAD mode (see below),
will DOM parse the incoming messages into DOM Elements or keep the payload as a javax.xml.transform.Source
object that would allow streaming in some cases.
The serviceName and portName are QNames, so if you provide them be sure to prefix
them with their {namespace} as shown in the examples above.
NOTE From CAMEL 1.5.1 , the serviceClass for a CXF producer (that is, the to
endpoint) should be a Java interface.
The descriptions of the dataformats
DataFormat
Description
POJO
POJOs (Plain old Java objects) are the Java parameters to the method being invoked on the target server. Both Protocol and Logical JAX-WS handlers
are supported.
PAYLOAD
PAYLOAD is the message payload (the contents of the soap:body) after message configuration in the CXF endpoint is applied. Only Protocol JAXWS handler is supported. Logical JAX-WS handler is not supported.
MESSAGE
MESSAGE is the raw message that is received from the transport layer. It is not suppose to touch or change Stream, so you can't see any soap
headers after the camel-cxf consumer and JAX-WS handler is not supported.
You can determine the data format mode of an exchange by retrieving the exchange property,
CamelCXFDataFormat. The exchange key constant is defined in
org.apache.camel.component.cxf.CxfConstants.DATA_FORMAT_PROPERTY.
How to enable CXF's LoggingOutInterceptor in MESSAGE mode
CXF's LoggingOutInterceptor outputs outbound message that goes on the wire to
logging system (Java Util Logging). Since the LoggingOutInterceptor is in PRE_STREAM
phase (but PRE_STREAM phase is removed in MESSAGE mode), you have to configure
LoggingOutInterceptor to be run during the WRITE phase. The following is an example.
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Description of relayHeaders option
There are in-band and out-of-band on-the-wire headers from the perspective of a JAXWS
WSDL-first developer.
The in-band headers are headers that are explicitly defined as part of the WSDL binding
contract for an endpoint such as SOAP headers.
The out-of-band headers are headers that are serialized over the wire, but are not explicitly
part of the WSDL binding contract.
Headers relaying/filtering is bi-directional.
When a route has a CXF endpoint and the developer needs to have on-the-wire headers,
such as SOAP headers, be relayed along the route to be consumed say by another JAXWS
endpoint, then relayHeaders should be set to true, which is the default value.
Available in Release 1.6.1 and after (only in POJO mode)
The relayHeaders=true express an intent to relay the headers. The actual decision on
whether a given header is relayed is delegated to a pluggable instance that implements the
MessageHeadersRelay interface. A concrete implementation of
MessageHeadersRelay will be consulted to decide if a header needs to be relayed or not.
There is already an implementation of SoapMessageHeadersRelay which binds itself to
well-known SOAP name spaces. Currently only out-of-band headers are filtered, and in-band
headers will always be relayed when relayHeaders=true. If there is a header on the wire,
whose name space is unknown to the runtime, then a fall back
DefaultMessageHeadersRelay will be used, which simply allows all headers to be
relayed.
The relayHeaders=false setting asserts that all headers in-band and out-of-band will
be dropped.
You can plugin your own MessageHeadersRelay implementations overriding or adding
additional ones to the list of relays. In order to override a preloaded relay instance just make
sure that your MessageHeadersRelay implementation services the same name spaces as
the one you looking to override. Also note, that the overriding relay has to service all of the
name spaces as the one you looking to override, or else a runtime exception on route start up
will be thrown as this would introduce an ambiguity in name spaces to relay instance mappings.
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Take a look at the tests that show how you'd be able to relay/drop headers here:
https://svn.apache.org/repos/asf/camel/branches/camel-1.x/components/camel-cxf/src/test/
java/org/apache/camel/component/cxf/soap/headers/CxfMessageHeadersRelayTest.java
Changes since Release 2.0
• POJO and PAYLOAD modes are supported. In POJO mode, only out-of-band message
headers are available for filtering as the in-band headers have been processed and
removed from header list by CXF. The in-band headers are incorporated into the
MessageContentList in POJO mode. The camel-cxf component does make
any attempt to remove the in-band headers from the MessageContentList as it
does in 1.6.1. If filtering of in-band headers is required, please use PAYLOAD mode or
plug in a (pretty straightforward) CXF interceptor/JAXWS Handler to the CXF
endpoint.
• The Message Header Relay mechanism has been merged into
CxfHeaderFilterStrategy. The relayHeaders option, its semantics, and
default value remain the same, but it is a property of
CxfHeaderFilterStrategy.
Here is an example of configuring it.
Then, your endpoint can reference the CxfHeaderFilterStrategy.
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• The MessageHeadersRelay interface has changed slightly and has been renamed
to MessageHeaderFilter. It is a property of CxfHeaderFilterStrategy.
Here is an example of configuring user defined Message Header Filters:
• Other than relayHeaders, there are new properties that can be configured in
CxfHeaderFilterStrategy.
Name
Required
relayHeaders
No
relayAllMessageHeaders
No
allowFilterNamespaceClash
No
Description
All message headers will be processed by Message Header Filters
Type: boolean
Default: true (1.6.1 behavior)
All message headers will be propagated (without processing by Message Header Filters)
Type: boolean
Default: false (1.6.1 behavior)
If two filters overlap in activation namespace, the property control how it should be handled. If
the value is true, last one wins. If the value is false, it will throw an exception
Type: boolean
Default: false (1.6.1 behavior)
Configure the CXF endpoints with Spring
You can configure the CXF endpoint with the Spring configuration file shown below,
and you can also embed the endpoint into the camelContext tags. When you are
invoking the service endpoint, you can set the operationName and
operationNameSpace headers to explicitly state which operation you are calling.
NOTE In Camel 2.x we change to use {{http:?//camel.apache.org/schema/cxf}} as the
CXF endpoint's target namespace.
...
Be sure to include the JAX-WS schemaLocation attribute specified on the root
beans element. This allows CXF to validate the file and is required. Also note the
namespace declarations at the end of the tag--these are
required because the combined {namespace}localName syntax is presently not
supported for this tag's attribute values.
The cxf:cxfEndpoint element supports many additional attributes:
Name
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PortName
The endpoint name this service is implementing, it maps to the wsdl:port@name. In the format of ns:PORT_NAME where ns is a
namespace prefix valid at this scope.
serviceName
The service name this service is implementing, it maps to the wsdl:service@name. In the format of ns:SERVICE_NAME where ns is
a namespace prefix valid at this scope.
wsdlURL
The location of the WSDL. Can be on the classpath, file system, or be hosted remotely.
bindingId
The bindingId for the service model to use.
address
The service publish address.
bus
The bus name that will be used in the JAX-WS endpoint.
serviceClass
The class name of the SEI (Service Endpoint Interface) class which could have JSR181 annotation or not.
It also supports many child elements:
Name
Value
cxf:inInterceptors
The incoming interceptors for this endpoint. A list of or .
cxf:inFaultInterceptors
The incoming fault interceptors for this endpoint. A list of or .
cxf:outInterceptors
The outgoing interceptors for this endpoint. A list of or .
cxf:outFaultInterceptors
The outgoing fault interceptors for this endpoint. A list of or .
cxf:properties
A properties map which should be supplied to the JAX-WS endpoint. See below.
cxf:handlers
A JAX-WS handler list which should be supplied to the JAX-WS endpoint. See below.
cxf:dataBinding
You can specify the which DataBinding will be use in the endpoint. This can be supplied using the Spring syntax.
cxf:binding
You can specify the BindingFactory for this endpoint to use. This can be supplied using the Spring syntax.
cxf:features
The features that hold the interceptors for this endpoint. A list of {{}}s or {{}}s
cxf:schemaLocations
The schema locations for endpoint to use. A list of {{}}s
cxf:serviceFactory
The service factory for this endpoint to use. This can be supplied using the Spring syntax
You can find more advanced examples which show how to provide interceptors , properties
and handlers here:
http://cwiki.apache.org/CXF20DOC/jax-ws-configuration.html
NOTE
You can use cxf:properties to set the camel-cxf endpoint's dataFormat and setDefaultBus
properties from spring configuration file.
Configuring the CXF Endpoints with Apache Aries Blueprint.
Since camel 2.8 there is support for utilizing aries blueprint dependency injection for your CXF
endpoints.
The schema utilized is very similar to the spring schema so the transition is fairly transparent.
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Example
Currently the endpoint element is the first supported CXF namespacehandler.
You can also use the bean references just as in spring
How to make the camel-cxf component use log4j instead of java.util.logging
CXF's default logger is java.util.logging. If you want to change it to log4j, proceed as
follows. Create a file, in the classpath, named META-INF/cxf/
org.apache.cxf.logger. This file should contain the fully-qualified name of the class,
org.apache.cxf.common.logging.Log4jLogger, with no comments, on a single
line.
How to let camel-cxf response message with xml start document
If you are using some soap client such as PHP, you will get this kind of error, because CXF
doesn't add the XML start document ""
Error:sendSms: SoapFault exception: [Client] looks like we got no XML document in [...]
To resolved this issue, you just need to tell StaxOutInterceptor to write the XML start
document for you.
public class WriteXmlDeclarationInterceptor extends
AbstractPhaseInterceptor {
public WriteXmlDeclarationInterceptor() {
super(Phase.PRE_STREAM);
addBefore(StaxOutInterceptor.class.getName());
}
public void handleMessage(SoapMessage message) throws Fault {
message.put("org.apache.cxf.stax.force-start-document", Boolean.TRUE);
}
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}
You can add a customer interceptor like this and configure it into you camel-cxf endpont
Or adding a message header for it like this if you are using Camel 2.4.
// set up the response context which force start document
Map map = new HashMap();
map.put("org.apache.cxf.stax.force-start-document", Boolean.TRUE);
exchange.getOut().setHeader(Client.RESPONSE_CONTEXT, map);
How to consume a message from a camel-cxf endpoint in POJO data format
The camel-cxf endpoint consumer POJO data format is based on the cxf invoker, so the
message header has a property with the name of CxfConstants.OPERATION_NAME and
the message body is a list of the SEI method parameters.
public class PersonProcessor implements Processor {
private static final transient Logger LOG =
LoggerFactory.getLogger(PersonProcessor.class);
@SuppressWarnings("unchecked")
public void process(Exchange exchange) throws Exception {
LOG.info("processing exchange in camel");
BindingOperationInfo boi =
(BindingOperationInfo)exchange.getProperty(BindingOperationInfo.class.toString());
if (boi != null) {
LOG.info("boi.isUnwrapped" + boi.isUnwrapped());
}
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// Get the parameters list which element is the holder.
MessageContentsList msgList = (MessageContentsList)exchange.getIn().getBody();
Holder personId = (Holder)msgList.get(0);
Holder ssn = (Holder)msgList.get(1);
Holder name = (Holder)msgList.get(2);
if (personId.value == null || personId.value.length() == 0) {
LOG.info("person id 123, so throwing exception");
// Try to throw out the soap fault message
org.apache.camel.wsdl_first.types.UnknownPersonFault personFault =
new org.apache.camel.wsdl_first.types.UnknownPersonFault();
personFault.setPersonId("");
org.apache.camel.wsdl_first.UnknownPersonFault fault =
new org.apache.camel.wsdl_first.UnknownPersonFault("Get the null value
of person name", personFault);
// Since camel has its own exception handler framework, we can't throw the
exception to trigger it
// We just set the fault message in the exchange for camel-cxf component
handling and return
exchange.getOut().setFault(true);
exchange.getOut().setBody(fault);
return;
}
name.value = "Bonjour";
ssn.value = "123";
LOG.info("setting Bonjour as the response");
// Set the response message, first element is the return value of the
operation,
// the others are the holders of method parameters
exchange.getOut().setBody(new Object[] {null, personId, ssn, name});
}
}
How to prepare the message for the camel-cxf endpoint in POJO data
format
The camel-cxf endpoint producer is based on the cxf client API. First you need to specify
the operation name in the message header, then add the method parameters to a list, and
initialize the message with this parameter list. The response message's body is a
messageContentsList, you can get the result from that list.
NOTE After Camel 1.5 , we change the message body from object array to message
content list. If you still want to get the object array from the message body, you can get the
body using message.getbody(Object[].class), as follows:
Exchange senderExchange = new DefaultExchange(context, ExchangePattern.InOut);
final List params = new ArrayList();
// Prepare the request message for the camel-cxf procedure
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params.add(TEST_MESSAGE);
senderExchange.getIn().setBody(params);
senderExchange.getIn().setHeader(CxfConstants.OPERATION_NAME, ECHO_OPERATION);
Exchange exchange = template.send("direct:EndpointA", senderExchange);
org.apache.camel.Message out = exchange.getOut();
// The response message's body is an MessageContentsList which first element is the
return value of the operation,
// If there are some holder parameters, the holder parameter will be filled in the
reset of List.
// The result will be extract from the MessageContentsList with the String class type
MessageContentsList result = (MessageContentsList)out.getBody();
LOG.info("Received output text: " + result.get(0));
Map responseContext =
CastUtils.cast((Map)out.getHeader(Client.RESPONSE_CONTEXT));
assertNotNull(responseContext);
assertEquals("We should get the response context here", "UTF-8",
responseContext.get(org.apache.cxf.message.Message.ENCODING));
assertEquals("Reply body on Camel is wrong", "echo " + TEST_MESSAGE, result.get(0));
How to deal with the message for a camel-cxf endpoint in PAYLOAD data
format
PAYLOAD means that you process the payload message from the SOAP envelope. You can use
the Header.HEADER_LIST as the key to set or get the SOAP headers and use the
List to set or get SOAP body elements.
Camel 1.x branch, you can get the List and header from the CXF Message, but if
you want to set the response message, you need to create the CXF message using the CXF
API.
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from(SIMPLE_ENDPOINT_URI +
"&dataFormat=PAYLOAD").to("log:info").process(new Processor() {
public void process(final Exchange exchange) throws Exception {
Message inMessage = exchange.getIn();
if (inMessage instanceof CxfMessage) {
CxfMessage cxfInMessage = (CxfMessage) inMessage;
CxfMessage cxfOutMessage = (CxfMessage) exchange.getOut();
List inElements =
cxfInMessage.getMessage().get(List.class);
List outElements = new ArrayList();
XmlConverter converter = new XmlConverter();
String documentString = ECHO_RESPONSE;
if (inElements.get(0).getLocalName().equals("echoBoolean")) {
documentString = ECHO_BOOLEAN_RESPONSE;
}
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org.apache.cxf.message.Exchange ex =
((CxfExchange)exchange).getExchange();
Endpoint ep = ex.get(Endpoint.class);
org.apache.cxf.message.Message response =
ep.getBinding().createMessage();
Document outDocument = converter.toDOMDocument(documentString);
outElements.add(outDocument.getDocumentElement());
response.put(List.class, outElements);
cxfOutMessage.setMessage(response);
}
}
});
}
};
}
Change in 2.0, There is no more CxfMessage, we just use the common Camel
DefaultMessageImpl under layer. Message.getBody() will return an
org.apache.camel.component.cxf.CxfPayload object, which has getters for
SOAP message headers and Body elements. This change enables decoupling the native CXF
message from the Camel message.
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from(simpleEndpointURI + "&dataFormat=PAYLOAD").to("log:info").process(new
Processor() {
@SuppressWarnings("unchecked")
public void process(final Exchange exchange) throws Exception {
CxfPayload requestPayload =
exchange.getIn().getBody(CxfPayload.class);
List inElements = requestPayload.getBodySources();
List outElements = new ArrayList();
// You can use a customer toStringConverter to turn a CxfPayLoad
message into String as you want
String request = exchange.getIn().getBody(String.class);
XmlConverter converter = new XmlConverter();
String documentString = ECHO_RESPONSE;
Element in = new XmlConverter().toDOMElement(inElements.get(0));
// Just check the element namespace
if (!in.getNamespaceURI().equals(ELEMENT_NAMESPACE)) {
throw new IllegalArgumentException("Wrong element namespace");
}
if (in.getLocalName().equals("echoBoolean")) {
documentString = ECHO_BOOLEAN_RESPONSE;
checkRequest("ECHO_BOOLEAN_REQUEST", request);
} else {
documentString = ECHO_RESPONSE;
checkRequest("ECHO_REQUEST", request);
}
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Document outDocument = converter.toDOMDocument(documentString);
outElements.add(new DOMSource(outDocument.getDocumentElement()));
// set the payload header with null
CxfPayload responsePayload = new
CxfPayload(null, outElements, null);
exchange.getOut().setBody(responsePayload);
}
});
}
};
}
How to get and set SOAP headers in POJO mode
POJO means that the data format is a "list of Java objects" when the Camel-cxf endpoint
produces or consumes Camel exchanges. Even though Camel expose message body as POJOs
in this mode, Camel-cxf still provides access to read and write SOAP headers. However, since
CXF interceptors remove in-band SOAP headers from Header list after they have been
processed, only out-of-band SOAP headers are available to Camel-cxf in POJO mode.
The following example illustrate how to get/set SOAP headers. Suppose we have a route
that forwards from one Camel-cxf endpoint to another. That is, SOAP Client -> Camel -> CXF
service. We can attach two processors to obtain/insert SOAP headers at (1) before request
goes out to the CXF service and (2) before response comes back to the SOAP Client.
Processor (1) and (2) in this example are InsertRequestOutHeaderProcessor and
InsertResponseOutHeaderProcessor. Our route looks like this:
In 2.x SOAP headers are propagated to and from Camel Message headers. The Camel
message header name is "org.apache.cxf.headers.Header.list" which is a constant defined in CXF
(org.apache.cxf.headers.Header.HEADER_LIST). The header value is a List of CXF SoapHeader
objects (org.apache.cxf.binding.soap.SoapHeader). The following snippet is the
InsertResponseOutHeaderProcessor (that insert a new SOAP header in the response message).
The way to access SOAP headers in both InsertResponseOutHeaderProcessor and
InsertRequestOutHeaderProcessor are actually the same. The only difference between the two
processors is setting the direction of the inserted SOAP header.
public static class InsertResponseOutHeaderProcessor implements Processor {
@SuppressWarnings("unchecked")
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public void process(Exchange exchange) throws Exception {
List soapHeaders =
(List)exchange.getIn().getHeader(Header.HEADER_LIST);
// Insert a new header
String xml = ""
+
"New_testOobHeaderNew_testOobHeaderValue";
SoapHeader newHeader = new SoapHeader(soapHeaders.get(0).getName(),
DOMUtils.readXml(new StringReader(xml)).getDocumentElement());
// make sure direction is OUT since it is a response message.
newHeader.setDirection(Direction.DIRECTION_OUT);
//newHeader.setMustUnderstand(false);
soapHeaders.add(newHeader);
}
}
In 1.x SOAP headers are not propagated to and from Camel Message headers. Users have to
go deeper into CXF APIs to access SOAP headers. Also, accessing the SOAP headers in a
request message is slight different than in a response message. The
InsertRequestOutHeaderProcessor and InsertResponseOutHeaderProcessor are as follow.
public static class InsertRequestOutHeaderProcessor implements Processor {
public void process(Exchange exchange) throws Exception {
CxfMessage message = exchange.getIn().getBody(CxfMessage.class);
Message cxf = message.getMessage();
List soapHeaders = (List)cxf.get(Header.HEADER_LIST);
// Insert a new header
String xml = ""
+
"New_testOobHeaderNew_testOobHeaderValue";
SoapHeader newHeader = new SoapHeader(soapHeaders.get(0).getName(),
DOMUtils.readXml(new
StringReader(xml)).getDocumentElement());
// make sure direction is IN since it is a request message.
newHeader.setDirection(Direction.DIRECTION_IN);
//newHeader.setMustUnderstand(false);
soapHeaders.add(newHeader);
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}
}
public static class InsertResponseOutHeaderProcessor implements Processor {
public void process(Exchange exchange) throws Exception {
CxfMessage message = exchange.getIn().getBody(CxfMessage.class);
Map responseContext = (Map)message.getMessage().get(Client.RESPONSE_CONTEXT);
List soapHeaders = (List)responseContext.get(Header.HEADER_LIST);
// Insert a new header
String xml = ""
+
"New_testOobHeaderNew_testOobHeaderValue";
SoapHeader newHeader = new SoapHeader(soapHeaders.get(0).getName(),
DOMUtils.readXml(new StringReader(xml)).getDocumentElement());
// make sure direction is OUT since it is a response message.
newHeader.setDirection(Direction.DIRECTION_OUT);
//newHeader.setMustUnderstand(false);
soapHeaders.add(newHeader);
}
}
How to get and set SOAP headers in PAYLOAD mode
We've already shown how to access SOAP message (CxfPayload object) in PAYLOAD mode
(See "How to deal with the message for a camel-cxf endpoint in PAYLOAD data format").
In 2.x Once you obtain a CxfPayload object, you can invoke the CxfPayload.getHeaders()
method that returns a List of DOM Elements (SOAP headers).
from(getRouterEndpointURI()).process(new Processor() {
@SuppressWarnings("unchecked")
public void process(Exchange exchange) throws Exception {
CxfPayload payload = exchange.getIn().getBody(CxfPayload.class);
List elements = payload.getBodySources();
assertNotNull("We should get the elements here", elements);
assertEquals("Get the wrong elements size", 1, elements.size());
Element el = new XmlConverter().toDOMElement(elements.get(0));
elements.set(0, new DOMSource(el));
assertEquals("Get the wrong namespace URI", "http://camel.apache.org/pizza/
types",
el.getNamespaceURI());
List headers = payload.getHeaders();
assertNotNull("We should get the headers here", headers);
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assertEquals("Get the wrong headers size", headers.size(), 1);
assertEquals("Get the wrong namespace URI",
((Element)(headers.get(0).getObject())).getNamespaceURI(),
"http://camel.apache.org/pizza/types");
}
})
.to(getServiceEndpointURI());
*In 1.x" You can get/set to the CXF Message by the key "org.apache.cxf.headers.Header.list"
which is a constant defined in CXF (org.apache.cxf.headers.Header.HEADER_LIST).
from(routerEndpointURI).process(new Processor() {
@SuppressWarnings("unchecked")
public void process(Exchange exchange) throws Exception {
Message inMessage = exchange.getIn();
CxfMessage message = (CxfMessage) inMessage;
List elements = message.getMessage().get(List.class);
assertNotNull("We should get the payload elements here" , elements);
assertEquals("Get the wrong elements size" , elements.size(), 1);
assertEquals("Get the wrong namespace URI" ,
elements.get(0).getNamespaceURI(), "http://camel.apache.org/pizza/types");
List headers =
CastUtils.cast((List)message.getMessage().get(Header.HEADER_LIST));
assertNotNull("We should get the headers here", headers);
assertEquals("Get the wrong headers size", headers.size(), 1);
assertEquals("Get the wrong namespace URI" ,
((Element)(headers.get(0).getObject())).getNamespaceURI(), "http://camel.apache.org/
pizza/types");
}
})
.to(serviceEndpointURI);
SOAP headers are not available in MESSAGE mode
SOAP headers are not available in MESSAGE mode as SOAP processing is skipped.
How to throw a SOAP Fault from Camel
If you are using a camel-cxf endpoint to consume the SOAP request, you may need to
throw the SOAP Fault from the camel context.
Basically, you can use the throwFault DSL to do that; it works for POJO, PAYLOAD and
MESSAGE data format.
You can define the soap fault like this
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SOAP_FAULT = new SoapFault(EXCEPTION_MESSAGE, SoapFault.FAULT_CODE_CLIENT);
Element detail = SOAP_FAULT.getOrCreateDetail();
Document doc = detail.getOwnerDocument();
Text tn = doc.createTextNode(DETAIL_TEXT);
detail.appendChild(tn);
Then throw it as you like
from(routerEndpointURI).setFaultBody(constant(SOAP_FAULT));
If your CXF endpoint is working in the MESSAGE data format, you could set the the SOAP
Fault message in the message body and set the response code in the message header.
from(routerEndpointURI).process(new Processor() {
public void process(Exchange exchange) throws Exception {
Message out = exchange.getOut();
// Set the message body with the
out.setBody(this.getClass().getResourceAsStream("SoapFaultMessage.xml"));
// Set the response code here
out.setHeader(org.apache.cxf.message.Message.RESPONSE_CODE, new Integer(500));
}
});
NOTE the response code setting only works in Camel's version >= 1.5.1
Same for using POJO data format. You can set the SOAPFault on the out body and also
indicate it's a fault by calling Message.setFault(true):
from("direct:start").onException(SoapFault.class).maximumRedeliveries(0).handled(true)
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
SoapFault fault = exchange
.getProperty(Exchange.EXCEPTION_CAUGHT, SoapFault.class);
exchange.getOut().setFault(true);
exchange.getOut().setBody(fault);
}
}).end().to(serviceURI);
How to propagate a camel-cxf endpoint's request and response context
cxf client API provides a way to invoke the operation with request and response context. If you
are using a camel-cxf endpoint producer to invoke the outside web service, you can set the
request context and get response context with the following code:
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CxfExchange exchange = (CxfExchange)template.send(getJaxwsEndpointUri(), new
Processor() {
public void process(final Exchange exchange) {
final List params = new ArrayList();
params.add(TEST_MESSAGE);
// Set the request context to the inMessage
Map requestContext = new HashMap();
requestContext.put(BindingProvider.ENDPOINT_ADDRESS_PROPERTY,
JAXWS_SERVER_ADDRESS);
exchange.getIn().setBody(params);
exchange.getIn().setHeader(Client.REQUEST_CONTEXT , requestContext);
exchange.getIn().setHeader(CxfConstants.OPERATION_NAME,
GREET_ME_OPERATION);
}
});
org.apache.camel.Message out = exchange.getOut();
// The output is an object array, the first element of the array is the
return value
Object\[\] output = out.getBody(Object\[\].class);
LOG.info("Received output text: " + output\[0\]);
// Get the response context form outMessage
Map responseContext =
CastUtils.cast((Map)out.getHeader(Client.RESPONSE_CONTEXT));
assertNotNull(responseContext);
assertEquals("Get the wrong wsdl opertion name", "{http://apache.org/
hello_world_soap_http}greetMe",
responseContext.get("javax.xml.ws.wsdl.operation").toString());
Attachment Support
POJO Mode: Both SOAP with Attachment and MTOM are supported (see example in
Payload Mode for enabling MTOM).Ê However, SOAP with Attachment is not tested.Ê Since
attachments are marshalled and unmarshalled into POJOs, users typically do not need to deal
with the attachment themself.Ê Attachments are propagated to Camel message's attachments
since 2.1.Ê So, it is possible to retreive attachments by Camel Message API
DataHandler Message.getAttachment(String id)
.
Payload Mode: MTOM is supported since 2.1. Attachments can be retrieved by Camel
Message APIs mentioned above. SOAP with Attachment (SwA) is supported and attachments
can be retrieved since 2.5. SwA is the default (same as setting the CXF endpoint property
"mtom_enabled" to false).Ê
To enable MTOM, set the CXF endpoint property "mtom_enabled" to true. (I believe you
can only do it with Spring.)
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You can produce a Camel message with attachment to send to a CXF endpoint in Payload
mode.
Exchange exchange = context.createProducerTemplate().send("direct:testEndpoint", new
Processor() {
public void process(Exchange exchange) throws Exception {
exchange.setPattern(ExchangePattern.InOut);
List elements = new ArrayList();
elements.add(new DOMSource(DOMUtils.readXml(new
StringReader(MtomTestHelper.REQ_MESSAGE)).getDocumentElement()));
CxfPayload body = new CxfPayload(new
ArrayList(),
elements, null);
exchange.getIn().setBody(body);
exchange.getIn().addAttachment(MtomTestHelper.REQ_PHOTO_CID,
new DataHandler(new ByteArrayDataSource(MtomTestHelper.REQ_PHOTO_DATA,
"application/octet-stream")));
exchange.getIn().addAttachment(MtomTestHelper.REQ_IMAGE_CID,
new DataHandler(new ByteArrayDataSource(MtomTestHelper.requestJpeg, "image/
jpeg")));
}
});
// process response
CxfPayload out = exchange.getOut().getBody(CxfPayload.class);
Assert.assertEquals(1, out.getBody().size());
Map ns = new HashMap();
ns.put("ns", MtomTestHelper.SERVICE_TYPES_NS);
ns.put("xop", MtomTestHelper.XOP_NS);
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XPathUtils xu = new XPathUtils(ns);
Element oute = new XmlConverter().toDOMElement(out.getBody().get(0));
Element ele = (Element)xu.getValue("//ns:DetailResponse/ns:photo/xop:Include", oute,
XPathConstants.NODE);
String photoId = ele.getAttribute("href").substring(4); // skip "cid:"
ele = (Element)xu.getValue("//ns:DetailResponse/ns:image/xop:Include", oute,
XPathConstants.NODE);
String imageId = ele.getAttribute("href").substring(4); // skip "cid:"
DataHandler dr = exchange.getOut().getAttachment(photoId);
Assert.assertEquals("application/octet-stream", dr.getContentType());
MtomTestHelper.assertEquals(MtomTestHelper.RESP_PHOTO_DATA,
IOUtils.readBytesFromStream(dr.getInputStream()));
dr = exchange.getOut().getAttachment(imageId);
Assert.assertEquals("image/jpeg", dr.getContentType());
BufferedImage image = ImageIO.read(dr.getInputStream());
Assert.assertEquals(560, image.getWidth());
Assert.assertEquals(300, image.getHeight());
You can also consume a Camel message received from a CXF endpoint in Payload mode.
public static class MyProcessor implements Processor {
@SuppressWarnings("unchecked")
public void process(Exchange exchange) throws Exception {
CxfPayload in = exchange.getIn().getBody(CxfPayload.class);
// verify request
Assert.assertEquals(1, in.getBody().size());
Map ns = new HashMap();
ns.put("ns", MtomTestHelper.SERVICE_TYPES_NS);
ns.put("xop", MtomTestHelper.XOP_NS);
XPathUtils xu = new XPathUtils(ns);
Element body = new XmlConverter().toDOMElement(in.getBody().get(0));
Element ele = (Element)xu.getValue("//ns:Detail/ns:photo/xop:Include", body,
XPathConstants.NODE);
String photoId = ele.getAttribute("href").substring(4); // skip "cid:"
Assert.assertEquals(MtomTestHelper.REQ_PHOTO_CID, photoId);
ele = (Element)xu.getValue("//ns:Detail/ns:image/xop:Include", body,
XPathConstants.NODE);
String imageId = ele.getAttribute("href").substring(4); // skip "cid:"
Assert.assertEquals(MtomTestHelper.REQ_IMAGE_CID, imageId);
DataHandler dr = exchange.getIn().getAttachment(photoId);
Assert.assertEquals("application/octet-stream", dr.getContentType());
MtomTestHelper.assertEquals(MtomTestHelper.REQ_PHOTO_DATA,
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IOUtils.readBytesFromStream(dr.getInputStream()));
dr = exchange.getIn().getAttachment(imageId);
Assert.assertEquals("image/jpeg", dr.getContentType());
MtomTestHelper.assertEquals(MtomTestHelper.requestJpeg,
IOUtils.readBytesFromStream(dr.getInputStream()));
// create response
List elements = new ArrayList();
elements.add(new DOMSource(DOMUtils.readXml(new
StringReader(MtomTestHelper.RESP_MESSAGE)).getDocumentElement()));
CxfPayload sbody = new CxfPayload(new
ArrayList(),
elements, null);
exchange.getOut().setBody(sbody);
exchange.getOut().addAttachment(MtomTestHelper.RESP_PHOTO_CID,
new DataHandler(new ByteArrayDataSource(MtomTestHelper.RESP_PHOTO_DATA,
"application/octet-stream")));
exchange.getOut().addAttachment(MtomTestHelper.RESP_IMAGE_CID,
new DataHandler(new ByteArrayDataSource(MtomTestHelper.responseJpeg,
"image/jpeg")));
}
}
Message Mode: Attachments are not supported as it does not process the message at all.
Streaming Support in PAYLOAD mode
In 2.8.2, the camel-cxf component now supports streaming of incoming messages when using
PAYLOAD mode. Previously, the incoming messages would have been completely DOM
parsed. For large messages, this is time consuming and uses a significant amount of memory.
Starting in 2.8.2, the incoming messages can remain as a javax.xml.transform.Source while being
routed and, if nothing modifies the payload, can then be directly streamed out to the target
destination. For common "simple proxy" use cases (example: from("cxf:...").to("cxf:...")), this can
provide very significant performance increases as well as significantly lowered memory
requirements.
However, there are cases where streaming may not be appropriate or desired. Due to the
streaming nature, invalid incoming XML may not be caught until later in the processing chain.
Also, certain actions may require the message to be DOM parsed anyway (like WS-Security or
message tracing and such) in which case the advantages of the streaming is limited. At this point,
there are two ways to control the streaming:
• Endpoint property: you can add "allowStreaming=false" as an endpoint property to
turn the streaming on/off.
• Component property: the CxfComponent object also has an allowStreaming property
that can set the default for endpoints created from that component.
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• Global system property: you can add a system property of
"org.apache.camel.component.cxf.streaming" to "false" to turn if off. That sets the
global default, but setting the endpoint property above will override this value for that
endpoint.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
CXF BEAN COMPONENT (2.0 OR LATER)
The cxfbean: component allows other Camel endpoints to send exchange and invoke Web
service bean objects. (Currently, it only supports JAXRS, JAXWS(new to
camel2.1) annotated service bean.)
URI format
cxfbean:serviceBeanRef
Where serviceBeanRef is a registry key to look up the service bean object. If
serviceBeanRef references a List object, elements of the List are the service bean
objects accepted by the endpoint.
Options
Name
Description
Example
Required?
Defaul
cxfBeanBinding
CXF bean binding specified by the # notation. The referenced object must be
an instance of
org.apache.camel.component.cxf.cxfbean.CxfBeanBinding.
cxfBinding=#bindingName
No
DefaultCx
bus
CXF bus reference specified by the # notation. The referenced object must be
an instance of org.apache.cxf.Bus.
bus=#busName
No
Default bus c
Factory
headerFilterStrategy
Header filter strategy specified by the # notation. The referenced object must
be an instance of org.apache.camel.spi.HeaderFilterStrategy.
headerFilterStrategy=#strategyName
No
CxfHeader
setDefaultBus
Will set the default bus when CXF endpoint create a bus by itself.
true, false
No
false
populateFromClass
Since 2.3, the wsdlLocation annotated in the POJO is ignored (by default)
unless this option is set toÊ false. Prior to 2.3, the wsdlLocation annotated
in the POJO is always honored and it is not possible to ignore.
true, false
No
true
providers
Since 2.5, setting the providers for the CXFRS endpoint.
providers=#providerRef1,#providerRef2
No
null
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CxfBeanEndpoint is a ProcessorEndpoint so it has no consumers. It
works similarly to a Bean component.
Headers
Name
Description
Type
Required?
Default
Value
In/
Out
Examples
CamelHttpCharacterEncoding
(before 2.0-m2:
CamelCxfBeanCharacterEncoding)
Character encoding
String
No
None
In
ISO-8859-1
CamelContentType (before 2.0-m2:
CamelCxfBeanContentType)
Content type
String
No
*/*
In
text/xml
CamelHttpBaseUri
(2.0-m3 and before:
CamelCxfBeanRequestBasePath)
The value of this header will be set in
the CXF message as the
Message.BASE_PATH property. It
is needed by CXF JAX-RS processing.
Basically, it is the scheme, host and
port portion of the request URI.
String
Yes
The Endpoint
URI of the
source
endpoint in the
Camel
exchange
In
http://localhost:9000
CamelHttpPath (before 2.0-m2:
CamelCxfBeanRequestPath)
Request URI's path
String
Yes
None
In
consumer/123
CamelHttpMethod (before 2.0-m2:
CamelCxfBeanVerb)
RESTful request verb
String
Yes
None
In
GET, PUT, POST,
DELETE
CamelHttpResponseCode
HTTP response code
Integer
No
None
Out
200
A Working Sample
This sample shows how to create a route that starts a Jetty HTTP server. The route sends
requests to a CXF Bean and invokes a JAXRS annotated service.
First, create a route as follows. The from endpoint is a Jetty HTTP endpoint that is listening
on port 9000. Notice that the matchOnUriPrefix option must be set to true because
RESTful request URI will not match the endpoint's URI http:?//localhost:9000 exactly.
The to endpoint is a CXF Bean with bean name customerServiceBean. The name will be
looked up from the registry. Next, we make sure our service bean is available in Spring registry.
We create a bean definition in the Spring configuration. In this example, we create a List of
service beans (of one element). We could have created just a single bean without a List.
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Currently, CXF Bean component has (only) been tested with Jetty HTTP
component it can understand headers from Jetty HTTP component without
requiring conversion.
That's it. Once the route is started, the web service is ready for business. A HTTP client can
make a request and receive response.
CXFRS COMPONENT
The cxfrs: component provides integration with Apache CXF for connecting to JAX-RS
services hosted in CXF.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-cxfx.x.x
URI format
cxfrs://address?options
Where address represents the CXF endpoint's address
cxfrs:bean:rsEndpoint
Where rsEndpoint represents the spring bean's name which presents the CXFRS client or
server
For either style above, you can append options to the URI as follows:
cxfrs:bean:cxfEndpoint?resourceClass=org.apache.camel.rs.Example
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When using CXF as a consumer, the CXF Bean Component allows you to factor
out how message payloads are received from their processing as a RESTful or SOAP
web service. This has the potential of using a multitude of transports to consume
web services. The bean component's configuration is also simpler and provides the
fastest method to implement web services using Camel and CXF.
Options
Name
Description
Example
Required?
default
value
resourceClasses
The resource classes which
you want to export as REST
service
resourceClasses
=org.apache.camel.rs.Example1,org.apache.camel.rs.Exchange2
No
None
httpClientAPI
new to Camel 2.1 If it is
true, the CxfRsProducer will
use the HttpClientAPI to
invoke the service
If it is false, the
CxfRsProducer will use the
ProxyClientAPI to invoke the
service
httpClientAPI=true
No
true
synchronous
New in 2.5, this option will let
CxfRsConsumer decide to
use sync or async API to do
the underlying work. The
default value is false which
means it will try to use async
API by default.
synchronous=true
No
false
throwExceptionOnFailure
New in 2.6, this option tells
the CxfRsProducer to inspect
return codes and will
generate an Exception if the
return code is larger than
207.
throwExceptionOnFailure=true
No
true
maxClientCacheSize
New in 2.6, you can set a IN
message header
CamelDestinationOverrideUrl
to dynamically override the
target destination Web
Service or REST Service
defined in your routes.Ê The
implementation caches CXF
clients or ClientFactoryBean
in CxfProvider and
CxfRsProvider.Ê This option
allows you to configure the
maximum size of the cache.
maxClientCacheSize=5
No
10
setDefaultBus
New in 2.9.0. Will set the
default bus when CXF
endpoint create a bus by itself
setDefaultBus=true
No
false
bus
New in 2.9.0. A default bus
created by CXF Bus Factory.
Use # notation to reference a
bus object from the registry.
The referenced object must
be an instance of
org.apache.cxf.Bus.
bus=#busName
No
None
You can also configure the CXF REST endpoint through the spring configuration. Since there
are lots of difference between the CXF REST client and CXF REST Server, we provides
different configuration for them.
Please check out the schema file and CXF REST user guide for more information.
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How to configure the REST endpoint in Camel
In camel-cxf schema file, there are two elements for the REST endpoint definition.
cxf:rsServer for REST consumer, cxf:rsClient for REST producer.
You can find an camel REST service route configuration example here.
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True
How to consume the REST request in Camel
CXF JAXRS front end implements the JAXRS(JSR311) API, so we can export the resources
classes as a REST service. And we leverage the CXF Invoker API to turn a REST request into a
normal Java object method invocation.
Unlike the camel-restlet, you don't need to specify the URI template within your restlet
endpoint, CXF take care of the REST request URI to resource class method mapping according
to the JSR311 specification. All you need to do in Camel is delegate this method request to a
right processor or endpoint.
Here is an example of a CXFRS route...
private static final String CXF_RS_ENDPOINT_URI = "cxfrs://http://localhost:" + CXT +
"/rest?resourceClasses=org.apache.camel.component.cxf.jaxrs.testbean.CustomerServiceResource";
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() {
errorHandler(new NoErrorHandlerBuilder());
from(CXF_RS_ENDPOINT_URI).process(new Processor() {
public void process(Exchange exchange) throws Exception {
Message inMessage = exchange.getIn();
// Get the operation name from in message
String operationName =
inMessage.getHeader(CxfConstants.OPERATION_NAME, String.class);
if ("getCustomer".equals(operationName)) {
String httpMethod = inMessage.getHeader(Exchange.HTTP_METHOD,
String.class);
assertEquals("Get a wrong http method", "GET", httpMethod);
String path = inMessage.getHeader(Exchange.HTTP_PATH,
String.class);
// The parameter of the invocation is stored in the body of in
message
String id = (String) inMessage.getBody(String.class);
if ("/customerservice/customers/126".equals(path))
{
Customer customer = new Customer();
customer.setId(Long.parseLong(id));
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customer.setName("Willem");
// We just put the response Object into the out message
body
exchange.getOut().setBody(customer);
} else {
if ("/customerservice/customers/400".equals(path)) {
// We return the remote client IP address this time
org.apache.cxf.message.Message cxfMessage =
inMessage.getHeader(CxfConstants.CAMEL_CXF_MESSAGE,
org.apache.cxf.message.Message.class);
ServletRequest request = (ServletRequest)
cxfMessage.get("HTTP.REQUEST");
String remoteAddress = request.getRemoteAddr();
Response r = Response.status(200).entity("The
remoteAddress is " + remoteAddress).build();
exchange.getOut().setBody(r);
return;
}
if ("/customerservice/customers/123".equals(path)) {
// send a customer response back
Response r = Response.status(200).entity("customer
response back!").build();
exchange.getOut().setBody(r);
return;
}
if ("/customerservice/customers/456".equals(path)) {
Response r = Response.status(404).entity("Can't found
the customer with uri " + path).build();
throw new WebApplicationException(r);
} else {
throw new RuntimeCamelException("Can't found the
customer with uri " + path);
}
}
}
if ("updateCustomer".equals(operationName)) {
assertEquals("Get a wrong customer message header",
"header1;header2", inMessage.getHeader("test"));
String httpMethod = inMessage.getHeader(Exchange.HTTP_METHOD,
String.class);
assertEquals("Get a wrong http method", "PUT", httpMethod);
Customer customer = inMessage.getBody(Customer.class);
assertNotNull("The customer should not be null.", customer);
// Now you can do what you want on the customer object
assertEquals("Get a wrong customer name.", "Mary",
customer.getName());
// set the response back
exchange.getOut().setBody(Response.ok().build());
}
}
});
}
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};
}
And the corresponding resource class used to configure the endpoint...
@Path("/customerservice/")
public class CustomerServiceResource {
public CustomerServiceResource() {
}
@GET
@Path("/customers/{id}/")
public Customer getCustomer(@PathParam("id") String id) {
return null;
}
@PUT
@Path("/customers/")
public Response updateCustomer(Customer customer) {
return null;
}
}
How to invoke the REST service through camel-cxfrs producer
CXF JAXRS front end implements a proxy based client API, with this API you can invoke the
remote REST service through a proxy.
camel-cxfrs producer is based on this proxy API.
So, you just need to specify the operation name in the message header and prepare the
parameter in the message body, camel-cxfrs producer will generate right REST request for you.
Here is an example
Exchange exchange = template.send("direct://proxy", new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.setPattern(ExchangePattern.InOut);
Message inMessage = exchange.getIn();
setupDestinationURL(inMessage);
// set the operation name
inMessage.setHeader(CxfConstants.OPERATION_NAME, "getCustomer");
// using the proxy client API
inMessage.setHeader(CxfConstants.CAMEL_CXF_RS_USING_HTTP_API, Boolean.FALSE);
// set the parameters , if you just have one parameter
// camel will put this object into an Object[] itself
inMessage.setBody("123");
}
});
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note about the resource class
This class is used to configure the JAXRS properties ONLY. The methods will NOT
be executed during the routing of messages to the endpoint, the route itself is
responsible for ALL processing instead.
// get the response message
Customer response = (Customer) exchange.getOut().getBody();
assertNotNull("The response should not be null ", response);
assertEquals("Get a wrong customer id ", String.valueOf(response.getId()), "123");
assertEquals("Get a wrong customer name", response.getName(), "John");
assertEquals("Get a wrong response code", 200,
exchange.getOut().getHeader(Exchange.HTTP_RESPONSE_CODE));
CXF JAXRS front end also provides a http centric client API, You can also invoke this API from
camel-cxfrs producer. You need to specify the HTTP_PATH and Http method and let the
the producer know to use the http centric client by using the URI option httpClientAPI or
set the message header with CxfConstants.CAMEL_CXF_RS_USING_HTTP_API. You can
turn the response object to the type class that you specify with
CxfConstants.CAMEL_CXF_RS_RESPONSE_CLASS.
Exchange exchange = template.send("direct://http", new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.setPattern(ExchangePattern.InOut);
Message inMessage = exchange.getIn();
setupDestinationURL(inMessage);
// using the http central client API
inMessage.setHeader(CxfConstants.CAMEL_CXF_RS_USING_HTTP_API, Boolean.TRUE);
// set the Http method
inMessage.setHeader(Exchange.HTTP_METHOD, "GET");
// set the relative path
inMessage.setHeader(Exchange.HTTP_PATH, "/customerservice/customers/
123");
// Specify the response class , cxfrs will use InputStream as the response
object type
inMessage.setHeader(CxfConstants.CAMEL_CXF_RS_RESPONSE_CLASS, Customer.class);
// since we use the Get method, so we don't need to set the message body
inMessage.setBody(null);
}
});
// get the response message
Customer response = (Customer) exchange.getOut().getBody();
assertNotNull("The response should not be null ", response);
assertEquals("Get a wrong customer id ", String.valueOf(response.getId()), "123");
assertEquals("Get a wrong customer name", response.getName(), "John");
CH APT ER 11 - CO M PO N EN T APPEN DIX
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assertEquals("Get a wrong response code", 200,
exchange.getOut().getHeader(Exchange.HTTP_RESPONSE_CODE));
From Camel 2.1, we also support to specify the query parameters from cxfrs URI for the
CXFRS http centric client.
Exchange exchange = template.send("cxfrs://http://localhost:" + getPort2() + "/" +
getClass().getSimpleName() + "/testQuery?httpClientAPI=true&q1=12&q2=13"
To support the Dynamical routing, you can override the URI's query parameters by using the
CxfConstants.CAMEL_CXF_RS_QUERY_MAP header to set the parameter map for it.To
support the Dynamical routing, you can override the URI's query parameters by using the
CxfConstants.CAMEL_CXF_RS_QUERY_MAP header to set the parameter map for it.
Map queryMap = new LinkedHashMap();
queryMap.put("q1", "new");
queryMap.put("q2", "world");
inMessage.setHeader(CxfConstants.CAMEL_CXF_RS_QUERY_MAP, queryMap);
DATASET COMPONENT
Testing of distributed and asynchronous processing is notoriously difficult. The Mock, Test and
DataSet endpoints work great with the Camel Testing Framework to simplify your unit and
integration testing using Enterprise Integration Patterns and Camel's large range of Components
together with the powerful Bean Integration.
The DataSet component (available since 1.3.0) provides a mechanism to easily perform load &
soak testing of your system. It works by allowing you to create DataSet instances both as a
source of messages and as a way to assert that the data set is received.
Camel will use the throughput logger when sending dataset's.
URI format
dataset:name[?options]
Where name is used to find the DataSet instance in the Registry
Camel ships with a support implementation of
org.apache.camel.component.dataset.DataSet, the
org.apache.camel.component.dataset.DataSetSupport class, that can be used
as a base for implementing your own DataSet. Camel also ships with a default implementation,
the org.apache.camel.component.dataset.SimpleDataSet that can be used for
testing.
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Options
Option
Default
Description
produceDelay
3
Allows a delay in ms to be specified, which causes producers to pause in order to simulate slow producers. Uses a minimum of 3 ms delay
unless you set this option to -1 to force no delay at all.
consumeDelay
0
Allows a delay in ms to be specified, which causes consumers to pause in order to simulate slow consumers.
preloadSize
0
Sets how many messages should be preloaded (sent) before the route completes its initialization.
initialDelay
1000
Camel 2.1: Time period in millis to wait before starting sending messages.
minRate
0
Wait until the DataSet contains at least this number of messages
You can append query options to the URI in the following format,
?option=value&option=value&...
Configuring DataSet
Camel will lookup in the Registry for a bean implementing the DataSet interface. So you can
register your own DataSet as:
Example
For example, to test that a set of messages are sent to a queue and then consumed from the
queue without losing any messages:
// send the dataset to a queue
from("dataset:foo").to("activemq:SomeQueue");
// now lets test that the messages are consumed correctly
from("activemq:SomeQueue").to("dataset:foo");
The above would look in the Registry to find the foo DataSet instance which is used to create
the messages.
Then you create a DataSet implementation, such as using the SimpleDataSet as
described below, configuring things like how big the data set is and what the messages look like
etc.
Properties on SimpleDataSet
Property
Type
Description
defaultBody
Object
Specifies the default message body. For SimpleDataSet it is a constant payload; though if you want to create custom payloads per message,
create your own derivation of DataSetSupport.
reportGroup
long
Specifies the number of messages to be received before reporting progress. Useful for showing progress of a large load test.
size
long
Specifies how many messages to send/consume.
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See Also
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
Spring Testing
DB4O COMPONENT
Available as of Camel 2.5
The db4o: component allows you to work with db4o NoSQL database. The camel-db4o
library is provided by the Camel Extra project which hosts all *GPL related components for
Camel.
Sending to the endpoint
Sending POJO object to the db4o endpoint adds and saves object into the database. The body
of the message is assumed to be a POJO that has to be saved into the db40 database store.
Consuming from the endpoint
Consuming messages removes (or updates) POJO objects in the database. This allows you to
use a Db4o datastore as a logical queue; consumers take messages from the queue and then
delete them to logically remove them from the queue.
If you do not wish to delete the object when it has been processed, you can specify
consumeDelete=false on the URI. This will result in the POJO being processed each poll.
URI format
db4o:className[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
571
Name
Default
Value
Description
consumeDelete
true
Option for Db4oConsumer only. Specifies whether or not the entity is deleted after it is consumed.
consumer.delay
500
Option for HibernateConsumer only. Delay in millis between each poll.
consumer.initialDelay
1000
Option for HibernateConsumer only. Millis before polling starts.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
consumer.userFixedDelay
false
Option for HibernateConsumer only. Set to true to use fixed delay between polls, otherwise fixed rate is used. See
ScheduledExecutorService in JDK for details.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
DIRECT COMPONENT
The direct: component provides direct, synchronous invocation of any consumers when a
producer sends a message exchange.
This endpoint can be used to connect existing routes in the same camel context.
URI format
direct:someName[?options]
Where someName can be any string to uniquely identify the endpoint
Options
Name
Default
Value
Description
allowMultipleConsumers
true
@deprecated If set to false, then when a second consumer is started on the endpoint, an
IllegalStateException is thrown. Will be removed in Camel 2.1: Direct endpoint does not support multiple
consumers.
You can append query options to the URI in the following format,
?option=value&option=value&...
Samples
In the route below we use the direct component to link the two routes together:
from("activemq:queue:order.in")
.to("bean:orderServer?method=validate")
.to("direct:processOrder");
from("direct:processOrder")
.to("bean:orderService?method=process")
.to("activemq:queue:order.out");
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Asynchronous
The SEDA component provides asynchronous invocation of any consumers when a
producer sends a message exchange.
Connection to other camel contexts
The VM component provides connections between Camel contexts as long they run
in the same JVM.
And the sample using spring DSL:
See also samples from the SEDA component, how they can be used together.
See Also
•
•
•
•
▪
▪
Configuring Camel
Component
Endpoint
Getting Started
SEDA
VM
DNS
Available as of Camel 2.7
This is an additional component for Camel to run DNS queries, using DNSJava. The
component is a thin layer on top of DNSJava.
The component offers the following operations:
▪ ip, to resolve a domain by its ip
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▪ lookup, to lookup information about the domain
▪ dig, to run DNS queries
Maven users will need to add the following dependency to their pom.xml for this component:
org.apache.camelcamel-dnsx.x.x
URI format
The URI scheme for a DNS component is as follows
dns://operation
This component only supports producers.
Options
None.
Headers
Header
Type
Operations
Description
dns.domain
String
ip
The domain name. Mandatory.
dns.name
String
lookup
The name to lookup. Mandatory.
dns.type
▪
lookup, dig
The type of the lookup. Should match the values of org.xbill.dns.Type. Optional.
dns.class
▪
lookup, dig
he DNS class of the lookup. Should match the values of org.xbill.dns.DClass. Optional.
dns.query
String
dig
The query itself. Mandatory.
dns.server
String
dig
The server in particular for the query. If none is given, the default one specified by the OS will be used.
Optional.
Examples
IP lookup
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This looks up a domain's IP. For example, www.example.com resolves to 192.0.32.10.
The IP address to lookup must be provided in the header with key "dns.domain".
DNS lookup
This returns a set of DNS records associated with a domain.
The name to lookup must be provided in the header with key "dns.name".
DNS Dig
Dig is a Unix command-line utility to run DNS queries.
The query must be provided in the header with key "dns.query".
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
EJB COMPONENT
Available as of Camel 2.4
The ejb: component binds EJBs to Camel message exchanges.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-ejb
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x.x.x
URI format
ejb:ejbName[?options]
Where ejbName can be any string which is used to look up the EJB in the Application Server
JNDI Registry
Options
Name
Type
Default
Description
method
String
null
The method name that bean will be invoked. If not provided, Camel will try to pick the method itself. In case of
ambiguity an exception is thrown. See Bean Binding for more details.
multiParameterArray
boolean
false
How to treat the parameters which are passed from the message body; if it is true, the In message body should
be an array of parameters.
You can append query options to the URI in the following format,
?option=value&option=value&...
The EJB component extends the Bean component in which most of the details from the
Bean component applies to this component as well.
Bean Binding
How bean methods to be invoked are chosen (if they are not specified explicitly through the
method parameter) and how parameter values are constructed from the Message are all
defined by the Bean Binding mechanism which is used throughout all of the various Bean
Integration mechanisms in Camel.
Examples
In the following examples we use the Greater EJB which is defined as follows:
Listing 65. GreaterLocal.java
public interface GreaterLocal {
String hello(String name);
String bye(String name);
}
And the implementation
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Listing 66. GreaterImpl.java
@Stateless
public class GreaterImpl implements GreaterLocal {
public String hello(String name) {
return "Hello " + name;
}
public String bye(String name) {
return "Bye " + name;
}
}
Using Java DSL
In this example we want to invoke the hello method on the EJB. Since this example is based
on an unit test using Apache OpenEJB we have to set a JndiContext on the EJB component
with the OpenEJB settings.
@Override
protected CamelContext createCamelContext() throws Exception {
CamelContext answer = new DefaultCamelContext();
// enlist EJB component using the JndiContext
EjbComponent ejb = answer.getComponent("ejb", EjbComponent.class);
ejb.setContext(createEjbContext());
return answer;
}
private static Context createEjbContext() throws NamingException {
// here we need to define our context factory to use OpenEJB for our testing
Properties properties = new Properties();
properties.setProperty(Context.INITIAL_CONTEXT_FACTORY,
"org.apache.openejb.client.LocalInitialContextFactory");
return new InitialContext(properties);
}
Then we are ready to use the EJB in the Camel route:
from("direct:start")
// invoke the greeter EJB using the local interface and invoke the hello method
.to("ejb:GreaterImplLocal?method=hello")
.to("mock:result");
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In a real application server
In a real application server you most likely do not have to setup a JndiContext
on the EJB component as it will create a default JndiContext on the same JVM
as the application server, which usually allows it to access the JNDI registry and
lookup the EJBs.
However if you need to access a application server on a remote JVM or the likes,
you have to prepare the properties beforehand.
Using Spring XML
And this is the same example using Spring XML instead:
Again since this is based on an unit test we need to setup the EJB component:
org.apache.openejb.client.LocalInitialContextFactory
Before we are ready to use EJB in the Camel routes:
See Also
•
•
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
Bean
Bean Binding
Bean Integration
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ESPER
The Esper component supports the Esper Library for Event Stream Processing. The camelesper library is provided by the Camel Extra project which hosts all *GPL related components
for Camel.
URI format
esper:name[?options]
When consuming from an Esper endpoint you must specify a pattern or eql statement to
query the event stream.
For example
from("esper://cheese?pattern=every event=MyEvent(bar=5)").
to("activemq:Foo");
Options
Name
Default Value
Description
pattern
Ê
The Esper Pattern expression as a String to filter events
eql
Ê
The Esper EQL expression as a String to filter events
You can append query options to the URI in the following format,
?option=value&option=value&...
Demo
There is a demo which shows how to work with ActiveMQ, Camel and Esper in the Camel
Extra project
See Also
•
•
•
•
•
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Component
Endpoint
Getting Started
Esper Camel Demo
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
EVENT COMPONENT
The event: component provides access to the Spring ApplicationEvent objects. This allows
you to publish ApplicationEvent objects to a Spring ApplicationContext or to consume them.
You can then use Enterprise Integration Patterns to process them such as Message Filter.
URI format
spring-event://default
If you use Camel 1.x then you may need to remove the // to get it working with the Spring
event notification
spring-event:default
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
FILE COMPONENT - CAMEL 2.0 ONWARDS
The File component provides access to file systems, allowing files to be processed by any other
Camel Components or messages from other components to be saved to disk.
URI format
file:directoryName[?options]
or
file://directoryName[?options]
Where directoryName represents the underlying file directory.
You can append query options to the URI in the following format,
?option=value&option=value&...
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Using Camel 1.x
This documentation is only for Camel 2.0 or newer. If you are using Camel 1.x then
see this link instead.
Only directories
Camel 2.0 only support endpoints configured with a starting directory. So the
directoryName must be a directory.
If you want to consume a single file only, you can use the fileName option, e.g. by
setting fileName=thefilename.
Also, the starting directory must not contain dynamic expressions with ${ }
placeholders. Again use the fileName option to specify the dynamic part of the
filename.
In Camel 1.x you could also configure a file and this caused more harm than good as it could
lead to confusing situations.
Avoid reading files currently being written by another application
Beware the JDK File IO API is a bit limited in detecting whether another application
is currently writing/copying a file. And the implementation can be different
depending on OS platform as well. This could lead to that Camel thinks the file is
not locked by another process and start consuming it. Therefore you have to do
you own investigation what suites your environment. To help with this Camel
provides different readLock options and doneFileOption option that you can
use. See also the section Consuming files from folders where others drop files directly.
URI Options
Common
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Name
Default
Value
Description
autoCreate
true
Automatically create missing directories in the file's pathname. For the file consumer, that means creating the starting
directory. For the file producer, it means the directory the files should be written to.
bufferSize
128kb
Write buffer sized in bytes.
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fileName
null
Use Expression such as File Language to dynamically set the filename. For consumers, it's used as a filename filter. For
producers, it's used to evaluate the filename to write. If an expression is set, it take precedence over the
CamelFileName header. (Note: The header itself can also be an Expression). The expression options support both
String and Expression types. If the expression is a String type, it is always evaluated using the File Language.
If the expression is an Expression type, the specified Expression type is used - this allows you, for instance, to
use OGNL expressions. For the consumer, you can use it to filter filenames, so you can for instance consume today's
file using the File Language syntax: mydata-${date:now:yyyyMMdd}.txt.
flatten
false
Flatten is used to flatten the file name path to strip any leading paths, so it's just the file name. This allows you to
consume recursively into sub-directories, but when you eg write the files to another directory they will be written in a
single directory. Setting this to true on the producer enforces that any file name recived in CamelFileName header
will be stripped for any leading paths.
charset
null
Camel 2.5: this option is used to specify the encoding of the file, and camel will set the Exchange property with
Exchange.CHARSET_NAME with the value of this option.
copyAndDeleteOnRenameFail
true
Camel 2.9: whether to fallback and do a copy and delete file, in case the file could not be renamed directly. This
option is not available for the FTP component.
Consumer
Name
Default
Value
Description
initialDelay
1000
Milliseconds before polling the file/directory starts.
delay
500
Milliseconds before the next poll of the file/directory.
useFixedDelay
Ê
Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details. In Camel
2.7.x or older the default value is false. From Camel 2.8 onwards the default value is true.
runLoggingLevel
TRACE
Camel 2.8: The consumer logs a start/complete log line when it polls. This option allows you to configure
the logging level for that.
recursive
false
If a directory, will look for files in all the sub-directories as well.
delete
false
If true, the file will be deleted after it is processed
noop
false
If true, the file is not moved or deleted in any way. This option is good for readonly data, or for ETL type
requirements. If noop=true, Camel will set idempotent=true as well, to avoid consuming the same
files over and over again.
preMove
null
Expression (such as File Language) used to dynamically set the filename when moving it before processing.
For example to move in-progress files into the order directory set this value to order.
move
.camel
Expression (such as File Language) used to dynamically set the filename when moving it after processing. To
move files into a .done subdirectory just enter .done.
moveFailed
null
Expression (such as File Language) used to dynamically set a different target directory when moving files after
processing (configured via move defined above) failed. For example, to move files into a .error
subdirectory use: .error. Note: When moving the files to the ÒfailÓ location Camel will handle the
error and will not pick up the file again.
include
null
Is used to include files, if filename matches the regex pattern.
exclude
null
Is used to exclude files, if filename matches the regex pattern.
idempotent
false
Option to use the Idempotent Consumer EIP pattern to let Camel skip already processed files. Will by
default use a memory based LRUCache that holds 1000 entries. If noop=true then idempotent will be
enabled as well to avoid consuming the same files over and over again.
idempotentRepository
null
Pluggable repository as a org.apache.camel.processor.idempotent.MessageIdRepository class. Will by default
use MemoryMessageIdRepository if none is specified and idempotent is true.
inProgressRepository
memory
Pluggable in-progress repository as a org.apache.camel.processor.idempotent.MessageIdRepository class. The
in-progress repository is used to account the current in progress files being consumed. By default a memory
based repository is used.
filter
null
Pluggable filter as a org.apache.camel.component.file.GenericFileFilter class. Will skip
files if filter returns false in its accept() method. Camel also ships with an ANT path matcher filter
in the camel-spring component. More details in section below.
sorter
null
Pluggable sorter as a java.util.Comparator class.
sortBy
null
Built-in sort using the File Language. Supports nested sorts, so you can have a sort by file name and as a 2nd
group sort by modified date. See sorting section below for details.
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readLock
markerFile
▪
readLockTimeout
Used by consumer, to only poll the files if it has exclusive read-lock on the file (i.e. the file is not in-progress
or being written). Camel will wait until the file lock is granted.
This option provides the build in strategies:
markerFile is the behaviour from Camel 1.x, where Camel will create a marker file and hold a lock on
the marker file. This option is not avail for the FTP component.
changed is using file length/modification timestamp to detect whether the file is currently being copied or
not. Will at least use 1 sec. to determine this, so this option cannot consume files as fast as the others, but
can be more reliable as the JDK IO API cannot always determine whether a file is currently being used by
another process. This option is only avail for the FTP component from Camel 2.8 onwards.
fileLock is for using java.nio.channels.FileLock. This option is not avail for the FTP
component.
rename is for using a try to rename the file as a test if we can get exclusive read-lock.
none is for no read locks at all.
Optional timeout in millis for the read-lock, if supported by the read-lock. If the read-lock could not be
granted and the timeout triggered, then Camel will skip the file. At next poll Camel, will try the file again, and
this time maybe the read-lock could be granted. Use a value of 0 or lower to indicate forever. In Camel 2.0
the default value is 0. In Camel 2.1 the default value is 10000. Currently fileLock, changed and
rename support the timeout. For FTP the default readLockTimeout value is 20000.
readLockCheckInterval
1000
Camel 2.6: Interval in millis for the read-lock, if supported by the read lock. This interval is used for
sleeping between attempts to acquire the read lock. For example when using the changed read lock, you
can set a higher interval period to cater for slow writes. The default of 1 sec. may be too fast if the producer is
very slow writing the file. For FTP the default readLockCheckInterval is 5000.
directoryMustExist
false
Camel 2.5: Similar to startingDirectoryMustExist but this applies during polling recursive sub
directories.
doneFileName
null
Camel 2.6: If provided, Camel will only consume files if a done file exists. This option configures what file
name to use. Either you can specify a fixed name. Or you can use dynamic placeholders. The done file is
always expected in the same folder as the original file. See using done file and writing done file sections for
examples.
exclusiveReadLockStrategy
null
Pluggable read-lock as a
org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy
implementation.
maxMessagesPerPoll
0
An integer to define a maximum messages to gather per poll. By default no maximum is set. Can be used to
set a limit of e.g. 1000 to avoid when starting up the server that there are thousands of files. Set a value of 0
or negative to disabled it. See more details at Batch Consumer.
minDepth
0
Camel 2.8: The minimum depth to start processing when recursively processing a directory. Using
minDepth=1 means the base directory. Using minDepth=2 means the first sub directory. This option is
supported by FTP consumer from Camel 2.8.2, 2.9 onwards.
maxDepth
Integer.MAX_VALUE
Camel 2.8: The maximum depth to traverse when recursively processing a directory. This option is
supported by FTP consumer from Camel 2.8.2, 2.9 onwards.
processStrategy
null
A pluggable org.apache.camel.component.file.GenericFileProcessStrategy allowing
you to implement your own readLock option or similar. Can also be used when special conditions must be
met before a file can be consumed, such as a special ready file exists. If this option is set then the readLock
option does not apply.
startingDirectoryMustExist
false
Camel 2.5: Whether the starting directory must exist. Mind that the autoCreate option is default
enabled, which means the starting directory is normally auto created if it doesn't exist. You can disable
autoCreate and enable this to ensure the starting directory must exist. Will thrown an exception if the
directory doesn't exist.
pollStrategy
null
Camel 2.0: A pluggable org.apache.camel.PollingConsumerPollStrategy allowing you to
provide your custom implementation to control error handling usually occurred during the poll operation
before an Exchange have been created and being routed in Camel. In other words the error occurred while
the polling was gathering information, for instance access to a file network failed so Camel cannot access it
to scan for files. The default implementation will log the caused exception at WARN level and ignore it.
sendEmptyMessageWhenIdle
false
Camel 2.9: If the polling consumer did not poll any files, you can enable this option to send an empty
message (no body) instead.
Default behavior for file consumer
• By default the file is locked for the duration of the processing.
• After the route has completed, files are moved into the .camel subdirectory, so
that they appear to be deleted.
• The File Consumer will always skip any file whose name starts with a dot, such as .,
.camel, .m2 or .groovy.
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• Only files (not directories) are matched for valid filename, if options such as:
include or exclude are used.
Producer
Name
Default
Value
Description
fileExist
Override
What to do if a file already exists with the same name. The following values can be specified: Override, Append, Fail and
Ignore. Override, which is the default, replaces the existing file. Append adds content to the existing file. Fail throws a
GenericFileOperationException, indicating that there is already an existing file. Ignore silently ignores the
problem and does not override the existing file, but assumes everything is okay.
tempPrefix
null
This option is used to write the file using a temporary name and then, after the write is complete, rename it to the real name.
Can be used to identify files being written and also avoid consumers (not using exclusive read locks) reading in progress files.
Is often used by FTP when uploading big files.
tempFileName
null
Camel 2.1: The same as tempPrefix option but offering a more fine grained control on the naming of the temporary
filename as it uses the File Language.
keepLastModified
false
Camel 2.2: Will keep the last modified timestamp from the source file (if any). Will use the
Exchange.FILE_LAST_MODIFIED header to located the timestamp. This header can contain either a
java.util.Date or long with the timestamp. If the timestamp exists and the option is enabled it will set this timestamp
on the written file. Note: This option only applies to the file producer. You cannot use this option with any of the ftp
producers.
eagerDeleteTargetFile
true
Camel 2.3: Whether or not to eagerly delete any existing target file. This option only applies when you use
fileExists=Override and the tempFileName option as well. You can use this to disable (set it to false) deleting the
target file before the temp file is written. For example you may write big files and want the target file to exists during the
temp file is being written. This ensure the target file is only deleted until the very last moment, just before the temp file is
being renamed to the target filename.
doneFileName
null
Camel 2.6: If provided, then Camel will write a 2nd done file when the original file has been written. The done file will be
empty. This option configures what file name to use. Either you can specify a fixed name. Or you can use dynamic
placeholders. The done file will always be written in the same folder as the original file. See writing done file section for
examples.
Default behavior for file producer
• By default it will override any existing file, if one exist with the same name.
Move and Delete operations
Any move or delete operations is executed after (post command) the routing has completed;
so during processing of the Exchange the file is still located in the inbox folder.
Lets illustrate this with an example:
from("file://inbox?move=.done").to("bean:handleOrder");
When a file is dropped in the inbox folder, the file consumer notices this and creates a new
FileExchange that is routed to the handleOrder bean. The bean then processes the
File object. At this point in time the file is still located in the inbox folder. After the bean
completes, and thus the route is completed, the file consumer will perform the move operation
and move the file to the .done sub-folder.
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Override is now default
In Camel 1.x the Append is the default for the file producer. We have changed this
to Override in Camel 2.0 as this is also the default file operation using
java.io.File.
And also the default for the FTP library we use in the camel-ftp component.
The move and preMove options should be a directory name, which can be either relative
or absolute. If relative, the directory is created as a sub-folder from within the folder where the
file was consumed.
By default, Camel will move consumed files to the .camel sub-folder relative to the
directory where the file was consumed.
If you want to delete the file after processing, the route should be:
from("file://inobox?delete=true").to("bean:handleOrder");
We have introduced a pre move operation to move files before they are processed. This
allows you to mark which files have been scanned as they are moved to this sub folder before
being processed.
from("file://inbox?preMove=inprogress").to("bean:handleOrder");
You can combine the pre move and the regular move:
from("file://inbox?preMove=inprogress&move=.done").to("bean:handleOrder");
So in this situation, the file is in the inprogress folder when being processed and after it's
processed, it's moved to the .done folder.
Fine grained control over Move and PreMove option
The move and preMove option is Expression-based, so we have the full power of the File
Language to do advanced configuration of the directory and name pattern.
Camel will, in fact, internally convert the directory name you enter into a File Language
expression. So when we enter move=.done Camel will convert this into:
${file:parent}/.done/${file:onlyname}. This is only done if Camel detects that
you have not provided a ${ } in the option value yourself. So when you enter a ${ } Camel will
not convert it and thus you have the full power.
So if we want to move the file into a backup folder with today's date as the pattern, we can
do:
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move=backup/${date:now:yyyyMMdd}/${file:name}
About moveFailed
The moveFailed option allows you to move files that could not be processed succesfully
to another location such as a error folder of your choice. For example to move the files in an
error folder with a timestamp you can use moveFailed=/error/
${file:name.noext}-${date:now:yyyyMMddHHmmssSSS}.${file:ext}.
See more examples at File Language
Message Headers
The following headers are supported by this component:
File producer only
Header
Description
CamelFileName
Specifies the name of the file to write (relative to the endpoint directory). The name can be a String; a String with a File Language or
Simple expression; or an Expression object. If it's null then Camel will auto-generate a filename based on the message unique ID.
CamelFileNameProduced
The actual absolute filepath (path + name) for the output file that was written. This header is set by Camel and its purpose is providing end-users
with the name of the file that was written.
File consumer only
Header
Description
CamelFileName
Name of the consumed file as a relative file path with offset from the starting directory configured on the endpoint.
CamelFileNameOnly
Only the file name (the name with no leading paths).
CamelFileAbsolute
A boolean option specifying whether the consumed file denotes an absolute path or not. Should normally be false for relative paths.
Absolute paths should normally not be used but we added to the move option to allow moving files to absolute paths. But can be used
elsewhere as well.
CamelFileAbsolutePath
The absolute path to the file. For relative files this path holds the relative path instead.
CamelFilePath
The file path. For relative files this is the starting directory + the relative filename. For absolute files this is the absolute path.
CamelFileRelativePath
The relative path.
CamelFileParent
The parent path.
CamelFileLength
A long value containing the file size.
CamelFileLastModified
A Date value containing the last modified timestamp of the file.
Batch Consumer
This component implements the Batch Consumer.
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Exchange Properties, file consumer only
As the file consumer is BatchConsumer it supports batching the files it polls. By batching it
means that Camel will add some properties to the Exchange so you know the number of files
polled the current index in that order.
Property
Description
CamelBatchSize
The total number of files that was polled in this batch.
CamelBatchIndex
The current index of the batch. Starts from 0.
CamelBatchComplete
A boolean value indicating the last Exchange in the batch. Is only true for the last entry.
This allows you for instance to know how many files exists in this batch and for instance let the
Aggregator2 aggregate this number of files.
Common gotchas with folder and filenames
When Camel is producing files (writing files) there are a few gotchas affecting how to set a
filename of your choice. By default, Camel will use the message ID as the filename, and since the
message ID is normally a unique generated ID, you will end up with filenames such as: IDMACHINENAME-2443-1211718892437-1-0. If such a filename is not desired, then you
must provide a filename in the CamelFileName message header. The constant,
Exchange.FILE_NAME, can also be used.
The sample code below produces files using the message ID as the filename:
from("direct:report").to("file:target/reports");
To use report.txt as the filename you have to do:
from("direct:report").setHeader(Exchange.FILE_NAME, constant("report.txt")).to(
"file:target/reports");
... the same as above, but with CamelFileName:
from("direct:report").setHeader("CamelFileName", constant("report.txt")).to(
"file:target/reports");
And a syntax where we set the filename on the endpoint with the fileName URI option.
from("direct:report").to("file:target/reports/?fileName=report.txt");
Filename Expression
Filename can be set either using the expression option or as a string-based File Language
expression in the CamelFileName header. See the File Language for syntax and samples.
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Consuming files from folders where others drop files directly
Beware if you consume files from a folder where other applications write files directly. Take a
look at the different readLock options to see what suits your use cases. The best approach is
however to write to another folder and after the write move the file in the drop folder.
However if you write files directly to the drop folder then the option changed could better
detect whether a file is currently being written/copied as it uses a file changed algorithm to see
whether the file size / modification changes over a period of time. The other read lock options
rely on Java File API that sadly is not always very good at detecting this. You may also want to
look at the doneFileName option, which uses a marker file (done) to signal when a file is
done and ready to be consumed.
Using done files
Available as of Camel 2.6
See also section writing done files below.
If you want only to consume files when a done file exists, then you can use the
doneFileName option on the endpoint.
from("file:bar?doneFileName=done");
Will only consume files from the bar folder, if a file name done exists in the same directory as
the target files. Camel will automatically delete the done file when it's done consuming the files.
However its more common to have one done file per target file. This means there is a 1:1
correlation. To do this you must use dynamic placeholders in the doneFileName option.
Currently Camel supports the following two dynamic tokens: file:name and
file:name.noext which must be enclosed in ${ }. The consumer only supports the static
part of the done file name as either prefix or suffix (not both).
from("file:bar?doneFileName=${file:name}.done");
In this example only files will be polled if there exists a done file with the name file name.done.
For example
▪ hello.txt - is the file to be consumed
▪ hello.txt.done - is the associated done file
You can also use a prefix for the done file, such as:
from("file:bar?doneFileName=ready-${file:name}");
▪ hello.txt - is the file to be consumed
▪ ready-hello.txt - is the associated done file
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Writing done files
Available as of Camel 2.6
After you have written af file you may want to write an additional done file as a kinda of
marker, to indicate to others that the file is finished and has been written. To do that you can
use the doneFileName option on the file producer endpoint.
.to("file:bar?doneFileName=done");
Will simply create a file named done in the same directory as the target file.
However its more common to have one done file per target file. This means there is a 1:1
correlation. To do this you must use dynamic placeholders in the doneFileName option.
Currently Camel supports the following two dynamic tokens: file:name and
file:name.noext which must be enclosed in ${ }.
.to("file:bar?doneFileName=done-${file:name}");
Will for example create a file named done-foo.txt if the target file was foo.txt in the
same directory as the target file.
.to("file:bar?doneFileName=${file:name}.done");
Will for example create a file named foo.txt.done if the target file was foo.txt in the
same directory as the target file.
.to("file:bar?doneFileName=${file:name.noext}.done");
Will for example create a file named foo.done if the target file was foo.txt in the same
directory as the target file.
Samples
Read from a directory and write to another directory
from("file://inputdir/?delete=true").to("file://outputdir")
Listen on a directory and create a message for each file dropped there. Copy the contents to
the outputdir and delete the file in the inputdir.
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Reading recursively from a directory and writing to another
from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")
Listen on a directory and create a message for each file dropped there. Copy the contents to
the outputdir and delete the file in the inputdir. Will scan recursively into subdirectories. Will lay out the files in the same directory structure in the outputdir as the
inputdir, including any sub-directories.
inputdir/foo.txt
inputdir/sub/bar.txt
Will result in the following output layout:
outputdir/foo.txt
outputdir/sub/bar.txt
Using flatten
If you want to store the files in the outputdir directory in the same directory, disregarding the
source directory layout (e.g. to flatten out the path), you just add the flatten=true option
on the file producer side:
from("file://inputdir/?recursive=true&delete=true").to("file://outputdir?flatten=true")
Will result in the following output layout:
outputdir/foo.txt
outputdir/bar.txt
Reading from a directory and the default move operation
Camel will by default move any processed file into a .camel subdirectory in the directory the
file was consumed from.
from("file://inputdir/?recursive=true&delete=true").to("file://outputdir")
Affects the layout as follows:
before
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inputdir/foo.txt
inputdir/sub/bar.txt
after
inputdir/.camel/foo.txt
inputdir/sub/.camel/bar.txt
outputdir/foo.txt
outputdir/sub/bar.txt
Read from a directory and process the message in java
from("file://inputdir/").process(new Processor() {
public void process(Exchange exchange) throws Exception {
Object body = exchange.getIn().getBody();
// do some business logic with the input body
}
});
The body will be a File object that points to the file that was just dropped into the
inputdir directory.
Read files from a directory and send the content to a jms queue
from("file://inputdir/").convertBodyTo(String.class).to("jms:test.queue")
By default the file endpoint sends a FileMessage which contains a File object as the body.
If you send this directly to the JMS component the JMS message will only contain the File
object but not the content. By converting the File to a String, the message will contain the
file content which is probably what you want.
The route above using Spring DSL:
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Writing to files
Camel is of course also able to write files, i.e. produce files. In the sample below we receive
some reports on the SEDA queue that we process before they are written to a directory.
public void testToFile() throws Exception {
MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedMessageCount(1);
mock.expectedFileExists("target/test-reports/report.txt");
template.sendBody("direct:reports", "This is a great report");
assertMockEndpointsSatisfied();
}
protected JndiRegistry createRegistry() throws Exception {
// bind our processor in the registry with the given id
JndiRegistry reg = super.createRegistry();
reg.bind("processReport", new ProcessReport());
return reg;
}
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
// the reports from the seda queue is processed by our processor
// before they are written to files in the target/reports directory
from("direct:reports").processRef("processReport").to("file://target/
test-reports", "mock:result");
}
};
}
private static class ProcessReport implements Processor {
public void process(Exchange exchange) throws Exception {
String body = exchange.getIn().getBody(String.class);
// do some business logic here
// set the output to the file
exchange.getOut().setBody(body);
// set the output filename using java code logic, notice that this is done by
setting
// a special header property of the out exchange
exchange.getOut().setHeader(Exchange.FILE_NAME, "report.txt");
}
}
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Write to subdirectory using Exchange.FILE_NAME
Using a single route, it is possible to write a file to any number of subdirectories. If you have a
route setup as such:
You can have myBean set the header Exchange.FILE_NAME to values such as:
Exchange.FILE_NAME = hello.txt => /rootDirectory/hello.txt
Exchange.FILE_NAME = foo/bye.txt => /rootDirectory/foo/bye.txt
This allows you to have a single route to write files to multiple destinations.
Using expression for filenames
In this sample we want to move consumed files to a backup folder using today's date as a subfolder name:
from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");
See File Language for more samples.
Avoiding reading the same file more than once (idempotent consumer)
Camel supports Idempotent Consumer directly within the component so it will skip already
processed files. This feature can be enabled by setting the idempotent=true option.
from("file://inbox?idempotent=true").to("...");
By default Camel uses a in memory based store for keeping track of consumed files, it uses a
least recently used cache holding up to 1000 entries. You can plugin your own implementation
of this store by using the idempotentRepository option using the # sign in the value to
indicate it's a referring to a bean in the Registry with the specified id.
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Camel will log at DEBUG level if it skips a file because it has been consumed before:
DEBUG FileConsumer is idempotent and the file has been consumed before. Will skip this
file: target\idempotent\report.txt
Using a file based idempotent repository
In this section we will use the file based idempotent repository
org.apache.camel.processor.idempotent.FileIdempotentRepository
instead of the in-memory based that is used as default.
This repository uses a 1st level cache to avoid reading the file repository. It will only use the file
repository to store the content of the 1st level cache. Thereby the repository can survive
server restarts. It will load the content of the file into the 1st level cache upon startup. The file
structure is very simple as it stores the key in separate lines in the file. By default, the file store
has a size limit of 1mb. When the file grows larger Camel will truncate the file store, rebuilding
the content by flushing the 1st level cache into a fresh empty file.
We configure our repository using Spring XML creating our file idempotent repository and
define our file consumer to use our repository with the idempotentRepository using #
sign to indicate Registry lookup:
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Using a JPA based idempotent repository
In this section we will use the JPA based idempotent repository instead of the in-memory based
that is used as default.
First we need a persistence-unit in META-INF/persistence.xml where we need to
use the class
org.apache.camel.processor.idempotent.jpa.MessageProcessed as model.
org.apache.camel.processor.idempotent.jpa.MessageProcessed
Then we need to setup a Spring jpaTemplate in the spring XML file:
And finally we can create our JPA idempotent repository in the spring XML file as well:
And yes then we just need to refer to the jpaStore bean in the file consumer endpoint using
the [[idempotentRepository}} using the # syntax option:
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Filter using org.apache.camel.component.file.GenericFileFilter
Camel supports pluggable filtering strategies. You can then configure the endpoint with such a
filter to skip certain files being processed.
In the sample we have built our own filter that skips files starting with skip in the filename:
public class MyFileFilter implements GenericFileFilter {
public boolean accept(GenericFile pathname) {
// we dont accept any files starting with skip in the name
return !pathname.getFileName().startsWith("skip");
}
}
And then we can configure our route using the filter attribute to reference our filter (using #
notation) that we have defined in the spring XML file:
Filtering using ANT path matcher
The ANT path matcher is shipped out-of-the-box in the camel-spring jar. So you need to
depend on camel-spring if you are using Maven.
The reasons is that we leverage Spring's AntPathMatcher to do the actual matching.
The file paths is matched with the following rules:
▪ ? matches one character
▪ * matches zero or more characters
▪ ** matches zero or more directories in a path
The sample below demonstrates how to use it:
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Sorting using Comparator
Camel supports pluggable sorting strategies. This strategy it to use the build in
java.util.Comparator in Java. You can then configure the endpoint with such a
comparator and have Camel sort the files before being processed.
In the sample we have built our own comparator that just sorts by file name:
public class MyFileSorter implements Comparator {
public int compare(GenericFile o1, GenericFile o2) {
return o1.getFileName().compareToIgnoreCase(o2.getFileName());
}
}
And then we can configure our route using the sorter option to reference to our sorter
(mySorter) we have defined in the spring XML file:
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URI options can reference beans using the # syntax
In the Spring DSL route about notice that we can refer to beans in the Registry by
prefixing the id with #. So writing sorter=#mySorter, will instruct Camel to go
look in the Registry for a bean with the ID, mySorter.
Sorting using sortBy
Camel supports pluggable sorting strategies. This strategy it to use the File Language to
configure the sorting. The sortBy option is configured as follows:
sortBy=group 1;group 2;group 3;...
Where each group is separated with semi colon. In the simple situations you just use one
group, so a simple example could be:
sortBy=file:name
This will sort by file name, you can reverse the order by prefixing reverse: to the group, so
the sorting is now Z..A:
sortBy=reverse:file:name
As we have the full power of File Language we can use some of the other parameters, so if we
want to sort by file size we do:
sortBy=file:length
You can configure to ignore the case, using ignoreCase: for string comparison, so if you
want to use file name sorting but to ignore the case then we do:
sortBy=ignoreCase:file:name
You can combine ignore case and reverse, however reverse must be specified first:
sortBy=reverse:ignoreCase:file:name
In the sample below we want to sort by last modified file, so we do:
sortBy=file:modifed
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And then we want to group by name as a 2nd option so files with same modifcation is sorted by
name:
sortBy=file:modifed;file:name
Now there is an issue here, can you spot it? Well the modified timestamp of the file is too fine
as it will be in milliseconds, but what if we want to sort by date only and then subgroup by
name?
Well as we have the true power of File Language we can use the its date command that
supports patterns. So this can be solved as:
sortBy=date:file:yyyyMMdd;file:name
Yeah, that is pretty powerful, oh by the way you can also use reverse per group, so we could
reverse the file names:
sortBy=date:file:yyyyMMdd;reverse:file:name
Using GenericFileProcessStrategy
The option processStrategy can be used to use a custom
GenericFileProcessStrategy that allows you to implement your own begin, commit
and rollback logic.
For instance lets assume a system writes a file in a folder you should consume. But you should
not start consuming the file before another ready file has been written as well.
So by implementing our own GenericFileProcessStrategy we can implement this
as:
▪ In the begin() method we can test whether the special ready file exists. The begin
method returns a boolean to indicate if we can consume the file or not.
▪ in the commit() method we can move the actual file and also delete the ready file.
Debug logging
This component has log level TRACE that can be helpful if you have problems.
See Also
•
•
•
•
▪
599
Configuring Camel
Component
Endpoint
Getting Started
File Language
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▪ FTP2
▪ Polling Consumer
FLATPACK COMPONENT
The Flatpack component supports fixed width and delimited file parsing via the FlatPack library.
Notice: This component only supports consuming from flatpack files to Object model. You
can not (yet) write from Object model to flatpack format.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-flatpackx.x.x
URI format
flatpack:[delim|fixed]:flatPackConfig.pzmap.xml[?options]
Or for a delimited file handler with no configuration file just use
flatpack:someName[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
URI Options
Name
Default Value
Description
delimiter
,
The default character delimiter for delimited files.
textQualifier
"
The text qualifier for delimited files.
ignoreFirstRecord
true
Whether the first line is ignored for delimited files (for the column headers).
splitRows
true
As of Camel 1.5, the component can either process each row one by one or the entire content at once.
Examples
• flatpack:fixed:foo.pzmap.xml creates a fixed-width endpoint using the
foo.pzmap.xml file configuration.
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• flatpack:delim:bar.pzmap.xml creates a delimited endpoint using the
bar.pzmap.xml file configuration.
• flatpack:foo creates a delimited endpoint called foo with no file configuration.
Message Headers
Camel will store the following headers on the IN message:
Header
Description
camelFlatpackCounter
The current row index. For splitRows=false the counter is the total number of rows.
Message Body
The component delivers the data in the IN message as a
org.apache.camel.component.flatpack.DataSetList object that has
converters for java.util.Map or java.util.List.
Usually you want the Map if you process one row at a time (splitRows=true). Use List
for the entire content (splitRows=false), where each element in the list is a Map.
Each Map contains the key for the column name and its corresponding value.
For example to get the firstname from the sample below:
Map row = exchange.getIn().getBody(Map.class);
String firstName = row.get("FIRSTNAME");
However, you can also always get it as a List (even for splitRows=true). The same
example:
List data = exchange.getIn().getBody(List.class);
Map row = (Map)data.get(0);
String firstName = row.get("FIRSTNAME");
Header and Trailer records
In Camel 1.5 onwards the header and trailer notions in Flatpack are supported. However, you
must use fixed record IDs:
• header for the header record (must be lowercase)
• trailer for the trailer record (must be lowercase)
The example below illustrates this fact that we have a header and a trailer. You can omit one or
both of them if not needed.
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name="LASTNAME" length="35" />
name="ADDRESS" length="100" />
name="CITY" length="100" />
name="STATE" length="2" />
name="ZIP" length="5" />
Using the endpoint
A common use case is sending a file to this endpoint for further processing in a separate route.
For example:
...
You can also convert the payload of each message created to a Map for easy Bean Integration
FLATPACK DATAFORMAT
The Flatpack component ships with the Flatpack data format that can be used to format
between fixed width or delimited text messages to a List of rows as Map.
▪ marshal = from List> to OutputStream (can be
converted to String)
▪ unmarshal = from java.io.InputStream (such as a File or String) to a
java.util.List as an
org.apache.camel.component.flatpack.DataSetList instance.
The result of the operation will contain all the data. If you need to process each row
one by one you can split the exchange, using Splitter.
Notice: The Flatpack library does currently not support header and trailers for the marshal
operation.
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Options
The data format has the following options:
Option
Default
Description
definition
null
The flatpack pzmap configuration file. Can be
omitted in simpler situations, but its preferred to
use the pzmap.
fixed
false
Delimited or fixed.
ignoreFirstRecord
true
Whether the first line is ignored for delimited files
(for the column headers).
textQualifier
"
If the text is qualified with a char such as ".
delimiter
,
The delimiter char (could be ; , or similar)
parserFactory
null
Uses the default Flatpack parser factory.
Usage
To use the data format, simply instantiate an instance and invoke the marhsal or unmarshal
operation in the route builder:
FlatpackDataFormat fp = new FlatpackDataFormat();
fp.setDefinition(new ClassPathResource("INVENTORY-Delimited.pzmap.xml"));
...
from("file:order/in").unmarshal(df).to("seda:queue:neworder");
The sample above will read files from the order/in folder and unmarshal the input using the
Flatpack configuration file INVENTORY-Delimited.pzmap.xml that configures the
structure of the files. The result is a DataSetList object we store on the SEDA queue.
FlatpackDataFormat df = new FlatpackDataFormat();
df.setDefinition(new ClassPathResource("PEOPLE-FixedLength.pzmap.xml"));
df.setFixed(true);
df.setIgnoreFirstRecord(false);
from("seda:people").marshal(df).convertBodyTo(String.class).to("jms:queue:people");
In the code above we marshal the data from a Object representation as a List of rows as
Maps. The rows as Map contains the column name as the key, and the the corresponding
value. This structure can be created in Java code from e.g. a processor. We marshal the data
according to the Flatpack format and convert the result as a String object and store it on a
JMS queue.
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Dependencies
To use Flatpack in your camel routes you need to add the a dependency on camel-flatpack
which implements this data format.
If you use maven you could just add the following to your pom.xml, substituting the version
number for the latest & greatest release (see the download page for the latest versions).
org.apache.camelcamel-flatpack1.5.0
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
FREEMARKER
Available as of Camel 1.6
The freemarker: component allows you to process a message using a FreeMarker
template. This can be ideal when using Templating to generate responses for requests.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-freemarkerx.x.x
URI format
freemarker:templateName[?options]
Where templateName is the classpath-local URI of the template to invoke; or the complete
URL of the remote template (eg: file://folder/myfile.ftl).
You can append query options to the URI in the following format,
?option=value&option=value&...
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Options
Option
Default
Description
contentCache
true
Cache for the resource content when its loaded.
Note : as of Camel 2.9 cached resource content can be cleared via JMX using the endpoint's clearContentCache
operation.
encoding
null
Character encoding of the resource content.
templateUpdateDelay
5
Camel 2.9: Number of seconds the loaded template resource will remain in the cache.
Ê
Headers
Headers set during the FreeMarker evaluation are returned to the message and added as
headers. Then its kinda possible to return values from FreeMarker to the Message.
An example: Set the header value of fruit in the FreeMarker template:
${request.setHeader('fruit', 'Apple')}
The header, fruit, is now accessible from the message.out.headers.
FreeMarker Context
Camel will provide exchange information in the FreeMarker context (just a Map). The
Exchange is transfered as:
key
value
exchange
The Exchange itself.
exchange.properties
The Exchange properties.
headers
The headers of the In message.
camelContext
The Camel Context.
request
The In message.
body
The In message body.
response
The Out message (only for InOut message exchange pattern).
Hot reloading
The FreeMarker template resource is by default not hot reloadable for both file and classpath
resources (expanded jar). If you set contentCache=false, then Camel will not cache the
resource and hot reloading is thus enabled. This scenario can be used in development.
Dynamic templates
Camel provides two headers by which you can define a different resource location for a
template or the template content itself. If any of these headers is set then Camel uses this over
the endpoint configured resource. This allows you to provide a dynamic template at runtime.
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Header
Type
Description
Support
Version
FreemarkerConstants.FREEMARKER_RESOURCE
org.springframework.core.io.Resource
The template resource
<= 1.6.2, <= 2.1
String
A URI for the template resource to use instead of
the endpoint configured.
>= 2.1
String
The template to use instead of the endpoint
configured.
>= 2.1
FreemarkerConstants.FREEMARKER_RESOURCE_URI
FreemarkerConstants.FREEMARKER_TEMPLATE
Samples
For example you could use something like:
from("activemq:My.Queue").
to("freemarker:com/acme/MyResponse.ftl");
To use a FreeMarker template to formulate a response for a message for InOut message
exchanges (where there is a JMSReplyTo header).
If you want to use InOnly and consume the message and send it to another destination you
could use:
from("activemq:My.Queue").
to("freemarker:com/acme/MyResponse.ftl").
to("activemq:Another.Queue");
And to disable the content cache, e.g. for development usage where the .ftl template should
be hot reloaded:
from("activemq:My.Queue").
to("freemarker:com/acme/MyResponse.ftl?contentCache=false").
to("activemq:Another.Queue");
And a file-based resource:
from("activemq:My.Queue").
to("freemarker:file://myfolder/MyResponse.ftl?contentCache=false").
to("activemq:Another.Queue");
In Camel 2.1 it's possible to specify what template the component should use dynamically via
a header, so for example:
from("direct:in").
setHeader(FreemarkerConstants.FREEMARKER_RESOURCE_URI).constant("path/to/my/
template.ftl").
to("freemarker:dummy");
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The Email Sample
In this sample we want to use FreeMarker templating for an order confirmation email. The
email template is laid out in FreeMarker as:
Dear ${headers.lastName}, ${headers.firstName}
Thanks for the order of ${headers.item}.
Regards Camel Riders Bookstore
${body}
And the java code:
private Exchange createLetter() {
Exchange exchange = context.getEndpoint("direct:a").createExchange();
Message msg = exchange.getIn();
msg.setHeader("firstName", "Claus");
msg.setHeader("lastName", "Ibsen");
msg.setHeader("item", "Camel in Action");
msg.setBody("PS: Next beer is on me, James");
return exchange;
}
@Test
public void testFreemarkerLetter() throws Exception {
MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedMessageCount(1);
mock.expectedBodiesReceived("Dear Ibsen, Claus\n\nThanks for the order of Camel in
Action."
+ "\n\nRegards Camel Riders Bookstore\nPS: Next beer is on me, James");
template.send("direct:a", createLetter());
mock.assertIsSatisfied();
}
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
from("direct:a")
.to("freemarker:org/apache/camel/component/freemarker/letter.ftl")
.to("mock:result");
}
};
}
See Also
• Configuring Camel
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• Component
• Endpoint
• Getting Started
FTP/SFTP/FTPS COMPONENT - CAMEL 2.0 ONWARDS
This component provides access to remote file systems over the FTP and SFTP protocols.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-ftpx.x.x
URI format
ftp://[username@]hostname[:port]/directoryname[?options]
sftp://[username@]hostname[:port]/directoryname[?options]
ftps://[username@]hostname[:port]/directoryname[?options]
Where directoryname represents the underlying directory. Can contain nested folders.
If no username is provided, then anonymous login is attempted using no password.
If no port number is provided, Camel will provide default values according to the protocol (ftp
= 21, sftp = 22, ftps = 2222).
You can append query options to the URI in the following format,
?option=value&option=value&...
This component uses two different libraries for the actual FTP work. FTP and FTPS uses
Apache Commons Net while SFTP uses JCraft JSCH.
The FTPS component is only available in Camel 2.2 or newer.
FTPS (also known as FTP Secure) is an extension to FTP that adds support for the Transport
Layer Security (TLS) and the Secure Sockets Layer (SSL) cryptographic protocols.
URI Options
The options below are exclusive for the FTP2 component.
Name
Default
Value
Description
username
null
Specifies the username to use to log in to the remote file systen.
password
null
Specifies the password to use to log in to the remote file system.
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Using Camel 1.x
If you are using Camel 1.x then see this link for documentation.
This page is only for Camel 2.0 or newer.
More options
See File2 for more options as all the options from File2 is inherited.
Consuming from remote FTP server
Make sure you read the section titled Default when consuming files further below for
details related to consuming files.
More options
See File2 for more options as all the options from File2 is inherited.
609
binary
false
Specifies the file transfer mode, BINARY or ASCII. Default is ASCII (false).
disconnect
false
Camel 2.2: Whether or not to disconnect from remote FTP server right after use. Can be used for both
consumer and producer. Disconnect will only disconnect the current connection to the FTP server. If you
have a consumer which you want to stop, then you need to stop the consumer/route instead.
localWorkDirectory
null
When consuming, a local work directory can be used to store the remote file content directly in local files,
to avoid loading the content into memory. This is beneficial, if you consume a very big remote file and thus
can conserve memory. See below for more details.
passiveMode
false
FTP and FTPS only: Specifies whether to use passive mode connections. Default is active mode
(false).
securityProtocol
TLS
FTPS only: Sets the underlying security protocol. The following values are defined:
TLS: Transport Layer Security
SSL: Secure Sockets Layer
disableSecureDataChannelDefaults
false
Camel 2.4: FTPS only: Whether or not to disable using default values for execPbsz and execProt
when using secure data transfer. You can set this option to true if you want to be in absolute full control
what the options execPbsz and execProt should be used.
execProt
null
Camel 2.4: FTPS only: Will by default use option P if secure data channel defaults hasn't been disabled.
Possible values are:
C: Clear
S: Safe (SSL protocol only)
E: Confidential (SSL protocol only)
P: Private
execPbsz
null
Camel 2.4: FTPS only: This option specifies the buffer size of the secure data channel. If option
useSecureDataChannel has been enabled and this option has not been explicit set, then value 0 is used.
isImplicit
false
FTPS only: Sets the security mode(implicit/explicit). Default is explicit (false).
knownHostsFile
null
SFTP only: Sets the known_hosts file, so that the SFTP endpoint can do host key verification.
privateKeyFile
null
SFTP only: Set the private key file to that the SFTP endpoint can do private key verification.
privateKeyFilePassphrase
null
SFTP only: Set the private key file passphrase to that the SFTP endpoint can do private key verification.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
ciphers
null
Camel 2.8.2, 2.9: SFTP only Set a comma separated list of ciphers that will be used in order of
preference. Possible cipher names are defined by JCraft JSCH. Some examples include:
aes128-ctr,aes128-cbc,3des-ctr,3des-cbc,blowfish-cbc,aes192-cbc,aes256-cbc. If not specified the default list
from JSCH will be used.
fastExistsCheck
false
Camel 2.8.2, 2.9: If set this option to be true, camel-ftp will use the list file directly to check if the file
exists. Since some FTP server may not support to list the file directly, if the option is false, camel-ftp will use
the old way to list the directory and check if the file exists.
strictHostKeyChecking
no
SFTP only: Camel 2.2: Sets whether to use strict host key checking. Possible values are: no, yes and
ask. ask does not make sense to use as Camel cannot answer the question for you as its meant for human
intervention. Note: The default in Camel 2.1 and below was ask.
maximumReconnectAttempts
3
Specifies the maximum reconnect attempts Camel performs when it tries to connect to the remote FTP
server. Use 0 to disable this behavior.
reconnectDelay
1000
Delay in millis Camel will wait before performing a reconnect attempt.
connectTimeout
10000
Camel 2.4: Is the connect timeout in millis. This corresponds to using ftpClient.connectTimeout
for the FTP/FTPS. For SFTP this option is also used when attempting to connect.
soTimeout
null
FTP and FTPS Only: Camel 2.4: Is the SocketOptions.SO_TIMEOUT value in millis. Note SFTP
will automatic use the connectTimeout as the soTimeout.
timeout
30000
FTP and FTPS Only: Camel 2.4: Is the data timeout in millis. This corresponds to using
ftpClient.dataTimeout for the FTP/FTPS. For SFTP there is no data timeout.
throwExceptionOnConnectFailed
false
Camel 2.5: Whether or not to thrown an exception if a successful connection and login could not be
establish. This allows a custom pollStrategy to deal with the exception, for example to stop the
consumer or the likes.
siteCommand
null
FTP and FTPS Only: Camel 2.5: To execute site commands after successful login. Multiple site
commands can be separated using a new line character (\n). Use help site to see which site commands
your FTP server supports.
stepwise
true
Camel 2.6: Whether or not stepwise traversing directories should be used or not. Stepwise means that it
will CD one directory at a time. See more details below. You can disable this in case you can't use this
approach.
separator
Auto
Camel 2.6: Dictates what path separator char to use when uploading files. Auto = Use the path provided
without altering it. UNIX = Use unix style path separators. Windows = Use Windows style path separators.
chmod
null
SFTP Producer Only: Camel 2.9: Allows you to set chmod on the stored file. For example
chmod=640.
compression
0
SFTP Only: Camel 2.8.3/2.9: To use compression. Specify a level from 1 to 10. Important: You must
manually add the needed JSCH zlib JAR to the classpath for compression support.
ftpClient
null
FTP and FTPS Only: Camel 2.1: Allows you to use a custom
org.apache.commons.net.ftp.FTPClient instance.
ftpClientConfig
null
FTP and FTPS Only: Camel 2.1: Allows you to use a custom
org.apache.commons.net.ftp.FTPClientConfig instance.
serverAliveInterval
0
SFTP Only: Camel 2.8 Allows you to set the serverAliveInterval of the sftp session
serverAliveCountMax
1
SFTP Only: Camel 2.8 Allows you to set the serverAliveCountMax of the sftp session
ftpClient.trustStore.file
null
FTPS Only: Sets the trust store file, so that the FTPS client can look up for trusted certificates.
ftpClient.trustStore.type
JKS
FTPS Only: Sets the trust store type.
ftpClient.trustStore.algorithm
SunX509
FTPS Only: Sets the trust store algorithm.
ftpClient.trustStore.password
null
FTPS Only: Sets the trust store password.
ftpClient.keyStore.file
null
FTPS Only: Sets the key store file, so that the FTPS client can look up for the private certificate.
ftpClient.keyStore.type
JKS
FTPS Only: Sets the key store type.
ftpClient.keyStore.algorithm
SunX509
FTPS Only: Sets the key store algorithm.
ftpClient.keyStore.password
null
FTPS Only: Sets the key store password.
ftpClient.keyStore.keyPassword
null
FTPS Only: Sets the private key password.
sslContextParameters
null
FTPS Only: Camel 2.9: Reference to a
org.apache.camel.util.jsse.SSLContextParameters in the Registry.Ê This reference
overrides any configured SSL related options on ftpClient as well as the securityProtocol (SSL, TLS, etc.) set
on FtpsConfiguration.Ê See Using the JSSE Configuration Utility.
You can configure additional options on the ftpClient and ftpClientConfig from the
URI directly by using the ftpClient. or ftpClientConfig. prefix.
For example to set the setDataTimeout on the FTPClient to 30 seconds you can do:
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FTPS component default trust store
When using the ftpClient. properties related to SSL with the FTPS component,
the trust store accept all certificates. If you only want trust selective certificates,
you have to configure the trust store with the ftpClient.trustStore.xxx
options or by configuring a custom ftpClient.
When using sslContextParameters, the trust store is managed by the configuration of
the provided SSLContextParameters instance.
from("ftp://foo@myserver?password=secret&ftpClient.dataTimeout=30000").to("bean:foo");
You can mix and match and have use both prefixes, for example to configure date format or
timezones.
from("ftp://foo@myserver?password=secret&ftpClient.dataTimeout=30000&ftpClientConfig.serverLanguageCod
You can have as many of these options as you like.
See the documentation of the Apache Commons FTP FTPClientConfig for possible options
and more details.
And as well for Apache Commons FTP FTPClient.
If you do not like having many and long configuration in the url you can refer to the
ftpClient or ftpClientConfig to use by letting Camel lookup in the Registry for it.
For example:
And then let Camel lookup this bean when you use the # notation in the url.
from("ftp://foo@myserver?password=secret&ftpClientConfig=#myConfig").to("bean:foo");
More URI options
Examples
ftp://someone@someftpserver.com/public/upload/images/
holiday2008?password=secret&binary=true
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See File2 as all the options there also applies for this component.
ftp://someoneelse@someotherftpserver.co.uk:12049/reports/2008/
password=secret&binary=false
ftp://publicftpserver.com/download
Default when consuming files
The FTP consumer will by default leave the consumed files untouched on the remote FTP
server. You have to configure it explicitly if you want it to delete the files or move them to
another location. For example you can use delete=true to delete the files, or use
move=.done to move the files into a hidden done sub directory.
The regular File consumer is different as it will by default move files to a .camel sub
directory. The reason Camel does not do this by default for the FTP consumer is that it may
lack permissions by default to be able to move or delete files.
limitations
The option readLock can be used to force Camel not to consume files that is currently in
the progress of being written. However, this option is turned off by default, as it requires that
the user has write access. See the options table at File2 for more details about read locks.
There are other solutions to avoid consuming files that are currently being written over FTP;
for instance, you can write to a temporary destination and move the file after it has been
written.
When moving files using move or preMove option the files are restricted to the
FTP_ROOT folder. That prevents you from moving files outside the FTP area. If you want to
move files to another area you can use soft links and move files into a soft linked folder.
Message Headers
The following message headers can be used to affect the behavior of the component
Header
Description
CamelFileName
Specifies the output file name (relative to the endpoint directory) to be used for the output message when sending to the endpoint. If this is
not present and no expression either, then a generated message ID is used as the filename instead.
CamelFileNameProduced
The actual absolute filepath (path + name) for the output file that was written. This header is set by Camel and its purpose is providing endusers the name of the file that was written.
CamelFileBatchIndex
Current index out of total number of files being consumed in this batch.
CamelFileBatchSize
Total number of files being consumed in this batch.
CamelFileHost
The remote hostname.
CamelFileLocalWorkPath
Path to the local work file, if local work directory is used.
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FTP Consumer does not support concurrency
The FTP consumer (with the same endpoint) does not support concurrency (the
backing FTP client is not thread safe).
You can use multiple FTP consumers to poll from different endpoints. It is only a
single endpoint that does not support concurrent consumers.
The FTP producer does not have this issue, it supports concurrency.
More information
This component is an extension of the File2 component. So there are more samples
and details on the File2 component page.
About timeouts
The two set of libraries (see top) has different API for setting timeout. You can use the
connectTimeout option for both of them to set a timeout in millis to establish a network
connection. An individual soTimeout can also be set on the FTP/FTPS, which corresponds to
using ftpClient.soTimeout. Notice SFTP will automatically use connectTimeout as
its soTimeout. The timeout option only applies for FTP/FTSP as the data timeout, which
corresponds to the ftpClient.dataTimeout value. All timeout values are in millis.
Using Local Work Directory
Camel supports consuming from remote FTP servers and downloading the files directly into a
local work directory. This avoids reading the entire remote file content into memory as it is
streamed directly into the local file using FileOutputStream.
Camel will store to a local file with the same name as the remote file, though with
.inprogress as extension while the file is being downloaded. Afterwards, the file is renamed
to remove the .inprogress suffix. And finally, when the Exchange is complete the local file
is deleted.
So if you want to download files from a remote FTP server and store it as files then you
need to route to a file endpoint such as:
from("ftp://someone@someserver.com?password=secret&localWorkDirectory=/
tmp").to("file://inbox");
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Optimization by renaming work file
The route above is ultra efficient as it avoids reading the entire file content into
memory. It will download the remote file directly to a local file stream. The
java.io.File handle is then used as the Exchange body. The file producer
leverages this fact and can work directly on the work file java.io.File handle
and perform a java.io.File.rename to the target filename. As Camel knows
it's a local work file, it can optimize and use a rename instead of a file copy, as the
work file is meant to be deleted anyway.
Stepwise changing directories
Camel FTP can operate in two modes in terms of traversing directories when consuming files
(eg downloading) or producing files (eg uploading)
▪ stepwise
▪ not stepwise
You may want to pick either one depending on your situation and security issues. Some Camel
end users can only download files if they use stepwise, while others can only download if they
do not. At least you have the choice to pick (from Camel 2.6 onwards).
In Came 2.0 - 2.5 there is only one mode and it is:
▪ 2.0 to 2.4 not stepwise
▪ 2.5 stepwise
From Camel 2.6 onwards there is now an option stepwise you can use to control the
behavior.
Note that stepwise changing of directory will in most cases only work when the user is
confined to it's home directory and when the home directory is reported as "/".
The difference between the two of them is best illustrated with an example. Suppose we
have the following directory structure on the remote FTP server we need to traverse and
download files:
/
/one
/one/two
/one/two/sub-a
/one/two/sub-b
And that we have a file in each of sub-a (a.txt) and sub-b (b.txt) folder.
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Using stepwise=true (default mode)
TYPE A
200 Type set to A
PWD
257 "/" is current directory.
CWD one
250 CWD successful. "/one" is current directory.
CWD two
250 CWD successful. "/one/two" is current directory.
SYST
215 UNIX emulated by FileZilla
PORT 127,0,0,1,17,94
200 Port command successful
LIST
150 Opening data channel for directory list.
226 Transfer OK
CWD sub-a
250 CWD successful. "/one/two/sub-a" is current directory.
PORT 127,0,0,1,17,95
200 Port command successful
LIST
150 Opening data channel for directory list.
226 Transfer OK
CDUP
200 CDUP successful. "/one/two" is current directory.
CWD sub-b
250 CWD successful. "/one/two/sub-b" is current directory.
PORT 127,0,0,1,17,96
200 Port command successful
LIST
150 Opening data channel for directory list.
226 Transfer OK
CDUP
200 CDUP successful. "/one/two" is current directory.
CWD /
250 CWD successful. "/" is current directory.
PWD
257 "/" is current directory.
CWD one
250 CWD successful. "/one" is current directory.
CWD two
250 CWD successful. "/one/two" is current directory.
PORT 127,0,0,1,17,97
200 Port command successful
RETR foo.txt
150 Opening data channel for file transfer.
226 Transfer OK
CWD /
250 CWD successful. "/" is current directory.
PWD
257 "/" is current directory.
CWD one
250 CWD successful. "/one" is current directory.
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CWD two
250 CWD successful. "/one/two" is current directory.
CWD sub-a
250 CWD successful. "/one/two/sub-a" is current directory.
PORT 127,0,0,1,17,98
200 Port command successful
RETR a.txt
150 Opening data channel for file transfer.
226 Transfer OK
CWD /
250 CWD successful. "/" is current directory.
PWD
257 "/" is current directory.
CWD one
250 CWD successful. "/one" is current directory.
CWD two
250 CWD successful. "/one/two" is current directory.
CWD sub-b
250 CWD successful. "/one/two/sub-b" is current directory.
PORT 127,0,0,1,17,99
200 Port command successful
RETR b.txt
150 Opening data channel for file transfer.
226 Transfer OK
CWD /
250 CWD successful. "/" is current directory.
QUIT
221 Goodbye
disconnected.
As you can see when stepwise is enabled, it will traverse the directory structure using CD xxx.
Using stepwise=false
230 Logged on
TYPE A
200 Type set to A
SYST
215 UNIX emulated by FileZilla
PORT 127,0,0,1,4,122
200 Port command successful
LIST one/two
150 Opening data channel for directory list
226 Transfer OK
PORT 127,0,0,1,4,123
200 Port command successful
LIST one/two/sub-a
150 Opening data channel for directory list
226 Transfer OK
PORT 127,0,0,1,4,124
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200 Port command successful
LIST one/two/sub-b
150 Opening data channel for
226 Transfer OK
PORT 127,0,0,1,4,125
200 Port command successful
RETR one/two/foo.txt
150 Opening data channel for
226 Transfer OK
PORT 127,0,0,1,4,126
200 Port command successful
RETR one/two/sub-a/a.txt
150 Opening data channel for
226 Transfer OK
PORT 127,0,0,1,4,127
200 Port command successful
RETR one/two/sub-b/b.txt
150 Opening data channel for
226 Transfer OK
QUIT
221 Goodbye
disconnected.
directory list
file transfer.
file transfer.
file transfer.
As you can see when not using stepwise, there are no CD operation invoked at all.
Samples
In the sample below we set up Camel to download all the reports from the FTP server once
every hour (60 min) as BINARY content and store it as files on the local file system.
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
// we use a delay of 60 minutes (eg. once pr. hour we poll the FTP server
long delay = 60 * 60 * 1000L;
// from the given FTP server we poll (= download) all the files
// from the public/reports folder as BINARY types and store this as files
// in a local directory. Camel will use the filenames from the FTPServer
//
"consumer." in
//
consumer.delay
//
Component.
notice that the FTPConsumer properties must be prefixed with
the URL
the delay parameter is from the FileConsumer component so we should use
as
the URI parameter name. The FTP Component is an extension of the File
from("ftp://tiger:scott@localhost/public/reports?binary=true&consumer.delay=" + delay).
to("file://target/test-reports");
}
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};
}
And the route using Spring DSL:
Consuming a remote FTPS server (implicit SSL) and client
authentication
from("ftps://admin@localhost:2222/public/camel?password=admin&securityProtocol=SSL&isImplicit=true
&ftpClient.keyStore.file=./src/test/resources/server.jks
&ftpClient.keyStore.password=password&ftpClient.keyStore.keyPassword=password")
.to("bean:foo");
Consuming a remote FTPS server (explicit TLS) and a custom
trust store configuration
from("ftps://admin@localhost:2222/public/camel?password=admin&ftpClient.trustStore.file=./
src/test/resources/server.jks&ftpClient.trustStore.password=password")
.to("bean:foo");
Filter using org.apache.camel.component.file.GenericFileFilter
Camel supports pluggable filtering strategies. This strategy it to use the build in
org.apache.camel.component.file.GenericFileFilter in Java. You can then
configure the endpoint with such a filter to skip certain filters before being processed.
In the sample we have built our own filter that only accepts files starting with report in the
filename.
public class MyFileFilter implements GenericFileFilter {
public boolean accept(GenericFile file) {
// we only want report files
return file.getFileName().startsWith("report");
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}
}
And then we can configure our route using the filter attribute to reference our filter (using #
notation) that we have defined in the spring XML file:
Filtering using ANT path matcher
The ANT path matcher is a filter that is shipped out-of-the-box in the camel-spring jar. So
you need to depend on camel-spring if you are using Maven.
The reason is that we leverage Spring's AntPathMatcher to do the actual matching.
The file paths are matched with the following rules:
▪ ? matches one character
▪ * matches zero or more characters
▪ ** matches zero or more directories in a path
The sample below demonstrates how to use it:
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Debug logging
This component has log level TRACE that can be helpful if you have problems.
See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
File2
CAMEL COMPONENTS FOR GOOGLE APP ENGINE
The Camel components for Google App Engine (GAE) are part of the camel-gae project and
provide connectivity to GAE's cloud computing services. They make the GAE cloud computing
environment accessible to applications via Camel interfaces. Following this pattern for other
cloud computing environments could make it easier to port Camel applications from one cloud
computing provider to another. The following table lists the cloud computing services provided
by Google and the supporting Camel components. The documentation of each component can
be found by following the link in the Camel Component column.
GAE
service
Camel
component
Component description
URL fetch
service
ghttp
Provides connectivity to the GAE URL fetch service but can also be used to receive messages from servlets.
Task queueing
service
gtask
Supports asynchronous message processing on GAE by using the task queueing service as message queue.
Mail service
gmail
Supports sending of emails via the GAE mail service. Receiving mails is not supported yet but will be added later.
Memcache
service
Ê
Not supported yet.
XMPP service
Ê
Not supported yet.
Images service
Ê
Not supported yet.
Datastore
service
Ê
Not supported yet.
Accounts
service
gauth
glogin
These components interact with the Google Accounts API for authentication and authorization. Google Accounts is not specific to
Google App Engine but is often used by GAE applications for implementing security. The gauth component is used by web
applications to implement a Google-specific OAuth consumer. This component can also be used to OAuth-enable non-GAE web
applications. The glogin component is used by Java clients (outside GAE) for programmatic login to GAE applications. For instructions
how to protect GAE applications against unauthorized access refer to the Security for Camel GAE applications page.
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Tutorials
• A good starting point for using Camel on GAE is the Tutorial for Camel
on Google App Engine
• The OAuth tutorial demonstrates how to implement OAuth in web
applications.
Camel context
Setting up a SpringCamelContext on Google App Engine differs between Camel 2.1 and
higher versions. The problem is that usage of the Camel-specific Spring configuration XML
schema from the http://camel.apache.org/schema/spring namespace requires
JAXB and Camel 2.1 depends on a Google App Engine SDK version that doesn't support JAXB
yet. This limitation has been removed since Camel 2.2.
JMX must be disabled in any case because the javax.management package isn't on the
App Engine JRE whitelist.
Camel 2.1
camel-gae 2.1 comes with the following CamelContext implementations.
• org.apache.camel.component.gae.context.GaeDefaultCamelContext
(extends org.apache.camel.impl.DefaultCamelContext)
• org.apache.camel.component.gae.context.GaeSpringCamelContext
(extends org.apache.camel.spring.SpringCamelContext)
Both disable JMX before startup. The GaeSpringCamelContext additionally provides
setter methods adding route builders as shown in the next example.
Listing 67. appctx.xml
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Alternatively, use the routeBuilders property of the GaeSpringCamelContext for
setting a list of route builders. Using this approach, a SpringCamelContext can be
configured on GAE without the need for JAXB.
Camel 2.2 or higher
With Camel 2.2 or higher, applications can use the http://camel.apache.org/
schema/spring namespace for configuring a SpringCamelContext but still need to
disable JMX. Here's an example.
Listing 68. appctx.xml
The web.xml
Running Camel on GAE requires usage of the CamelHttpTransportServlet from
camel-servlet. The following example shows how to configure this servlet together with a
Spring application context XML file.
Listing 69. web.xml
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CamelServletorg.apache.camel.component.servlet.CamelHttpTransportServletcontextConfigLocationappctx.xmlCamelServlet/camel/*CamelServlet/worker/*
The location of the Spring application context XML file is given by the
contextConfigLocation init parameter. The appctx.xml file must be on the classpath.
The servlet mapping makes the Camel application accessible under
http://.appspot.com/camel/... when deployed to Google App Engine
where must be replaced by a real GAE application name. The second servlet
mapping is used internally by the task queueing service for background processing via web
hooks. This mapping is relevant for the gtask component and is explained there in more detail.
HAZELCAST COMPONENT
Available as of Camel 2.7
The hazelcast: component allows you to work with the Hazelcast distributed data grid /
cache. Hazelcast is a in memory data grid, entirely written in Java (single jar). It offers a great
palette of different data stores like map, multi map (same key, n values), queue, list and atomic
number. The main reason to use Hazelcast is its simple cluster support. If you have enabled
multicast on your network you can run a cluster with hundred nodes with no extra
configuration. Hazelcast can simply configured to add additional features like n copies between
nodes (default is 1), cache persistence, network configuration (if needed), near cache, enviction
and so on. For more information consult the Hazelcast documentation on
http://www.hazelcast.com/documentation.jsp.
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Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-hazelcastx.x.x
URI format
hazelcast:[ map | multimap | queue | seda | set | atomicvalue |
instance]:cachename[?options]
Sections
1.
2.
3.
4.
5.
6.
7.
Usage of map
Usage of multimap
Usage of queue
Usage of list
Usage of seda
Usage of atomic number
Usage of cluster support (instance)
Usage of Map
map cache producer - to("hazelcast:map:foo")
If you want to store a value in a map you can use the map cache producer. The map cache
producer provides 5 operations (put, get, update, delete, query). For the first 4 you have to
provide the operation inside the "hazelcast.operation.type" header variable. In Java DSL you can
use the constants from
org.apache.camel.component.hazelcast.HazelcastConstants.
Header Variables for the request message:
Name
Type
Description
hazelcast.operation.type
String
valid values are: put, delete, get, update,
query
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You have to use the second prefix to define which type of data store you want to
use.
hazelcast.objectId
String
the object id to store / find your object
inside the cache (not needed for the query
operation)
Name
Type
Description
CamelHazelcastOperationType
String
valid values are: put, delete, get,
update, query Version 2.8
String
the object id to store / find your
object inside the cache (not needed
for the query operation) Version
2.8
CamelHazelcastObjectId
You can call the samples with:
template.sendBodyAndHeader("direct:[put|get|update|delete|query]", "my-foo",
HazelcastConstants.OBJECT_ID, "4711");
Sample for put:
Java DSL:
from("direct:put")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.PUT_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
put
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Header variables have changed in Camel 2.8
Sample for get:
Java DSL:
from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.GET_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.to("seda:out");
Spring DSL:
get
Sample for update:
Java DSL:
from("direct:update")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.UPDATE_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
update
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Sample for delete:
Java DSL:
from("direct:delete")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.DELETE_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
delete
Sample for query
Java DSL:
from("direct:query")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.QUERY_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.to("seda:out");
Spring DSL:
query
For the query operation Hazelcast offers a SQL like syntax to query your distributed map.
String q1 = "bar > 1000";
template.sendBodyAndHeader("direct:query", null, HazelcastConstants.QUERY, q1);
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map cache consumer - from("hazelcast:map:foo")
Hazelcast provides event listeners on their data grid. If you want to be notified if a cache will be
manipulated, you can use the map consumer. There're 4 events: put, update, delete and
envict. The event type will be stored in the "hazelcast.listener.action" header variable.
The map consumer provides some additional information inside these variables:
Header Variables inside the response message:
Name
Type
Description
hazelcast.listener.time
Long
time of the event in millis
hazelcast.listener.type
String
the map consumer sets here
"cachelistener"
hazelcast.listener.action
String
type of event - here added, updated,
envicted and removed
hazelcast.objectId
String
the oid of the object
hazelcast.cache.name
String
the name of the cache - e.g. "foo"
hazelcast.cache.type
String
the type of the cache - here map
Name
Type
Description
CamelHazelcastListenerTime
Long
time of the event in millis Version
2.8
CamelHazelcastListenerType
String
the map consumer sets here
"cachelistener" Version 2.8
CamelHazelcastListenerAction
String
type of event - here added,
updated, envicted and
removed. Version 2.8
CamelHazelcastObjectId
String
the oid of the object Version 2.8
CamelHazelcastCacheName
String
the name of the cache - e.g. "foo"
Version 2.8
CamelHazelcastCacheType
String
the type of the cache - here map
Version 2.8
The object value will be stored within put and update actions inside the message body.
Here's a sample:
fromF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.log("object...")
.choice()
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.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ENVICTED))
.log("...envicted")
.to("mock:envicted")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.UPDATED))
.log("...updated")
.to("mock:updated")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.REMOVED))
.log("...removed")
.to("mock:removed")
.otherwise()
.log("fail!");
Usage of Multi Map
multimap cache producer - to("hazelcast:multimap:foo")
A multimap is a cache where you can store n values to one key. The multimap producer
provides 4 operations (put, get, removevalue, delete).
Header Variables for the request message:
629
Name
Type
Description
hazelcast.operation.type
String
valid values are: put, get, removevalue,
delete
hazelcast.objectId
String
the object id to store / find your object
inside the cache
Name
Type
Description
CamelHazelcastOperationType
String
valid values are: put, delete, get,
update, query Available as of
Camel 2.8
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CamelHazelcastObjectId
String
the object id to store / find your
object inside the cache (not needed
for the query operation) Version
2.8
You can call the samples with:
template.sendBodyAndHeader("direct:[put|get|update|delete|query]", "my-foo",
HazelcastConstants.OBJECT_ID, "4711");
Sample for put:
Java DSL:
from("direct:put")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.PUT_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
put
Sample for get:
Java DSL:
from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.GET_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.to("seda:out");
Spring DSL:
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get
Sample for update:
Java DSL:
from("direct:update")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.UPDATE_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
update
Sample for delete:
Java DSL:
from("direct:delete")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.DELETE_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX);
Spring DSL:
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delete
Sample for query
Java DSL:
from("direct:query")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.QUERY_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.to("seda:out");
Spring DSL:
query
For the query operation Hazelcast offers a SQL like syntax to query your distributed map.
String q1 = "bar > 1000";
template.sendBodyAndHeader("direct:query", null, HazelcastConstants.QUERY, q1);
map cache consumer - from("hazelcast:map:foo")
Hazelcast provides event listeners on their data grid. If you want to be notified if a cache will be
manipulated, you can use the map consumer. There're 4 events: put, update, delete and
envict. The event type will be stored in the "hazelcast.listener.action" header variable.
The map consumer provides some additional information inside these variables:
Header Variables inside the response message:
Name
Type
Description
hazelcast.listener.time
Long
time of the event in millis
hazelcast.listener.type
String
the map consumer sets here
"cachelistener"
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hazelcast.listener.action
String
type of event - here added, updated,
envicted and removed
hazelcast.objectId
String
the oid of the object
hazelcast.cache.name
String
the name of the cache - e.g. "foo"
hazelcast.cache.type
String
the type of the cache - here map
Name
Type
Description
CamelHazelcastListenerTime
Long
time of the event in millis Version
2.8
CamelHazelcastListenerType
String
the map consumer sets here
"cachelistener" Version 2.8
CamelHazelcastListenerAction
String
type of event - here added,
updated, envicted and
removed. Version 2.8
CamelHazelcastObjectId
String
the oid of the object Version 2.8
CamelHazelcastCacheName
String
the name of the cache - e.g. "foo"
Version 2.8
CamelHazelcastCacheType
String
the type of the cache - here map
Version 2.8
The object value will be stored within put and update actions inside the message body.
Here's a sample:
fromF("hazelcast:%sfoo", HazelcastConstants.MAP_PREFIX)
.log("object...")
.choice()
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ENVICTED))
.log("...envicted")
.to("mock:envicted")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.UPDATED))
.log("...updated")
.to("mock:updated")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.REMOVED))
.log("...removed")
.to("mock:removed")
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.otherwise()
.log("fail!");
Usage of Multi Map
multimap cache producer - to("hazelcast:multimap:foo")
A multimap is a cache where you can store n values to one key. The multimap producer
provides 4 operations (put, get, removevalue, delete).
Header Variables for the request message:
Name
Type
Description
hazelcast.operation.type
String
valid values are: put, get, removevalue,
delete
hazelcast.objectId
String
the object id to store / find your object
inside the cache
Name
Type
Description
CamelHazelcastOperationType
String
valid values are: put, get, removevalue,
delete Version 2.8
CamelHazelcastObjectId
String
the object id to store / find your
object inside the cache Version 2.8
Sample for put:
Java DSL:
from("direct:put")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.PUT_OPERATION))
.to(String.format("hazelcast:%sbar", HazelcastConstants.MULTIMAP_PREFIX));
Spring DSL:
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put
Sample for removevalue:
Java DSL:
from("direct:removevalue")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.REMOVEVALUE_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.MULTIMAP_PREFIX);
Spring DSL:
removevalue
To remove a value you have to provide the value you want to remove inside the message body.
If you have a multimap object {key: "4711" values: { "my-foo", "my-bar"}} you
have to put "my-foo" inside the message body to remove the "my-foo" value.
Sample for get:
Java DSL:
from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.GET_OPERATION))
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.toF("hazelcast:%sbar", HazelcastConstants.MULTIMAP_PREFIX)
.to("seda:out");
Spring DSL:
get
Sample for delete:
Java DSL:
from("direct:delete")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.DELETE_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.MULTIMAP_PREFIX);
Spring DSL:
delete
you can call them in your test class with:
template.sendBodyAndHeader("direct:[put|get|removevalue|delete]", "my-foo",
HazelcastConstants.OBJECT_ID, "4711");
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multimap cache consumer - from("hazelcast:multimap:foo")
For the multimap cache this component provides the same listeners / variables as for the map
cache consumer (except the update and enviction listener). The only difference is the
multimap prefix inside the URI. Here is a sample:
fromF("hazelcast:%sbar", HazelcastConstants.MULTIMAP_PREFIX)
.log("object...")
.choice()
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
//.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ENVICTED))
//
.log("...envicted")
//
.to("mock:envicted")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.REMOVED))
.log("...removed")
.to("mock:removed")
.otherwise()
.log("fail!");
Header Variables inside the response message:
Name
Type
Description
hazelcast.listener.time
Long
time of the event in millis
hazelcast.listener.type
String
the map consumer sets here
"cachelistener"
hazelcast.listener.action
String
type of event - here added and
removed (and soon envicted)
hazelcast.objectId
String
the oid of the object
hazelcast.cache.name
String
the name of the cache - e.g. "foo"
hazelcast.cache.type
String
the type of the cache - here multimap
Eviction will be added as feature, soon (this is a Hazelcast issue).
637
Name
Type
Description
CamelHazelcastListenerTime
Long
time of the event in millis Version
2.8
CamelHazelcastListenerType
String
the map consumer sets here
"cachelistener" Version 2.8
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Header variables have changed in Camel 2.8
CamelHazelcastListenerAction
String
type of event - here added and
removed (and soon envicted)
Version 2.8
CamelHazelcastObjectId
String
the oid of the object Version 2.8
CamelHazelcastCacheName
String
the name of the cache - e.g. "foo"
Version 2.8
CamelHazelcastCacheType
String
the type of the cache - here
multimap Version 2.8
Usage of Queue
Queue producer Ð to(Òhazelcast:queue:fooÓ)
The queue producer provides 6 operations (add, put, poll, peek, offer, removevalue).
Sample for add:
from("direct:add")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.ADD_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
Sample for put:
from("direct:put")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.PUT_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
Sample for poll:
from("direct:poll")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.POLL_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
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Sample for peek:
from("direct:peek")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.PEEK_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
Sample for offer:
from("direct:offer")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.OFFER_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
Sample for removevalue:
from("direct:removevalue")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.REMOVEVALUE_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.QUEUE_PREFIX);
Queue consumer Ð from(Òhazelcast:queue:fooÓ)
The queue consumer provides 2 operations (add, remove).
fromF("hazelcast:%smm", HazelcastConstants.QUEUE_PREFIX)
.log("object...")
.choice()
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.REMOVED))
.log("...removed")
.to("mock:removed")
.otherwise()
.log("fail!");
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Usage of List
List producer Ð to(Òhazelcast:list:fooÓ)
The list producer provides 4 operations (add, set, get, removevalue).
Sample for add:
from("direct:add")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.ADD_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.LIST_PREFIX);
Sample for get:
from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.GET_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.LIST_PREFIX)
.to("seda:out");
Sample for setvalue:
from("direct:set")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.SETVALUE_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.LIST_PREFIX);
Sample for removevalue:
from("direct:removevalue")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.REMOVEVALUE_OPERATION))
.toF("hazelcast:%sbar", HazelcastConstants.LIST_PREFIX);
List consumer Ð from(Òhazelcast:list:fooÓ)
The list consumer provides 2 operations (add, remove).
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Please note that set,get and removevalue and not yet supported by hazelcast, will be
added in the future..
fromF("hazelcast:%smm", HazelcastConstants.LIST_PREFIX)
.log("object...")
.choice()
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.REMOVED))
.log("...removed")
.to("mock:removed")
.otherwise()
.log("fail!");
Usage of SEDA
SEDA component differs from the rest components provided. It implements a work-queue in
order to support asynchronous SEDA architectures, similar to the core "SEDA" component.
SEDA producer Ð to(Òhazelcast:seda:fooÓ)
The SEDA producer provides no operations. You only send data to the specified queue.
Name
default
value
Description
transferExchange
false
Camel 2.8.0: if set to true the whole Exchange will
be transfered. If header or body contains not
serializable objects, they will be skipped.
Java DSL :
from("direct:foo")
.to("hazelcast:seda:foo");
Spring DSL :
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SEDA consumer Ð from(Òhazelcast:seda:fooÓ)
The SEDA consumer provides no operations. You only retrieve data from the specified queue.
Java DSL :
from("hazelcast:seda:foo")
.to("mock:result");
Spring DSL:
Usage of Atomic Number
atomic number producer - to("hazelcast:atomicnumber:foo")
An atomic number is an object that simply provides a grid wide number (long). The operations
for this producer are setvalue (set the number with a given value), get, increase (+1), decrease
(-1) and destroy.
Header Variables for the request message:
Name
Type
Description
hazelcast.operation.type
String
valid values are: setvalue, get, increase,
decrease, destroy
Name
Type
Description
CamelHazelcastOperationType
String
valid values are: setvalue, get, increase,
decrease, destroy Available as of
Camel version 2.8
Sample for set:
Java DSL:
from("direct:set")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.SETVALUE_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.ATOMICNUMBER_PREFIX);
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There is no consumer for this endpoint!
Header variables have changed in Camel 2.8
Spring DSL:
setvalue
Provide the value to set inside the message body (here the value is 10):
template.sendBody("direct:set", 10);
Sample for get:
Java DSL:
from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastConstants.GET_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.ATOMICNUMBER_PREFIX);
Spring DSL:
get
You can get the number with long body =
template.requestBody("direct:get", null, Long.class);.
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Sample for increment:
Java DSL:
from("direct:increment")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.INCREMENT_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.ATOMICNUMBER_PREFIX);
Spring DSL:
increment
The actual value (after increment) will be provided inside the message body.
Sample for decrement:
Java DSL:
from("direct:decrement")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.DECREMENT_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.ATOMICNUMBER_PREFIX);
Spring DSL:
decrement
The actual value (after decrement) will be provided inside the message body.
Sample for destroy
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There's a bug inside Hazelcast. So this feature may not work properly. Will be fixed
in 1.9.3.
Java DSL:
from("direct:destroy")
.setHeader(HazelcastConstants.OPERATION,
constant(HazelcastConstants.DESTROY_OPERATION))
.toF("hazelcast:%sfoo", HazelcastConstants.ATOMICNUMBER_PREFIX);
Spring DSL:
destroy
cluster support
instance consumer - from("hazelcast:instance:foo")
Hazelcast makes sense in one single "server node", but it's extremly powerful in a clustered
environment. The instance consumer fires if a new cache instance will join or leave the cluster.
Here's a sample:
fromF("hazelcast:%sfoo", HazelcastConstants.INSTANCE_PREFIX)
.log("instance...")
.choice()
.when(header(HazelcastConstants.LISTENER_ACTION).isEqualTo(HazelcastConstants.ADDED))
.log("...added")
.to("mock:added")
.otherwise()
.log("...removed")
.to("mock:removed");
Each event provides the following information inside the message header:
Header Variables inside the response message:
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This endpoint provides no producer!
Name
Type
Description
hazelcast.listener.time
Long
time of the event in millis
hazelcast.listener.type
String
the map consumer sets here
"instancelistener"
hazelcast.listener.action
String
type of event - here added or
removed
hazelcast.instance.host
String
host name of the instance
hazelcast.instance.port
Integer
port number of the instance
Name
Type
Description
CamelHazelcastListenerTime
Long
time of the event in millis
Version 2.8
CamelHazelcastListenerType
String
the map consumer sets here
"instancelistener" Version 2.8
CamelHazelcastListenerActionn
String
type of event - here added or
removed. Version 2.8
CamelHazelcastInstanceHost
String
host name of the instance
Version 2.8
CamelHazelcastInstancePort
Integer
port number of the instance
Version 2.8
HDFS COMPONENT
Available as of Camel 2.8
The hdfs component enables you to read and write messages from/to an HDFS file system.
HDFS is the distributed file system at the heart of Hadoop.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-hadoopx.x.x
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URI format
hdfs://hostname[:port][/path][?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
The path is treated in the following way:
1. as a consumer, if it's a file, it just reads the file, otherwise if it represents a directory it
scans all the file under the path satisfying the configured pattern. All the files under
that directory must be of the same type.
2. as a producer, if at least one split strategy is defined, the path is considered a
directory and under that directory the producer creates a different file per split
named seg0, seg1, seg2, etc.
Options
647
Name
Default Value
Description
overwrite
true
The file can be overwritten
bufferSize
4096
The buffer size used by HDFS
replication
3
The HDFS replication factor
blockSize
67108864
The size of the HDFS blocks
fileType
NORMAL_FILE
It can be SEQUENCE_FILE, MAP_FILE, ARRAY_FILE, or BLOOMMAP_FILE, see Hadoop
fileSystemType
HDFS
It can be LOCAL for local filesystem
keyType
NULL
The type for the key in case of sequence or map files. See below.
valueType
TEXT
The type for the key in case of sequence or map files. See below.
splitStrategy
Ê
A string describing the strategy on how to split the file based on different criteria. See below.
openedSuffix
opened
When a file is opened for reading/writing the file is renamed with this suffix to avoid to read it during the writing phase.
readSuffix
read
Once the file has been read is renamed with this suffix to avoid to read it again.
initialDelay
0
For the consumer, how much to wait (milliseconds) before to start scanning the directory.
delay
0
The interval (milliseconds) between the directory scans.
pattern
*
The pattern used for scanning the directory
chunkSize
4096
When reading a normal file, this is split into chunks producing a message per chunk.
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KeyType and ValueType
• NULL it means that the key or the value is absent
• BYTE for writing a byte, the java Byte class is mapped into a BYTE
• BYTES for writing a sequence of bytes. It maps the java ByteBuffer class
• INT for writing java integer
• FLOAT for writing java float
• LONG for writing java long
• DOUBLE for writing java double
• TEXT for writing java strings
BYTES is also used with everything else, for example, in Camel a file is sent around as an
InputStream, int this case is written in a sequence file or a map file as a sequence of bytes.
Splitting Strategy
In the current version of Hadoop opening a file in append mode is disabled since it's not enough
reliable. So, for the moment, it's only possible to create new files. The Camel HDFS endpoint
tries to solve this problem in this way:
• If the split strategy option has been defined, the actual file name will become a
directory name and a /seg0 will be initially created.
• Every time a splitting condition is met a new file is created with name /segN where N is 1, 2, 3, etc.
The splitStrategy option is defined as a string with the following syntax:
splitStrategy=:,:,*
where can be:
• BYTES a new file is created, and the old is closed when the number of written bytes is
more than
• MESSAGES a new file is created, and the old is closed when the number of written
messages is more than
• IDLE a new file is created, and the old is closed when no writing happened in the last
milliseconds
for example:
hdfs://localhost/tmp/simple-file?splitStrategy=IDLE:1000,BYTES:5
it means: a new file is created either when it has been idle for more than 1 second or if more
than 5 bytes have been written. So, running hadoop fs -ls /tmp/simple-file you'll
find the following files seg0, seg1, seg2, etc
Using this component in OSGi
This component is fully functional in an OSGi environment however, it requires some actions
from the user. Hadoop uses the thread context class loader in order to load resources. Usually,
the thread context classloader will be the bundle class loader of the bundle that contains the
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routes. So, the default configuration files need to be visible from the bundle class loader. A
typical way to deal with it is to keep a copy of core-default.xml in your bundle root. That file
can be found in the hadoop-common.jar.
HIBERNATE COMPONENT
The hibernate: component allows you to work with databases using Hibernate as the object
relational mapping technology to map POJOs to database tables. The camel-hibernate
library is provided by the Camel Extra project which hosts all *GPL related components for
Camel.
Sending to the endpoint
Sending POJOs to the hibernate endpoint inserts entities into the database. The body of the
message is assumed to be an entity bean that you have mapped to a relational table using the
hibernate .hbm.xml files.
If the body does not contain an entity bean, use a Message Translator in front of the
endpoint to perform the necessary conversion first.
Consuming from the endpoint
Consuming messages removes (or updates) entities in the database. This allows you to use a
database table as a logical queue; consumers take messages from the queue and then delete/
update them to logically remove them from the queue.
If you do not wish to delete the entity when it has been processed, you can specify
consumeDelete=false on the URI. This will result in the entity being processed each poll.
If you would rather perform some update on the entity to mark it as processed (such as to
exclude it from a future query) then you can annotate a method with @Consumed which will
be invoked on your entity bean when the entity bean is consumed.
URI format
hibernate:[entityClassName][?options]
For sending to the endpoint, the entityClassName is optional. If specified it is used to help
use the Type Conversion to ensure the body is of the correct type.
For consuming the entityClassName is mandatory.
You can append query options to the URI in the following format,
?option=value&option=value&...
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Note that Camel also ships with a JPA component. The JPA component abstracts
from the underlying persistence provider and allows you to work with Hibernate,
OpenJPA or EclipseLink.
Options
Name
Default
Value
Description
entityType
entityClassName
Is the provided entityClassName from the URI.
consumeDelete
true
Option for HibernateConsumer only. Specifies whether or not the entity is deleted after it is consumed.
consumeLockEntity
true
Option for HibernateConsumer only. Specifies whether or not to use exclusive locking of each entity while processing
the results from the pooling.
flushOnSend
true
Option for HibernateProducer only. Flushes the EntityManager after the entity bean has been persisted.
maximumResults
-1
Option for HibernateConsumer only. Set the maximum number of results to retrieve on the Query.
consumer.delay
500
Option for HibernateConsumer only. Delay in millis between each poll.
consumer.initialDelay
1000
Option for HibernateConsumer only. Millis before polling starts.
consumer.userFixedDelay
false
Option for HibernateConsumer only. Set to true to use fixed delay between polls, otherwise fixed rate is used. See
ScheduledExecutorService in JDK for details.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
HL7 COMPONENT
The hl7 component is used for working with the HL7 MLLP protocol and the HL7 model using
the HAPI library.
This component supports the following:
▪ HL7 MLLP codec for Mina
▪ Agnostic data format using either plain String objects or HAPI HL7 model objects.
▪ Type Converter from/to HAPI and String
▪ HL7 DataFormat using HAPI library
▪ Even more easy-of-use as its integrated well with the camel-mina component.
Maven users will need to add the following dependency to their pom.xml for this component:
org.apache.camelcamel-hl7x.x.x
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HL7 MLLP protocol
HL7 is often used with the HL7 MLLP protocol that is a text based TCP socket based protocol.
This component ships with a Mina Codec that conforms to the MLLP protocol so you can easily
expose a HL7 listener that accepts HL7 requests over the TCP transport.
To expose a HL7 listener service we reuse the existing camel-mina component where we
just use the HL7MLLPCodec as codec.
The HL7 MLLP codec has the following options:
Name
Default
Value
Description
startByte
0x0b
The start byte spanning the HL7 payload. Is the HL7 default value of 0x0b (11 decimal).
endByte1
0x1c
The first end byte spanning the HL7 payload. Is the HL7 default value of 0x1c (28 decimal).
endByte2
0x0d
The 2nd end byte spanning the HL7 payload. Is the HL7 default value of 0x0d (13 decimal).
charset
JVM Default
The encoding (is a charset name) to use for the codec. If not provided, Camel will use the JVM default Charset.
convertLFtoCR
true
Will convert \n to \r (0x0d, 13 decimal) as HL7 usually uses \r as segment terminators. The HAPI library requires the use
of \r.
validate
true
Camel 2.0: Whether HAPI Parser should validate or not.
Exposing a HL7 listener
In our Spring XML file, we configure an endpoint to listen for HL7 requests using TCP:
Notice we configure it to use camel-mina with TCP on the localhost on port 8888. We
use sync=true to indicate that this listener is synchronous and therefore will return a HL7
response to the caller. Then we setup mina to use our HL7 codec with codec=#hl7codec.
Notice that hl7codec is just a Spring bean ID, so we could have named it
mygreatcodecforhl7 or whatever. The codec is also set up in the Spring XML file:
And here we configure the charset encoding to use, and iso-8859-1 is commonly used.
The endpoint hl7listener can then be used in a route as a consumer, as this java DSL
example illustrates:
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from("hl7socket").to("patientLookupService");
This is a very simple route that will listen for HL7 and route it to a service named
patientLookupService that is also a Spring bean ID we have configured in the Spring XML
as:
And another powerful feature of Camel is that we can have our busines logic in POJO classes
that is not at all tied to Camel as shown here:
public class PatientLookupService {
public Message lookupPatient(Message input) throws HL7Exception {
QRD qrd = (QRD)input.get("QRD");
String patientId = qrd.getWhoSubjectFilter(0).getIDNumber().getValue();
// find patient data based on the patient id and create a HL7 model object
with the response
Message response = ... create and set response data
return response
}
Notice that this class is just using imports from the HAPI library and none from Camel.
HL7 Model using java.lang.String
The HL7MLLP codec uses plain String as data format. And Camel uses Type Converter to
convert from/to strings to the HAPI HL7 model objects. However, you can use the plain
String objects if you prefer, for instance if you need to parse the data yourself.
See samples for such an example.
HL7 Model using HAPI
The HL7 model is Java objects from the HAPI library. Using this library, we can encode and
decode from the EDI format (ER7) that is mostly used with HL7.
With this model you can code with Java objects instead of the EDI based HL7 format that can
be hard for humans to read and understand.
The ER7 sample below is a request to lookup a patient with the patient ID, 0101701234.
MSH|^~\\&|MYSENDER|MYRECEIVER|MYAPPLICATION||200612211200||QRY^A19|1234|P|2.4
QRD|200612211200|R|I|GetPatient|||1^RD|0101701234|DEM||
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Using the HL7 model we can work with the data as a
ca.uhn.hl7v2.model.Message.Message object.
To retrieve the patient ID for the patient in the ER7 above, you can do this in java code:
Message msg = exchange.getIn().getBody(Message.class);
QRD qrd = (QRD)msg.get("QRD");
String patientId = qrd.getWhoSubjectFilter(0).getIDNumber().getValue();
Camel has built-in type converters, so when this operation is invoked:
Message msg = exchange.getIn().getBody(Message.class);
Camel will convert the received HL7 data from String to Message. This is powerful when
combined with the HL7 listener, then you as the end-user don't have to work with byte[],
String or any other simple object formats. You can just use the HAPI HL7 model objects.
HL7 DataFormat
The HL7 component ships with a HL7 data format that can be used to format between
String and HL7 model objects.
▪ marshal = from Message to byte stream (can be used when returning as response
using the HL7 MLLP codec)
▪ unmarshal = from byte stream to Message (can be used when receiving streamed
data from the HL7 MLLP
To use the data format, simply instantiate an instance and invoke the marhsal or unmarshl
operation in the route builder:
DataFormat hl7 = new HL7DataFormat();
...
from("direct:hl7in").marshal(hl7).to("jms:queue:hl7out");
In the sample above, the HL7 is marshalled from a HAPI Message object to a byte stream and
put on a JMS queue.
The next example is the opposite:
DataFormat hl7 = new HL7DataFormat();
...
from("jms:queue:hl7out").unmarshal(hl7).to("patientLookupService");
Here we unmarshal the byte stream into a HAPI Message object that is passed to our patient
lookup service.
Notice there is a shorthand syntax in Camel for well-known data formats that is commonly
used.
Then you don't need to create an instance of the HL7DataFormat object:
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from("direct:hl7in").marshal().hl7().to("jms:queue:hl7out");
from("jms:queue:hl7out").unmarshal().hl7().to("patientLookupService");
Message Headers
The unmarshal operation adds these MSH fields as headers on the Camel message:
Camel 1.x
Key
MSH field
Example
hl7.msh.sendingApplication
MSH-3
MYSERVER
hl7.msh.sendingFacility
MSH-4
MYSERVERAPP
hl7.msh.receivingApplication
MSH-5
MYCLIENT
hl7.msh.receivingFacility
MSH-6
MYCLIENTAPP
hl7.msh.timestamp
MSH-7
20071231235900
hl7.msh.security
MSH-8
null
hl7.msh.messageType
MSH-9-1
ADT
hl7.msh.triggerEvent
MSH-9-2
A01
hl7.msh.messageControl
MSH-10
1234
hl7.msh.processingId
MSH-11
P
hl7.msh.versionId
MSH-12
2.4
Key
MSH field
Example
CamelHL7SendingApplication
MSH-3
MYSERVER
CamelHL7SendingFacility
MSH-4
MYSERVERAPP
CamelHL7ReceivingApplication
MSH-5
MYCLIENT
CamelHL7ReceivingFacility
MSH-6
MYCLIENTAPP
CamelHL7Timestamp
MSH-7
20071231235900
CamelHL7Security
MSH-8
null
CamelHL7MessageType
MSH-9-1
ADT
CamelHL7TriggerEvent
MSH-9-2
A01
CamelHL7MessageControl
MSH-10
1234
CamelHL7ProcessingId
MSH-11
P
CamelHL7VersionId
MSH-12
2.4
Camel 2.0
All headers are String types. If a header value is missing, its value is null.
Options
The HL7 Data Format supports the following options:
Option
Default
Description
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validate
true
Camel 2.0: Whether the HAPI Parser should validate.
Dependencies
To use HL7 in your camel routes you need to add a dependency on camel-hl7, which
implements this data format.
If you use Maven, you could just add the following to your pom.xml, substituting the
version number for the latest & greatest release (see the download page for the latest
versions).
org.apache.camelcamel-hl72.2.0
Since HAPI 0.6, the library has been split into a base library and several structures libraries, one
for each HL7v2 message version:
• v2.1 structures library
• v2.2 structures library
• v2.3 structures library
• v2.3.1 structures library
• v2.4 structures library
• v2.5 structures library
• v2.5.1 structures library
• v2.6 structures library
By default camel-hl7 only references the HAPI base library. Applications are responsible for
including structures libraries themselves. For example, if a application works with HL7v2
message versions 2.4 and 2.5 then the following dependencies must be added:
ca.uhn.hapihapi-structures-v241.0ca.uhn.hapihapi-structures-v251.0
OSGi
An OSGi bundle containing the base library, all structures libraries and required dependencies
(on the bundle classpath) can be downloaded from the HAPI Maven repository as well.
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ca.uhn.hapihapi-osgi-base1.0.1
Samples
In the following example we send a HL7 request to a HL7 listener and retrieves a response. We
use plain String types in this example:
String line1 =
"MSH|^~\\&|MYSENDER|MYRECEIVER|MYAPPLICATION||200612211200||QRY^A19|1234|P|2.4";
String line2 = "QRD|200612211200|R|I|GetPatient|||1^RD|0101701234|DEM||";
StringBuilder in = new StringBuilder();
in.append(line1);
in.append("\n");
in.append(line2);
String out =
(String)template.requestBody("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec",
in.toString());
In the next sample, we want to route HL7 requests from our HL7 listener to our business logic.
We have our business logic in a plain POJO that we have registered in the registry as
hl7service = for instance using Spring and letting the bean id = hl7service.
Our business logic is a plain POJO only using the HAPI library so we have these operations
defined:
public class MyHL7BusinessLogic {
// This is a plain POJO that has NO imports whatsoever on Apache Camel.
// its a plain POJO only importing the HAPI library so we can much easier work
with the HL7 format.
public Message handleA19(Message msg) throws Exception {
// here you can have your business logic for A19 messages
assertTrue(msg instanceof QRY_A19);
// just return the same dummy response
return createADR19Message();
}
public Message handleA01(Message msg) throws Exception {
// here you can have your business logic for A01 messages
assertTrue(msg instanceof ADT_A01);
// just return the same dummy response
return createADT01Message();
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}
}
Then we set up the Camel routes using the RouteBuilder as follows:
DataFormat hl7 = new HL7DataFormat();
// we setup or HL7 listener on port 8888 (using the hl7codec) and in sync mode so we
can return a response
from("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec")
// we use the HL7 data format to unmarshal from HL7 stream to the HAPI Message
model
// this ensures that the camel message has been enriched with hl7 specific headers
to
// make the routing much easier (see below)
.unmarshal(hl7)
// using choice as the content base router
.choice()
// where we choose that A19 queries invoke the handleA19 method on our
hl7service bean
.when(header("CamelHL7TriggerEvent").isEqualTo("A19"))
.beanRef("hl7service", "handleA19")
.to("mock:a19")
// and A01 should invoke the handleA01 method on our hl7service bean
.when(header("CamelHL7TriggerEvent").isEqualTo("A01")).to("mock:a01")
.beanRef("hl7service", "handleA01")
.to("mock:a19")
// other types should go to mock:unknown
.otherwise()
.to("mock:unknown")
// end choice block
.end()
// marhsal response back
.marshal(hl7);
Notice that we use the HL7 DataFormat to enrich our Camel Message with the MSH fields
preconfigued on the Camel Message. This lets us much more easily define our routes using the
fluent builders.
If we do not use the HL7 DataFormat, then we do not gains these headers and we must resort
to a different technique for computing the MSH trigger event (= what kind of HL7 message it
is). This is a big advantage of the HL7 DataFormat over the plain HL7 type converters.
Sample using plain String objects
In this sample we use plain String objects as the data format, that we send, process and
receive. As the sample is part of a unit test, there is some code for assertions, but you should
be able to understand what happens. First we send the plain string, Hello World, to the
HL7MLLPCodec and receive the response as a plain string, Bye World.
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MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedBodiesReceived("Bye World");
// send plain hello world as String
Object out =
template.requestBody("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec", "Hello
World");
assertMockEndpointsSatisfied();
// and the response is also just plain String
assertEquals("Bye World", out);
Here we process the incoming data as plain String and send the response also as plain String:
from("mina:tcp://127.0.0.1:8888?sync=true&codec=#hl7codec")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
// use plain String as message format
String body = exchange.getIn().getBody(String.class);
assertEquals("Hello World", body);
// return the response as plain string
exchange.getOut().setBody("Bye World");
}
})
.to("mock:result");
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
HTTP COMPONENT
The http: component provides HTTP based endpoints for consuming external HTTP
resources (as a client to call external servers using HTTP).
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-httpx.x.x
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URI format
http:hostname[:port][/resourceUri][?param1=value1][¶m2=value2]
Will by default use port 80 for HTTP and 443 for HTTPS.
Examples
Call the url with the body using POST and return response as out message. If body is null call
URL using GET and return response as out message
Java DSL
Spring DSL
from("direct:start")
.to("http://myhost/mypath");
You can override the HTTP endpoint URI by adding a header. Camel will call the
http://newhost. This is very handy for e.g. REST urls.
Java DSL
from("direct:start")
.setHeader(Exchange.HTTP_URI, simple("http://myserver/orders/${header.orderId}"))
.to("http://dummyhost");
URI parameters can either be set directly on the endpoint URI or as a header
Java DSL
from("direct:start")
.to("http://oldhost?order=123&detail=short");
from("direct:start")
.setHeader(Exchange.HTTP_QUERY, constant("order=123&detail=short"))
.to("http://oldhost");
Set the HTTP request method to POST
Java DSL
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Spring DSL
camel-http vs camel-jetty
You can only produce to endpoints generated by the HTTP component. Therefore
it should never be used as input into your camel Routes. To bind/expose an HTTP
endpoint via a HTTP server as input to a camel route, you can use the Jetty
Component or the Servlet Component
from("direct:start")
.setHeader(Exchange.HTTP_METHOD,
constant("POST"))
.to("http://www.google.com");
POST
HttpEndpoint Options
Name
Default
Value
Description
throwExceptionOnFailure
true
Option to disable throwing the HttpOperationFailedException in case of failed responses from the remote
server. This allows you to get all responses regardles of the HTTP status code.
bridgeEndpoint
false
If the option is true , HttpProducer will ignore the Exchange.HTTP_URI header, and use the endpoint's URI for request.
You may also set the throwExcpetionOnFailure to be false to let the HttpProducer send all the fault response back.
Camel 2.3: If the option is true, HttpProducer and CamelServlet will skip the gzip processing if the content-encoding is
"gzip".
disableStreamCache
false
DefaultHttpBinding will copy the request input stream into a stream cache and put it into message body if this option is
false to support read it twice, otherwise DefaultHttpBinding will set the request input stream direct into the message
body.
httpBindingRef
null
Reference to a org.apache.camel.component.http.HttpBinding in the Registry. From Camel 2.3 onwards
prefer to use the httpBinding option.
httpBinding
null
Reference to a org.apache.camel.component.http.HttpBinding in the Registry.
httpClientConfigurerRef
null
Reference to a org.apache.camel.component.http.HttpClientConfigurer in the Registry. From Camel
2.3 onwards prefer to use the httpClientConfigurer option.
httpClientConfigurer
null
Reference to a org.apache.camel.component.http.HttpClientConfigurer in the Registry.
httpClient.XXX
null
Setting options on the HttpClientParams. For instance httpClient.soTimeout=5000 will set the SO_TIMEOUT to
5 seconds.
clientConnectionManager
null
To use a custom org.apache.http.conn.ClientConnectionManager.
transferException
false
Camel 2.6: If enabled and an Exchange failed processing on the consumer side, and if the caused Exception was send
back serialized in the response as a application/x-java-serialized-object content type (for example using
Jetty or SERVLET Camel components). On the producer side the exception will be deserialized and thrown as is, instead
of the HttpOperationFailedException. The caused exception is required to be serialized.
Authentication and Proxy
The following authentication options can also be set on the HttpEndpoint:
Name
Default Value
Description
authMethod
null
Authentication method, either as Basic, Digest or NTLM.
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authMethodPriority
null
Priority of authentication methods. Is a list separated with comma. For example: Basic,Digest to exclude NTLM.
authUsername
null
Username for authentication
authPassword
null
Password for authentication
authDomain
null
Domain for NTML authentication
authHost
null
Optional host for NTML authentication
proxyHost
null
The proxy host name
proxyPort
null
The proxy port number
proxyAuthMethod
null
Authentication method for proxy, either as Basic, Digest or NTLM.
proxyAuthUsername
null
Username for proxy authentication
proxyAuthPassword
null
Password for proxy authentication
proxyAuthDomain
null
Domain for proxy NTML authentication
proxyAuthHost
null
Optional host for proxy NTML authentication
When using authentication you must provide the choice of method for the authMethod or
authProxyMethod options.
You can configure the proxy and authentication details on either the HttpComponent or the
HttpEndoint. Values provided on the HttpEndpoint will take precedence over
HttpComponent. Its most likely best to configure this on the HttpComponent which
allows you to do this once.
The HTTP component uses convention over configuration which means that if you have not
explicit set a authMethodPriority then it will fallback and use the select(ed)
authMethod as priority as well. So if you use authMethod.Basic then the
auhtMethodPriority will be Basic only.
HttpComponent Options
Name
Default Value
Description
httpBinding
null
To use a custom org.apache.camel.component.http.HttpBinding.
httpClientConfigurer
null
To use a custom org.apache.camel.component.http.HttpClientConfigurer.
httpConnectionManager
null
To use a custom org.apache.commons.httpclient.HttpConnectionManager.
httpConfiguration
null
To use a custom org.apache.camel.component.http.HttpConfiguration
HttpConfiguration contains all the options listed in the table above under the section
HttpConfiguration - Setting Authentication and Proxy.
Message Headers
661
Name
Type
Description
Exchange.HTTP_URI
String
URI to call. Will override existing URI set directly on the endpoint.
Exchange.HTTP_METHOD
String
HTTP Method / Verb to use (GET/POST/PUT/DELETE/HEAD/OPTIONS/TRACE)
Exchange.HTTP_PATH
String
Request URI's path, the header will be used to build the request URI with the HTTP_URI.
Camel 2.3.0: If the path is start with "/", http producer will try to find the relative path based
on the Exchange.HTTP_BASE_URI header or the exchange.getFromEndpoint().getEndpointUri();
Exchange.HTTP_QUERY
String
URI parameters. Will override existing URI parameters set directly on the endpoint.
Exchange.HTTP_RESPONSE_CODE
int
The HTTP response code from the external server. Is 200 for OK.
Exchange.HTTP_CHARACTER_ENCODING
String
Character encoding.
Exchange.CONTENT_TYPE
String
The HTTP content type. Is set on both the IN and OUT message to provide a content type, such
as text/html.
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Exchange.CONTENT_ENCODING
String
The HTTP content encoding. Is set on both the IN and OUT message to provide a content
encoding, such as gzip.
Exchange.HTTP_SERVLET_REQUEST
HttpServletRequest
The HttpServletRequest object.
Exchange.HTTP_SERVLET_RESPONSE
HttpServletResponse
The HttpServletResponse object.
Exchange.HTTP_PROTOCOL_VERSION
String
Camel 2.5: You can set the http protocol version with this header, eg. "HTTP/1.0". If you didn't
specify the header, HttpProducer will use the default value "HTTP/1.1"
The header name above are constants. For the spring DSL you have to use the value of the
constant instead of the name.
Message Body
Camel will store the HTTP response from the external server on the OUT body. All headers
from the IN message will be copied to the OUT message, so headers are preserved during
routing. Additionally Camel will add the HTTP response headers as well to the OUT message
headers.
Response code
Camel will handle according to the HTTP response code:
▪ Response code is in the range 100..299, Camel regards it as a success response.
▪ Response code is in the range 300..399, Camel regards it as a redirection response
and will throw a HttpOperationFailedException with the information.
▪ Response code is 400+, Camel regards it as an external server failure and will throw a
HttpOperationFailedException with the information.
HttpOperationFailedException
This exception contains the following information:
▪ The HTTP status code
▪ The HTTP status line (text of the status code)
▪ Redirect location, if server returned a redirect
▪ Response body as a java.lang.String, if server provided a body as response
Calling using GET or POST
The following algorithm is used to determine if either GET or POST HTTP method should be
used:
1. Use method provided in header.
2. GET if query string is provided in header.
3. GET if endpoint is configured with a query string.
4. POST if there is data to send (body is not null).
5. GET otherwise.
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throwExceptionOnFailure
The option, throwExceptionOnFailure, can be set to false to prevent the
HttpOperationFailedException from being thrown for failed response
codes. This allows you to get any response from the remote server.
There is a sample below demonstrating this.
How to get access to HttpServletRequest and HttpServletResponse
You can get access to these two using the Camel type converter system using
HttpServletRequest request = exchange.getIn().getBody(HttpServletRequest.class);
HttpServletRequest response = exchange.getIn().getBody(HttpServletResponse.class);
Using client tineout - SO_TIMEOUT
See the unit test in this link
MORE EXAMPLES
Configuring a Proxy
Java DSL
from("direct:start")
.to("http://oldhost?proxyHost=www.myproxy.com&proxyPort=80");
There is also support for proxy authentication via the proxyUsername and
proxyPassword options.
Using proxy settings outside of URI
Java DSL
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Spring DSL
context.getProperties().put("http.proxyHost",
"172.168.18.9");
context.getProperties().put("http.proxyPort"
"8080");
Options on Endpoint will override options on the context.
Configuring charset
If you are using POST to send data you can configure the charset
setProperty(Exchange.CHARSET_NAME, "iso-8859-1");
Sample with scheduled poll
The sample polls the Google homepage every 10 seconds and write the page to the file
message.html:
from("timer://foo?fixedRate=true&delay=0&period=10000")
.to("http://www.google.com")
.setHeader(FileComponent.HEADER_FILE_NAME, "message.html").to("file:target/
google");
Getting the Response Code
You can get the HTTP response code from the HTTP component by getting the value from the
Out message header with HttpProducer.HTTP_RESPONSE_CODE.
Exchange exchange = template.send("http://www.google.com/search", new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getIn().setHeader(Exchange.HTTP_QUERY,
constant("hl=en&q=activemq"));
}
});
Message out = exchange.getOut();
int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);
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Using throwExceptionOnFailure=false to get any response back
In the route below we want to route a message that we enrich with data returned from a
remote HTTP call. As we want any response from the remote server, we set the
throwExceptionOnFailure option to false so we get any response in the
AggregationStrategy. As the code is based on a unit test that simulates a HTTP status
code 404, there is some assertion code etc.
// We set throwExceptionOnFailure to false to let Camel return any response from the
remove HTTP server without thrown
// HttpOperationFailedException in case of failures.
// This allows us to handle all responses in the aggregation strategy where we can
check the HTTP response code
// and decide what to do. As this is based on an unit test we assert the code is 404
from("direct:start").enrich("http://localhost:{{port}}/
myserver?throwExceptionOnFailure=false&user=Camel", new AggregationStrategy() {
public Exchange aggregate(Exchange original, Exchange resource) {
// get the response code
Integer code = resource.getIn().getHeader(Exchange.HTTP_RESPONSE_CODE,
Integer.class);
assertEquals(404, code.intValue());
return resource;
}
}).to("mock:result");
// this is our jetty server where we simulate the 404
from("jetty://http://localhost:{{port}}/myserver")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getOut().setBody("Page not found");
exchange.getOut().setHeader(Exchange.HTTP_RESPONSE_CODE, 404);
}
});
Disabling Cookies
To disable cookies you can set the HTTP Client to ignore cookies by adding this URI option:
httpClient.cookiePolicy=ignoreCookies
Advanced Usage
If you need more control over the HTTP producer you should use the HttpComponent
where you can set various classes to give you custom behavior.
Setting MaxConnectionsPerHost
The HTTP Component has a
org.apache.commons.httpclient.HttpConnectionManager where you can
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configure various global configuration for the given component.
By global, we mean that any endpoint the component creates has the same shared
HttpConnectionManager. So, if we want to set a different value for the max connection
per host, we need to define it on the HTTP component and not on the endpoint URI that we
usually use. So here comes:
First, we define the http component in Spring XML. Yes, we use the same scheme name,
http, because otherwise Camel will auto-discover and create the component with default
settings. What we need is to overrule this so we can set our options. In the sample below we
set the max connection to 5 instead of the default of 2.
And then we can just use it as we normally do in our routes:
Using preemptive authentication
An end user reported that he had problem with authenticating with HTTPS. The problem was
eventually resolved when he discovered the HTTPS server did not return a HTTP code 401
Authorization Required. The solution was to set the following URI option:
httpClient.authenticationPreemptive=true
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Accepting self signed certificates from remote server
See this link from a mailing list discussion with some code to outline how to do this with the
Apache Commons HTTP API.
Setting up SSL for HTTP Client
Using the JSSE Configuration Utility
As of Camel 2.8, the HTTP4 component supports SSL/TLS configuration through the Camel
JSSE Configuration Utility.Ê This utility greatly decreases the amount of component specific
code you need to write and is configurable at the endpoint and component levels.Ê The
following examples demonstrate how to use the utility with the HTTP4 component.
The version of the Apache HTTP client used in this component resolves SSL/TLS
information from a global "protocol" registry.Ê This component provides an implementation,
org.apache.camel.component.http.SSLContextParametersSecureProtocolSocketFac
of the HTTP client's protocol socket factory in order to support the use of the Camel JSSE
Configuration utility.Ê The following example demonstrates how to configure the protocol
registry and use the registered protocol information in a route.
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/keystore.jks");
ksp.setPassword("keystorePassword");
KeyManagersParameters kmp = new KeyManagersParameters();
kmp.setKeyStore(ksp);
kmp.setKeyPassword("keyPassword");
SSLContextParameters scp = new SSLContextParameters();
scp.setKeyManagers(kmp);
ProtocolSocketFactory factory =
new SSLContextParametersSecureProtocolSocketFactory(scp);
Protocol.registerProtocol("https",
new Protocol(
ÊÊÊÊÊÊÊ "https",
ÊÊÊÊÊÊÊ factory,
ÊÊÊÊÊÊÊ 443));
from("direct:start")
.to("https://mail.google.com/mail/").to("mock:results");
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Configuring Apache HTTP Client Directly
Basically camel-http component is built on the top of Apache HTTP client, and you can
implement a custom
org.apache.camel.component.http.HttpClientConfigurer to do some
configuration on the http client if you need full control of it.
However if you just want to specify the keystore and truststore you can do this with Apache
HTTP HttpClientConfigurer, for example:
Protocol authhttps = new Protocol("https", new AuthSSLProtocolSocketFactory(
new URL("file:my.keystore"), "mypassword",
new URL("file:my.truststore"), "mypassword"), 443);
Protocol.registerProtocol("https", authhttps);
And then you need to create a class that implements HttpClientConfigurer, and
registers https protocol providing a keystore or truststore per example above. Then, from your
camel route builder class you can hook it up like so:
HttpComponent httpComponent = getContext().getComponent("http", HttpComponent.class);
httpComponent.setHttpClientConfigurer(new MyHttpClientConfigurer());
If you are doing this using the Spring DSL, you can specify your HttpClientConfigurer
using the URI. For example:
As long as you implement the HttpClientConfigurer and configure your keystore and truststore
as described above, it will work fine.
See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
Jetty
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IBATIS
The ibatis: component allows you to query, poll, insert, update and delete data in a relational
database using Apache iBATIS.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-ibatisx.x.x
URI format
ibatis:statementName[?options]
Where statementName is the name in the iBATIS XML configuration file which maps to
the query, insert, update or delete operation you wish to evaluate.
You can append query options to the URI in the following format,
?option=value&option=value&...
This component will by default load the iBatis SqlMapConfig file from the root of the
classpath and expected named as SqlMapConfig.xml.
It uses Spring resource loading so you can define it using classpath, file or http as
prefix to load resources with those schemes.
In Camel 2.2 you can configure this on the iBatisComponent with the
setSqlMapConfig(String) method.
Options
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Option
Type
Default
Description
consumer.onConsume
String
null
Statements to run after consuming. Can be used, for example, to
update rows after they have been consumed and processed in
Camel. See sample later. Multiple statements can be separated with
comma.
consumer.useIterator
boolean
true
If true each row returned when polling will be processed
individually. If false the entire List of data is set as the IN body.
consumer.routeEmptyResultSet
boolean
false
Camel 2.0: Sets whether empty result set should be routed or not.
By default, empty result sets are not routed.
statementType
StatementType
null
Camel 1.6.1/2.0: Mandatory to specify for IbatisProducer to
control which iBatis SqlMapClient method to invoke. The enum
values are: QueryForObject, QueryForList, Insert,
Update, Delete.
maxMessagesPerPoll
int
0
Camel 2.0: An integer to define a maximum messages to gather
per poll. By default, no maximum is set. Can be used to set a limit of
e.g. 1000 to avoid when starting up the server that there are
thousands of files. Set a value of 0 or negative to disabled it.
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isolation
isolation
String
String
TRANSACTION_REPEATABLE_READ
TRANSACTION_REPEATABLE_READ
Camel 2.9: A String the defines the transaction isolation level of
the will be used. Allowed values are TRANSACTION_NONE,
TRANSACTION_READ_UNCOMMITTED,
TRANSACTION_READ_COMMITTED,
TRANSACTION_REPEATABLE_READ,
TRANSACTION_SERIALIZABLE
Camel 2.9: A String the defines the transaction isolation level of the will be used. Allowed values are
TRANSACTION_NONE, TRANSACTION_READ_UNCOMMITTED,
TRANSACTION_READ_COMMITTED, TRANSACTION_REPEATABLE_READ,
TRANSACTION_SERIALIZABLE
Message Headers
Camel will populate the result message, either IN or OUT with a header with the
operationName used:
Header
Type
Description
org.apache.camel.ibatis.queryName
String
Camel 1.x: The statementName used (for example: insertAccount).
CamelIBatisStatementName
String
Camel 2.0: The statementName used (for example: insertAccount).
CamelIBatisResult
Object
Camel 1.6.2/2.0: The response returned from iBatis in any of the operations. For instance an INSERT could
return the auto-generated key, or number of rows etc.
Message Body
Camel 1.6.1: The response from iBatis will be set as OUT body
Camel 1.6.2/2.0: The response from iBatis will only be set as body if it's a SELECT
statement. That means, for example, for INSERT statements Camel will not replace the body.
This allows you to continue routing and keep the original body. The response from iBatis is
always stored in the header with the key CamelIBatisResult.
Samples
For example if you wish to consume beans from a JMS queue and insert them into a database
you could do the following:
from("activemq:queue:newAccount").
to("ibatis:insertAccount?statementType=Insert");
Notice we have to specify the statementType, as we need to instruct Camel which
SqlMapClient operation to invoke.
Where insertAccount is the iBatis ID in the SQL map file:
insert into ACCOUNT (
ACC_ID,
ACC_FIRST_NAME,
ACC_LAST_NAME,
ACC_EMAIL
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)
values (
#id#, #firstName#, #lastName#, #emailAddress#
)
Using StatementType for better control of IBatis
Available as of Camel 1.6.1/2.0
When routing to an iBatis endpoint you want more fine grained control so you can control
whether the SQL statement to be executed is a SELEECT, UPDATE, DELETE or INSERT etc.
This is now possible in Camel 1.6.1/2.0. So for instance if we want to route to an iBatis
endpoint in which the IN body contains parameters to a SELECT statement we can do:
from("direct:start")
.to("ibatis:selectAccountById?statementType=QueryForObject")
.to("mock:result");
In the code above we can invoke the iBatis statement selectAccountById and the IN body
should contain the account id we want to retrieve, such as an Integer type.
We can do the same for some of the other operations, such as QueryForList:
from("direct:start")
.to("ibatis:selectAllAccounts?statementType=QueryForList")
.to("mock:result");
And the same for UPDATE, where we can send an Account object as IN body to iBatis:
from("direct:start")
.to("ibatis:updateAccount?statementType=Update")
.to("mock:result");
Scheduled polling example
Since this component does not support scheduled polling, you need to use another mechanism
for triggering the scheduled polls, such as the Timer or Quartz components.
In the sample below we poll the database, every 30 seconds using the Timer component and
send the data to the JMS queue:
from("timer://pollTheDatabase?delay=30000").to("ibatis:selectAllAccounts?statementType=QueryForList").
And the iBatis SQL map file used:
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Using onConsume
This component supports executing statements after data have been consumed and processed
by Camel. This allows you to do post updates in the database. Notice all statements must be
UPDATE statements. Camel supports executing multiple statements whose name should be
separated by comma.
The route below illustrates we execute the consumeAccount statement data is
processed. This allows us to change the status of the row in the database to processed, so we
avoid consuming it twice or more.
from("ibatis:selectUnprocessedAccounts?consumer.onConsume=consumeAccount").to("mock:results");
And the statements in the sqlmap file:
update ACCOUNT set PROCESSED = true where ACC_ID = #id#
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
IRC COMPONENT
The irc component implements an IRC (Internet Relay Chat) transport.
Maven users will need to add the following dependency to their pom.xml for this
component:
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org.apache.camelcamel-ircx.x.x
URI format
irc:nick@host[:port]/#room[?options]
In Camel 2.0, you can also use the following format:
irc:nick@host[:port]?channels=#channel1,#channel2,#channel3[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
673
Name
Description
Example
Default
Value
channels
Camel 2.0: Comma separated list of IRC channels to join.
channels=#channel1,#channel2
null
nickname
The nickname used in chat.
irc:MyNick@irc.server.org#channel or
irc:irc.server.org#channel?nickname=MyUser
null
username
The IRC server user name.
irc:MyUser@irc.server.org#channel or
irc:irc.server.org#channel?username=MyUser
Same as
nickname.
password
The IRC server password.
password=somepass
None
realname
The IRC user's actual name.
realname=MyName
None
colors
Whether or not the server supports color codes.
true, false
true
onReply
Whether or not to handle general responses to commands or
informational messages.
true, false
false
onNick
Handle nickname change events.
true, false
true
onQuit
Handle user quit events.
true, false
true
onJoin
Handle user join events.
true, false
true
onKick
Handle kick events.
true, false
true
onMode
Handle mode change events.
true, false
true
onPart
Handle user part events.
true, false
true
onTopic
Handle topic change events.
true, false
true
onPrivmsg
Handle message events.
true, false
true
trustManager
Camel 2.0: The trust manager used to verify the SSL server's
certificate.
trustManager=#referenceToTrustManagerBean
The default
trust manager,
which accepts
all certificates,
will be used.
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keys
Camel 2.2: Comma separated list of IRC channel keys. Important
to be listed in same order as channels. When joining multiple
channels with only some needing keys just insert an empty value for
that channel.
irc:MyNick@irc.server.org/
#channel?keys=chankey
null
sslContextParameters
Camel 2.9: Reference to a
org.apache.camel.util.jsse.SSLContextParameters
in the Registry.Ê This reference overrides any configured
SSLContextParameters at the component level.Ê See Using the JSSE
Configuration Utility.Ê Note that this setting overrides the
trustManager option.
#mySslContextParameters
null
SSL Support
Using the JSSE Configuration Utility
As of Camel 2.9, the IRC component supports SSL/TLS configuration through the Camel JSSE
Configuration Utility.Ê This utility greatly decreases the amount of component specific code you
need to write and is configurable at the endpoint and component levels.Ê The following
examples demonstrate how to use the utility with the IRC component.
Programmatic configuration of the endpoint
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/truststore.jks");
ksp.setPassword("keystorePassword");
TrustManagersParameters tmp = new TrustManagersParameters();
tmp.setKeyStore(ksp);
SSLContextParameters scp = new SSLContextParameters();
scp.setTrustManagers(tmp);
Registry registry = ...
registry.bind("sslContextParameters", scp);
...
from(...)
.to("ircs://camel-prd-user@server:6669/
#camel-test?nickname=camel-prd&password=password&sslContextParameters=#sslContextParameters");
Spring DSL based configuration of endpoint
...
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...
...
...
Using the legacy basic configuration options
As of Camel 2.0, you can also connect to an SSL enabled IRC server, as follows:
ircs:host[:port]/#room?username=user&password=pass
By default, the IRC transport uses SSLDefaultTrustManager. If you need to provide your own
custom trust manager, use the trustManager parameter as follows:
ircs:host[:port]/
#room?username=user&password=pass&trustManager=#referenceToMyTrustManagerBean
Using keys
Available as of Camel 2.2
Some irc rooms requires you to provide a key to be able to join that channel. The key is just
a secret word.
For example we join 3 channels where as only channel 1 and 3 uses a key.
irc:nick@irc.server.org?channels=#chan1,#chan2,#chan3&keys=chan1Key,,chan3key
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
JASYPT COMPONENT
Available as of Camel 2.5
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Jasypt is a simplified encryption library which makes encryption and decryption easy. Camel
integrates with Jasypt to allow sensitive information in Properties files to be encrypted. By
dropping camel-jasypt on the classpath those encrypted values will automatic be decrypted
on-the-fly by Camel. This ensures that human eyes can't easily spot sensitive information such
as usernames and passwords.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jasyptx.x.x
Tooling
The Jasypt component provides a little command line tooling to encrypt or decrypt values.
The console output the syntax and which options it provides:
Apache Camel Jasypt takes the following options
-h
-c
-p
-i
-a
or
or
or
or
or
-help = Displays the help screen
-command = Command either encrypt or decrypt
-password = Password to use
-input = Text to encrypt or decrypt
-algorithm = Optional algorithm to use
For example to encrypt the value tiger you run with the following parameters. In the apache
camel kit, you cd into the lib folder and run the following java cmd, where is
where you have downloaded and extract the Camel distribution.
$ cd /lib
$ java -jar camel-jasypt-2.5.0.jar -c encrypt -p secret -i tiger
Which outputs the following result
Encrypted text: qaEEacuW7BUti8LcMgyjKw==
This means the encrypted representation qaEEacuW7BUti8LcMgyjKw== can be decrypted
back to tiger if you know the master password which was secret.
If you run the tool again then the encrypted value will return a different result. But decrypting
the value will always return the correct original value.
So you can test it by running the tooling using the following parameters:
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$ cd /lib
$ java -jar camel-jasypt-2.5.0.jar -c decrypt -p secret -i qaEEacuW7BUti8LcMgyjKw==
Which outputs the following result:
Decrypted text: tiger
The idea is then to use those encrypted values in your Properties files. Notice how the
password value is encrypted and the value has the tokens surrounding ENC(value here)
# refer to a mock endpoint name by that encrypted password
cool.result=mock:{{cool.password}}
# here is a password which is encrypted
cool.password=ENC(bsW9uV37gQ0QHFu7KO03Ww==)
Tooling dependencies for Camel 2.5 and 2.6
The tooling requires the following JARs in the classpath, which has been enlisted in the
MANIFEST.MF file of camel-jasypt with optional/ as prefix. Hence why the java cmd
above can pickup the needed JARs from the Apache Distribution in the optional directory.
jasypt-1.6.jar commons-lang-2.4.jar commons-codec-1.4.jar icu4j-4.0.1.jar
Tooling dependencies for Camel 2.7 or better
Jasypt 1.7 onwards is now fully standalone so no additional JARs is needed.
URI Options
The options below are exclusive for the Jasypt component.
Name
Default Value
Type
Description
password
null
String
Specifies the master password to use for decrypting. This option is mandatory. See below for more details.
algorithm
null
String
Name of an optional algorithm to use.
Protecting the master password
The master password used by Jasypt must be provided, so its capable of decrypting the values.
However having this master password out in the opening may not be an ideal solution.
Therefore you could for example provided it as a JVM system property or as a OS environment
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Java 1.5 users
The icu4j-4.0.1.jar is only needed when running on JDK 1.5.
This JAR is not distributed by Apache Camel and you have to download it manually and copy
it to the lib/optional directory of the Camel distribution.
You can download it from Apache Central Maven repo.
setting. If you decide to do so then the password option supports prefixes which dictates
this. sysenv: means to lookup the OS system environment with the given key. sys: means
to lookup a JVM system property.
For example you could provided the password before you start the application
$ export CAMEL_ENCRYPTION_PASSWORD=secret
Then start the application, such as running the start script.
When the application is up and running you can unset the environment
$ unset CAMEL_ENCRYPTION_PASSWORD
The password option is then a matter of defining as follows:
password=sysenv:CAMEL_ENCRYPTION_PASSWORD.
Example with Java DSL
In Java DSL you need to configure Jasypt as a JasyptPropertiesParser instance and set
it on the Properties component as show below:
// create the jasypt properties parser
JasyptPropertiesParser jasypt = new JasyptPropertiesParser();
// and set the master password
jasypt.setPassword("secret");
// create the properties component
PropertiesComponent pc = new PropertiesComponent();
pc.setLocation("classpath:org/apache/camel/component/jasypt/myproperties.properties");
// and use the jasypt properties parser so we can decrypt values
pc.setPropertiesParser(jasypt);
// add properties component to camel context
context.addComponent("properties", pc);
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The properties file myproperties.properties then contain the encrypted value, such as
shown below. Notice how the password value is encrypted and the value has the tokens
surrounding ENC(value here)
# refer to a mock endpoint name by that encrypted password
cool.result=mock:{{cool.password}}
# here is a password which is encrypted
cool.password=ENC(bsW9uV37gQ0QHFu7KO03Ww==)
Example with Spring XML
In Spring XML you need to configure the JasyptPropertiesParser which is shown
below. Then the Camel Properties component is told to use jasypt as the properties parser,
which means Jasypt have its chance to decrypt values looked up in the properties.
The Properties component can also be inlined inside the tag which is
shown below. Notice how we use the propertiesParserRef attribute to refer to Jasypt.
See Also
▪ Security
▪ Properties
▪ Encrypted passwords in ActiveMQ - ActiveMQ has a similar feature as this cameljasypt component
JAVASPACE COMPONENT
Available as of Camel 2.1
The javaspace component is a transport for working with any JavaSpace compliant
implementation and this component has been tested with both the Blitz implementation and the
GigaSpace implementation .
This component can be used for sending and receiving any object inheriting from the Jini
net.jini.core.entry.Entry class. It is also possible to pass the bean ID of a template
that can be used for reading/taking the entries from the space.
This component can be used for sending/receiving any serializable object acting as a sort of
generic transport. The JavaSpace component contains a special optimization for dealing with the
BeanExchange. It can be used to invoke a POJO remotely, using a JavaSpace as a transport.
This latter feature can provide a simple implementation of the master/worker pattern, where a
POJO provides the business logic for the worker.
Look at the test cases for examples of various use cases for this component.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-javaspacex.x.x
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URI format
javaspace:jini://host[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default Value
Description
spaceName
null
Specifies the JavaSpace name.
verb
take
Specifies the verb for getting JavaSpace entries. The values can be: take or read.
transactional
false
If true, sending and receiving entries is performed within a transaction.
transactionalTimeout
Long.MAX_VALUE
Specifies the transaction timeout.
concurrentConsumers
1
Specifies the number of concurrent consumers getting entries from the JavaSpace.
templateId
null
If present, this option specifies the Spring bean ID of the template to use for reading/taking entries.
Examples
Sending and Receiving Entries
// sending route
from("direct:input")
.to("javaspace:jini://localhost?spaceName=mySpace");
// receiving Route
from("javaspace:jini://localhost?spaceName=mySpace&templateId=template&verb=take&concurrentConsumers=1
.to("mock:foo");
In this case the payload can be any object that inherits from the Jini Entry type.
Sending and receiving serializable objects
Using the preceding routes, it is also possible to send and receive any serializable object. The
JavaSpace component detects that the payload is not a Jini Entry and then it automatically
wraps the payload with a Camel Jini Entry. In this way, a JavaSpace can be used as a generic
transport mechanism.
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Using JavaSpace as a remote invocation transport
The JavaSpace component has been tailored to work in combination with the Camel bean
component. It is therefore possible to call a remote POJO using JavaSpace as the transport:
// client side
from("direct:input")
.to("javaspace:jini://localhost?spaceName=mySpace");
// server side
from("javaspace:jini://localhost?concurrentConsumers=10&spaceName=mySpace")
.to("mock:foo");
In the code there are two test cases showing how to use a POJO to realize the master/worker
pattern. The idea is to use the POJO to provide the business logic and rely on Camel for
sending/receiving requests/replies with the proper correlation.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
JBI COMPONENT
The jbi component is implemented by the ServiceMix Camel module and provides integration
with a JBI Normalized Message Router, such as the one provided by Apache ServiceMix.
The following code:
from("jbi:endpoint:http://foo.bar.org/MyService/MyEndpoint")
Automatically exposes a new endpoint to the bus, where the service QName is
{http://foo.bar.org}MyService and the endpoint name is MyEndpoint (see URIformat).
When a JBI endpoint appears at the end of a route, for example:
to("jbi:endpoint:http://foo.bar.org/MyService/MyEndpoint")
The messages sent by this producer endpoint are sent to the already deployed JBI endpoint.
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See below for information about how to use StreamSource types from
ServiceMix in Camel.
URI format
jbi:service:serviceNamespace[sep]serviceName[?options]
jbi:endpoint:serviceNamespace[sep]serviceName[sep]endpointName[?options]
jbi:name:endpointName[?options]
The separator that should be used in the endpoint URL is:
• / (forward slash), if serviceNamespace starts with http://, or
• : (colon), if serviceNamespace starts with urn:foo:bar.
For more details of valid JBI URIs see the ServiceMix URI Guide.
Using the jbi:service: or jbi:endpoint: URI formats sets the service QName on
the JBI endpoint to the one specified. Otherwise, the default Camel JBI Service QName is used,
which is:
{http://activemq.apache.org/camel/schema/jbi}endpoint
You can append query options to the URI in the following format,
?option=value&option=value&...
Examples
jbi:service:http://foo.bar.org/MyService
jbi:endpoint:urn:foo:bar:MyService:MyEndpoint
jbi:endpoint:http://foo.bar.org/MyService/MyEndpoint
jbi:name:cheese
URI options
683
Name
Default value
Description
mep
MEP of the Camel
Exchange
Allows users to override the MEP set on
the Exchange object. Valid values for this
option are in-only, in-out, robustin-out and in-optional-out.
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operation
serialization
convertException
Value of the
jbi.operation
header property
Specifies the JBI operation for the
MessageExchange. If no value is
supplied, the JBI binding will use the value of
the jbi.operation header property.
basic
Default value (basic) will check if headers
are serializable by looking at the type,
setting this option to strict will detect
objects that can not be serialized although
they implement the Serializable
interface. Set to nocheck to disable this
check altogether, note that this should only
be used for in-memory transports like
SEDAFlow, otherwise you can expect to get
NotSerializableException thrown
at runtime.
false
false: send any exceptions thrown from
the Camel route back unmodified
true: convert all exceptions to a JBI
FaultException (can be used to avoid nonserializable exceptions or to implement
generic error handling
Examples
jbi:service:http://foo.bar.org/MyService?mep=in-out
(override the MEP, use InOut
JBI MessageExchanges)
jbi:endpoint:urn:foo:bar:MyService:MyEndpoint?mep=in
(override the MEP, use
InOnly JBI MessageExchanges)
jbi:endpoint:urn:foo:bar:MyService:MyEndpoint?operation={http://www.mycompany.org}AddNumbers
(overide the operation for the JBI Exchange to {http://www.mycompany.org}AddNumbers)
Using Stream bodies
If you are using a stream type as the message body, you should be aware that a stream is only
capable of being read once. So if you enable DEBUG logging, the body is usually logged and thus
read. To deal with this, Camel has a streamCaching option that can cache the stream,
enabling you to read it multiple times.
from("jbi:endpoint:http://foo.bar.org/MyService/
MyEndpoint").streamCaching().to("xslt:transform.xsl", "bean:doSomething");
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From Camel 1.5 onwards, the stream caching is default enabled, so it is not necessary to set
the streamCaching() option.
In Camel 2.0 we store big input streams (by default, over 64K) in a temp file using
CachedOutputStream. When you close the input stream, the temp file will be deleted.
Creating a JBI Service Unit
If you have some Camel routes that you want to deploy inside JBI as a Service Unit, you can use
the JBI Service Unit Archetype to create a new Maven project for the Service Unit.
If you have an existing Maven project that you need to convert into a JBI Service Unit, you
may want to consult ServiceMix Maven JBI Plugins for further help. The key steps are as follows:
• Create a Spring XML file at src/main/resources/camel-context.xml to
bootstrap your routes inside the JBI Service Unit.
• Change the POM file's packaging to jbi-service-unit.
Your pom.xml should look something like this to enable the jbi-service-unit
packaging:
4.0.0myGroupIdmyArtifactIdjbi-service-unit1.0-SNAPSHOTA Camel based JBI Service Unithttp://www.myorganization.org1.0.03.3org.apache.servicemixservicemix-camel${servicemix-version}org.apache.servicemixservicemix-core${servicemix-version}
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providedinstallorg.apache.maven.pluginsmaven-compiler-plugin1.51.5org.apache.servicemix.toolingjbi-maven-plugin${servicemix-version}true
See Also
•
•
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
ServiceMix Camel module
Using Camel with ServiceMix
Cookbook on using Camel with ServiceMix
JCR COMPONENT
The jcr component allows you to add nodes to a JCR compliant content repository (for
example, Apache Jackrabbit).
Maven users will need to add the following dependency to their pom.xml for this
component:
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org.apache.camelcamel-jcrx.x.x
URI format
jcr://user:password@repository/path/to/node
Usage
The repository element of the URI is used to look up the JCR Repository object in the
Camel context registry.
If a message is sent to a JCR producer endpoint:
• A new node is created in the content repository,
• All the message properties of the IN message are transformed to JCR Value
instances and added to the new node,
• The node's UUID is returned in the OUT message.
Message properties
All message properties are converted to node properties, except for the
CamelJcrNodeName property (you can refer to JcrConstants.NODE_NAME in your
code), which is used to determine the node name.
Example
The snippet below creates a node named node under the /home/test node in the content
repository. One additional attribute is added to the node as well: my.contents.property
which will contain the body of the message being sent.
from("direct:a").setProperty(JcrConstants.JCR_NODE_NAME, constant("node"))
.setProperty("my.contents.property", body()).to("jcr://user:pass@repository/home/
test");
See Also
• Configuring Camel
• Component
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• Endpoint
• Getting Started
JDBC COMPONENT
The jdbc component enables you to access databases through JDBC, where SQL queries and
operations are sent in the message body. This component uses the standard JDBC API, unlike
the SQL Component component, which uses spring-jdbc.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jdbcx.x.x
URI format
jdbc:dataSourceName[?options]
This component only supports producer endpoints.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
readSize
Default
Value
Description
0/
2000
The default maximum
number of rows that can be
read by a polling query. The
default value is 2000 for
Camel 1.5.0 or older. In
newer releases the default
value is 0.
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This component can only be used to define producer endpoints, which means that
you cannot use the JDBC component in a from() statement.
This component can not be used as a Transactional Client. If you need transaction
support in your route, you should use the SQL component instead.
statement.
useJDBC4ColumnNameAndLabelSemantics
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null
Camel 2.1: Sets additional
options on the
java.sql.Statement
that is used behind the scenes
to execute the queries. For
instance,
statement.maxRows=10.
For detailed documentation,
see the
java.sql.Statement
javadoc documentation.
true
Camel 1.6.3/2.2: Sets
whether to use JDBC 4/3
column label/name semantics.
You can use this option to
turn it false in case you
have issues with your JDBC
driver to select data. This
only applies when using SQL
SELECT using aliases (e.g.
SQL SELECT id as
identifier, name as
given_name from
persons).
resetAutoCommit
true
Camel 2.9: Camel will set
the autoCommit on the
JDBC connection to be false,
commit the change after
executed the statement and
reset the autoCommit flag of
the connection at the end, if
the resetAutoCommit is true.
If the JDBC connection
doesn't support to reset the
autoCommit flag, you can set
the resetAutoCommit flag to
be false, and Camel will not
try to reset the autoCommit
flag.
Result
The result is returned in the OUT body as an ArrayList>. The List object contains the list of rows and the Map objects contain each row
with the String key as the column name.
Note: This component fetches ResultSetMetaData to be able to return the column
name as the key in the Map.
Message Headers
Header
Description
CamelJdbcRowCount
If the query is a SELECT, query the row count is returned
in this OUT header.
CamelJdbcUpdateCount
If the query is an UPDATE, query the update count is
returned in this OUT header.
Samples
In the following example, we fetch the rows from the customer table.
First we register our datasource in the Camel registry as testdb:
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JndiRegistry reg = super.createRegistry();
reg.bind("testdb", db);
return reg;
Then we configure a route that routes to the JDBC component, so the SQL will be executed.
Note how we refer to the testdb datasource that was bound in the previous step:
// lets add simple route
public void configure() throws Exception {
from("direct:hello").to("jdbc:testdb?readSize=100");
}
Or you can create a DataSource in Spring like this:
select * from customer
We create an endpoint, add the SQL query to the body of the IN message, and then send the
exchange. The result of the query is returned in the OUT body:
// first we create our exchange using the endpoint
Endpoint endpoint = context.getEndpoint("direct:hello");
Exchange exchange = endpoint.createExchange();
// then we set the SQL on the in body
exchange.getIn().setBody("select * from customer order by ID");
// now we send the exchange to the endpoint, and receives the response from Camel
Exchange out = template.send(endpoint, exchange);
// assertions of the response
assertNotNull(out);
assertNotNull(out.getOut());
ArrayList> data = out.getOut().getBody(ArrayList.class);
assertNotNull(data);
assertEquals(3, data.size());
HashMap row = data.get(0);
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assertEquals("cust1", row.get("ID"));
assertEquals("jstrachan", row.get("NAME"));
row = data.get(1);
assertEquals("cust2", row.get("ID"));
assertEquals("nsandhu", row.get("NAME"));
If you want to work on the rows one by one instead of the entire ResultSet at once you need
to use the Splitter EIP such as:
from("direct:hello")
// here we split the data from the testdb into new messages one by one
// so the mock endpoint will receive a message per row in the table
.to("jdbc:testdb").split(body()).to("mock:result");
Sample - Polling the database every minute
If we want to poll a database using the JDBC component, we need to combine it with a polling
scheduler such as the Timer or Quartz etc. In the following example, we retrieve data from the
database every 60 seconds:
from("timer://foo?period=60000").setBody(constant("select * from
customer")).to("jdbc:testdb").to("activemq:queue:customers");
See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
SQL
JETTY COMPONENT
The jetty component provides HTTP-based endpoints for consuming HTTP requests. That is,
the Jetty component behaves as a simple Web server.
Jetty can also be used as a http client which mean you can also use it with Camel as a Producer.
URI format
jetty:http://hostname[:port][/resourceUri][?options]
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Upgrading from Jetty 6 to 7
You can read more about upgrading Jetty here
Stream
Jetty is stream based, which means the input it receives is submitted to Camel as a
stream. That means you will only be able to read the content of the stream once.
If you find a situation where the message body appears to be empty or you need to
access the data multiple times (eg: doing multicasting, or redelivery error handling)
you should use Stream caching or convert the message body to a String which is
safe to be re-read multiple times.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
sessionSupport
false
Specifies whether to enable the session manager on the server side of Jetty.
httpClient.XXX
null
Camel 1.6.0/2.0: Configuration of Jetty's HttpClient. For example, setting httpClient.idleTimeout=30000
sets the idle timeout to 30 seconds.
httpBindingRef
null
Camel 1.6.0/2.0: Reference to an org.apache.camel.component.http.HttpBinding in the Registry.
HttpBinding can be used to customize how a response should be written.
jettyHttpBindingRef
null
Camel 2.6.0+: Reference to an org.apache.camel.component.jetty.JettyHttpBinding in the Registry.
JettyHttpBinding can be used to customize how a response should be written.
matchOnUriPrefix
false
Camel 2.0: Whether or not the CamelServlet should try to find a target consumer by matching the URI prefix if no
exact match is found. See here How do I let Jetty match wildcards.
handlers
null
Camel 1.6.1/2.0: Specifies a comma-delimited set of org.mortbay.jetty.Handler instances in your Registry
(such as your Spring ApplicationContext). These handlers are added to the Jetty servlet context (for example, to
add security).
chunked
true
Camel 2.2: If this option is false Jetty servlet will disable the HTTP streaming and set the content-length header on the
response
enableJmx
false
Camel 2.3: If this option is true, Jetty JMX support will be enabled for this endpoint. See Jetty JMX support for more
details.
false
Camel 2.3: Determines whether or not the raw input stream from Jetty is cached or not (Camel will read the stream
into a in memory/overflow to file, Stream caching) cache. By default Camel will cache the Jetty input stream to support
reading it multiple times to ensure it Camel can retrieve all data from the stream. However you can set this option to
true when you for example need to access the raw stream, such as streaming it directly to a file or other persistent
store. DefaultHttpBinding will copy the request input stream into a stream cache and put it into message body if this
option is false to support reading the stream multiple times. If you use Jetty to bridge/proxy an endpoint then consider
enabling this option to improve performance, in case you do not need to read the message payload multiple times.
bridgeEndpoint
false
Camel 2.1: If the option is true , HttpProducer will ignore the Exchange.HTTP_URI header, and use the endpoint's URI
for request. You may also set the throwExceptionOnFailure to be false to let the HttpProducer send all the fault
response back.
Camel 2.3: If the option is true, HttpProducer and CamelServlet will skip the gzip processing if the content-encoding is
"gzip". Also consider setting disableStreamCache to true to optimize when bridging.
enableMultipartFilter
true
Camel 2.5: Whether Jetty org.eclipse.jetty.servlets.MultiPartFilter is enabled or not. You should
set this value to false when bridging endpoints, to ensure multipart requests is proxied/bridged as well.
disableStreamCache
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multipartFilterRef
null
Camel 2.6: Allows using a custom multipart filter. Note: setting multipartFilterRef forces the value of
enableMultipartFilter to true.
FiltersRef
null
Camel 2.9: Allows using a custom filters which is putted into a list and can be find in the Registry
continuationTimeout
null
Camel 2.6: Allows to set a timeout in millis when using Jetty as consumer (server). By default Jetty uses 30000. You can
use a value of <= 0 to never expire. If a timeout occurs then the request will be expired and Jetty will return back a http
error 503 to the client. This option is only in use when using Jetty with the Asynchronous Routing Engine.
useContinuation
true
Camel 2.6: Whether or not to use Jetty continuations for the Jetty Server.
sslContextParametersRef
null
Camel 2.8: Reference to a org.apache.camel.util.jsse.SSLContextParameters in the Registry.Ê This
reference overrides any configured SSLContextParameters at the component level.Ê See Using the JSSE Configuration
Utility.
Message Headers
Camel uses the same message headers as the HTTP component.
From Camel 2.2, it also uses (Exchange.HTTP_CHUNKED,CamelHttpChunked) header to turn
on or turn off the chuched encoding on the camel-jetty consumer.
Camel also populates all request.parameter and request.headers. For example, given a client
request with the URL, http://myserver/myserver?orderid=123, the exchange will
contain a header named orderid with the value 123. This feature was introduced in Camel
1.5.
From Camel 1.6.3 and Camel 2.2.0, you can get the request.parameter from the message
header not only from Get Method, but also other HTTP method.
Usage
The Jetty component only supports consumer endpoints. Therefore a Jetty endpoint URI
should be used only as the input for a Camel route (in a from() DSL call). To issue HTTP
requests against other HTTP endpoints, use the HTTP Component
Component Options
The JettyHttpComponent provides the following options:
Name
Default
Value
Description
enableJmx
false
Camel 2.3: If this option is true, Jetty JMX support will be enabled for this endpoint. See Jetty JMX support for
more details.
sslKeyPassword
null
Consumer only: The password for the keystore when using SSL.
sslPassword
null
Consumer only: The password when using SSL.
sslKeystore
null
Consumer only: The path to the keystore.
minThreads
null
Camel 2.5 Consumer only: To set a value for minimum number of threads in server thread pool.
maxThreads
null
Camel 2.5 Consumer only: To set a value for maximum number of threads in server thread pool.
threadPool
null
Camel 2.5 Consumer only: To use a custom thread pool for the server.
sslSocketConnectors
null
Camel 2.3 Consumer only: A map which contains per port number specific SSL connectors. See section SSL
support for more details.
socketConnectors
null
Camel 2.5 Consumer only: A map which contains per port number specific HTTP connectors. Uses the same
principle as sslSocketConnectors and therefore see section SSL support for more details.
sslSocketConnectorProperties
null
Camel 2.5 Consumer only. A map which contains general SSL connector properties. See section SSL support
for more details.
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socketConnectorProperties
null
Camel 2.5 Consumer only. A map which contains general HTTP connector properties. Uses the same
principle as sslSocketConnectorProperties and therefore see section SSL support for more details.
httpClient
null
Producer only: To use a custom HttpClient with the jetty producer.
httpClientMinThreads
null
Producer only: To set a value for minimum number of threads in HttpClient thread pool.
httpClientMaxThreads
null
Producer only: To set a value for maximum number of threads in HttpClient thread pool.
httpClientThreadPool
null
Producer only: To use a custom thread pool for the client.
sslContextParameters
null
Camel 2.8: To configure a custom SSL/TLS configuration options at the component level.Ê SeeÊ Using the JSSE
Configuration Utility for more details.
Sample
In this sample we define a route that exposes a HTTP service at
http://localhost:8080/myapp/myservice:
from("jetty:http://localhost:{{port}}/myapp/myservice").process(new MyBookService());
Our business logic is implemented in the MyBookService class, which accesses the HTTP
request contents and then returns a response.
Note: The assert call appears in this example, because the code is part of an unit test.
public class MyBookService implements Processor {
public void process(Exchange exchange) throws Exception {
// just get the body as a string
String body = exchange.getIn().getBody(String.class);
// we have access to the HttpServletRequest here and we can grab it if we need
it
HttpServletRequest req = exchange.getIn().getBody(HttpServletRequest.class);
assertNotNull(req);
// for unit testing
assertEquals("bookid=123", body);
// send a html response
exchange.getOut().setBody("Book 123 is Camel in
Action");
}
}
The following sample shows a content-based route that routes all requests containing the URI
parameter, one, to the endpoint, mock:one, and all others to mock:other.
from("jetty:" + serverUri)
.choice()
.when().simple("${header.one}").to("mock:one")
.otherwise()
.to("mock:other");
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Usage of localhost
When you specify localhost in a URL, Camel exposes the endpoint only on the
local TCP/IP network interface, so it cannot be accessed from outside the machine
it operates on.
If you need to expose a Jetty endpoint on a specific network interface, the numerical IP
address of this interface should be used as the host. If you need to expose a Jetty endpoint
on all network interfaces, the 0.0.0.0 address should be used.
So if a client sends the HTTP request, http://serverUri?one=hello, the Jetty
component will copy the HTTP request parameter, one to the exchange's in.header. We
can then use the simple language to route exchanges that contain this header to a specific
endpoint and all others to another. If we used a language more powerful than Simple--such as
EL or OGNL--we could also test for the parameter value and do routing based on the header
value as well.
Session Support
The session support option, sessionSupport, can be used to enable a HttpSession
object and access the session object while processing the exchange. For example, the following
route enables sessions:
The myCode Processor can be instantiated by a Spring bean element:
Where the processor implementation can access the HttpSession as follows:
public void process(Exchange exchange) throws Exception {
HttpSession session = exchange.getIn(HttpMessage.class).getRequest().getSession();
...
}
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SSL Support (HTTPS)
Using the JSSE Configuration Utility
As of Camel 2.8, the Jetty component supports SSL/TLS configuration through the Camel JSSE
Configuration Utility.Ê This utility greatly decreases the amount of component specific code you
need to write and is configurable at the endpoint and component levels.Ê The following
examples demonstrate how to use the utility with the Jetty component.
Programmatic configuration of the component
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/keystore.jks");
ksp.setPassword("keystorePassword");
KeyManagersParameters kmp = new KeyManagersParameters();
kmp.setKeyStore(ksp);
kmp.setKeyPassword("keyPassword");
SSLContextParameters scp = new SSLContextParameters();
scp.setKeyManagers(kmp);
JettyComponent jettyComponent = getContext().getComponent("jetty",
JettyComponent.class);
jettyComponent.setSslContextParameters(scp);
Spring DSL based configuration of endpoint
...
...
...
...
Configuring Jetty Directly
Jetty provides SSL support out of the box. To enable Jetty to run in SSL mode, simply format
the URI with the https:// prefix---for example:
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Jetty also needs to know where to load your keystore from and what passwords to use in
order to load the correct SSL certificate. Set the following JVM System Properties:
until Camel 2.2
• jetty.ssl.keystore specifies the location of the Java keystore file, which
contains the Jetty server's own X.509 certificate in a key entry. A key entry stores the
X.509 certificate (effectively, the public key) and also its associated private key.
• jetty.ssl.password the store password, which is required to access the
keystore file (this is the same password that is supplied to the keystore command's
-storepass option).
• jetty.ssl.keypassword the key password, which is used to access the
certificate's key entry in the keystore (this is the same password that is supplied to
the keystore command's -keypass option).
from Camel 2.3 onwards
• org.eclipse.jetty.ssl.keystore specifies the location of the Java keystore
file, which contains the Jetty server's own X.509 certificate in a key entry. A key entry
stores the X.509 certificate (effectively, the public key) and also its associated private
key.
• org.eclipse.jetty.ssl.password the store password, which is required to
access the keystore file (this is the same password that is supplied to the keystore
command's -storepass option).
• org.eclipse.jetty.ssl.keypassword the key password, which is used to
access the certificate's key entry in the keystore (this is the same password that is
supplied to the keystore command's -keypass option).
For details of how to configure SSL on a Jetty endpoint, read the following documentation at
the Jetty Site: http://docs.codehaus.org/display/JETTY/How+to+configure+SSL
Some SSL properties aren't exposed directly by Camel, however Camel does expose the
underlying SslSocketConnector, which will allow you to set properties like needClientAuth for
mutual authentication requiring a client certificate or wantClientAuth for mutual authentication
where a client doesn't need a certificate but can have one. There's a slight difference between
Camel 1.6.x and 2.x:
Camel 1.x
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until Camel 2.2
Camel 2.3, 2.4
*From Camel 2.5 we switch to use SslSelectChannelConnector *
The value you use as keys in the above map is the port you configure Jetty to listen on.
Configuring general SSL properties
Available as of Camel 2.5
Instead of a per port number specific SSL socket connector (as shown above) you can now
configure general properties which applies for all SSL socket connectors (which is not explicit
configured as above with the port number as entry).
How to obtain reference to the X509Certificate
Jetty stores a reference to the certificate in the HttpServletRequest which you can access from
code as follows:
HttpServletRequest req = exchange.getIn().getBody(HttpServletRequest.class);
X509Certificate cert = (X509Certificate)
req.getAttribute("javax.servlet.request.X509Certificate")
Configuring general HTTP properties
Available as of Camel 2.5
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Instead of a per port number specific HTTP socket connector (as shown above) you can
now configure general properties which applies for all HTTP socket connectors (which is not
explicit configured as above with the port number as entry).
Default behavior for returning HTTP status codes
The default behavior of HTTP status codes is defined by the
org.apache.camel.component.http.DefaultHttpBinding class, which handles
how a response is written and also sets the HTTP status code.
If the exchange was processed successfully, the 200 HTTP status code is returned.
If the exchange failed with an exception, the 500 HTTP status code is returned, and the
stacktrace is returned in the body. If you want to specify which HTTP status code to return, set
the code in the HttpProducer.HTTP_RESPONSE_CODE header of the OUT message.
Customizing HttpBinding
Available as of Camel 1.5.1/2.0
By default, Camel uses the
org.apache.camel.component.http.DefaultHttpBinding to handle how a
response is written. If you like, you can customize this behavior either by implementing your
own HttpBinding class or by extending DefaultHttpBinding and overriding the
appropriate methods.
The following example shows how to customize the DefaultHttpBinding in order to
change how exceptions are returned:
public class MyJettyHttpBinding extends DefaultJettyHttpBinding {
@Override
protected void populateResponse(Exchange exchange, JettyContentExchange
httpExchange, Message in,
HeaderFilterStrategy strategy, int responseCode)
throws IOException {
Message answer = exchange.getOut();
answer.setHeaders(in.getHeaders());
answer.setHeader(Exchange.HTTP_RESPONSE_CODE, responseCode);
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answer.setBody("Not exactly the message the server returned.");
}
}
We can then create an instance of our binding and register it in the Spring registry as follows:
And then we can reference this binding when we define the route:
Jetty handlers and security configuration
Available as of Camel 1.6.1/2.0: You can configure a list of Jetty handlers on the
endpoint, which can be useful for enabling advanced Jetty security features. These handlers are
configured in Spring XML as follows:
<-- Jetty Security handling -->
And from Camel 2.3 onwards you can configure a list of Jetty handlers as follows:
<-- Jetty Security handling -->
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You can then define the endpoint as:
from("jetty:http://0.0.0.0:9080/myservice?handlers=securityHandler")
If you need more handlers, set the handlers option equal to a comma-separated list of bean
IDs.
How to return a custom HTTP 500 reply message
You may want to return a custom reply message when something goes wrong, instead of the
default reply message Camel Jetty replies with.
You could use a custom HttpBinding to be in control of the message mapping, but often it
may be easier to use Camel's Exception Clause to construct the custom reply message. For
example as show here, where we return Dude something went wrong with HTTP error
code 500:
from("jetty://http://localhost:{{port}}/myserver")
// use onException to catch all exceptions and return a custom reply message
.onException(Exception.class)
.handled(true)
// create a custom failure response
.transform(constant("Dude something went wrong"))
// we must remember to set error code 500 as handled(true)
// otherwise would let Camel thing its a OK response (200)
.setHeader(Exchange.HTTP_RESPONSE_CODE, constant(500))
.end()
// now just force an exception immediately
.throwException(new IllegalArgumentException("I cannot do this"));
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Multi-part Form support
From Camel 2.3.0, camel-jetty support to multipart form post out of box. The submitted formdata are mapped into the message header. Camel-jetty creates an attachment for each uploaded
file. The file name is mapped to the name of the attachment. The content type is set as the
content type of the attachment file name. You can find the example here.
Listing 70. Note: getName() functions as shown below in versions 2.5 and
higher. In earlier versions you receive the temporary file name for the
attachment instead
// Set the jetty temp directory which store the file for multi part form
// camel-jetty will clean up the file after it handled the request.
// The option works rightly from Camel 2.4.0
getContext().getProperties().put("CamelJettyTempDir", "target");
from("jetty://http://localhost:{{port}}/test").process(new Processor() {
public void process(Exchange exchange) throws Exception {
Message in = exchange.getIn();
assertEquals("Get a wrong attachement size", 1, in.getAttachments().size());
// The file name is attachment id
DataHandler data = in.getAttachment("NOTICE.txt");
assertNotNull("Should get the DataHandle NOTICE.txt", data);
// This assert is wrong, but the correct content-type (application/
octet-stream)
// will not be returned until Jetty makes it available - currently the
content-type
// returned is just the default for FileDataHandler (for the implentation
being used)
//assertEquals("Get a wrong content type", "text/plain",
data.getContentType());
assertEquals("Got the wrong name", "NOTICE.txt", data.getName());
assertTrue("We should get the data from the DataHandle", data.getDataSource()
.getInputStream().available() > 0);
// The other form date can be get from the message header
exchange.getOut().setBody(in.getHeader("comment"));
}
});
Jetty JMX support
From Camel 2.3.0, camel-jetty supports the enabling of Jetty's JMX capabilities at the
component and endpoint level with the endpoint configuration taking priority. Note that JMX
must be enabled within the Camel context in order to enable JMX support in this component
as the component provides Jetty with a reference to the MBeanServer registered with the
Camel context. Because the camel-jetty component caches and reuses Jetty resources for a
given protocol/host/port pairing, this configuration option will only be evaluated during the
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creation of the first endpoint to use a protocol/host/port pairing. For example, given two
routes created from the following XML fragments, JMX support would remain enabled for all
endpoints listening on "https://0.0.0.0".
The camel-jetty component also provides for direct configuration of the Jetty MBeanContainer.
Jetty creates MBean names dynamically. If you are running another instance of Jetty outside of
the Camel context and sharing the same MBeanServer between the instances, you can provide
both instances with a reference to the same MBeanContainer in order to avoid name collisions
when registering Jetty MBeans.
See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
HTTP
JING COMPONENT
The Jing component uses the Jing Library to perform XML validation of the message body using
either
• RelaxNG XML Syntax
• RelaxNG Compact Syntax
Maven users will need to add the following dependency to their pom.xml for this component:
org.apache.camelcamel-jingx.x.x
Note that the MSV component can also support RelaxNG XML syntax.
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URI format
rng:someLocalOrRemoteResource
rnc:someLocalOrRemoteResource
Where rng means use the RelaxNG XML Syntax whereas rnc means use RelaxNG Compact
Syntax. The following examples show possible URI values
Example
Description
rng:foo/bar.rng
References the XML file foo/bar.rng on the classpath
rnc: http://foo.com/
bar.rnc
References the RelaxNG Compact Syntax file from the URL,
http://foo.com/bar.rnc
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
useDom
false
Camel 2.0: Specifies whether DOMSource/DOMResult or
SaxSource/SaxResult should be used by the validator.
Example
The following example shows how to configure a route from the endpoint direct:start which
then goes to one of two endpoints, either mock:valid or mock:invalid based on whether
or not the XML matches the given RelaxNG Compact Syntax schema (which is supplied on the
classpath).
org.apache.camel.ValidationException
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See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
JMS COMPONENT
The JMS component allows messages to be sent to (or consumed from) a JMS Queue or Topic.
The implementation of the JMS Component uses Spring's JMS support for declarative
transactions, using Spring's JmsTemplate for sending and a
MessageListenerContainer for consuming.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jmsx.x.x
URI format
jms:[queue:|topic:]destinationName[?options]
Where destinationName is a JMS queue or topic name. By default, the
destinationName is interpreted as a queue name. For example, to connect to the queue,
FOO.BAR use:
jms:FOO.BAR
You can include the optional queue: prefix, if you prefer:
jms:queue:FOO.BAR
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Using ActiveMQ
If you are using Apache ActiveMQ, you should prefer the ActiveMQ component as
it has been optimized for ActiveMQ. All of the options and samples on this page are
also valid for the ActiveMQ component.
Transacted and caching
See section Transactions and Cache Levels below if you are using transactions with
JMS as it can impact performance.
To connect to a topic, you must include the topic: prefix. For example, to
connect to the topic, Stocks.Prices, use:
jms:topic:Stocks.Prices
You append query options to the URI using the following format,
?option=value&option=value&...
Notes
Using ActiveMQ
The JMS component reuses Spring 2's JmsTemplate for sending messages. This is not ideal
for use in a non-J2EE container and typically requires some caching in the JMS provider to avoid
poor performance.
If you intend to use Apache ActiveMQ as your Message Broker - which is a good choice as
ActiveMQ rocks
, then we recommend that you either:
• Use the ActiveMQ component, which is already optimized to use ActiveMQ
efficiently
• Use the PoolingConnectionFactory in ActiveMQ.
Transactions and Cache Levels
If you are consuming messages and using transactions (transacted=true) then the default
settings for cache level can impact performance.
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If you are using XA transactions then you cannot cache as it can cause the XA transaction not
to work properly.
If you are not using XA, then you should consider caching as it speedup performance, such
as setting cacheLevelName=CACHE_CONSUMER.
Through Camel 2.7.x, the default setting for cacheLevelName is CACHE_CONSUMER.
You will need to explicitly set cacheLevelName=CACHE_NONE.
In Camel 2.8 onwards, the default setting for cacheLevelName is CACHE_AUTO. This
default auto detects the mode and sets the cache level accordingly to:
▪ CACHE_CONSUMER = if transacted=false
▪ CACHE_NONE = if transacted=true
So you can say the default setting is conservative. Consider using
cacheLevelName=CACHE_CONSUMER if you are using non-XA transactions.
Durable Subscriptions
If you wish to use durable topic subscriptions, you need to specify both clientId and
durableSubscriptionName. The value of the clientId must be unique and can only be
used by a single JMS connection instance in your entire network. You may prefer to use Virtual
Topics instead to avoid this limitation. More background on durable messaging here.
Message Header Mapping
When using message headers, the JMS specification states that header names must be valid Java
identifiers. So, by default, Camel ignores any headers that do not match this rule. So try to
name your headers as if they are valid Java identifiers. One benefit of doing this is that you can
then use your headers inside a JMS Selector (whose SQL92 syntax mandates Java identifier
syntax for headers).
From Camel 1.4 onwards, a simple strategy for mapping header names is used by default.
The strategy is to replace any dots in the header name with the underscore character and to
reverse the replacement when the header name is restored from a JMS message sent over the
wire. What does this mean? No more losing method names to invoke on a bean component, no
more losing the filename header for the File Component, and so on.
The current header name strategy for accepting header names in Camel is as follows:
▪ Replace all dots with underscores (for example,
org.apache.camel.MethodName becomes
org_apache_camel_MethodName).
▪ Test if the name is a valid java identifier using the JDK core classes.
▪ If the test success, the header is added and sent over the wire; otherwise it is
dropped (and logged at DEBUG level).
In Camel 2.0 this strategy has been change a bit to use the following replacement strategy:
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▪ Dots are replaced by _DOT_ and the replacement is reversed when Camel consume
the message
▪ Hyphen is replaced by _HYPHEN_ and the replacement is reversed when Camel
consumes the message
Options
You can configure many different properties on the JMS endpoint which map to properties on
the JMSConfiguration POJO.
The options are divided into two tables, the first one with the most common options used. The
latter contains the rest.
Most commonly used options
Option
Default
Value
Description
clientId
null
Sets the JMS client ID to use. Note that this value, if specified, must be unique and can only be used by a single JMS
connection instance. It is typically only required for durable topic subscriptions. You may prefer to use Virtual Topics
instead.
concurrentConsumers
1
Specifies the default number of concurrent consumers.
disableReplyTo
false
If true, a producer will behave like a InOnly exchange with the exception that JMSReplyTo header is sent out and not
be suppressed like in the case of InOnly. Like InOnly the producer will not wait for a reply. A consumer with this flag
will behave like InOnly. This feature can be used to bridge InOut requests to another queue so that a route on the
other queue will send it«s response directly back to the original JMSReplyTo.
durableSubscriptionName
null
The durable subscriber name for specifying durable topic subscriptions. The clientId option must be configured as
well.
maxConcurrentConsumers
1
Specifies the maximum number of concurrent consumers.
preserveMessageQos
false
Camel 2.0: Set to true, if you want to send message using the QoS settings specified on the message, instead of the
QoS settings on the JMS endpoint. The following three headers are considered JMSPriority, JMSDeliveryMode,
and JMSExpiration. You can provide all or only some of them. If not provided, Camel will fall back to use the values
from the endpoint instead. So, when using this option, the headers override the values from the endpoint. The
explicitQosEnabled option, by contrast, will only use options set on the endpoint, and not values from the message
header.
replyTo
null
Provides an explicit ReplyTo destination, which overrides any incoming value of Message.getJMSReplyTo(). If you
do Request Reply over JMS then read the section further below for more details.
replyToType
null
Camel 2.9: Allows to explicit specify which kind of strategy to use for replyTo queues when doing request/reply over
JMS. Possible values are: Temporary, Shared, or Exclusive. By default Camel will use temporary queues. However
if replyTo has been configured, then Shared is used by default. This option allows you to use exclusive instead of
shared queues. See further below for more details, and especially the notes about the implications if running in a clustered
environment.
requestTimeout
20000
Producer only: The timeout for waiting for a reply when using the InOut Exchange Pattern (in milliseconds). The
default is 20 seconds. See below in section About time to live for more details.
selector
null
Sets the JMS Selector, which is an SQL 92 predicate that is used to filter messages within the broker. You may have to
encode special characters such as = as %3D Before Camel 2.3.0, we don't support this option in
CamelConsumerTemplate
timeToLive
null
When sending messages, specifies the time-to-live of the message (in milliseconds). See below in section About time to live
for more details.
transacted
false
Specifies whether to use transacted mode for sending/receiving messages using the InOnly Exchange Pattern.
testConnectionOnStartup
false
Camel 2.1: Specifies whether to test the connection on startup. This ensures that when Camel starts that all the JMS
consumers have a valid connection to the JMS broker. If a connection cannot be granted then Camel throws an exception
on startup. This ensure that Camel is not started with failed connections. From Camel 2.8 onwards also the JMS
producers is tested as well.
All the other options
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Mapping to Spring JMS
Many of these properties map to properties on Spring JMS, which Camel uses for
sending and receiving messages. So you can get more information about these
properties by consulting the relevant Spring documentation.
Option
Default Value
Description
autoStartup
true
Specifies whether the consumer container should auto-startup.
acceptMessagesWhileStopping
false
Specifies whether the consumer accept messages while it is stopping.
acknowledgementModeName
AUTO_ACKNOWLEDGE
The JMS acknowledgement name, which is one of: TRANSACTED, CLIENT_ACKNOWLEDGE,
AUTO_ACKNOWLEDGE, DUPS_OK_ACKNOWLEDGE
acknowledgementMode
-1
The JMS acknowledgement mode defined as an Integer. Allows you to set vendor-specific
extensions to the acknowledgment mode. For the regular modes, it is preferable to use the
acknowledgementModeName instead.
alwaysCopyMessage
false
If true, Camel will always make a JMS message copy of the message when it is passed to the
producer for sending. Copying the message is needed in some situations, such as when a
replyToDestinationSelectorName is set (incidentally, Camel will set the
alwaysCopyMessage option to true, if a replyToDestinationSelectorName is
set)
false
Camel 2.9: Whether the JmsConsumer processes the Exchange asynchronously. If enabled
then the JmsConsumer may pickup the next message from the JMS queue, while the
previous message is being processed asynchronously (by the Asynchronous Routing Engine).
This means that messages may be processed not 100% strictly in order. If disabled (as default)
then the Exchange is fully processed before the JmsConsumer will pickup the next message
from the JMS queue. Note if transacted has been enabled, then asyncConsumer=true
does not run asynchronously, as transactions must be executed synchronously (Camel 3.0 may
support async transactions).
asyncConsumer
711
cacheLevelName
▪
Sets the cache level by name for the underlying JMS resources. Possible values are:
CACHE_AUTO, CACHE_CONNECTION, CACHE_CONSUMER, CACHE_NONE, and
CACHE_SESSION. The default setting for Camel 2.8 and newer is CACHE_AUTO. For
Camel 2.7.1 and older the default is CACHE_CONSUMER. See the Spring documentation and
Transactions Cache Levels for more information.
cacheLevel
▪
Sets the cache level by ID for the underlying JMS resources. See cacheLevelName option
for more details.
consumerType
Default
The consumer type to use, which can be one of: Simple or Default. The consumer type
determines which Spring JMS listener to use. Default will use
org.springframework.jms.listener.DefaultMessageListenerContainer,
Simple will use
org.springframework.jms.listener.SimpleMessageListenerContainer.
This option was temporary removed in Camel 2.7 and 2.8. But has been added back from
Camel 2.9 onwards.
connectionFactory
null
The default JMS connection factory to use for the listenerConnectionFactory and
templateConnectionFactory, if neither is specified.
deliveryPersistent
true
Specifies whether persistent delivery is used by default.
destination
null
Camel 2.0: Specifies the JMS Destination object to use on this endpoint.
destinationName
null
Camel 2.0: Specifies the JMS destination name to use on this endpoint.
destinationResolver
null
A pluggable
org.springframework.jms.support.destination.DestinationResolver
that allows you to use your own resolver (for example, to lookup the real destination in a
JNDI registry).
disableTimeToLive
false
Camel 2.8: Use this option to force disabling time to live. For example when you do
request/reply over JMS, then Camel will by default use the requestTimeout value as time
to live on the message being send. The problem is that the sender and receiver systems have
to have their clocks synchronized, so they are in sync. This is not always so easy to archive. So
you can use disableTimeToLive=true to not set a time to live value on the send
message. Then the message will not expire on the receiver system. See below in section About
time to live for more details.
eagerLoadingOfProperties
false
Enables eager loading of JMS properties as soon as a message is received, which is generally
inefficient, because the JMS properties might not be required. But this feature can sometimes
catch early any issues with the underlying JMS provider and the use of JMS properties. This
feature can also be used for testing purposes, to ensure JMS properties can be understood and
handled correctly.
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exceptionListener
null
Specifies the JMS Exception Listener that is to be notified of any underlying JMS exceptions.
errorHandler
null
Camel 2.8.2, 2.9: Specifies a org.springframework.util.ErrorHandler to be
invoked in case of any uncaught exceptions thrown while processing a Message. By default
these exceptions will be logged at the ERROR level.
explicitQosEnabled
false
Set if the deliveryMode, priority or timeToLive qualities of service should be used
when sending messages. This option is based on Spring's JmsTemplate. The
deliveryMode, priority and timeToLive options are applied to the current
endpoint. This contrasts with the preserveMessageQos option, which operates at
message granularity, reading QoS properties exclusively from the Camel In message headers.
exposeListenerSession
true
Specifies whether the listener session should be exposed when consuming messages.
forceSendOriginalMessage
false
Camel 2.7: When using mapJmsMessage=false Camel will create a new JMS message
to send to a new JMS destination if you touch the headers (get or set) during the route. Set
this option to true to force Camel to send the original JMS message that was received.
idleTaskExecutionLimit
1
Specifies the limit for idle executions of a receive task, not having received any message within
its execution. If this limit is reached, the task will shut down and leave receiving to other
executing tasks (in the case of dynamic scheduling; see the maxConcurrentConsumers
setting).
idleConsumerLimit
1
Camel 2.8.2, 2.9: Specify the limit for the number of consumers that are allowed to be idle
at any given time.
jmsMessageType
null
Camel 2.0: Allows you to force the use of a specific javax.jms.Message
implementation for sending JMS messages. Possible values are: Bytes, Map, Object,
Stream, Text. By default, Camel would determine which JMS message type to use from the
In body type. This option allows you to specify it.
jmsKeyFormatStrategy
default
Camel 2.0: Pluggable strategy for encoding and decoding JMS keys so they can be compliant
with the JMS specification. Camel provides two implementations out of the box: default
and passthrough. The default strategy will safely marshal dots and hyphens (. and -).
The passthrough strategy leaves the key as is. Can be used for JMS brokers which do not
care whether JMS header keys contain illegal characters. You can provide your own
implementation of the
org.apache.camel.component.jms.JmsKeyFormatStrategy and refer to it
using the # notation.
jmsOperations
null
Allows you to use your own implementation of the
org.springframework.jms.core.JmsOperations interface. Camel uses
JmsTemplate as default. Can be used for testing purpose, but not used much as stated in
the spring API docs.
lazyCreateTransactionManager
true
Camel 2.0: If true, Camel will create a JmsTransactionManager, if there is no
transactionManager injected when option transacted=true.
listenerConnectionFactory
null
The JMS connection factory used for consuming messages.
mapJmsMessage
true
Camel 1.6.2/2.0: Specifies whether Camel should auto map the received JMS message to an
appropiate payload type, such as javax.jms.TextMessage to a String etc. See section
about how mapping works below for more details.
maxMessagesPerTask
-1
The number of messages per task. -1 is unlimited.
maximumBrowseSize
-1
Limits the number of messages fetched at most, when browsing endpoints using Browse or
JMX API.
messageConverter
null
Camel 1.6.2/2.0: To use a custom Spring
org.springframework.jms.support.converter.MessageConverter so you
can be 100% in control how to map to/from a javax.jms.Message.
messageIdEnabled
true
When sending, specifies whether message IDs should be added.
messageTimestampEnabled
true
Specifies whether timestamps should be enabled by default on sending messages.
password
null
The password for the connector factory.
priority
4
Values greater than 1 specify the message priority when sending (where 0 is the lowest
priority and 9 is the highest). The explicitQosEnabled option must also be enabled in
order for this option to have any effect.
pubSubNoLocal
false
Specifies whether to inhibit the delivery of messages published by its own connection.
receiveTimeout
None
The timeout for receiving messages (in milliseconds).
recoveryInterval
5000
Specifies the interval between recovery attempts, i.e. when a connection is being refreshed, in
milliseconds. The default is 5000 ms, that is, 5 seconds.
replyToDestinationSelectorName
null
Sets the JMS Selector using the fixed name to be used so you can filter out your own replies
from the others when using a shared queue (that is, if you are not using a temporary reply
queue).
replyToDeliveryPersistent
true
Specifies whether to use persistent delivery by default for replies.
subscriptionDurable
false
@deprecated: Enabled by default, if you specify a durableSubscriberName and a
clientId.
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taskExecutor
null
Allows you to specify a custom task executor for consuming messages.
taskExecutorSpring2
null
Camel 2.6: To use when using Spring 2.x with Camel. Allows you to specify a custom task
executor for consuming messages.
templateConnectionFactory
null
The JMS connection factory used for sending messages.
transactedInOut
false
@deprecated: Specifies whether to use transacted mode for sending messages using the
InOut Exchange Pattern. Applies only to producer endpoints. See section Enabling Transacted
Consumption for more details.
transactionManager
null
The Spring transaction manager to use.
transactionName
"JmsConsumer[destinationName]"
The name of the transaction to use.
transactionTimeout
null
The timeout value of the transaction, if using transacted mode.
transferException
false
Camel 2.0: If enabled and you are using Request Reply messaging (InOut) and an Exchange
failed on the consumer side, then the caused Exception will be send back in response as a
javax.jms.ObjectMessage. If the client is Camel, the returned Exception is
rethrown. This allows you to use Camel JMS as a bridge in your routing - for example, using
persistent queues to enable robust routing. Notice that if you also have transferExchange
enabled, this option takes precedence. The caught exception is required to be serializable. The
original Exception on the consumer side can be wrapped in an outer exception such as
org.apache.camel.RuntimeCamelException when returned to the producer.
transferExchange
false
Camel 2.0: You can transfer the exchange over the wire instead of just the body and
headers. The following fields are transferred: In body, Out body, Fault body, In headers, Out
headers, Fault headers, exchange properties, exchange exception. This requires that the
objects are serializable. Camel will exclude any non-serializable objects and log it at WARN
level.
username
null
The username for the connector factory.
useMessageIDAsCorrelationID
false
Specifies whether JMSMessageID should always be used as JMSCorrelationID for
InOut messages.
useVersion102
false
@deprecated (removed from Camel 2.5 onwards): Specifies whether the old JMS
API should be used.
Message Mapping between JMS and Camel
Camel automatically maps messages between javax.jms.Message and
org.apache.camel.Message.
When sending a JMS message, Camel converts the message body to the following JMS
message types:
Body Type
JMS Message
Comment
String
javax.jms.TextMessage
Ê
org.w3c.dom.Node
javax.jms.TextMessage
The DOM will be converted to String.
Map
javax.jms.MapMessage
Ê
java.io.Serializable
javax.jms.ObjectMessage
Ê
byte[]
javax.jms.BytesMessage
Ê
java.io.File
javax.jms.BytesMessage
Ê
java.io.Reader
javax.jms.BytesMessage
Ê
java.io.InputStream
javax.jms.BytesMessage
Ê
java.nio.ByteBuffer
javax.jms.BytesMessage
Ê
When receiving a JMS message, Camel converts the JMS message to the following body type:
713
JMS Message
Body Type
javax.jms.TextMessage
String
javax.jms.BytesMessage
byte[]
javax.jms.MapMessage
Map
javax.jms.ObjectMessage
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Disabling auto-mapping of JMS messages
Available as of Camel 1.6.2/2.0
You can use the mapJmsMessage option to disable the auto-mapping above. If disabled,
Camel will not try to map the received JMS message, but instead uses it directly as the payload.
This allows you to avoid the overhead of mapping and let Camel just pass through the JMS
message. For instance, it even allows you to route javax.jms.ObjectMessage JMS
messages with classes you do not have on the classpath.
Using a custom MessageConverter
Available as of Camel 1.6.2/2.0
You can use the messageConverter option to do the mapping yourself in a Spring
org.springframework.jms.support.converter.MessageConverter class.
For example, in the route below we use a custom message converter when sending a
message to the JMS order queue:
from("file://inbox/
order").to("jms:queue:order?messageConverter=#myMessageConverter");
You can also use a custom message converter when consuming from a JMS destination.
Controlling the mapping strategy selected
Available as of Camel 2.0
You can use the jmsMessageType option on the endpoint URL to force a specific
message type for all messages.
In the route below, we poll files from a folder and send them as javax.jms.TextMessage
as we have forced the JMS producer endpoint to use text messages:
from("file://inbox/order").to("jms:queue:order?jmsMessageType=Text");
You can also specify the message type to use for each messabe by setting the header with the
key CamelJmsMessageType. For example:
from("file://inbox/order").setHeader("CamelJmsMessageType",
JmsMessageType.Text).to("jms:queue:order");
The possible values are defined in the enum class,
org.apache.camel.jms.JmsMessageType.
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Message format when sending
The exchange that is sent over the JMS wire must conform to the JMS Message spec.
For the exchange.in.header the following rules apply for the header keys:
▪ Keys starting with JMS or JMSX are reserved.
▪ exchange.in.headers keys must be literals and all be valid Java identifiers (do
not use dots in the key name).
▪ From Camel 1.4 until Camel 1.6.x, Camel automatically replaces all dots with
underscores in key names. This replacement is reversed when Camel consumes JMS
messages.
▪ From Camel 2.0 onwards, Camel replaces dots & hyphens and the reverse when
when consuming JMS messages:
. is replaced by _DOT_ and the reverse replacement when Camel consumes the
message.
- is replaced by _HYPHEN_ and the reverse replacement when Camel consumes the
message.
▪ See also the option jmsKeyFormatStrategy introduced in Camel 2.0, which
allows you to use your own custom strategy for formatting keys.
For the exchange.in.header, the following rules apply for the header values:
▪ The values must be primitives or their counter objects (such as Integer, Long,
Character). The types, String, CharSequence, Date, BigDecimal and
BigInteger are all converted to their toString() representation. All other
types are dropped.
Camel will log with category org.apache.camel.component.jms.JmsBinding at
DEBUG level if it drops a given header value. For example:
2008-07-09 06:43:04,046 [main
] DEBUG JmsBinding
- Ignoring non primitive header: order of class:
org.apache.camel.component.jms.issues.DummyOrder with value: DummyOrder{orderId=333,
itemId=4444, quantity=2}
Message format when receiving
Camel adds the following properties to the Exchange when it receives a message:
Property
Type
Description
org.apache.camel.jms.replyDestination
javax.jms.Destination
The reply destination.
Camel adds the following JMS properties to the In message headers when it receives a JMS
message:
715
Header
Type
Description
JMSCorrelationID
String
The JMS correlation ID.
JMSDeliveryMode
int
The JMS delivery mode.
JMSDestination
javax.jms.Destination
The JMS destination.
JMSExpiration
long
The JMS expiration.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
JMSMessageID
String
The JMS unique message ID.
JMSPriority
int
The JMS priority (with 0 as the lowest priority and 9 as the highest).
JMSRedelivered
boolean
Is the JMS message redelivered.
JMSReplyTo
javax.jms.Destination
The JMS reply-to destination.
JMSTimestamp
long
The JMS timestamp.
JMSType
String
The JMS type.
JMSXGroupID
String
The JMS group ID.
As all the above information is standard JMS you can check the JMS documentation for further
details.
About using Camel to send and receive messages and JMSReplyTo
The JMS component is complex and you have to pay close attention to how it works in some
cases. So this is a short summary of some of the areas/pitfalls to look for.
When Camel sends a message using its JMSProducer, it checks the following conditions:
▪ The message exchange pattern,
▪ Whether a JMSReplyTo was set in the endpoint or in the message headers,
▪ Whether any of the following options have been set on the JMS endpoint:
disableReplyTo, preserveMessageQos, explicitQosEnabled.
All this can be a tad complex to understand and configure to support your use case.
JmsProducer
The JmsProducer behaves as follows, depending on configuration:
Exchange
Pattern
Other
options
Description
InOut
-
Camel will expect a reply, set a temporary JMSReplyTo, and after sending the message, it will start to listen for the reply message on
the temporary queue.
InOut
JMSReplyTo
is set
Camel will expect a reply and, after sending the message, it will start to listen for the reply message on the specified JMSReplyTo
queue.
InOnly
-
Camel will send the message and not expect a reply.
InOnly
JMSReplyTo
is set
By default, Camel discards the JMSReplyTo destination and clears the JMSReplyTo header before sending the message. Camel then
sends the message and does not expect a reply. Camel logs this in the log at WARN level (changed to DEBUG level from Camel 2.6
onwards. You can use preserveMessageQuo=true to instruct Camel to keep the JMSReplyTo. In all situations the
JmsProducer does not expect any reply and thus continue after sending the message.
JmsConsumer
The JmsConsumer behaves as follows, depending on configuration:
Exchange Pattern
Other options
Description
InOut
-
Camel will send the reply back to the JMSReplyTo queue.
InOnly
-
Camel will not send a reply back, as the pattern is InOnly.
-
disableReplyTo=true
This option suppresses replies.
So pay attention to the message exchange pattern set on your exchanges.
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If you send a message to a JMS destination in the middle of your route you can specify the
exchange pattern to use, see more at Request Reply.
This is useful if you want to send an InOnly message to a JMS topic:
from("activemq:queue:in")
.to("bean:validateOrder")
.to(ExchangePattern.InOnly, "activemq:topic:order")
.to("bean:handleOrder");
Reuse endpoint and send to different destinations computed at runtime
Available as of Camel 1.6.2/2.0
If you need to send messages to a lot of different JMS destinations, it makes sense to reuse a
JMS endpoint and specify the real destination in a message header. This allows Camel to reuse
the same endpoint, but send to different destinations. This greatly reduces the number of
endpoints created and economizes on memory and thread resources.
You can specify the destination in the following headers:
Header
Type
Description
CamelJmsDestination
javax.jms.Destination
Camel 2.0: A destination object.
CamelJmsDestinationName
String
Camel 1.6.2/2.0: The destination name.
For example, the following route shows how you can compute a destination at run time and
use it to override the destination appearing in the JMS URL:
from("file://inbox")
.to("bean:computeDestination")
.to("activemq:queue:dummy");
The queue name, dummy, is just a placeholder. It must be provided as part of the JMS endpoint
URL, but it will be ignored in this example.
In the computeDestination bean, specify the real destination by setting the
CamelJmsDestinationName header as follows:
public void setJmsHeader(Exchange exchange) {
String id = ....
exchange.getIn().setHeader("CamelJmsDestinationName", "order:" + id");
}
Then Camel will read this header and use it as the destination instead of the one configured on
the endpoint. So, in this example Camel sends the message to activemq:queue:order:2,
assuming the id value was 2.
If both the CamelJmsDestination and the CamelJmsDestinationName headers
are set, CamelJmsDestination takes priority.
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Configuring different JMS providers
You can configure your JMS provider in Spring XML as follows:
Basically, you can configure as many JMS component instances as you wish and give them a
unique name using the id attribute. The preceding example configures an activemq
component. You could do the same to configure MQSeries, TibCo, BEA, Sonic and so on.
Once you have a named JMS component, you can then refer to endpoints within that
component using URIs. For example for the component name, activemq, you can then refer
to destinations using the URI format, activemq:[queue:|topic:]destinationName.
You can use the same approach for all other JMS providers.
This works by the SpringCamelContext lazily fetching components from the spring context
for the scheme name you use for Endpoint URIs and having the Component resolve the
endpoint URIs.
Using JNDI to find the ConnectionFactory
If you are using a J2EE container, you might need to look up JNDI to find the JMS
ConnectionFactory rather than use the usual mechanism in Spring. You can do
this using Spring's factory bean or the new Spring XML namespace. For example:
See The jee schema in the Spring reference documentation for more details about JNDI lookup.
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Concurrent Consuming
A common requirement with JMS is to consume messages concurrently in multiple threads in
order to make an application more responsive. You can set the concurrentConsumers
option to specify the number of threads servicing the JMS endpoint, as follows:
from("jms:SomeQueue?concurrentConsumers=20").
bean(MyClass.class);
You can configure this option in one of the following ways:
• On the JmsComponent,
• On the endpoint URI or,
• By invoking setConcurrentConsumers() directly on the JmsEndpoint.
Request-reply over JMS
Camel supports Request Reply over JMS. In essence the MEP of the Exchange should be InOut
when you send a message to a JMS queue.
The JmsProducer detects the InOut and provides a JMSReplyTo header with the reply
destination to be used. By default Camel uses a temporary queue, but you can use the
replyTo option on the endpoint to specify a fixed reply queue (see more below about fixed
reply queue).
Camel will automatic setup a consumer which listen on the reply queue, so you should not
do anything.
This consumer is a Spring DefaultMessageListenerContainer which listen for replies.
However it's fixed to 1 concurrent consumer.
That means replies will be processed in sequence as there are only 1 thread to process the
replies. If you want to process replies faster, then we need to use concurrency. But not using
the concurrentConsumer option. We should use the threads from the Camel DSL
instead, as shown in the route below:
from(xxx)
.inOut().to("activemq:queue:foo")
.threads(5)
.to(yyy)
.to(zzz);
In this route we instruct Camel to route replies asynchronously using a thread pool with 5
threads.
Request-reply over JMS and using a shared fixed reply queue
If you use a fixed reply queue when doing Request Reply over JMS as shown in the example
below, then pay attention.
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from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar")
.to(yyy)
In this example the fixed reply queue named "bar" is used. By default Camel assumes the queue
is shared when using fixed reply queues, and therefore it uses a JMSSelector to only pickup
the expected reply messages (eg based on the JMSCorrelationID). See next section for
exclusive fixed reply queues. That means its not as fast as temporary queues. You can speedup
how often Camel will pull for reply messages using the receiveTimeout option. By default
its 1000 millis. So to make it faster you can set it to 250 millis to pull 4 times per second as
shown:
from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar&receiveTimeout=250")
.to(yyy)
Notice this will cause the Camel to send pull requests to the message broker more frequent,
and thus require more network traffic.
It is generally recommended to use temporary queues if possible.
Request-reply over JMS and using an exclusive fixed reply
queue
Available as of Camel 2.9
In the previous example, Camel would anticipate the fixed reply queue named "bar" was
shared, and thus it uses a JMSSelector to only consume reply messages which it expects.
However there is a drawback doing this as JMS selectos is slower. Also the consumer on the
reply queue is slower to update with new JMS selector ids. In fact it only updates when the
receiveTimeout option times out, which by default is 1 second. So in theory the reply
messages could take up till about 1 sec to be detected. On the other hand if the fixed reply
queue is exclusive to the Camel reply consumer, then we can avoid using the JMS selectors, and
thus be more performant. In fact as fast as using temporary queues. So in Camel 2.9 onwards
we introduced the ReplyToType option which you can configure to Exclusive
to tell Camel that the reply queue is exclusive as shown in the example below:
from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar?replyToType=Exclusive")
.to(yyy)
Mind that the queue must be exclusive to each and every endpoint. So if you have two routes,
then they each need an unique reply queue as shown in the next example:
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from(xxx)
.inOut().to("activemq:queue:foo?replyTo=bar?replyToType=Exclusive")
.to(yyy)
from(aaa)
.inOut().to("activemq:queue:order?replyTo=order.reply?replyToType=Exclusive")
.to(bbb)
The same applies if you run in a clustered environment. Then each node in the cluster must use
an unique reply queue name. As otherwise each node in the cluster may pickup messages which
was intended as a reply on another node. For clustered environments its recommended to use
shared reply queues instead.
Synchronizing clocks between senders and receivers
When doing messaging between systems, its desirable that the systems have synchronized
clocks. For example when sending a JMS message, then you can set a time to live value on the
message. Then the receiver can inspect this value, and determine if the message is already
expired, and thus drop the message instead of consume and process it. However this requires
that both sender and receiver have synchronized clocks. If you are using ActiveMQ then you
can use the timestamp plugin to synchronize clocks.
About time to live
Read first above about synchronized clocks.
When you do request/reply (InOut) over JMS with Camel then Camel uses a timeout on the
sender side, which is default 20 seconds from the requestTimeout option. You can control
this by setting a higher/lower value. However the time to live value is still set on the JMS
message being send. So that requires the clocks to be synchronized between the systems. If
they are not, then you may want to disable the time to live value being set. This is now possible
using the disableTimeToLive option from Camel 2.8 onwards. So if you set this option
to disableTimeToLive=true, then Camel does not set any time to live value when
sending JMS messages. But the request timeout is still active. So for example if you do request/
reply over JMS and have disabled time to live, then Camel will still use a timeout by 20 seconds
(the requestTimeout option). That option can of course also be configured. So the two
options requestTimeout and disableTimeToLive gives you fine grained control when
doing request/reply.
When you do fire and forget (InOut) over JMS with Camel then Camel by default does not
set any time to live value on the message. You can configure a value by using the timeToLive
option. For example to indicate a 5 sec., you set timeToLive=5000. The option
disableTimeToLive can be used to force disabling the time to live, also for InOnly
messaging. The requestTimeout option is not being used for InOnly messaging.
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Enabling Transacted Consumption
A common requirement is to consume from a queue in a transaction and then process the
message using the Camel route. To do this, just ensure that you set the following properties on
the component/endpoint:
• transacted = true
• transactionManager = a Transsaction Manager - typically the
JmsTransactionManager
See the Transactional Client EIP pattern for further details.
Using JMSReplyTo for late replies
Avaiable as of Camel 2.0
When using Camel as a JMS listener, it sets an Exchange property with the value of the
ReplyTo javax.jms.Destination object, having the key ReplyTo. You can obtain this
Destination as follows:
Destination replyDestination =
exchange.getIn().getHeader(JmsConstants.JMS_REPLY_DESTINATION, Destination.class);
And then later use it to send a reply using regular JMS or Camel.
// we need to pass in the JMS component, and in this sample we use ActiveMQ
JmsEndpoint endpoint = JmsEndpoint.newInstance(replyDestination,
activeMQComponent);
// now we have the endpoint we can use regular Camel API to send a message to it
template.sendBody(endpoint, "Here is the late reply.");
A different solution to sending a reply is to provide the replyDestination object in the
same Exchange property when sending. Camel will then pick up this property and use it for the
real destination. The endpoint URI must include a dummy destination, however. For example:
// we pretend to send it to some non existing dummy queue
template.send("activemq:queue:dummy, new Processor() {
public void process(Exchange exchange) throws Exception {
// and here we override the destination with the ReplyTo destination
object so the message is sent to there instead of dummy
exchange.getIn().setHeader(JmsConstants.JMS_DESTINATION, replyDestination);
exchange.getIn().setBody("Here is the late reply.");
}
}
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Transactions and Request Reply over JMS
When using Request Reply over JMS you cannot use a single transaction; JMS will
not send any messages until a commit is performed, so the server side won't
receive anything at all until the transaction commits. Therefore to use Request
Reply you must commit a transaction after sending the request and then use a
separate transaction for receiving the response.
To address this issue the JMS component uses different properties to specify transaction use
for oneway messaging and request reply messaging:
The transacted property applies only to the InOnly message Exchange Pattern
(MEP).
The transactedInOut property applies to the InOut(Request Reply) message
Exchange Pattern (MEP).
If you want to use transactions for Request Reply(InOut MEP), you must set
transactedInOut=true.
Using a request timeout
In the sample below we send a Request Reply style message Exchange (we use the
requestBody method = InOut) to the slow queue for further processing in Camel and we
wait for a return reply:
// send a in-out with a timeout for 5 sec
Object out = template.requestBody("activemq:queue:slow?requestTimeout=5000", "Hello
World");
Samples
JMS is used in many examples for other components as well. But we provide a few samples
below to get started.
Receiving from JMS
In the following sample we configure a route that receives JMS messages and routes the
message to a POJO:
from("jms:queue:foo").
to("bean:myBusinessLogic");
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You can of course use any of the EIP patterns so the route can be context based. For example,
here's how to filter an order topic for the big spenders:
from("jms:topic:OrdersTopic").
filter().method("myBean", "isGoldCustomer").
to("jms:queue:BigSpendersQueue");
Sending to a JMS
In the sample below we poll a file folder and send the file content to a JMS topic. As we want
the content of the file as a TextMessage instead of a BytesMessage, we need to convert
the body to a String:
from("file://orders").
convertBodyTo(String.class).
to("jms:topic:OrdersTopic");
Using Annotations
Camel also has annotations so you can use POJO Consuming and POJO Producing.
Spring DSL sample
The preceding examples use the Java DSL. Camel also supports Spring XML DSL. Here is the
big spender sample using Spring DSL:
Other samples
JMS appears in many of the examples for other components and EIP patterns, as well in this
Camel documentation. So feel free to browse the documentation. If you have time, check out
the this tutorial that uses JMS but focuses on how well Spring Remoting and Camel works
together Tutorial-JmsRemoting.
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Using JMS as a Dead Letter Queue storing Exchange
Available as of Camel 2.0
Normally, when using JMS as the transport, it only transfers the body and headers as the
payload. If you want to use JMS with a Dead Letter Channel, using a JMS queue as the Dead
Letter Queue, then normally the caused Exception is not stored in the JMS message. You can,
however, use the transferExchange option on the JMS dead letter queue to instruct Camel
to store the entire Exchange in the queue as a javax.jms.ObjectMessage that holds a
org.apache.camel.impl.DefaultExchangeHolder. This allows you to consume
from the Dead Letter Queue and retrieve the caused exception from the Exchange property
with the key Exchange.EXCEPTION_CAUGHT. The demo below illustrates this:
// setup error handler to use JMS as queue and store the entire Exchange
errorHandler(deadLetterChannel("jms:queue:dead?transferExchange=true"));
Then you can consume from the JMS queue and analyze the problem:
from("jms:queue:dead").to("bean:myErrorAnalyzer");
// and in our bean
String body = exchange.getIn().getBody();
Exception cause = exchange.getProperty(Exchange.EXCEPTION_CAUGHT, Exception.class);
// the cause message is
String problem = cause.getMessage();
Using JMS as a Dead Letter Channel storing error only
You can use JMS to store the cause error message or to store a custom body, which you can
initialize yourself. The following example uses the Message Translator EIP to do a
transformation on the failed exchange before it is moved to the JMS dead letter queue:
// we sent it to a seda dead queue first
errorHandler(deadLetterChannel("seda:dead"));
// and on the seda dead queue we can do the custom transformation before its sent to
the JMS queue
from("seda:dead").transform(exceptionMessage()).to("jms:queue:dead");
Here we only store the original cause error message in the transform. You can, however, use
any Expression to send whatever you like. For example, you can invoke a method on a Bean or
use a custom processor.
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Sending an InOnly message and keeping the JMSReplyTo header
When sending to a JMS destination using camel-jms the producer will use the MEP to detect
if its InOnly or InOut messaging. However there can be times where you want to send an
InOnly message but keeping the JMSReplyTo header. To do so you have to instruct Camel to
keep it, otherwise the JMSReplyTo header will be dropped.
For example to send an InOnly message to the foo queue, but with a JMSReplyTo with bar
queue you can do as follows:
template.send("activemq:queue:foo?preserveMessageQos=true", new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getIn().setBody("World");
exchange.getIn().setHeader("JMSReplyTo", "bar");
}
});
Notice we use preserveMessageQos=true to instruct Camel to keep the JMSReplyTo
header.
Setting JMS provider options on the destination
Some JMS providers, like IBM's WebSphere MQ need options to be set on the JMS destination.
For example, you may need to specify the targetClient option. Since targetClient is a
WebSphere MQ option and not a Camel URI option, you need to set that on the JMS
destination name like so:
...
.setHeader("CamelJmsDestinationName", constant("queue:///MY_QUEUE?targetClient=1"))
.to("wmq:queue:MY_QUEUE?useMessageIDAsCorrelationID=true");
Some versions of WMQ won't accept this option on the destination name and you will get an
exception like:
com.ibm.msg.client.jms.DetailedJMSException: JMSCC0005: The specified value
'MY_QUEUE?targetClient=1' is not allowed for 'XMSC_DESTINATION_NAME'
A workaround is to use a custom DestinationResolver:
JmsComponent wmq = new JmsComponent(connectionFactory);
wmq.setDestinationResolver(new DestinationResolver(){
public Destination resolveDestinationName(Session session, String destinationName,
boolean pubSubDomain) throws JMSException {
MQQueueSession wmqSession = (MQQueueSession) session;
return wmqSession.createQueue("queue:///" + destinationName +
"?targetClient=1");
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}
});
See Also
•
•
•
•
▪
▪
▪
▪
Configuring Camel
Component
Endpoint
Getting Started
Transactional Client
Bean Integration
Tutorial-JmsRemoting
JMSTemplate gotchas
JMX COMPONENT
Available as of Camel 2.6
Standard JMX Consumer Configuration
Component allows consumers to subscribe to an mbean's Notifications. The component
supports passing the Notification object directly through the Exchange or serializing it to XML
according to the schema provided within this project. This is a consumer only component.
Exceptions are thrown if you attempt to create a producer for it.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jmxx.x.x
URI Format
The component can connect to the local platform mbean server with the following URI:
jmx://platform?options
A remote mbean server url can be provided following the initial JMX scheme like so:
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jmx:service:jmx:rmi:///jndi/rmi://localhost:1099/jmxrmi?options
You can append query options to the URI in the following format,
?options=value&option2=value&...
URI Options
Property
Required
Default
Description
format
Ê
xml
Format for the message body. Either "xml" or "raw". If xml, the notification is serialized to xml. If raw, then the
raw java object is set as the body.
user
Ê
Ê
Credentials for making a remote connection.
password
Ê
Ê
Credentials for making a remote connection.
objectDomain
yes
Ê
The domain for the mbean you're connecting to.
objectName
Ê
Ê
The name key for the mbean you're connecting to. This value is mutually exclusive with the object properties that
get passed. (see below)
notificationFilter
Ê
Ê
Reference to a bean that implements the NotificationFilter. The #ref syntax should be used to reference
the bean via the Registry.
handback
Ê
Ê
Value to handback to the listener when a notification is received. This value will be put in the message header with
the key "jmx.handback"
ObjectName Construction
The URI must always have the objectDomain property. In addition, the URI must contain either
objectName or one or more properties that start with "key."
Domain with Name property
When the objectName property is provided, the following constructor is used to build the
ObjectName? for the mbean:
ObjectName(String domain, String key, String value)
The key value in the above will be "name" and the value will be the value of the objectName
property.
Domain with Hashtable
ObjectName(String domain, Hashtable table)
The Hashtable is constructed by extracting properties that start with "key." The properties will
have the "key." prefixed stripped prior to building the Hashtable. This allows the URI to contain
a variable number of properties to identify the mbean.
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Example
from("jmx:platform?objectDomain=jmxExample&key.name=simpleBean").
to("log:jmxEvent");
Full example
Monitor Type Consumer
Available as of Camel 2.8
One popular use case for JMX is creating a monitor bean to monitor an attribute on a deployed
bean. This requires writing a few lines of Java code to create the JMX monitor and deploy it. As
shown below:
CounterMonitor monitor = new CounterMonitor();
monitor.addObservedObject(makeObjectName("simpleBean"));
monitor.setObservedAttribute("MonitorNumber");
monitor.setNotify(true);
monitor.setInitThreshold(1);
monitor.setGranularityPeriod(500);
registerBean(monitor, makeObjectName("counter"));
monitor.start();
The 2.8 version introduces a new type of consumer that automatically creates and registers a
monitor bean for the specified objectName and attribute. Additional endpoint attributes allow
the user to specify the attribute to monitor, type of monitor to create, and any other required
properties. The code snippet above is condensed into a set of endpoint properties. The
consumer uses these properties to create the CounterMonitor, register it, and then subscribe
to its changes. All of the JMX monitor types are supported.
Example
from("jmx:platform?objectDomain=myDomain&objectName=simpleBean&" +
"monitorType=counter&observedAttribute=MonitorNumber&initThreshold=1&" +
"granularityPeriod=500").to("mock:sink");
The example above will cause a new Monitor Bean to be created and depoyed to the local
mbean server that monitors the "MonitorNumber" attribute on the "simpleBean." Additional
types of monitor beans and options are detailed below. The newly deployed monitor bean is
automatically undeployed when the consumer is stopped.
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URI Options for Monitor Type
property
type
applies
to
description
monitorType
enum
all
one of counter, guage, string
observedAttribute
string
all
the attribute being observed
granualityPeriod
long
all
granularity period (in millis) for the attribute
being observed. As per JMX, default is 10
seconds
initThreshold
number
counter
initial threshold value
offset
number
counter
offset value
modulus
number
counter
modulus value
differenceMode
boolean
counter,
gauge
true if difference should be reported, false for
actual value
notifyHigh
boolean
gauge
high notification on/off switch
notifyLow
boolean
gauge
low notification on/off switch
highThreshold
number
gauge
threshold for reporting high notification
lowThreshold
number
gauge
threshold for reporting low notificaton
notifyDiffer
boolean
string
true to fire notification when string differs
notifyMatch
boolean
string
true to fire notification when string matches
stringToCompare
string
string
string to compare against the attribute value
The monitor style consumer is only supported for the local mbean server. JMX does not
currently support remote deployment of mbeans without either having the classes already
remotely deployed or an adapter library on both the client and server to facilitate a proxy
deployment.
See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
Camel JMX
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JPA COMPONENT
The jpa component enables you to store and retrieve Java objects from persistent storage
using EJB 3's Java Persistence Architecture (JPA), which is a standard interface layer that wraps
Object/Relational Mapping (ORM) products such as OpenJPA, Hibernate, TopLink, and so on.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jpax.x.x
Sending to the endpoint
You can store a Java entity bean in a database by sending it to a JPA producer endpoint. The
body of the In message is assumed to be an entity bean (that is, a POJO with an @Entity
annotation on it) or a collection or array of entity beans.
If the body does not contain one of the previous listed types, put a Message Translator in
front of the endpoint to perform the necessary conversion first.
Consuming from the endpoint
Consuming messages from a JPA consumer endpoint removes (or updates) entity beans in the
database. This allows you to use a database table as a logical queue: consumers take messages
from the queue and then delete/update them to logically remove them from the queue.
If you do not wish to delete the entity bean when it has been processed, you can specify
consumeDelete=false on the URI. This will result in the entity being processed each poll.
If you would rather perform some update on the entity to mark it as processed (such as to
exclude it from a future query) then you can annotate a method with @Consumed which will
be invoked on your entity bean when the entity bean is consumed.
URI format
jpa:[entityClassName][?options]
For sending to the endpoint, the entityClassName is optional. If specified, it helps the Type
Converter to ensure the body is of the correct type.
For consuming, the entityClassName is mandatory.
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You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
entityType
entityClassName
Overrides the entityClassName from the URI.
persistenceUnit
camel
The JPA persistence unit used by default.
consumeDelete
true
JPA consumer only: If true, the entity is deleted after it is consumed; if false, the entity is not deleted.
consumeLockEntity
true
JPA consumer only: Specifies whether or not to set an exclusive lock on each entity bean while processing the results
from polling.
flushOnSend
true
JPA producer only: Flushes the EntityManager after the entity bean has been persisted.
maximumResults
-1
JPA consumer only: Set the maximum number of results to retrieve on the Query.
transactionManager
null
Camel 1.6.1/2.0: Specifies the transaction manager to use. If none provided, Camel will use a
JpaTransactionManager by default. Can be used to set a JTA transaction manager (for integration with an EJB
container).
consumer.delay
500
JPA consumer only: Delay in milliseconds between each poll.
consumer.initialDelay
1000
JPA consumer only: Milliseconds before polling starts.
consumer.useFixedDelay
false
JPA consumer only: Set to true to use fixed delay between polls, otherwise fixed rate is used. See
ScheduledExecutorService in JDK for details.
maxMessagesPerPoll
0
Camel 2.0: JPA consumer only: An integer value to define the maximum number of messages to gather per poll. By
default, no maximum is set. Can be used to avoid polling many thousands of messages when starting up the server. Set a
value of 0 or negative to disable.
consumer.query
Ê
JPA consumer only: To use a custom query when consuming data.
consumer.namedQuery
Ê
JPA consumer only: To use a named query when consuming data.
consumer.nativeQuery
Ê
JPA consumer only: To use a custom native query when consuming data.
consumer.resultClass
Ê
Camel 2.7: JPA consumer only: Defines the type of the returned payload (we will call
entityManager.createNativeQuery(nativeQuery, resultClass) instead of
entityManager.createNativeQuery(nativeQuery)). Without this option, we will return an object array. Only
has an affect when using in conjunction with native query when consuming data.
consumer.transacted
false
Camel 2.7.5/2.8.3/2.9: JPA consumer only: Whether to run the consumer in transacted mode, by which all
messages will either commit or rollback, when the entire batch has been processed. The default behavior (false) is to
commit all the previously successfully processed messages, and only rollback the last failed message.
usePersist
false
Camel 2.5: JPA producer only: Indicates to use entityManager.persist(entity) instead of
entityManager.merge(entity). Note: entityManager.persist(entity) doesn't work for detached
entities (where the EntityManager has to execute an UPDATE instead of an INSERT query)!
Message Headers
Camel adds the following message headers to the exchange:
Header
Type
Description
CamelJpaTemplate
JpaTemplate
Camel 2.0: The JpaTemplate object that is used to access the entity bean. You need this object in some situations, for instance
in a type converter or when you are doing some custom processing.
Configuring EntityManagerFactory
Its strongly advised to configure the JPA component to use a specific
EntityManagerFactory instance. If failed to do so each JpaEndpoint will auto create
their own instance of EntityManagerFactory which most often is not what you want.
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For example, you can instantiate a JPA component that references the myEMFactory
entity manager factory, as follows:
In Camel 2.3 the JpaComponent will auto lookup the EntityManagerFactory from
the Registry which means you do not need to configure this on the JpaComponent as shown
above. You only need to do so if there is ambiguity, in which case Camel will log a WARN.
Configuring TransactionManager
Its strongly advised to configure the TransactionManager instance used by the JPA
component. If failed to do so each JpaEndpoint will auto create their own instance of
TransactionManager which most often is not what you want.
For example, you can instantiate a JPA component that references the
myTransactionManager transaction manager, as follows:
In Camel 2.3 the JpaComponent will auto lookup the TransactionManager from the
Registry which means you do not need to configure this on the JpaComponent as shown
above. You only need to do so if there is ambiguity, in which case Camel will log a WARN.
Using a consumer with a named query
For consuming only selected entities, you can use the consumer.namedQuery URI query
option. First, you have to define the named query in the JPA Entity class:
@Entity
@NamedQuery(name = "step1", query = "select x from MultiSteps x where x.step = 1")
public class MultiSteps {
...
}
After that you can define a consumer uri like this one:
from("jpa://org.apache.camel.examples.MultiSteps?consumer.namedQuery=step1")
.to("bean:myBusinessLogic");
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Using a consumer with a query
For consuming only selected entities, you can use the consumer.query URI query option.
You only have to define the query option:
from("jpa://org.apache.camel.examples.MultiSteps?consumer.query=select o from
org.apache.camel.examples.MultiSteps o where o.step = 1")
.to("bean:myBusinessLogic");
Using a consumer with a native query
For consuming only selected entities, you can use the consumer.nativeQuery URI query
option. You only have to define the native query option:
from("jpa://org.apache.camel.examples.MultiSteps?consumer.nativeQuery=select * from
MultiSteps where step = 1")
.to("bean:myBusinessLogic");
If you use the native query option, you will receive an object array in the message body.
Example
See Tracer Example for an example using JPA to store traced messages into a database.
Using the JPA based idempotent repository
In this section we will use the JPA based idempotent repository.
First we need to setup a persistence-unit in the persistence.xml file:
org.apache.camel.processor.idempotent.jpa.MessageProcessed
Second we have to setup a org.springframework.orm.jpa.JpaTemplate which is
used by the
org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository:
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Afterwards we can configure our
org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository:
And finally we can create our JPA idempotent repository in the spring XML file as well:
messageId
See Also
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•
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•
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Configuring Camel
Component
Endpoint
Getting Started
Tracer Example
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JT/400 COMPONENT
The jt400 component allows you to exchanges messages with an AS/400 system using data
queues.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-jt400x.x.x
URI format
jt400://user:password@system/QSYS.LIB/LIBRARY.LIB/QUEUE.DTAQ[?options]
To call remote program (Camel 2.7)
jt400://user:password@system/QSYS.LIB/LIBRARY.LIB/program.PGM[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
URI options
For the data queue message exchange:
Name
Default
value
Description
ccsid
default system CCSID
Specifies the CCSID to use for the connection with the AS/400 system.
format
text
Specifies the data format for sending messages
valid options are: text (represented by String) and binary (represented by byte[])
consumer.delay
500
Delay in milliseconds between each poll.
consumer.initialDelay
1000
Milliseconds before polling starts.
consumer.userFixedDelay
false
true to use fixed delay between polls, otherwise fixed rate is used. See ScheduledExecutorService in JDK for
details.
guiAvailable
false
Camel 2.8: Specifies whether AS/400 prompting is enabled in the environment running Camel.
For the remote program call (Camel 2.7)
Name
Default value
Description
outputFieldsIdx
Ê
Specifies which fields (program parameters) are output parameters.
fieldsLength
Ê
Specifies the fields (program parameters) length as in the AS/400 program definition.
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Usage
When configured as a consumer endpoint, the endpoint will poll a data queue on a remote
system. For every entry on the data queue, a new Exchange is sent with the entry's data in
the In message's body, formatted either as a String or a byte[], depending on the format.
For a provider endpoint, the In message body contents will be put on the data queue as either
raw bytes or text.
Remote program call (Camel 2.7)
This endpoint expects the input to be a String array and handles all the CCSID handling trough
the native jt400 library mechanisms. After the program execution the endpoint returns a String
array with the values as they were returned by the program (the input only parameters will
contain the same data as the beginning of the invocation)
This endpoint does not implement a provider endpoint!
Example
In the snippet below, the data for an exchange sent to the direct:george endpoint will be
put in the data queue PENNYLANE in library BEATLES on a system named LIVERPOOL.
Another user connects to the same data queue to receive the information from the data queue
and forward it to the mock:ringo endpoint.
public class Jt400RouteBuilder extends RouteBuilder {
@Override
public void configure() throws Exception {
from("direct:george").to("jt400://GEORGE:EGROEG@LIVERPOOL/QSYS.LIB/BEATLES.LIB/
PENNYLANE.DTAQ");
from("jt400://RINGO:OGNIR@LIVERPOOL/QSYS.LIB/BEATLES.LIB/
PENNYLANE.DTAQ").to("mock:ringo");
}
}
Remote program call example (Camel 2.7)
In the snippet below, the data Exchange sent to the direct:work endpoint will contain three
string that will be used as the arguments for the program ÒcomputeÓ in the library ÒassetsÓ.
This program will write the output values in the 2nd and 3rd parameters. All the parameters
will be sent to the direct:play endpoint.
public class Jt400RouteBuilder extends RouteBuilder {
@Override
public void configure() throws Exception {
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from("direct:work").to("jt400://GRUPO:ATWORK@server/QSYS.LIB/assets.LIB/
compute.PGM?fieldsLength=10,10,512&ouputFieldsIdx=2,3").to(Òdirect:playÓ);
}
}
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
LANGUAGE
Available as of Camel 2.5
The language component allows you to send Exchange to an endpoint which executes a
script by any of the supported Languages in Camel.
By having a component to execute language scripts, it allows more dynamic routing capabilities.
For example by using the Routing Slip or Dynamic Router EIPs you can send messages to
language endpoints where the script is dynamic defined as well.
This component is provided out of the box in camel-core and hence no additional JARs
is needed. You only have to include additional Camel components if the language of choice
mandates it, such as using Groovy or JavaScript languages.
URI format
language://languageName[:script][?options]
URI Options
The component supports the following options.
Name
Default
Value
Type
Description
languageName
null
String
The name of the Language to use, such as simple, groovy, javascript etc. This option is mandatory.
script
null
String
The script to execute.
transform
true
boolean
Whether or not the result of the script should be used as the new message body. By setting to false the script is
executed but the result of the script is discarded.
contentCache
true
boolean
Camel 2.9: Whether to cache the script if loaded from a resource.
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Message Headers
The following message headers can be used to affect the behavior of the component
Header
Description
CamelLanguageScript
The script to execute provided in the header. Takes precedence over script configured on the endpoint.
Examples
For example you can use the Simple language to Message Translator a message:
String script = URLEncoder.encode("Hello ${body}", "UTF-8");
from("direct:start").to("language:simple:" + script).to("mock:result");
In case you want to convert the message body type you can do this as well:
String script = URLEncoder.encode("${mandatoryBodyAs(String)}", "UTF-8");
from("direct:start").to("language:simple:" + script).to("mock:result");
You can also use the Groovy language, such as this example where the input message will by
multiplied with 2:
String script = URLEncoder.encode("request.body * 2", "UTF-8");
from("direct:start").to("language:groovy:" + script).to("mock:result");
You can also provide the script as a header as shown below. Here we use XPath language to
extract the text from the tag.
Object out = producer.requestBodyAndHeader("language:xpath", "Hello World",
Exchange.LANGUAGE_SCRIPT, "/foo/text()");
assertEquals("Hello World", out);
Loading scripts from resources
Available as of Camel 2.9
You can specify a resource uri for a script to load in either the endpoint uri, or in the
Exchange.LANGUAGE_SCRIPT header.
The uri must start with one of the following schemes: file:, classpath:, or http:
For example to load a script from the classpath:
from("direct:start")
// load the script from the classpath
.to("language:simple:classpath:org/apache/camel/component/language/
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mysimplescript.txt")
.to("mock:result");
By default the script is loaded once and cached. However you can disable the contentCache
option and have the script loaded on each evaluation.
For example if the file myscript.txt is changed on disk, then the updated script is used:
from("direct:start")
// the script will be loaded on each message, as we disabled cache
.to("language:simple:file:target/script/myscript.txt?contentCache=false")
.to("mock:result");
See Also
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•
•
•
▪
▪
▪
Configuring Camel
Component
Endpoint
Getting Started
Languages
Routing Slip
Dynamic Router
LDAP COMPONENT
The ldap component allows you to perform searches in LDAP servers using filters as the
message payload.
This component uses standard JNDI (javax.naming package) to access the server.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-ldapx.x.x
URI format
ldap:ldapServerBean[?options]
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The ldapServerBean portion of the URI refers to a DirContext bean in the registry. The LDAP
component only supports producer endpoints, which means that an ldap URI cannot appear
in the from at the start of a route.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
base
ou=system
The base DN for searches.
scope
subtree
Specifies how deeply to search the tree of entries, starting at the base DN. Value can be object, onelevel, or subtree.
pageSize
no paging used
Camel 2.6: When specified the ldap module uses paging to retrieve all results (most LDAP Servers throw an exception when trying
to retrieve more than 1000 entries in one query). To be able to use this a LdapContext (subclass of DirContext) has to be passed in
as ldapServerBean (otherwise an exception is thrown)
returnedAttributes
depends on LDAP
Server (could be
all or none)
Camel 2.6: Comma-separated list of attributes that should be set in each entry of the result
Result
The result is returned in the Out body as a
ArrayList object.
DirContext
The URI, ldap:ldapserver, references a Spring bean with the ID, ldapserver. The
ldapserver bean may be defined as follows:
com.sun.jndi.ldap.LdapCtxFactoryldap://localhost:10389none
The preceding example declares a regular Sun based LDAP DirContext that connects
anonymously to a locally hosted LDAP server.
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DirContext objects are not required to support concurrency by contract. It is
therefore important that the directory context is declared with the setting,
scope="prototype", in the bean definition or that the context supports
concurrency. In the Spring framework, prototype scoped objects are instantiated
each time they are looked up.
Camel 1.6.1 and Camel 2.0 include a fix to support concurrency for LDAP
producers. ldapServerBean contexts are now looked up each time a request is sent
to the LDAP server. In addition, the contexts are released as soon as the producer
completes.
Samples
Following on from the Spring configuration above, the code sample below sends an LDAP
request to filter search a group for a member. The Common Name is then extracted from the
response.
ProducerTemplate template = exchange
.getContext().createProducerTemplate();
Collection results = (Collection) (template
.sendBody(
"ldap:ldapserver?base=ou=mygroup,ou=groups,ou=system",
"(member=uid=huntc,ou=users,ou=system)"));
if (results.size() > 0) {
// Extract what we need from the device's profile
Iterator resultIter = results.iterator();
SearchResult searchResult = (SearchResult) resultIter
.next();
Attributes attributes = searchResult
.getAttributes();
Attribute deviceCNAttr = attributes.get("cn");
String deviceCN = (String) deviceCNAttr.get();
...
If no specific filter is required - for example, you just need to look up a single entry - specify a
wildcard filter expression. For example, if the LDAP entry has a Common Name, use a filter
expression like:
(cn=*)
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Binding using credentials
A Camel end user donated this sample code he used to bind to the ldap server using
credentials.
Properties props = new Properties();
props.setProperty(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
props.setProperty(Context.PROVIDER_URL, "ldap://localhost:389");
props.setProperty(Context.URL_PKG_PREFIXES, "com.sun.jndi.url");
props.setProperty(Context.REFERRAL, "ignore");
props.setProperty(Context.SECURITY_AUTHENTICATION, "simple");
props.setProperty(Context.SECURITY_PRINCIPAL, "cn=Manager");
props.setProperty(Context.SECURITY_CREDENTIALS, "secret");
SimpleRegistry reg = new SimpleRegistry();
reg.put("myldap", new InitialLdapContext(props, null));
CamelContext context = new DefaultCamelContext(reg);
context.addRoutes(
new RouteBuilder() {
public void configure() throws Exception {
from("direct:start").to("ldap:myldap?base=ou=test");
}
}
);
context.start();
ProducerTemplate template = context.createProducerTemplate();
Endpoint endpoint = context.getEndpoint("direct:start");
Exchange exchange = endpoint.createExchange();
exchange.getIn().setBody("(uid=test)");
Exchange out = template.send(endpoint, exchange);
Collection data = out.getOut().getBody(Collection.class);
assert data != null;
assert !data.isEmpty();
System.out.println(out.getOut().getBody());
context.stop();
See Also
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Component
Endpoint
Getting Started
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LOG COMPONENT
The log: component logs message exchanges to the underlying logging mechanism.
Camel 2.7 or better uses sfl4j which allows you to configure logging via, among others:
• Log4j
• Logback
• JDK Util Logging logging
Camel 2.6 or lower uses commons-logging which allows you to configure logging via, among
others:
• Log4j
• JDK Util Logging logging
• SimpleLog - a simple provider in commons-logging
Refer to the commons-logging user guide for a more complete overview of how to use and
configure commons-logging.
URI format
log:loggingCategory[?options]
Where loggingCategory is the name of the logging category to use. You can append query
options to the URI in the following format, ?option=value&option=value&...
For example, a log endpoint typically specifies the logging level using the level option, as
follows:
log:org.apache.camel.example?level=DEBUG
The default logger logs every exchange (regular logging). But Camel also ships with the
Throughput logger, which is used whenever the groupSize option is specified.
Options
Option
Default
Type
Description
level
INFO
String
Logging level to use. Possible values: FATAL, ERROR, WARN, INFO, DEBUG, TRACE, OFF
Ê
Ê
Ê
Throughput logging options. By default regular logging is used.
marker
null
String
Camel 2.9: An optional Marker name to use.
groupSize
null
Integer
An integer that specifies a group size for throughput logging.
groupInterval
null
Integer
Camel 2.6: If specified will group message stats by this time interval (in millis)
groupDelay
0
Integer
Camel 2.6: Set the initial delay for stats (in millis)
groupActiveOnly
true
boolean
Camel 2.6: If true, will hide stats when no new messages have been received for a time interval, if false, show stats
regardless of message traffic
note: groupDelay and groupActiveOnly are only applicable when using groupInterval
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Also a log in the DSL
In Camel 2.2 onwards there is a log directly in the DSL, but it has a different
purpose. Its meant for lightweight and human logs. See more details at LogEIP.
Formatting
The log formats the execution of exchanges to log lines.
By default, the log uses LogFormatter to format the log output, where LogFormatter
has the following options:
Option
Default
Description
showAll
false
Quick option for turning all options on. (multiline, maxChars has to be manually set if to be used)
showExchangeId
false
Show the unique exchange ID.
showExchangePattern
true
Camel 2.3: Shows the Message Exchange Pattern (or MEP for short).
showProperties
false
Show the exchange properties.
showHeaders
false
Show the In message headers.
showBodyType
true
Show the In body Java type.
showBody
true
Show the In body.
showOut
false
If the exchange has an Out message, show the Out message.
showException
false
Camel 2.0: If the exchange has an exception, show the exception message (no stack trace).
showCaughtException
false
Camel 2.0: If the exchange has a caught exception, show the exception message (no stack trace). A caught exception is stored
as a property on the exchange (using the key Exchange.EXCEPTION_CAUGHT) and for instance a doCatch can catch
exceptions. See Try Catch Finally.
showStackTrace
false
Camel 2.0: Show the stack trace, if an exchange has an exception. Only effective if one of showAll, showException or
showCaughtException are enabled.
showFiles
false
Camel 2.9: Whether Camel should show file bodies or not (eg such as java.io.File).
showFuture
false
Camel 2.1: Whether Camel should show java.util.concurrent.Future bodies or not. If enabled Camel could
potentially wait until the Future task is done. Will by default not wait.
showStreams
false
Camel 2.8: Whether Camel should show stream bodies or not (eg such as java.io.InputStream). Beware if you enable this
option then you may not be able later to access the message body as the stream have already been read by this logger. To
remedy this you have to use Stream caching.
multiline
false
If true, each piece of information is logged on a new line.
maxChars
Ê
Camel 2.0: Limits the number of characters logged per line. The default value is 10000 from Camel 2.9 onwards.
Regular logger sample
In the route below we log the incoming orders at DEBUG level before the order is processed:
from("activemq:orders").to("log:com.mycompany.order?level=DEBUG").to("bean:processOrder");
Or using Spring XML to define the route:
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Logging stream bodies
Camel will by default not log stream or files bodies. You can force Camel to log
those by setting the property on the CamelContext properties
camelContext.getProperties().put(Exchange.LOG_DEBUG_BODY_STREAMS, true);
Regular logger with formatter sample
In the route below we log the incoming orders at INFO level before the order is processed.
from("activemq:orders").
to("log:com.mycompany.order?showAll=true&multiline=true").to("bean:processOrder");
Throughput logger with groupSize sample
In the route below we log the throughput of the incoming orders at DEBUG level grouped by
10 messages.
from("activemq:orders").
to("log:com.mycompany.order?level=DEBUG&groupSize=10").to("bean:processOrder");
Throughput logger with groupInterval sample
This route will result in message stats logged every 10s, with an initial 60s delay and stats should
be displayed even if there isn't any message traffic.
from("activemq:orders").
to("log:com.mycompany.order?level=DEBUG&groupInterval=10000&groupDelay=60000&groupActiveOnly=false").t
The following will be logged:
"Received: 1000 new messages, with total 2000 so far. Last group took: 10000 millis
which is: 100 messages per second. average: 100"
See Also
• Configuring Camel
• Component
• Endpoint
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•
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Getting Started
Tracer
How do I use log4j
How do I use Java 1.4 logging
LogEIP for using log directly in the DSL for human logs.
LUCENE (INDEXER AND SEARCH) COMPONENT
Available as of Camel 2.2
The lucene component is based on the Apache Lucene project. Apache Lucene is a
powerful high-performance, full-featured text search engine library written entirely in Java. For
more details about Lucene, please see the following links
• http://lucene.apache.org/java/docs/
• http://lucene.apache.org/java/docs/features.html
The lucene component in camel facilitates integration and utilization of Lucene endpoints in
enterprise integration patterns and scenarios. The lucene component does the following
• builds a searchable index of documents when payloads are sent to the Lucene
Endpoint
• facilitates performing of indexed searches in Camel
This component only supports producer endpoints.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-lucenex.x.x
URI format
lucene:searcherName:insert[?options]
lucene:searcherName:query[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Insert Options
Name
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Value
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analyzer
StandardAnalyzer
An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text. The value for
analyzer can be any class that extends the abstract class org.apache.lucene.analysis.Analyzer. Lucene also offers a rich set of analyzers
out of the box
indexDir
./indexDirectory
A file system directory in which index files are created upon analysis of the document by the specified analyzer
srcDir
null
An optional directory containing files to be used to be analyzed and added to the index at producer startup.
Query Options
Name
Default
Value
Description
analyzer
StandardAnalyzer
An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text. The value for
analyzer can be any class that extends the abstract class org.apache.lucene.analysis.Analyzer. Lucene also offers a rich set of analyzers
out of the box
indexDir
./indexDirectory
A file system directory in which index files are created upon analysis of the document by the specified analyzer
maxHits
10
An integer value that limits the result set of the search operation
Sending/Receiving Messages to/from the cache
Message Headers
Header
Description
QUERY
The Lucene Query to performed on the index. The query may include wildcards and phrases
Lucene Producers
This component supports 2 producer endpoints.
• insert - The insert producer builds a searchable index by analyzing the body in
incoming exchanges and associating it with a token ("content").
• query - The query producer performs searches on a pre-created index. The query
uses the searchable index to perform score & relevance based searches. Queries are
sent via the incoming exchange contains a header property name called 'QUERY'. The
value of the header property 'QUERY' is a Lucene Query. For more details on how to
create Lucene Queries check out http://lucene.apache.org/java/3_0_0/
queryparsersyntax.html
Lucene Processor
There is a processor called LuceneQueryProcessor available to perform queries against lucene
without the need to create a producer.
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Lucene Usage Samples
Example 1: Creating a Lucene index
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start").
to("lucene:whitespaceQuotesIndex:insert?
analyzer=#whitespaceAnalyzer&indexDir=#whitespace&srcDir=#load_dir").
to("mock:result");
}
};
Example 2: Loading properties into the JNDI registry in the
Camel Context
@Override
protected JndiRegistry createRegistry() throws Exception {
JndiRegistry registry =
new JndiRegistry(createJndiContext());
registry.bind("whitespace", new File("./whitespaceIndexDir"));
registry.bind("load_dir",
new File("src/test/resources/sources"));
registry.bind("whitespaceAnalyzer",
new WhitespaceAnalyzer());
return registry;
}
...
CamelContext context = new DefaultCamelContext(createRegistry());
Example 2: Performing searches using a Query Producer
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start").
setHeader("QUERY", constant("Seinfeld")).
to("lucene:searchIndex:query?
analyzer=#whitespaceAnalyzer&indexDir=#whitespace&maxHits=20").
to("direct:next");
from("direct:next").process(new Processor() {
public void process(Exchange exchange) throws Exception {
Hits hits = exchange.getIn().getBody(Hits.class);
printResults(hits);
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}
private void printResults(Hits hits) {
LOG.debug("Number of hits: " + hits.getNumberOfHits());
for (int i = 0; i < hits.getNumberOfHits(); i++) {
LOG.debug("Hit " + i + " Index Location:" +
hits.getHit().get(i).getHitLocation());
LOG.debug("Hit " + i + " Score:" + hits.getHit().get(i).getScore());
LOG.debug("Hit " + i + " Data:" + hits.getHit().get(i).getData());
}
}
}).to("mock:searchResult");
}
};
Example 3: Performing searches using a Query Processor
RouteBuilder builder = new RouteBuilder() {
public void configure() {
try {
from("direct:start").
setHeader("QUERY", constant("Rodney Dangerfield")).
process(new LuceneQueryProcessor("target/stdindexDir", analyzer, null,
20)).
to("direct:next");
} catch (Exception e) {
e.printStackTrace();
}
from("direct:next").process(new Processor() {
public void process(Exchange exchange) throws Exception {
Hits hits = exchange.getIn().getBody(Hits.class);
printResults(hits);
}
private void printResults(Hits hits) {
LOG.debug("Number of hits: " + hits.getNumberOfHits());
for (int i = 0; i < hits.getNumberOfHits(); i++) {
LOG.debug("Hit " + i + " Index Location:" +
hits.getHit().get(i).getHitLocation());
LOG.debug("Hit " + i + " Score:" +
hits.getHit().get(i).getScore());
LOG.debug("Hit " + i + " Data:" + hits.getHit().get(i).getData());
}
}
}).to("mock:searchResult");
}
};
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MAIL COMPONENT
The mail component provides access to Email via Spring's Mail support and the underlying
JavaMail system.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-mailx.x.x
URI format
Mail endpoints can have one of the following URI formats (for the protocols, SMTP, POP3, or
IMAP, respectively):
smtp://[username@]host[:port][?options]
pop3://[username@]host[:port][?options]
imap://[username@]host[:port][?options]
The mail component also supports secure variants of these protocols (layered over SSL). You
can enable the secure protocols by adding s to the scheme:
smtps://[username@]host[:port][?options]
pop3s://[username@]host[:port][?options]
imaps://[username@]host[:port][?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Sample endpoints
Typically, you specify a URI with login credentials as follows (taking SMTP as an example):
smtp://[username@]host[:port][?password=somepwd]
Alternatively, it is possible to specify both the user name and the password as query options:
smtp://host[:port]?password=somepwd&username=someuser
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Geronimo mail .jar
We have discovered that the geronimo mail .jar (v1.6) has a bug when polling
mails with attachments. It cannot correctly identify the Content-Type. So, if you
attach a .jpeg file to a mail and you poll it, the Content-Type is resolved as
text/plain and not as image/jpeg. For that reason, we have added an
org.apache.camel.component.ContentTypeResolver SPI interface
which enables you to provide your own implementation and fix this bug by
returning the correct Mime type based on the file name. So if the file name ends
with jpeg/jpg, you can return image/jpeg.
You can set your custom resolver on the MailComponent instance or on the
MailEndpoint instance. This feature is added in Camel 1.6.2/2.0.
POP3 or IMAP
POP3 has some limitations and end users are encouraged to use IMAP if possible.
Using mock-mail for testing
You can use a mock framework for unit testing, which allows you to test without
the need for a real mail server. However you should remember to not include the
mock-mail when you go into production or other environments where you need to
send mails to a real mail server. Just the presence of the mock-javamail.jar on the
classpath means that it will kick in and avoid sending the mails.
For example:
smtp://mycompany.mailserver:30?password=tiger&username=scott
Default ports
As of Camel 1.4, default port numbers are supported. If the port number is omitted, Camel
determines the port number to use based on the protocol.
Protocol
Default Port Number
SMTP
25
SMTPS
465
POP3
110
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POP3S
995
IMAP
143
IMAPS
993
Options
753
Property
Default
Description
host
Ê
The host name or IP address to connect to.
port
See DefaultPorts
The TCP port number to connect on.
username
Ê
The user name on the email server.
password
null
The password on the email server.
ignoreUriScheme
false
If false, Camel uses the scheme to determine the transport protocol (POP, IMAP, SMTP etc.)
defaultEncoding
null
The default encoding to use for Mime Messages.
contentType
text/plain
New option in Camel 1.5. The mail message content type. Use text/html for HTML mails.
folderName
INBOX
The folder to poll.
destination
username@host
@deprecated Use the to option instead. The TO recipients (receivers of the email).
to
username@host
As of Camel 1.4, the TO recipients (the receivers of the mail). Separate multiple email addresses
with a comma.
CC
null
As of Camel 1.4, the CC recipients (the receivers of the mail). Separate multiple email addresses
with a comma.
BCC
null
As of Camel 1.4, the BCC recipients (the receivers of the mail). Separate multiple email addresses
with a comma.
from
camel@localhost
The FROM email address.
subject
Ê
As of Camel 2.3, the Subject of the message being sent. Note: Setting the subject in the header
takes precedence over this option.
deleteProcessedMessages
true/false
Deletes the messages after they have been processed. This is done by setting the DELETED flag on
the mail message. If false, the SEEN flag is set instead. As of Camel 1.5, the default setting is
false. This option is named delete in Camel 2.0 onwards.
delete
false
Camel 2.0: Deletes the messages after they have been processed. This is done by setting the
DELETED flag on the mail message. If false, the SEEN flag is set instead.
processOnlyUnseenMessages
false/true
As of Camel 1.4, it is possible to configure a consumer endpoint so that it processes only unseen
messages (that is, new messages) or all messages. Note that Camel always skips deleted messages.
Setting this option to true will filter to only unseen messages. As of Camel 1.5, the default setting
is true. POP3 does not support the SEEN flag, so this option is not supported in POP3; use IMAP
instead. This option is named unseen in Camel 2.0 onwards.
unseen
true
Camel 2.0: Is used to fetch only unseen messages (that is, new messages). Note that POP3 does
not support the SEEN flag; use IMAP instead.
fetchSize
-1
As of Camel 1.4, this option sets the maximum number of messages to consume during a poll.
This can be used to avoid overloading a mail server, if a mailbox folder contains a lot of messages.
Default value of -1 means no fetch size and all messages will be consumed. Setting the value to 0 is
a special corner case, where Camel will not consume any messages at all.
alternateBodyHeader
mail_alternateBody
Camel 1.6.1: Specifies the key to an IN message header that contains an alternative email body.
For example, if you send emails in text/html format and want to provide an alternative mail body
for non-HTML email clients, set the alternative mail body with this key as a header. In Camel 2.0,
this option has been renamed to alternativeBodyHeader.
alternativeBodyHeader
CamelMailAlternativeBody
Camel 2.0: Specifies the key to an IN message header that contains an alternative email body. For
example, if you send emails in text/html format and want to provide an alternative mail body for
non-HTML email clients, set the alternative mail body with this key as a header.
debugMode
false
As of Camel 1.4, it is possible to enable debug mode on the underlying mail framework. The SUN
Mail framework logs the debug messages to System.out by default.
connectionTimeout
30000
As of Camel 1.4, the connection timeout can be configured in milliseconds. Default is 30 seconds.
consumer.initialDelay
1000
Milliseconds before the polling starts.
consumer.delay
60000
As of Camel 1.4, the default consumer delay is now 60 seconds. Camel will therefore only poll the
mailbox once a minute to avoid overloading the mail server. The default value in Camel 1.3 is 500
milliseconds.
consumer.useFixedDelay
false
Set to true to use a fixed delay between polls, otherwise fixed rate is used. See
ScheduledExecutorService in JDK for details.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
disconnect
false
Camel 2.8.3/2.9: Whether the consumer should disconnect after polling. If enabled this forces
Camel to connect on each poll.
mail.XXX
null
As of Camel 2.0, you can set any additional java mail properties. For instance if you want to set a
special property when using POP3 you can now provide the option directly in the URI such as:
mail.pop3.forgettopheaders=true. You can set multiple such options, for example:
mail.pop3.forgettopheaders=true&mail.mime.encodefilename=true.
mapMailMessage
true
Camel 2.8: Specifies whether Camel should map the received mail message to Camel body/
headers. If set to true, the body of the mail message is mapped to the body of the Camel IN
message and the mail headers are mapped to IN headers. If this option is set to false then the IN
message contains a raw javax.mail.Message. You can retrieve this raw message by calling
exchange.getIn().getBody(javax.mail.Message.class).
maxMessagesPerPoll
0
Camel 2.0: Specifies the maximum number of messages to gather per poll. By default, no
maximum is set. Can be used to set a limit of e.g. 1000 to avoid downloading thousands of files
when the server starts up. Set a value of 0 or negative to disable this option.
javaMailSender
null
Camel 2.0: Specifies a pluggable
org.springframework.mail.javamail.JavaMailSender instance in order to use a
custom email implementation. If none provided, Camel uses the default
org.springframework.mail.javamail.JavaMailSenderImpl.
ignoreUnsupportedCharset
false
Camel 2.0: Option to let Camel ignore unsupported charset in the local JVM when sending mails.
If the charset is unsupported then charset=XXX (where XXX represents the unsupported
charset) is removed from the content-type and it relies on the platform default instead.
SSL support
The underlying mail framework is responsible for providing SSL support. Camel uses SUN
JavaMail, which only trusts certificates issued by well known Certificate Authorities. So if you
issue your own certificate, you have to import it into the local Java keystore file (see
SSLNOTES.txt in JavaMail for details).
Defaults changed in Camel 1.4
As of Camel 1.4 the default consumer delay is now 60 seconds. Camel will therefore only poll
the mailbox once a minute to avoid overloading the mail server. The default value in Camel 1.3
is 500 milliseconds.
Defaults changed in Camel 1.5
In Camel 1.5 the following default options have changed:
▪ deleteProcessedMessages is now false, as we felt Camel should not delete
mails on the mail server by default.
▪ processOnlyUnseenMessages is now true, as we felt Camel should only poll
new mails by default.
Mail Message Content
Camel uses the message exchange's IN body as the MimeMessage text content. The body is
converted to String.class.
Camel copies all of the exchange's IN headers to the MimeMessage headers.
The subject of the MimeMessage can be configured using a header property on the IN
message. The code below demonstrates this:
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from("direct:a").setHeader("subject", constant(subject)).to("smtp://james2@localhost");
The same applies for other MimeMessage headers such as recipients, so you can use a header
property as To:
Map map = new HashMap();
map.put("To", "davsclaus@apache.org");
map.put("From", "jstrachan@apache.org");
map.put("Subject", "Camel rocks");
String body = "Hello Claus.\nYes it does.\n\nRegards James.";
template.sendBodyAndHeaders("smtp://davsclaus@apache.org", body, map);
Headers take precedence over pre-configured recipients
From Camel 1.5 onwards, the recipients specified in the message headers always take
precedence over recipients pre-configured in the endpoint URI. The idea is that if you provide
any recipients in the message headers, that is what you get. The recipients pre-configured in the
endpoint URI are treated as a fallback.
In the sample code below, the email message is sent to davsclaus@apache.org,
because it takes precedence over the pre-configured recipient, info@mycompany.com. Any
CC and BCC settings in the endpoint URI are also ignored and those recipients will not receive
any mail. The choice between headers and pre-configured settings is all or nothing: the mail
component either takes the recipients exclusively from the headers or exclusively from the preconfigured settings. It is not possible to mix and match headers and pre-configured settings.
Map headers = new HashMap();
headers.put("to", "davsclaus@apache.org");
template.sendBodyAndHeaders("smtp://admin@localhost?to=info@mycompany.com",
"Hello World", headers);
Multiple recipients for easier configuration
As of Camel 1.5, it is possible to set multiple recipients using a comma-separated or a
semicolon-separated list. This applies both to header settings and to settings in an endpoint
URI. For example:
Map headers = new HashMap();
headers.put("to", "davsclaus@apache.org ; jstrachan@apache.org ;
ningjiang@apache.org");
The preceding example uses a semicolon, ;, as the separator character.
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Setting sender name and email
You can specify recipients in the format, name , to include both the name and the
email address of the recipient.
For example, you define the following headers on the a Message:
Map headers = new HashMap();
map.put("To", "Claus Ibsen ");
map.put("From", "James Strachan ");
map.put("Subject", "Camel is cool");
SUN JavaMail
SUN JavaMail is used under the hood for consuming and producing mails.
We encourage end-users to consult these references when using either POP3 or IMAP
protocol. Note particularly that POP3 has a much more limited set of features than IMAP.
▪ SUN POP3 API
▪ SUN IMAP API
▪ And generally about the MAIL Flags
Samples
We start with a simple route that sends the messages received from a JMS queue as emails. The
email account is the admin account on mymailserver.com.
from("jms://queue:subscription").to("smtp://admin@mymailserver.com?password=secret");
In the next sample, we poll a mailbox for new emails once every minute. Notice that we use
the special consumer option for setting the poll interval, consumer.delay, as 60000
milliseconds = 60 seconds.
from("imap://admin@mymailserver.com
password=secret&unseen=true&consumer.delay=60000")
.to("seda://mails");
In this sample we want to send a mail to multiple recipients. This feature was introduced in
camel 1.4:
// all the recipients of this mail are:
// To: camel@riders.org , easy@riders.org
// CC: me@you.org
// BCC: someone@somewhere.org
String recipients =
"&To=camel@riders.org,easy@riders.org&CC=me@you.org&BCC=someone@somewhere.org";
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from("direct:a").to("smtp://you@mymailserver.com?password=secret&From=you@apache.org"
+ recipients);
Sending mail with attachment sample
The mail component supports attachments, which is a feature that was introduced in Camel 1.4.
In the sample below, we send a mail message containing a plain text message with a logo file
attachment.
// create an exchange with a normal body and attachment to be produced as email
Endpoint endpoint =
context.getEndpoint("smtp://james@mymailserver.com?password=secret");
// create the exchange with the mail message that is multipart with a file and a Hello
World text/plain message.
Exchange exchange = endpoint.createExchange();
Message in = exchange.getIn();
in.setBody("Hello World");
in.addAttachment("logo.jpeg", new DataHandler(new FileDataSource("src/test/data/
logo.jpeg")));
// create a producer that can produce the exchange (= send the mail)
Producer producer = endpoint.createProducer();
// start the producer
producer.start();
// and let it go (processes the exchange by sending the email)
producer.process(exchange);
SSL sample
In this sample, we want to poll our Google mail inbox for mails. To download mail onto a local
mail client, Google mail requires you to enable and configure SSL. This is done by logging into
your Google mail account and changing your settings to allow IMAP access. Google have
extensive documentation on how to do this.
from("imaps://imap.gmail.com?username=YOUR_USERNAME@gmail.com&password=YOUR_PASSWORD"
+ "&delete=false&unseen=true&consumer.delay=60000").to("log:newmail");
The preceding route polls the Google mail inbox for new mails once every minute and logs the
received messages to the newmail logger category.
Running the sample with DEBUG logging enabled, we can monitor the progress in the logs:
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Attachments are not support by all Camel components
The Attachments API is based on the Java Activation Framework and is generally only
used by the Mail API. Since many of the other Camel components do not support
attachments, the attachments could potentially be lost as they propagate along the
route. The rule of thumb, therefore, is to add attachments just before sending a
message to the mail endpoint.
2008-05-08 06:32:09,640 DEBUG MailConsumer - Connecting to MailStore
imaps//imap.gmail.com:993 (SSL enabled), folder=INBOX
2008-05-08 06:32:11,203 DEBUG MailConsumer - Polling mailfolder:
imaps//imap.gmail.com:993 (SSL enabled), folder=INBOX
2008-05-08 06:32:11,640 DEBUG MailConsumer - Fetching 1 messages. Total 1 messages.
2008-05-08 06:32:12,171 DEBUG MailConsumer - Processing message: messageNumber=[332],
from=[James Bond <007@mi5.co.uk>], to=YOUR_USERNAME@gmail.com], subject=[...
2008-05-08 06:32:12,187 INFO newmail - Exchange[MailMessage: messageNumber=[332],
from=[James Bond <007@mi5.co.uk>], to=YOUR_USERNAME@gmail.com], subject=[...
Consuming mails with attachment sample
In this sample we poll a mailbox and store all attachments from the mails as files. First, we
define a route to poll the mailbox. As this sample is based on google mail, it uses the same
route as shown in the SSL sample:
from("imaps://imap.gmail.com?username=YOUR_USERNAME@gmail.com&password=YOUR_PASSWORD"
+ "&delete=false&unseen=true&consumer.delay=60000").process(new MyMailProcessor());
Instead of logging the mail we use a processor where we can process the mail from java code:
public void process(Exchange exchange) throws Exception {
// the API is a bit clunky so we need to loop
Map attachments = exchange.getIn().getAttachments();
if (attachments.size() > 0) {
for (String name : attachments.keySet()) {
DataHandler dh = attachments.get(name);
// get the file name
String filename = dh.getName();
// get the content and convert it to byte[]
byte[] data = exchange.getContext().getTypeConverter()
.convertTo(byte[].class, dh.getInputStream());
// write the data to a file
FileOutputStream out = new FileOutputStream(filename);
out.write(data);
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out.flush();
out.close();
}
}
}
As you can see the API to handle attachments is a bit clunky but it's there so you can get the
javax.activation.DataHandler so you can handle the attachments using standard
API.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
MINA COMPONENT
The mina: component is a transport for working with Apache MINA
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-minax.x.x
URI format
mina:tcp://hostname[:port][?options]
mina:udp://hostname[:port][?options]
mina:vm://hostname[:port][?options]
From Camel 1.3 onwards you can specify a codec in the Registry using the codec option. If you
are using TCP and no codec is specified then the textline flag is used to determine if text
line based codec or object serialization should be used instead. By default the object
serialization is used.
For UDP if no codec is specified the default uses a basic ByteBuffer based codec.
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The VM protocol is used as a direct forwarding mechanism in the same JVM. See the MINA
VM-Pipe API documentation for details.
A Mina producer has a default timeout value of 30 seconds, while it waits for a response
from the remote server.
In normal use, camel-mina only supports marshalling the body contentÑmessage headers
and exchange properties are not sent.
However, the option, transferExchange, does allow you to transfer the exchange itself over
the wire. See options below.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Value
Description
codec
null
As of 1.3, you can refer to a named ProtocolCodecFactory instance in your Registry such as your Spring
ApplicationContext, which is then used for the marshalling.
codec
null
Camel 2.0: You must use the # notation to look up your codec in the Registry. For example, use #myCodec to look up a
bean with the id value, myCodec.
disconnect
false
Camel 2.3: Whether or not to disconnect(close) from Mina session right after use. Can be used for both consumer and
producer.
textline
false
Only used for TCP. If no codec is specified, you can use this flag in 1.3 or later to indicate a text line based codec; if not
specified or the value is false, then Object Serialization is assumed over TCP.
textlineDelimiter
DEFAULT
Camel 1.6.0/2.0 Only used for TCP and if textline=true. Sets the text line delimiter to use. Possible values are:
DEFAULT, AUTO, WINDOWS, UNIX or MAC. If none provided, Camel will use DEFAULT. This delimiter is used to mark the
end of text.
sync
false/true
As of 1.3, you can configure the exchange pattern to be either InOnly (default) or InOut. Setting sync=true means a
synchronous exchange (InOut), where the client can read the response from MINA (the exchange Out message). The default
value has changed in Camel 1.5 to true. In older releases, the default value is false.
lazySessionCreation
See description
As of 1.3, sessions can be lazily created to avoid exceptions, if the remote server is not up and running when the Camel
producer is started. From Camel 2.0 onwards, the default is true. In Camel 1.x, the default is false.
timeout
30000
As of 1.3, you can configure the timeout that specifies how long to wait for a response from a remote server. The timeout unit
is in milliseconds, so 60000 is 60 seconds. The timeout is only used for Mina producer.
encoding
JVM Default
As of 1.3, you can configure the encoding (a charset name) to use for the TCP textline codec and the UDP protocol. If not
provided, Camel will use the JVM default Charset.
transferExchange
false
Only used for TCP. As of 1.3, you can transfer the exchange over the wire instead of just the body. The following fields are
transferred: In body, Out body, fault body, In headers, Out headers, fault headers, exchange properties, exchange exception.
This requires that the objects are serializable. Camel will exclude any non-serializable objects and log it at WARN level.
minaLogger
false
As of 1.3, you can enable the Apache MINA logging filter. Apache MINA uses slf4j logging at INFO level to log all input and
output.
filters
null
As of 2.0, you can set a list of Mina IoFilters to register. The filters value must be one of the following:
•
Camel 2.2: comma-separated list of bean references (e.g. #filterBean1,#filterBean2) where
each bean must be of type org.apache.mina.common.IoFilter.
•
Camel 2.0: a reference to a bean of type List.
encoderMaxLineLength
-1
As of 2.1, you can set the textline protocol encoder max line length. By default the default value of Mina itself is used which are
Integer.MAX_VALUE.
decoderMaxLineLength
-1
As of 2.1, you can set the textline protocol decoder max line length. By default the default value of Mina itself is used which are
1024.
producerPoolSize
16
1.6.2 (only in 1.6.x): The TCP producer is now thread safe and supports concurrency much better. This option allows you
to configure the number of threads in its thread pool for concurrent producers. Note: Camel 2.0 have a pooled service which
ensured it was already thread safe and supported concurrency already. So this is a special patch for 1.6.x.
allowDefaultCodec
true
The mina component installs a default codec if both, codec is null and textline is false. Setting
allowDefaultCodec to false prevents the mina component from installing a default codec as the first element in the
filter chain. This is useful in scenarios where another filter must be the first in the filter chain, like the SSL filter.
disconnectOnNoReply
true
Camel 2.3: If sync is enabled then this option dictates MinaConsumer if it should disconnect where there is no reply to send
back.
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noReplyLogLevel
WARN
Camel 2.3: If sync is enabled this option dictates MinaConsumer which logging level to use when logging a there is no reply
to send back. Values are: FATAL, ERROR, INFO, DEBUG, OFF.
Default behavior changed
In Camel 2.0 the codec option must use # notation for lookup of the codec bean in the
Registry.
In Camel 2.0 the lazySessionCreation option now defaults to true.
In Camel 1.5 the sync option has changed its default value from false to true, as we felt
it was confusing for end-users when they used MINA to call remote servers and Camel
wouldn't wait for the response.
In Camel 1.4 or later codec=textline is no longer supported. Use the
textline=true option instead.
Using a custom codec
See the Mina documentation how to write your own codec. To use your custom codec with
camel-mina, you should register your codec in the Registry; for example, by creating a bean
in the Spring XML file. Then use the codec option to specify the bean ID of your codec. See
HL7 that has a custom codec.
Sample with sync=false
In this sample, Camel exposes a service that listens for TCP connections on port 6200. We use
the textline codec. In our route, we create a Mina consumer endpoint that listens on port
6200:
from("mina:tcp://localhost:" + port1 + "?textline=true&sync=false").to("mock:result");
As the sample is part of a unit test, we test it by sending some data to it on port 6200.
MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedBodiesReceived("Hello World");
template.sendBody("mina:tcp://localhost:" + port1 + "?textline=true&sync=false",
"Hello World");
assertMockEndpointsSatisfied();
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Sample with sync=true
In the next sample, we have a more common use case where we expose a TCP service on port
6201 also use the textline codec. However, this time we want to return a response, so we set
the sync option to true on the consumer.
from("mina:tcp://localhost:" + port2 + "?textline=true&sync=true").process(new
Processor() {
public void process(Exchange exchange) throws Exception {
String body = exchange.getIn().getBody(String.class);
exchange.getOut().setBody("Bye " + body);
}
});
Then we test the sample by sending some data and retrieving the response using the
template.requestBody() method. As we know the response is a String, we cast it to
String and can assert that the response is, in fact, something we have dynamically set in our
processor code logic.
String response = (String)template.requestBody("mina:tcp://localhost:" + port2 +
"?textline=true&sync=true", "World");
assertEquals("Bye World", response);
Sample with Spring DSL
Spring DSL can, of course, also be used for MINA. In the sample below we expose a TCP
server on port 5555:
In the route above, we expose a TCP server on port 5555 using the textline codec. We let the
Spring bean with ID, myTCPOrderHandler, handle the request and return a reply. For
instance, the handler bean could be implemented as follows:
public String handleOrder(String payload) {
...
return "Order: OK"
}
Configuring Mina endpoints using Spring bean style
Available as of Camel 2.0
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Configuration of Mina endpoints is now possible using regular Spring bean style configuration
in the Spring DSL.
However, in the underlying Apache Mina toolkit, it is relatively difficult to set up the
acceptor and the connector, because you can not use simple setters. To resolve this difficulty,
we leverage the MinaComponent as a Spring factory bean to configure this for us. If you
really need to configure this yourself, there are setters on the MinaEndpoint to set these
when needed.
The sample below shows the factory approach:
And then we can refer to our endpoint directly in the route, as follows:
Closing Session When Complete
Available as of Camel 1.6.1
When acting as a server you sometimes want to close the session when, for example, a
client conversion is finished. To instruct Camel to close the session, you should add a header
with the key CamelMinaCloseSessionWhenComplete set to a boolean true value.
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For instance, the example below will close the session after it has written the bye message
back to the client:
from("mina:tcp://localhost:8080?sync=true&textline=true").process(new
Processor() {
public void process(Exchange exchange) throws Exception {
String body = exchange.getIn().getBody(String.class);
exchange.getOut().setBody("Bye " + body);
exchange.getOut().setHeader(MinaConstants.MINA_CLOSE_SESSION_WHEN_COMPLETE, true);
}
});
Get the IoSession for message
Available since Camel 2.1
You can get the IoSession from the message header with this key
MinaEndpoint.HEADER_MINA_IOSESSION, and also get the local host address with the key
MinaEndpoint.HEADER_LOCAL_ADDRESS and remote host address with the key
MinaEndpoint.HEADER_REMOTE_ADDRESS.
Configuring Mina filters
Available since Camel 2.0
Filters permit you to use some Mina Filters, such as SslFilter. You can also implement
some customized filters. Please note that codec and logger are also implemented as Mina
filters of type, IoFilter. Any filters you may define are appended to the end of the filter
chain; that is, after codec and logger.
For instance, the example below will send a keep-alive message after 10 seconds of inactivity:
public class KeepAliveFilter extends IoFilterAdapter {
@Override
public void sessionCreated(NextFilter nextFilter, IoSession session)
throws Exception {
session.setIdleTime(IdleStatus.BOTH_IDLE, 10);
nextFilter.sessionCreated(session);
}
@Override
public void sessionIdle(NextFilter nextFilter, IoSession session,
IdleStatus status) throws Exception {
session.write("NOOP"); // NOOP is a FTP command for keep alive
nextFilter.sessionIdle(session, status);
}
}
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As Camel Mina may use a request-reply scheme, the endpoint as a client would like to drop
some message, such as greeting when the connection is established. For example, when you
connect to an FTP server, you will get a 220 message with a greeting (220 Welcome to
Pure-FTPd). If you don't drop the message, your request-reply scheme will be broken.
public class DropGreetingFilter extends IoFilterAdapter {
@Override
public void messageReceived(NextFilter nextFilter, IoSession session,
Object message) throws Exception {
if (message instanceof String) {
String ftpMessage = (String) message;
// "220" is given as greeting. "200 Zzz" is given as a response to "NOOP"
(keep alive)
if (ftpMessage.startsWith("220") || or ftpMessage.startsWith("200 Zzz")) {
// Dropping greeting
return;
}
}
nextFilter.messageReceived(session, message);
}
}
Then, you can configure your endpoint using Spring DSL:
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See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
Camel Netty
MOCK COMPONENT
Testing of distributed and asynchronous processing is notoriously difficult. The Mock, Test and
DataSet endpoints work great with the Camel Testing Framework to simplify your unit and
integration testing using Enterprise Integration Patterns and Camel's large range of Components
together with the powerful Bean Integration.
The Mock component provides a powerful declarative testing mechanism, which is similar to
jMock in that it allows declarative expectations to be created on any Mock endpoint before a
test begins. Then the test is run, which typically fires messages to one or more endpoints, and
finally the expectations can be asserted in a test case to ensure the system worked as expected.
This allows you to test various things like:
• The correct number of messages are received on each endpoint,
• The correct payloads are received, in the right order,
• Messages arrive on an endpoint in order, using some Expression to create an order
testing function,
• Messages arrive match some kind of Predicate such as that specific headers have
certain values, or that parts of the messages match some predicate, such as by
evaluating an XPath or XQuery Expression.
Note that there is also the Test endpoint which is a Mock endpoint, but which uses a second
endpoint to provide the list of expected message bodies and automatically sets up the Mock
endpoint assertions. In other words, it's a Mock endpoint that automatically sets up its
assertions from some sample messages in a File or database, for example.
URI format
mock:someName[?options]
Where someName can be any string that uniquely identifies the endpoint.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
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Mock endpoints keep received Exchanges in memory indefinitely
Remember that Mock is designed for testing. When you add Mock endpoints to a
route, each Exchange sent to the endpoint will be stored (to allow for later
validation) in memory until explicitly reset or the JVM is restarted. If you are
sending high volume and/or large messages, this may cause excessive memory use. If
your goal is to test deployable routes inline, consider using NotifyBuilder or
AdviceWith in your tests instead of adding Mock endpoints to routes directly.
reportGroup
null
A size to use a throughput logger for reporting
Simple Example
Here's a simple example of Mock endpoint in use. First, the endpoint is resolved on the
context. Then we set an expectation, and then, after the test has run, we assert that our
expectations have been met.
MockEndpoint resultEndpoint = context.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.expectedMessageCount(2);
// send some messages
...
// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();
You typically always call the assertIsSatisfied() method to test that the expectations were met
after running a test.
Camel will by default wait 10 seconds when the assertIsSatisfied() is invoked. This
can be configured by setting the setResultWaitTime(millis) method.
When the assertion is satisfied then Camel will stop waiting and continue from the
assertIsSatisfied method. That means if a new message arrives on the mock endpoint,
just a bit later, that arrival will not affect the outcome of the assertion. Suppose you do want to
test that no new messages arrives after a period thereafter, then you can do that by setting the
setAssertPeriod method.
Using assertPeriod
Available as of Camel 2.7
When the assertion is satisfied then Camel will stop waiting and continue from the
assertIsSatisfied method. That means if a new message arrives on the mock endpoint,
just a bit later, that arrival will not affect the outcome of the assertion. Suppose you do want to
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test that no new messages arrives after a period thereafter, then you can do that by setting the
setAssertPeriod method, for example:
MockEndpoint resultEndpoint = context.resolveEndpoint("mock:foo", MockEndpoint.class);
resultEndpoint.setAssertPeriod(5000);
resultEndpoint.expectedMessageCount(2);
// send some messages
...
// now lets assert that the mock:foo endpoint received 2 messages
resultEndpoint.assertIsSatisfied();
Setting expectations
You can see from the javadoc of MockEndpoint the various helper methods you can use to set
expectations. The main methods are as follows:
Method
Description
expectedMessageCount(int)
To define the expected message count on the endpoint.
expectedMinimumMessageCount(int)
To define the minimum number of expected messages on the endpoint.
expectedBodiesReceived(...)
To define the expected bodies that should be received (in order).
expectedHeaderReceived(...)
To define the expected header that should be received
expectsAscending(Expression)
To add an expectation that messages are received in order, using the given Expression to compare messages.
expectsDescending(Expression)
To add an expectation that messages are received in order, using the given Expression to compare messages.
expectsNoDuplicates(Expression)
To add an expectation that no duplicate messages are received; using an Expression to calculate a unique identifier for each message. This
could be something like the JMSMessageID if using JMS, or some unique reference number within the message.
Here's another example:
resultEndpoint.expectedBodiesReceived("firstMessageBody", "secondMessageBody",
"thirdMessageBody");
Adding expectations to specific messages
In addition, you can use the message(int messageIndex) method to add assertions about a
specific message that is received.
For example, to add expectations of the headers or body of the first message (using zerobased indexing like java.util.List), you can use the following code:
resultEndpoint.message(0).header("foo").isEqualTo("bar");
There are some examples of the Mock endpoint in use in the camel-core processor tests.
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Mocking existing endpoints
Available as of Camel 2.7
Camel now allows you to automatic mock existing endpoints in your Camel routes.
Suppose you have the given route below:
Listing 71. Route
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:start").to("direct:foo").to("log:foo").to("mock:result");
from("direct:foo").transform(constant("Bye World"));
}
};
}
You can then use the adviceWith feature in Camel to mock all the endpoints in a given
route from your unit test, as shown below:
Listing 72. adviceWith mocking all endpoints
public void testAdvisedMockEndpoints() throws Exception {
// advice the first route using the inlined AdviceWith route builder
// which has extended capabilities than the regular route builder
context.getRouteDefinitions().get(0).adviceWith(context, new
AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
// mock all endpoints
mockEndpoints();
}
});
getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// all the endpoints was mocked
assertNotNull(context.hasEndpoint("mock:direct:start"));
assertNotNull(context.hasEndpoint("mock:direct:foo"));
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How it works
Important: The endpoints are still in action, what happens is that a Mock
endpoint is injected and receives the message first, it then delegate the message to
the target endpoint. You can view this as a kind of intercept and delegate or
endpoint listener.
assertNotNull(context.hasEndpoint("mock:log:foo"));
}
Notice that the mock endpoints is given the uri mock:, for example
mock:direct:foo. Camel logs at INFO level the endpoints being mocked:
INFO
Adviced endpoint [direct://foo] with mock endpoint [mock:direct:foo]
Its also possible to only mock certain endpoints using a pattern. For example to mock all log
endpoints you do as shown:
Listing 73. adviceWith mocking only log endpoints using a pattern
public void testAdvisedMockEndpointsWithPattern() throws Exception {
// advice the first route using the inlined AdviceWith route builder
// which has extended capabilities than the regular route builder
context.getRouteDefinitions().get(0).adviceWith(context, new
AdviceWithRouteBuilder() {
@Override
public void configure() throws Exception {
// mock only log endpoints
mockEndpoints("log*");
}
});
// now we can refer to log:foo as a mock and set our expectations
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// only the log:foo endpoint was mocked
assertNotNull(context.hasEndpoint("mock:log:foo"));
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Mocked endpoints are without parameters
Endpoints which are mocked will have their parameters stripped off. For example
the endpoint "log:foo?showAll=true" will be mocked to the following endpoint
"mock:log:foo". Notice the parameters has been removed.
assertNull(context.hasEndpoint("mock:direct:start"));
assertNull(context.hasEndpoint("mock:direct:foo"));
}
The pattern supported can be a wildcard or a regular expression. See more details about this at
Intercept as its the same matching function used by Camel.
Mocking existing endpoints using the camel-test component
Instead of using the adviceWith to instruct Camel to mock endpoints, you can easily enable
this behavior when using the camel-test Test Kit.
The same route can be tested as follows. Notice that we return "*" from the
isMockEndpoints method, which tells Camel to mock all endpoints.
If you only want to mock all log endpoints you can return "log*" instead.
Listing 74. isMockEndpoints using camel-test kit
public class IsMockEndpointsJUnit4Test extends CamelTestSupport {
@Override
public String isMockEndpoints() {
// override this method and return the pattern for which endpoints to mock.
// use * to indicate all
return "*";
}
@Test
public void testMockAllEndpoints() throws Exception {
// notice we have automatic mocked all endpoints and the name of the endpoints
is "mock:uri"
getMockEndpoint("mock:direct:start").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:direct:foo").expectedBodiesReceived("Hello World");
getMockEndpoint("mock:log:foo").expectedBodiesReceived("Bye World");
getMockEndpoint("mock:result").expectedBodiesReceived("Bye World");
template.sendBody("direct:start", "Hello World");
assertMockEndpointsSatisfied();
// additional test to ensure correct endpoints in registry
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Mind that mocking endpoints causes the messages to be copied when they arrive on
the mock.
That means Camel will use more memory. This may not be suitable when you send
in a lot of messages.
assertNotNull(context.hasEndpoint("direct:start"));
assertNotNull(context.hasEndpoint("direct:foo"));
assertNotNull(context.hasEndpoint("log:foo"));
assertNotNull(context.hasEndpoint("mock:result"));
// all the endpoints was mocked
assertNotNull(context.hasEndpoint("mock:direct:start"));
assertNotNull(context.hasEndpoint("mock:direct:foo"));
assertNotNull(context.hasEndpoint("mock:log:foo"));
}
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:start").to("direct:foo").to("log:foo").to("mock:result");
from("direct:foo").transform(constant("Bye World"));
}
};
}
}
Mocking existing endpoints with XML DSL
If you do not use the camel-test component for unit testing (as shown above) you can use a
different approach when using XML files for routes.
The solution is to create a new XML file used by the unit test and then include the intended
XML file which has the route you want to test.
Suppose we have the route in the camel-route.xml file:
Listing 75. camel-route.xml
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Bye World
Then we create a new XML file as follows, where we include the camel-route.xml file and
define a spring bean with the class
org.apache.camel.impl.InterceptSendToMockEndpointStrategy which tells
Camel to mock all endpoints:
Listing 76. test-camel-route.xml
Then in your unit test you load the new XML file (test-camel-route.xml) instead of
camel-route.xml.
To only mock all Log endpoints you can define the pattern in the constructor for the bean:
Testing with arrival times
Available as of Camel 2.7
The Mock endpoint stores the arrival time of the message as a property on the Exchange.
Date time = exchange.getProperty(Exchange.RECEIVED_TIMESTAMP, Date.class);
You can use this information to know when the message arrived on the mock. But it also
provides foundation to know the time interval between the previous and next message arrived
on the mock. You can use this to set expectations using the arrives DSL on the Mock
endpoint.
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For example to say that the first message should arrive between 0-2 seconds before the
next you can do:
mock.message(0).arrives().noLaterThan(2).seconds().beforeNext();
You can also define this as that 2nd message (0 index based) should arrive no later than 0-2
seconds after the previous:
mock.message(1).arrives().noLaterThan(2).seconds().afterPrevious();
You can also use between to set a lower bound. For example suppose that it should be
between 1-4 seconds:
mock.message(1).arrives().between(1, 4).seconds().afterPrevious();
You can also set the expectation on all messages, for example to say that the gap between them
should be at most 1 second:
mock.allMessages().arrives().noLaterThan(1).seconds().beforeNext();
See Also
•
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
Spring Testing
Testing
MSV COMPONENT
The MSV component performs XML validation of the message body using the MSV Library and
any of the supported XML schema languages, such as XML Schema or RelaxNG XML Syntax.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-msvx.x.x
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time units
In the example above we use seconds as the time unit, but Camel offers
milliseconds, and minutes as well.
Note that the Jing component also supports RelaxNG Compact Syntax
URI format
msv:someLocalOrRemoteResource[?options]
Where someLocalOrRemoteResource is some URL to a local resource on the classpath
or a full URL to a remote resource or resource on the file system. For example
msv:org/foo/bar.rng
msv:file:../foo/bar.rng
msv:http://acme.com/cheese.rng
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
useDom
true
Camel 2.0: Whether DOMSource/DOMResult or SaxSource/SaxResult should be used by the validator. Note: DOM must be used by the
MSV component.
Example
The following example shows how to configure a route from endpoint direct:start which
then goes to one of two endpoints, either mock:valid or mock:invalid based on whether
or not the XML matches the given RelaxNG XML Schema (which is supplied on the classpath).
org.apache.camel.ValidationException
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See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
MYBATIS
Available as of Camel 2.7
The mybatis: component allows you to query, poll, insert, update and delete data in a
relational database using MyBatis.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-mybatisx.x.x
URI format
mybatis:statementName[?options]
Where statementName is the statement name in the MyBatis XML mapping file which
maps to the query, insert, update or delete operation you wish to evaluate.
You can append query options to the URI in the following format,
?option=value&option=value&...
This component will by default load the MyBatis SqlMapConfig file from the root of the
classpath and expected named as SqlMapConfig.xml.
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If the file is located in another location, you would have to configure the
configurationUri option on the MyBatisComponent component.
Options
Option
Type
Default
Description
consumer.onConsume
String
null
Statements to run after consuming. Can be used, for example, to update rows after they
have been consumed and processed in Camel. See sample later. Multiple statements can be
separated with comma.
consumer.useIterator
boolean
true
If true each row returned when polling will be processed individually. If false the entire
List of data is set as the IN body.
consumer.routeEmptyResultSet
boolean
false
Sets whether empty result set should be routed or not. By default, empty result sets are not
routed.
statementType
StatementType
null
Mandatory to specify for producer to control which kind of operation to invoke. The enum
values are: SelectOne, SelectList, Insert, Update, Delete.
maxMessagesPerPoll
int
0
An integer to define a maximum messages to gather per poll. By default, no maximum is set.
Can be used to set a limit of e.g. 1000 to avoid when starting up the server that there are
thousands of files. Set a value of 0 or negative to disabled it.
Message Headers
Camel will populate the result message, either IN or OUT with a header with the statement
used:
Header
Type
Description
CamelMyBatisStatementName
String
The statementName used (for example: insertAccount).
CamelMyBatisResult
Object
The response returned from MtBatis in any of the operations. For instance an INSERT could return the auto-generated
key, or number of rows etc.
Message Body
The response from MyBatis will only be set as body if it's a SELECT statement. That means, for
example, for INSERT statements Camel will not replace the body. This allows you to continue
routing and keep the original body. The response from MyBatis is always stored in the header
with the key CamelMyBatisResult.
Samples
For example if you wish to consume beans from a JMS queue and insert them into a database
you could do the following:
from("activemq:queue:newAccount").
to("mybatis:insertAccount?statementType=Insert");
Notice we have to specify the statementType, as we need to instruct Camel which kind of
operation to invoke.
Where insertAccount is the MyBatis ID in the SQL mapping file:
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insert into ACCOUNT (
ACC_ID,
ACC_FIRST_NAME,
ACC_LAST_NAME,
ACC_EMAIL
)
values (
#{id}, #{firstName}, #{lastName}, #{emailAddress}
)
Using StatementType for better control of MyBatis
When routing to an MyBatis endpoint you want more fine grained control so you can control
whether the SQL statement to be executed is a SELEECT, UPDATE, DELETE or INSERT etc.
So for instance if we want to route to an MyBatis endpoint in which the IN body contains
parameters to a SELECT statement we can do:
from("direct:start")
.to("mybatis:selectAccountById?statementType=SelectOne")
.to("mock:result");
In the code above we can invoke the MyBatis statement selectAccountById and the IN
body should contain the account id we want to retrieve, such as an Integer type.
We can do the same for some of the other operations, such as SelectList:
from("direct:start")
.to("mybatis:selectAllAccounts?statementType=SelectList")
.to("mock:result");
And the same for UPDATE, where we can send an Account object as IN body to MyBatis:
from("direct:start")
.to("mybatis:updateAccount?statementType=Update")
.to("mock:result");
Scheduled polling example
Since this component does not support scheduled polling, you need to use another mechanism
for triggering the scheduled polls, such as the Timer or Quartz components.
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In the sample below we poll the database, every 30 seconds using the Timer component and
send the data to the JMS queue:
from("timer://pollTheDatabase?delay=30000").to("mbatis:selectAllAccounts").to("activemq:queue:allAccou
And the MyBatis SQL mapping file used:
Using onConsume
This component supports executing statements after data have been consumed and processed
by Camel. This allows you to do post updates in the database. Notice all statements must be
UPDATE statements. Camel supports executing multiple statements whose name should be
separated by comma.
The route below illustrates we execute the consumeAccount statement data is
processed. This allows us to change the status of the row in the database to processed, so we
avoid consuming it twice or more.
from("mybatis:selectUnprocessedAccounts?consumer.onConsume=consumeAccount").to("mock:results");
And the statements in the sqlmap file:
update ACCOUNT set PROCESSED = true where ACC_ID = #{id}
See Also
•
•
•
•
779
Configuring Camel
Component
Endpoint
Getting Started
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
NAGIOS
Available as of Camel 2.3
The Nagios component allows you to send passive checks to Nagios.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-nagiosx.x.x
URI format
nagios://host[:port][?Options]
Camel provides two abilities with the Nagios component. You can send passive check messages
by sending a message to its endpoint.
Camel also provides a EventNotifer which allows you to send notifications to Nagios.
Options
Name
Default
Value
Description
host
none
This is the address of the Nagios host where checks should be send.
port
Ê
The port number of the host.
password
Ê
Password to be authenticated when sending checks to Nagios.
connectionTimeout
5000
Connection timeout in millis.
timeout
5000
Sending timeout in millis.
nagiosSettings
Ê
To use an already configured com.googlecode.jsendnsca.core.NagiosSettings object. Then any of the other
options are not in use, if using this.
sendSync
true
Whether or not to use synchronous when sending a passive check. Setting it to false will allow Camel to continue routing the
message and the passive check message will be send asynchronously.
encryptionMethod
No
Camel 2.9: To specify an encryption method. Possible values: No, Xor, or TripleDes.
Headers
Name
Description
CamelNagiosHostName
This is the address of the Nagios host where checks should be send. This header will override any existing hostname configured on the
endpoint.
CamelNagiosLevel
This is the severity level. You can use values CRITICAL, WARNING, OK. Camel will by default use OK.
CamelNagiosServiceName
The servie name. Will default use the CamelContext name.
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Sending message examples
You can send a message to Nagios where the message payload contains the message. By default
it will be OK level and use the CamelContext name as the service name. You can overrule these
values using headers as shown above.
For example we send the Hello Nagios message to Nagios as follows:
template.sendBody("direct:start", "Hello Nagios");
from("direct:start").to("nagios:127.0.0.1:5667?password=secret").to("mock:result");
To send a CRITICAL message you can send the headers such as:
Map headers = new HashMap();
headers.put(NagiosConstants.LEVEL, "CRITICAL");
headers.put(NagiosConstants.HOST_NAME, "myHost");
headers.put(NagiosConstants.SERVICE_NAME, "myService");
template.sendBodyAndHeaders("direct:start", "Hello Nagios", headers);
Using NagiosEventNotifer
The Nagios component also provides an EventNotifer which you can use to send events to
Nagios. For example we can enable this from Java as follows:
NagiosEventNotifier notifier = new NagiosEventNotifier();
notifier.getConfiguration().setHost("localhost");
notifier.getConfiguration().setPort(5667);
notifier.getConfiguration().setPassword("password");
CamelContext context = ...
context.getManagementStrategy().addEventNotifier(notifier);
return context;
In Spring XML its just a matter of defining a Spring bean with the type EventNotifier and
Camel will pick it up as documented here: Advanced configuration of CamelContext using
Spring.
See Also
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•
•
•
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Configuring Camel
Component
Endpoint
Getting Started
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
NETTY COMPONENT
Available as of Camel 2.3
The netty component in Camel is a socket communication component, based on the JBoss
Netty community offering (available under an Apache 2.0 license).
Netty is a NIO client server framework which enables quick and easy development of network
applications such as protocol servers and clients.
Netty greatly simplifies and streamlines network programming such as TCP and UDP socket
server.
This camel component supports both producer and consumer endpoints.
The netty component has several options and allows fine-grained control of a number of
TCP/UDP communication parameters (buffer sizes, keepAlives, tcpNoDelay etc) and facilitates
both In-Only and In-Out communication on a Camel route.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-nettyx.x.x
URI format
The URI scheme for a netty component is as follows
netty:tcp://localhost:99999[?options]
netty:udp://remotehost:99999/[?options]
This component supports producer and consumer endpoints for both TCP and UDP.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
keepAlive
true
Setting to ensure socket is not closed due to inactivity
tcpNoDelay
true
Setting to improve TCP protocol performance
broadcast
false
Setting to choose Multicast over UDP
connectTimeout
10000
Time to wait for a socket connection to be available. Value is in millis.
reuseAddress
true
Setting to facilitate socket multiplexing
sync
true
Setting to set endpoint as one-way or request-response
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ssl
false
Setting to specify whether SSL encryption is applied to this endpoint
sendBufferSize
65536
bytes
The TCP/UDP buffer sizes to be used during outbound communication. Size is bytes.
receiveBufferSize
65536
bytes
The TCP/UDP buffer sizes to be used during inbound communication. Size is bytes.
corePoolSize
10
The number of allocated threads at component startup. Defaults to 10
maxPoolSize
100
The maximum number of threads that may be allocated to this endpoint. Defaults to 100
disconnect
false
Whether or not to disconnect(close) from Netty Channel right after use. Can be used for both consumer and producer.
lazyChannelCreation
true
Channels can be lazily created to avoid exceptions, if the remote server is not up and running when the Camel producer is
started.
transferExchange
false
Only used for TCP. You can transfer the exchange over the wire instead of just the body. The following fields are
transferred: In body, Out body, fault body, In headers, Out headers, fault headers, exchange properties, exchange
exception. This requires that the objects are serializable. Camel will exclude any non-serializable objects and log it at
WARN level.
disconnectOnNoReply
true
If sync is enabled then this option dictates NettyConsumer if it should disconnect where there is no reply to send back.
noReplyLogLevel
WARN
If sync is enabled this option dictates NettyConsumer which logging level to use when logging a there is no reply to send
back. Values are: FATAL, ERROR, INFO, DEBUG, OFF.
allowDefaultCodec
true
Camel 2.4: The netty component installs a default codec if both, encoder/deocder is null and textline is false. Setting
allowDefaultCodec to false prevents the netty component from installing a default codec as the first element in the filter
chain.
textline
false
Camel 2.4: Only used for TCP. If no codec is specified, you can use this flag to indicate a text line based codec; if not
specified or the value is false, then Object Serialization is assumed over TCP.
delimiter
LINE
Camel 2.4: The delimiter to use for the textline codec. Possible values are LINE and NULL.
decoderMaxLineLength
1024
Camel 2.4: The max line length to use for the textline codec.
autoAppendDelimiter
true
Camel 2.4: Whether or not to auto append missing end delimiter when sending using the textline codec.
encoding
null
Camel 2.4: The encoding (a charset name) to use for the textline codec. If not provided, Camel will use the JVM default
Charset.
workerCount
null
Camel 2.9: When netty works on nio mode, it uses default workerCount parameter from Netty, which is
cpu_core_threads*2. User can use this operation to override the default workerCount from Netty
sslContextParametersRef
null
Camel 2.9: Reference to a org.apache.camel.util.jsse.SSLContextParameters in the Registry.Ê This
reference overrides any configured SSLContextParameters at the component level.Ê See Using the JSSE Configuration
Utility.
Ê
Registry based Options
Codec Handlers and SSL Keystores can be enlisted in the Registry, such as in the Spring XML
file.
The values that could be passed in, are the following:
783
Name
Description
passphrase
password setting to use in order to encrypt/decrypt payloads sent using SSH
keyStoreFormat
keystore format to be used for payload encryption. Defaults to "JKS" if not set
securityProvider
Security provider to be used for payload encryption. Defaults to "SunX509" if not set.
keyStoreFile
Client side certificate keystore to be used for encryption
trustStoreFile
Server side certificate keystore to be used for encryption
sslHandler
Reference to a class that could be used to return an SSL Handler
encoder
A custom Handler class that can be used to perform special marshalling of outbound payloads. Must override
org.jboss.netty.channel.ChannelDownStreamHandler.
encorders
A list of encoder to be used. You can use a String which have values separated by comma, and have the values be looked up in the Registry. Just
remember to prefix the value with # so Camel knows it should lookup.
decoder
A custom Handler class that can be used to perform special marshalling of inbound payloads. Must override
org.jboss.netty.channel.ChannelUpStreamHandler.
decoders
A list of decorder to be used. You can use a String which have values separated by comma, and have the values be looked up in the Registry. Just
remember to prefix the value with # so Camel knows it should lookup.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
Sending Messages to/from a Netty endpoint
Netty Producer
In Producer mode, the component provides the ability to send payloads to a socket endpoint
using either TCP or UDP protocols (with optional SSL support).
The producer mode supports both one-way and request-response based operations.
Netty Consumer
In Consumer mode, the component provides the ability to:
▪ listen on a specified socket using either TCP or UDP protocols (with optional SSL
support),
▪ receive requests on the socket using text/xml, binary and serialized object based
payloads and
▪ send them along on a route as message exchanges.
The consumer mode supports both one-way and request-response based operations.
Usage Samples
A UDP Netty endpoint using Request-Reply and serialized
object payload
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("netty:udp://localhost:5155?sync=true")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
Poetry poetry = (Poetry) exchange.getIn().getBody();
poetry.setPoet("Dr. Sarojini Naidu");
exchange.getOut().setBody(poetry);
}
}
}
};
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A TCP based Netty consumer endpoint using One-way
communication
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("netty:tcp://localhost:5150")
.to("mock:result");
}
};
An SSL/TCP based Netty consumer endpoint using RequestReply communication
Using the JSSE Configuration Utility
As of Camel 2.9, the Netty component supports SSL/TLS configuration through the Camel JSSE
Configuration Utility.Ê This utility greatly decreases the amount of component specific code you
need to write and is configurable at the endpoint and component levels.Ê The following
examples demonstrate how to use the utility with the Netty component.
Programmatic configuration of the component
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/keystore.jks");
ksp.setPassword("keystorePassword");
KeyManagersParameters kmp = new KeyManagersParameters();
kmp.setKeyStore(ksp);
kmp.setKeyPassword("keyPassword");
SSLContextParameters scp = new SSLContextParameters();
scp.setKeyManagers(kmp);
NettyComponent nettyComponent = getContext().getComponent("netty",
NettyComponent.class);
nettyComponent.setSslContextParameters(scp);
Spring DSL based configuration of endpoint
...
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...
...
...
Using Basic SSL/TLS configuration on the Jetty Component
JndiRegistry registry = new JndiRegistry(createJndiContext());
registry.bind("password", "changeit");
registry.bind("ksf", new File("src/test/resources/keystore.jks"));
registry.bind("tsf", new File("src/test/resources/keystore.jks"));
context.createRegistry(registry);
context.addRoutes(new RouteBuilder() {
public void configure() {
String netty_ssl_endpoint =
"netty:tcp://localhost:5150?sync=true&ssl=true&passphrase=#password"
+ "&keyStoreFile=#ksf&trustStoreFile=#tsf";
String return_string =
"When You Go Home, Tell Them Of Us And Say,"
+ "For Your Tomorrow, We Gave Our Today.";
from(netty_ssl_endpoint)
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getOut().setBody(return_string);
}
}
}
});
Using Multiple Codecs
In certain cases it may be necessary to add chains of encoders and decoders to the netty
pipeline. To add multpile codecs to a camel netty endpoint the 'encoders' and 'decoders' uri
parameters should be used. Like the 'encoder' and 'decoder' parameters they are used to supply
references (to lists of ChannelUpstreamHandlers and ChannelDownstreamHandlers) that
should be added to the pipeline. Note that if encoders is specified then the encoder param will
be ignored, similarly for decoders and the decoder param.
The lists of codecs need to be added to the Camel's registry so they can be resolved when
the endpoint is created.
CH APT ER 11 - CO M PO N EN T APPEN DIX
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LengthFieldBasedFrameDecoder lengthDecoder = new LengthFieldBasedFrameDecoder(1048576,
0, 4, 0, 4);
StringDecoder stringDecoder = new StringDecoder();
registry.bind("length-decoder", lengthDecoder);
registry.bind("string-decoder", stringDecoder);
LengthFieldPrepender lengthEncoder = new LengthFieldPrepender(4);
StringEncoder stringEncoder = new StringEncoder();
registry.bind("length-encoder", lengthEncoder);
registry.bind("string-encoder", stringEncoder);
List decoders = new ArrayList();
decoders.add(lengthDecoder);
decoders.add(stringDecoder);
List encoders = new ArrayList();
encoders.add(lengthEncoder);
encoders.add(stringEncoder);
registry.bind("encoders", encoders);
registry.bind("decoders", decoders);
Spring's native collections support can be used to specify the codec lists in an application
context
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The bean names can then be used in netty endpoint definitions either as a comma separated list
or contained in a List e.g.
from("direct:multiple-codec").to("netty:tcp://localhost:{{port}}?encoders=#encoders&sync=false");
from("netty:tcp://localhost:{{port}}?decoders=#length-decoder,#string-decoder&sync=false").to("mock:mu
}
};
}
}
or via spring.
Closing Channel When Complete
When acting as a server you sometimes want to close the channel when, for example, a client
conversion is finished.
You can do this by simply setting the endpoint option disconnect=true.
However you can also instruct Camel on a per message basis as follows.
To instruct Camel to close the channel, you should add a header with the key
CamelNettyCloseChannelWhenComplete set to a boolean true value.
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For instance, the example below will close the channel after it has written the bye message back
to the client:
from("netty:tcp://localhost:8080").process(new Processor() {
public void process(Exchange exchange) throws Exception {
String body = exchange.getIn().getBody(String.class);
exchange.getOut().setBody("Bye " + body);
// some condition which determines if we should close
if (close) {
exchange.getOut().setHeader(NettyConstants.NETTY_CLOSE_CHANNEL_WHEN_COMPLETE, true);
}
}
});
Adding custom channel pipeline factories to gain complete control over a
created pipeline
Available as of Camel 2.5
Custom channel pipelines provide complete control to the user over the handler/
interceptor chain by inserting custom handler(s), encoder(s) & decoders without having to
specify them in the Netty Endpoint URL in a very simple way.
In order to add a custom pipeline, a custom channel pipeline factory must be created and
registered with the context via the context registry (JNDIRegistry,or the camel-spring
ApplicationContextRegistry etc).
A custom pipeline factory must be constructed as follows
• A Producer linked channel pipeline factory must extend the abstract class
ClientPipelineFactory.
• A Consumer linked channel pipeline factory must extend the abstract class
ServerPipelineFactory.
• The classes can optionally override the getPipeline() method in order to insert
custom handler(s), encoder(s) and decoder(s). Not overriding the getPipeline()
method creates a pipeline with no handlers, encoders or decoders wired to the
pipeline.
The example below shows how ServerChannel Pipeline factory may be created
public class SampleServerChannelPipelineFactory extends ServerPipelineFactory {
private int maxLineSize = 1024;
private boolean invoked;
public ChannelPipeline getPipeline() throws Exception {
invoked = true;
ChannelPipeline channelPipeline = Channels.pipeline();
channelPipeline.addLast("encoder-SD", new StringEncoder(CharsetUtil.UTF_8));
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channelPipeline.addLast("decoder-DELIM", new
DelimiterBasedFrameDecoder(maxLineSize, true, Delimiters.lineDelimiter()));
channelPipeline.addLast("decoder-SD", new StringDecoder(CharsetUtil.UTF_8));
channelPipeline.addLast("handler", new ServerChannelHandler(consumer));
return channelPipeline;
}
public boolean isfactoryInvoked() {
return invoked;
}
}
The custom channel pipeline factory can then be added to the registry and instantiated/utilized
on a camel route in the following way
Registry registry = camelContext.getRegistry();
serverPipelineFactory = new TestServerChannelPipelineFactory();
registry.bind("spf", serverPipelineFactory);
context.addRoutes(new RouteBuilder() {
public void configure() {
String netty_ssl_endpoint =
"netty:tcp://localhost:5150?serverPipelineFactory=#spf"
String return_string =
"When You Go Home, Tell Them Of Us And Say,"
+ "For Your Tomorrow, We Gave Our Today.";
from(netty_ssl_endpoint)
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getOut().setBody(return_string);
}
}
}
});
See Also
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•
▪
Configuring Camel
Component
Endpoint
Getting Started
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NMR COMPONENT
The nmr component is an adapter to the Normalized Message Router (NMR) in ServiceMix,
which is intended for use by Camel applications deployed directly into the OSGi container. You
can exchange objects with NMR and not only XML like this is the case with the JBI specification.
The interest of this component is that you can interconnect camel routes deployed in different
OSGI bundles.
By contrast, the JBI component is intended for use by Camel applications deployed into the
ServiceMix JBI container.
Installing
The NMR component is provided with Apache ServiceMix. It is not distributed with Camel. To
install the NMR component in ServiceMix, enter the following command in the ServiceMix
console window:
features install nmr
You also need to instantiate the NMR component. You can do this by editing your Spring
configuration file, META-INF/spring/*.xml, and adding the following bean instance:
...
...
NMR consumer and producer endpoints
The following code:
from("nmr:MyServiceEndpoint")
Automatically exposes a new endpoint to the bus with endpoint name MyServiceEndpoint
(see URI-format).
When an NMR endpoint appears at the end of a route, for example:
to("nmr:MyServiceEndpoint")
The messages sent by this producer endpoint are sent to the already deployed JBI endpoint.
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URI format
nmr:endpointName
URI Options
Option
Default
Value
Description
runAsSubject
false
Apache ServiceMix 4.4: When this is set to true on a consumer endpoint, the endpoint will be invoked on behalf of the Subject
that is set on the Exchange (i.e. the call to Subject.getSubject(AccessControlContext) will return the Subject
instance)
synchronous
false
When this is set to true on a consumer endpoint, an incoming, synchronous NMR Exchange will be handled on the sender's thread
instead of being handled on a new thread of the NMR endpoint's thread pool
timeout
0
Apache ServiceMix 4.4: When this is set to a value greater than 0, the producer endpoint will timeout if it doesn't receive a response
from the NMR within the given timeout period (in milliseconds). Configuring a timeout value will switch to using synchronous interactions
with the NMR instead of the usual asynchronous messaging.
Examples
Consumer
from("nmr:MyServiceEndpoint") // consume nmr exchanges asynchronously
from("nmr:MyServiceEndpoint?synchronous=true").to() // consume nmr exchanges
synchronously and use the same thread as defined by NMR ThreadPool
Producer
from()...to("nmr:MyServiceEndpoint") // produce nmr exchanges asynchronously
from()...to("nmr:MyServiceEndpoint?timeout=10000") // produce nmr exchanges
synchronously and wait till 10s to receive response
Using Stream bodies
If you are using a stream type as the message body, you should be aware that a stream is only
capable of being read once. So if you enable DEBUG logging, the body is usually logged and thus
read. To deal with this, Camel has a streamCaching option that can cache the stream,
enabling you to read it multiple times.
from("nmr:MyEndpoint").streamCaching().to("xslt:transform.xsl", "bean:doSomething");
From Camel 1.5 onwards, the stream caching is default enabled, so it is not necessary to set
the streamCaching() option.
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In Camel 2.0 we store big input streams (by default, over 64K) in a temp file using
CachedOutputStream. When you close the input stream, the temp file will be deleted.
Testing
NMR camel routes can be tested using the camel unit test approach even if they will be
deployed next in different bundles on an OSGI runtime. With this aim in view, you will extend
the ServiceMixNMR Mock class
org.apache.servicemix.camel.nmr.AbstractComponentTest which will create
a NMR bus, register the Camel NMR Component and the endpoints defined into the Camel
routes.
public class ExchangeUsingNMRTest extends AbstractComponentTest {
@Test
public void testProcessing() throws InterruptedException {
MockEndpoint mock = getMockEndpoint("mock:simple");
mock.expectedBodiesReceived("Simple message body");
template.sendBody("direct:simple", "Simple message body");
assertMockEndpointsSatisfied();
}
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
from("direct:simple").to("nmr:simple");
from("nmr:simple?synchronous=true").to("mock:simple");
}
};
}
}
See Also
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•
•
•
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Component
Endpoint
Getting Started
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
QUARTZ COMPONENT
The quartz: component provides a scheduled delivery of messages using the Quartz
scheduler.
Each endpoint represents a different timer (in Quartz terms, a Trigger and JobDetail).
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-quartzx.x.x
URI format
quartz://timerName?options
quartz://groupName/timerName?options
quartz://groupName/timerName/cronExpression
quartz://groupName/timerName/?cron=expression
quartz://timerName?cron=expression
(@deprecated)
(Camel 2.0)
(Camel 2.0)
The component uses either a CronTrigger or a SimpleTrigger. If no cron expression is
provided, the component uses a simple trigger. If no groupName is provided, the quartz
component uses the Camel group name.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Parameter
Default
Description
cron
None
Specifies a cron expression (not compatible with the trigger.* or job.* options).
trigger.repeatCount
0
SimpleTrigger: How many times should the timer repeat?
trigger.repeatInterval
0
SimpleTrigger: The amount of time in milliseconds between repeated triggers.
job.name
null
Sets the job name.
job.XXX
null
Sets the job option with the XXX setter name.
trigger.XXX
null
Sets the trigger option with the XXX setter name.
stateful
false
Uses a Quartz StatefulJob instead of the default job.
fireNow
false
New to Camel 2.2.0, if it is true will fire the trigger when the route is start when using SimpleTrigger.
For example, the following routing rule will fire two timer events to the mock:results
endpoint:
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Using cron expressions
Configuring the cron expression in Camel 1.x is based on path separators. We
changed this to an URI option in Camel 2.0, allowing a more elegant configuration.
Also it is not possible to use the / cron special character (for increments) in
Camel 1.x, which Camel 2.0 also fixes.
You may need to escape certain URI characters such as using ? in the quartz cron expression.
from("quartz://myGroup/
myTimerName?trigger.repeatInterval=2&trigger.repeatCount=1").routeId("myRoute").to("mock:result");
When using a StatefulJob, the JobDataMap is re-persisted after every execution of the job, thus
preserving state for the next execution.
Configuring quartz.properties file
By default Quartz will look for a quartz.properties file in the root of the classpath. If you
are using WAR deployments this means just drop the quartz.properties in WEB-INF/
classes.
However the Camel Quartz component also allows you to configure properties:
Parameter
Default
Type
Description
properties
null
Properties
Camel 2.4: You can configure a java.util.Propoperties instance.
propertiesFile
null
String
Camel 2.4: File name of the properties to load from the classpath
To do this you can configure this in Spring XML as follows
Starting the Quartz scheduler
Available as of Camel 2.4
The Quartz component offers an option to let the Quartz scheduler be started delayed, or
not auto started at all.
Parameter
Default
Type
Description
startDelayedSeconds
0
int
Camel 2.4: Seconds to wait before starting the quartz scheduler.
autoStartScheduler
true
boolean
Camel 2.4: Whether or not the scheduler should be auto started.
To do this you can configure this in Spring XML as follows
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Clustering
Available as of Camel 2.4
If you use Quartz in clustered mode, e.g. the JobStore is clustered. Then from Camel 2.4
onwards the Quartz component will not pause/remove triggers when a node is being stopped/
shutdown. This allows the trigger to keep running on the other nodes in the cluster.
Note: When running in clustered node no checking is done to ensure unique job name/
group for endpoints.
Message Headers
Camel adds the getters from the Quartz Execution Context as header values. The following
headers are added:
calendar, fireTime, jobDetail, jobInstance, jobRuntTime,
mergedJobDataMap, nextFireTime, previousFireTime, refireCount, result,
scheduledFireTime, scheduler, trigger, triggerName, triggerGroup.
The fireTime header contains the java.util.Date of when the exchange was fired.
Using Cron Triggers
Available as of Camel 2.0
Quartz supports Cron-like expressions for specifying timers in a handy format. You can use
these expressions in the cron URI parameter; though to preserve valid URI encoding we allow
+ to be used instead of spaces. Quartz provides a little tutorial on how to use cron
expressions.
For example, the following will fire a message every five minutes starting at 12pm (noon) to
6pm on weekdays:
from("quartz://myGroup/myTimerName?cron=0+0/
5+12-18+?+*+MON-FRI").to("activemq:Totally.Rocks");
which is equivalent to using the cron expression
0 0/5 12-18 ? * MON-FRI
The following table shows the URI character encodings we use to preserve valid URI syntax:
URI Character
Cron character
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Space
+
Using Cron Triggers in Camel 1.x
@deprecated
Quartz supports Cron-like expressions for specifying timers in a handy format. You can use
these expressions in the URI; though to preserve valid URI encoding we allow / to be used
instead of spaces and $ to be used instead of ?.
For example, the following endpoint URI will fire a message at 12pm (noon) every day
from("quartz://myGroup/myTimerName/0/0/12/*/*/$").to("activemq:Totally.Rocks");
which is equivalent to using the cron expression
0 0 12 * * ?
The following table shows the URI character encodings we use to preserve valid URI syntax:
URI Character
Cron character
/
Space
$
?
Specifying time zone
Available as of Camel 2.8.1
The Quartz Scheduler allows you to configure time zone per trigger. For example to use a
timezone of your country, then you can do as follows:
quartz://groupName/timerName?cron=0+0/5+12-18+?+*+MON-FRI&trigger.timeZone=Europe/
Stockholm
The timeZone value is the values accepted by java.util.TimeZone.
In Camel 2.8.0 or older versions you would have to provide your custom String to
java.util.TimeZone Type Converter to be able configure this from the endpoint uri.
From Camel 2.8.1 onwards we have included such a Type Converter in the camel-core.
See Also
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•
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Configuring Camel
Component
Endpoint
Getting Started
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CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
QUICKFIX/J COMPONENT
Available as of Camel 2.0
The quickfix component adapts the QuickFIX/J FIX engine for using in Camel . This
component uses the standard Financial Interchange (FIX) protocol for message transport.
Maven users will need to add the following dependency to their pom.xml for this component:
org.apache.camelcamel-quickfixx.x.x
URI format
quickfix:configFile[?sessionID=sessionID]
The configFile is the name of the QuickFIX/J configuration to use for the FIX engine (located
as a resource found in your classpath). The optional sessionID identifies a specific FIX session.
The format of the sessionID is:
(BeginString):(SenderCompID)[/(SenderSubID)[/(SenderLocationID)]]->(TargetCompID)[/
(TargetSubID)[/(TargetLocationID)]]
Example URIs:
quickfix:config.cfg
quickfix:config.cfg?sessionID=FIX.4.2:MyTradingCompany->SomeExchange
ENDPOINTS
FIX sessions are endpoints for the quickfix component. An endpoint URI may specify a single
session or all sessions managed by a specific QuickFIX/J engine. Typical applications will use only
one FIX engine but advanced users may create multiple FIX engines by referencing different
configuration files in quickfix component endpoint URIs.
When a consumer does not include a session ID in the endpoint URI, it will receive
exchanges for all sessions managed by the FIX engine associated with the configuration file
specified in the URI. If a producer does not specify a session in the endpoint URI then it must
include the session-related fields in the FIX message being sent. If a session is specified in the
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Previous Versions
The quickfix component was rewritten for Camel 2.5. For information about
using the quickfix component prior to 2.5 see the documentation section below.
URI then the component will automatically inject the session-related fields into the FIX
message.
Exchange Format
The exchange headers include information to help with exchange filtering, routing and other
processing. The following headers are available:
Header
Name
Description
EventCategory
One of AppMessageReceived, AppMessageSent, AdminMessageReceived, AdminMessageSent, SessionCreated, SessionLogon,
SessionLogoff. See the QuickfixjEventCategory enum.
SessionID
The FIX message SessionID
MessageType
The FIX MsgType tag value
DataDictionary
Specifies a data dictionary to used for parsing an incoming message. Can be an instance of a data dictionary or a resource path for a QuickFIX/J data
dictionary file
The DataDictionary header is useful if string messages are being received and need to be parsed
in a route. QuickFIX/J requires a data dictionary to parse certain types of messages (with
repeating groups, for example). By injecting a DataDictionary header in the route after receiving
a message string, the FIX engine can properly parse the data.
QuickFIX/J Configuration Extensions
When using QuickFIX/J directly, one typically writes code to create instances of logging
adapters, message stores and communication connectors. The quickfix component will
automatically create instances of these classes based on information in the configuration file. It
also provides defaults for many of the common required settings and adds additional capabilities
(like the ability to activate JMX support).
The following sections describe how the quickfix component processes the QuickFIX/J
configuration. For comprehensive information about QuickFIX/J configuration, see the QFJ user
manual.
Communication Connectors
When the component detects an initiator or acceptor session setting in the QuickFIX/J
configuration file it will automatically create the corresponding initiator and/or acceptor
connector. These settings can be in the default or in a specific session section of the
configuration file.
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Session Setting
Component Action
ConnectionType=initiator
Create an initiator connector
ConnectionType=acceptor
Create an acceptor connector
The threading model for the QuickFIX/J session connectors can also be specified. These settings
affect all sessions in the configuration file and must be placed in the settings default section.
Default/Global Setting
Component Action
ThreadModel=ThreadPerConnector
Use SocketInitiator or SocketAcceptor (default)
ThreadModel=ThreadPerSession
Use ThreadedSocketInitiator or ThreadedSocketAcceptor
Logging
The QuickFIX/J logger implementation can be specified by including the following settings in the
default section of the configuration file. The ScreenLog is the default if none of the following
settings are present in the configuration. It's an error to include settings that imply more than
one log implementation. The log factory implementation can also be set directly on the Quickfix
component. This will override any related values in the QuickFIX/J settings file.
Default/Global Setting
Component Action
ScreenLogShowEvents
Use a ScreenLog
ScreenLogShowIncoming
Use a ScreenLog
ScreenLogShowOutgoing
Use a ScreenLog
SLF4J*
Camel 2.6+. Use a SLF4JLog. Any of the SLF4J settings will cause this log to be used.
FileLogPath
Use a FileLog
JdbcDriver
Use a JdbcLog
Message Store
The QuickFIX/J message store implementation can be specified by including the following
settings in the default section of the configuration file. The MemoryStore is the default if none
of the following settings are present in the configuration. It's an error to include settings that
imply more than one message store implementation. The message store factory implementation
can also be set directly on the Quickfix component. This will override any related values in the
QuickFIX/J settings file.
Default/Global Setting
Component Action
JdbcDriver
Use a JdbcStore
FileStorePath
Use a FileStore
SleepycatDatabaseDir
Use a SleepcatStore
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Message Factory
A message factory is used to construct domain objects from raw FIX messages. The default
message factory is DefaultMessageFactory. However, advanced applications may require
a custom message factory. This can be set on the QuickFIX/J component.
JMX
Default/Global Setting
Component Action
UseJmx
if Y, then enable QuickFIX/J JMX
Other Defaults
The component provides some default settings for what are normally required settings in
QuickFIX/J configuration files. SessionStartTime and SessionEndTime default to
"00:00:00", meaning the session will not be automatically started and stopped. The
HeartBtInt (heartbeat interval) defaults to 30 seconds.
Minimal Initiator Configuration Example
[SESSION]
ConnectionType=initiator
BeginString=FIX.4.4
SenderCompID=YOUR_SENDER
TargetCompID=YOUR_TARGET
Using the InOut Message Exchange Pattern
Camel 2.8+
Although the FIX protocol is event-driven and asynchronous, there are specific pairs of
messages
that represent a request-reply message exchange. To use an InOut exchange pattern, there
should
be a single request message and single reply message to the request. Examples include an
OrderStatusRequest message and UserRequest.
Implementing InOut Exchanges for Consumers
Add "exchangePattern=InOut" to the QuickFIX/J enpoint URI. The
MessageOrderStatusService in
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the example below is a bean with a synchronous service method. The method returns the
response
to the request (an ExecutionReport in this case) which is then sent back to the requestor
session.
from("quickfix:examples/
inprocess.cfg?sessionID=FIX.4.2:MARKET->TRADER&exchangePattern=InOut")
.filter(header(QuickfixjEndpoint.MESSAGE_TYPE_KEY).isEqualTo(MsgType.ORDER_STATUS_REQUEST))
.bean(new MarketOrderStatusService());
Implementing InOut Exchanges for Producers
For producers, sending a message will block until a reply is received or a timeout occurs. There
is no standard way to correlate reply messages in FIX. Therefore, a correlation criteria must be
defined for each type of InOut exchange. The correlation criteria and timeout can be specified
using Exchange properties.
Description
Key String
Key Constant
Default
Correlation
Criteria
"CorrelationCriteria"
QuickfixjProducer.CORRELATION_CRITERIA_KEY
None
Correlation
Timeout in
Milliseconds
"CorrelationTimeout"
QuickfixjProducer.CORRELATION_TIMEOUT_KEY
1000
The correlation criteria is defined with a MessagePredicate object. The following example
will treat
a FIX ExecutionReport from the specified session where the transaction type is STATUS and
the Order ID
matches our request. The session ID should be for the requestor, the sender and target CompID
fields
will be reversed when looking for the reply.
exchange.setProperty(QuickfixjProducer.CORRELATION_CRITERIA_KEY,
new MessagePredicate(new SessionID(sessionID), MsgType.EXECUTION_REPORT)
.withField(ExecTransType.FIELD, Integer.toString(ExecTransType.STATUS))
.withField(OrderID.FIELD, request.getString(OrderID.FIELD)));
Example
The source code contains an example called RequestReplyExample that demonstrates the
InOut exchanges
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for a consumer and producer. This example creates a simple HTTP server endpoint that
accepts order
status requests. The HTTP request is converted to a FIX OrderStatusRequestMessage, is
augmented with a
correlation criteria, and is then routed to a quickfix endpoint. The response is then converted
to a
JSON-formatted string and sent back to the HTTP server endpoint to be provided as the web
response.
The Spring configuration have changed from Camel 2.9 onwards. See further below for
example.
Spring Configuration
Camel 2.6 - 2.8.x
The QuickFIX/J component includes a Spring FactoryBean for configuring the session
settings within a Spring context. A type converter for QuickFIX/J session ID strings is also
included. The following example shows a simple configuration of an acceptor and initiator
session with default settings for both sessions.
${in.header.EventCategory} == 'AppMessageReceived'
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Camel 2.9 onwards
The QuickFIX/J component includes a QuickfixjConfiguration class for configuring
the session settings. A type converter for QuickFIX/J session ID strings is also included. The
following example shows a simple configuration of an acceptor and initiator session with default
settings for both sessions.
${in.header.EventCategory} == 'AppMessageReceived'
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Exception handling
QuickFIX/J behavior can be modified if certain exceptions are thrown during processing of a
message. If a RejectLogon exception is thrown while processing an incoming logon
administrative message, then the logon will be rejected.
Normally, QuickFIX/J handles the logon process automatically. However, sometimes an
outgoing logon message must be modified to include credentials required by a FIX
counterparty. If the FIX logon message body is modified when sending a logon message
(EventCategory=AdminMessageSent the modified message will be sent to the counterparty.
It is important that the outgoing logon message is being processed synchronously. If it is
processed asynchronously (on another thread), the FIX engine will immediately send the
unmodified outgoing message when it's callback method returns.
FIX Sequence Number Management
If an application exception is thrown during synchronous exchange processing, this will cause
QuickFIX/J to not increment incoming FIX message sequence numbers and will cause a resend
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of the counterparty message. This FIX protocol behavior is primarily intended to handle
transport errors rather than application errors. There are risks associated with using this
mechanism to handle application errors. The primary risk is that the message will repeatedly
cause application errors each time it's re-received. A better solution is to persist the incoming
message (database, JMS queue) immediately before processing it. This also allows the application
to process messages asynchronously without losing messages when errors occur.
Although it's possible to send messages to a FIX session before it's logged on (the messages
will be sent at logon time), it is usually a better practice to wait until the session is logged on.
This eliminates the required sequence number resynchronization steps at logon. Waiting for
session logon can be done by setting up a route that processes the SessionLogon event
category and signals the application to start sending messages.
See the FIX protocol specifications and the QuickFIX/J documentation for more details
about FIX sequence number management.
Route Examples
Several examples are included in the QuickFIX/J component source code (test subdirectories).
One of these examples implements a trival trade excecution simulation. The example defines an
application component that uses the URI scheme "trade-executor".
The following route receives messages for the trade executor session and passes application
messages to the trade executor component.
from("quickfix:examples/inprocess.cfg?sessionID=FIX.4.2:MARKET->TRADER").
filter(header(QuickfixjEndpoint.EVENT_CATEGORY_KEY).isEqualTo(QuickfixjEventCategory.AppMessageReceive
to("trade-executor:market");
The trade executor component generates messages that are routed back to the trade session.
The session ID must be set in the FIX message itself since no session ID is specified in the
endpoint URI.
from("trade-executor:market").to("quickfix:examples/inprocess.cfg");
The trader session consumes execution report messages from the market and processes them.
from("quickfix:examples/inprocess.cfg?sessionID=FIX.4.2:TRADER->MARKET").
filter(header(QuickfixjEndpoint.MESSAGE_TYPE_KEY).isEqualTo(MsgType.EXECUTION_REPORT)).
bean(new MyTradeExecutionProcessor());
QUICKFIX/J COMPONENT PRIOR TO CAMEL 2.5
Available since Camel 2.0
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The quickfix component is an implementation of the QuickFIX/J engine for Java . This
engine allows to connect to a FIX server which is used to exchange financial messages according
to FIX protocol standard.
Note: The component can be used to send/receives messages to a FIX server.
URI format
quickfix-server:config file
quickfix-client:config file
Where config file is the location (in your classpath) of the quickfix configuration file used to
configure the engine at the startup.
Note: Information about parameters available for quickfix can be found on QuickFIX/J web
site.
The quickfix-server endpoint must be used to receive from FIX server FIX messages and
quickfix-client endpoint in the case that you want to send messages to a FIX gateway.
Exchange data format
The QuickFIX/J engine is like CXF component a messaging bus using MINA as protocol layer to
create the socket connection with the FIX engine gateway.
When QuickFIX/J engine receives a message, then it create a QuickFix.Message instance
which is next received by the camel endpoint. This object is a 'mapping object' created from a
FIX message formatted initially as a collection of key value pairs data. You can use this object or
you can use the method 'toString' to retrieve the original FIX message.
Note: Alternatively, you can use camel bindy dataformat to transform the FIX message into
your own java POJO
When a message must be send to QuickFix, then you must create a QuickFix.Message
instance.
Samples
Direction : to FIX gateway
// bean method in charge to
transform message into a QuickFix.Message
// Quickfix engine who will
send the FIX messages to the gateway
Direction : from FIX gateway
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// QuickFix engine who
will receive the message from FIX gateway
// bean method parsing the
QuickFix.Message
"
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
PRINTER COMPONENT
Available as of Camel 2.1
The printer component provides a way to direct payloads on a route to a printer.
Obviously the payload has to be a formatted piece of payload in order for the component to
appropriately print it. The objective is to be able to direct specific payloads as jobs to a line
printer in a camel flow.
This component only supports a camel producer endpoint.
The functionality allows for the payload to be printed on a default printer, named local,
remote or wirelessly linked printer using the javax printing API under the covers.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-printerx.x.x
URI format
Since the URI scheme for a printer has not been standardized (the nearest thing to a standard
being the IETF print standard) and therefore not uniformly applied by vendors, we have chosen
"lpr" as the scheme.
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lpr://localhost/default[?options]
lpr://remotehost:port/path/to/printer[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default Value
Description
mediaSize
MediaSizeName.NA_LETTER
Sets the stationary as defined by enumeration settings in the javax.print.attribute.standard.MediaSizeName API. The default
setting is to use North American Letter sized stationary
copies
1
Sets number of copies based on the javax.print.attribute.standard.Copies API
sides
Sides.ONE_SIDED
Sets one sided or two sided printing based on the javax.print.attribute.standard.Sides API
flavor
DocFlavor.BYTE_ARRAY
Sets DocFlavor based on the javax.print.DocFlavor API
mimeType
AUTOSENSE
Sets mimeTypes supported by the javax.print.DocFlavor API
Sending Messages to a Printer
Printer Producer
Sending data to the printer is very straightforward and involves creating a producer endpoint
that can be sent message exchanges on in route.
Usage Samples
Example 1: Printing text based payloads on a Default printer
using letter stationary and one-sided mode
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from(file://inputdir/?delete=true)
.to("lpr://localhost/default?copies=2" +
"&flavor=DocFlavor.INPUT_STREAM&" +
"&mimeType=AUTOSENSE" +
"&mediaSize=na-letter" +
"&sides=one-sided")
}};
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Example 2: Printing GIF based payloads on a Remote printer
using A4 stationary and one-sided mode
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from(file://inputdir/?delete=true)
.to("lpr://remotehost/sales/salesprinter" +
"?copies=2&sides=one-sided" +
"&mimeType=GIF&mediaSize=iso-a4" +
"&flavor=DocFlavor.INPUT_STREAM")
}};
Example 3: Printing JPEG based payloads on a Remote printer
using Japanese Postcard stationary and one-sided mode
RouteBuilder builder = new RouteBuilder() {
public void configure() {
from(file://inputdir/?delete=true)
.to("lpr://remotehost/sales/salesprinter" +
"?copies=2&sides=one-sided" +
"&mimeType=JPEG" +
"&mediaSize=japanese-postcard" +
"&flavor=DocFlavor.INPUT_STREAM")
}};
PROPERTIES COMPONENT
Available as of Camel 2.3
URI format
properties:key[?options]
Where key is the key for the property to lookup
Options
Name
Type
Default
Description
cache
boolean
true
Whether or not to cache loaded properties.
locations
String
null
A list of locations to load properties. You can use comma to separate multiple locations. This
option will override any default locations and only use the locations from this option.
propertyPrefix
String
null
2.9 Optional prefix prepended to property names before resolution.
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propertySuffix
String
null
2.9 Optional suffix appended to property names before resolution.
fallbackToUnaugmentedProperty
boolean
true
2.9 If true, first attempt resolution of property name augmented with propertyPrefix and
propertySuffix before falling back the plain property name specified. If false, only the
augmented property name is searched.
prefixToken
String
{{
2.9 The token to indicate the beginning of a property token.
suffixToken
String
}}
2.9 The token to indicate the end of a property token.
USING PROPERTYPLACEHOLDER
Available as of Camel 2.3
Camel now provides a new PropertiesComponent in camel-core which allows you
to use property placeholders when defining Camel Endpoint URIs.
This works much like you would do if using Spring's tag.
However Spring have a limitation which prevents 3rd party frameworks to leverage Spring
property placeholders to the fullest. See more at How do I use Spring Property Placeholder
with Camel XML.
The property placeholder is generally in use when doing:
▪ lookup or creating endpoints
▪ lookup of beans in the Registry
▪ additional supported in Spring XML (see below in examples)
▪ using Blueprint PropertyPlaceholder with Camel Properties component
Syntax
The syntax to use Camel's property placeholder is to use {{key}} for example {{file.uri}}
where file.uri is the property key.
You can use property placeholders in parts of the endpoint URI's which for example you can
use placeholders for parameters in the URIs.
PropertyResolver
As usually Camel provides a pluggable mechanism which allows 3rd part to provide their own
resolver to lookup properties. Camel provides a default implementation
org.apache.camel.component.properties.DefaultPropertiesResolver
which is capable of loading properties from the file system, classpath or Registry. You can prefix
the locations with either:
▪ ref: Camel 2.4: to lookup in the Registry
▪ file: to load the from file system
▪ classpath: to load from classpath (this is also the default if no prefix is provided)
▪ blueprint: Camel 2.7: to use a specific OSGi blueprint placeholder service
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Resolving property from Java code
You can use the method resolvePropertyPlaceholders on the
CamelContext to resolve a property from any Java code.
Defining location
The PropertiesResolver need to know a location(s) where to resolve the properties.
You can define 1 to many locations. If you define the location in a single String property you can
separate multiple locations with comma such as:
pc.setLocation("com/mycompany/myprop.properties,com/mycompany/other.properties");
Using system and environment variables in locations
Available as of Camel 2.7
The location now supports using placeholders for JVM system properties and OS
environments variables.
For example:
location=file:${karaf.home}/etc/foo.properties
In the location above we defined a location using the file scheme using the JVM system property
with key karaf.home.
To use an OS environment variable instead you would have to prefix with env:
location=file:${env:APP_HOME}/etc/foo.properties
Where APP_HOME is an OS environment.
You can have multiple placeholders in the same location, such as:
location=file:${env:APP_HOME}/etc/${prop.name}.properties
Configuring in Java DSL
You have to create and register the PropertiesComponent under the name
properties such as:
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PropertiesComponent pc = new PropertiesComponent();
pc.setLocation("classpath:com/mycompany/myprop.properties");
context.addComponent("properties", pc);
Configuring in Spring XML
Spring XML offers two variations to configure. You can define a spring bean as a
PropertiesComponent which resembles the way done in Java DSL. Or you can use the
tag.
Using the tag makes the configuration a bit more fresh such as:
Using a Properties from the Registry
Available as of Camel 2.4
For example in OSGi you may want to expose a service which returns the properties as a
java.util.Properties object.
Then you could setup the Properties component as follows:
Where myProperties is the id to use for lookup in the OSGi registry. Notice we use the
ref: prefix to tell Camel that it should lookup the properties for the Registry.
Examples using properties component
When using property placeholders in the endpoint URIs you can either use the properties:
component or define the placeholders directly in the URI. We will show example of both cases,
starting with the former.
// properties
cool.end=mock:result
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// route
from("direct:start").to("properties:{{cool.end}}");
You can also use placeholders as a part of the endpoint uri:
// properties
cool.foo=result
// route
from("direct:start").to("properties:mock:{{cool.foo}}");
In the example above the to endpoint will be resolved to mock:result.
You can also have properties with refer to each other such as:
// properties
cool.foo=result
cool.concat=mock:{{cool.foo}}
// route
from("direct:start").to("properties:mock:{{cool.concat}}");
Notice how cool.concat refer to another property.
The properties: component also offers you to override and provide a location in the
given uri using the locations option:
from("direct:start").to("properties:bar.end?locations=com/mycompany/
bar.properties");
Examples
You can also use property placeholders directly in the endpoint uris without having to use
properties:.
// properties
cool.foo=result
// route
from("direct:start").to("mock:{{cool.foo}}");
And you can use them in multiple wherever you want them:
// properties
cool.start=direct:start
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cool.showid=true
cool.result=result
// route
from("{{cool.start}}")
.to("log:{{cool.start}}?showBodyType=false&showExchangeId={{cool.showid}}")
.to("mock:{{cool.result}}");
You can also your property placeholders when using ProducerTemplate for example:
template.sendBody("{{cool.start}}", "Hello World");
Example with Simple language
The Simple language now also support using property placeholders, for example in the route
below:
// properties
cheese.quote=Camel rocks
// route
from("direct:start")
.transform().simple("Hi ${body} do you think ${properties:cheese.quote}?");
You can also specify the location in the Simple language for example:
// bar.properties
bar.quote=Beer tastes good
// route
from("direct:start")
.transform().simple("Hi ${body}. ${properties:com/mycompany/
bar.properties:bar.quote}.");
Additional property placeholder supported in Spring XML
The property placeholders is also supported in many of the Camel Spring XML tags such as
, , , , ,
, and the others.
The example below has property placeholder in the tag:
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You can also define property placeholders in the various attributes on the tag
such as trace as shown here:
${in.body} World!
Overriding a property setting using a JVM System Property
Available as of Camel 2.5
It is possible to override a property value at runtime using a JVM System property without the
need to restart the application to pick up the change. This may also be accomplished from the
command line by creating a JVM System property of the same name as the property it replaces
with a new value. An example of this is given below
PropertiesComponent pc = context.getComponent("properties", PropertiesComponent.class);
pc.setCache(false);
System.setProperty("cool.end", "mock:override");
System.setProperty("cool.result", "override");
context.addRoutes(new RouteBuilder() {
@Override
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public void configure() throws Exception {
from("direct:start").to("properties:cool.end");
from("direct:foo").to("properties:mock:{{cool.result}}");
}
});
context.start();
getMockEndpoint("mock:override").expectedMessageCount(2);
template.sendBody("direct:start", "Hello World");
template.sendBody("direct:foo", "Hello Foo");
System.clearProperty("cool.end");
System.clearProperty("cool.result");
assertMockEndpointsSatisfied();
Using property placeholders for any kind of attribute in the XML DSL
Available as of Camel 2.7
Previously it was only the xs:string type attributes in the XML DSL that support
placeholders. For example often a timeout attribute would be a xs:int type and thus you
cannot set a string value as the placeholder key. This is now possible from Camel 2.7 onwards
using a special placeholder namespace.
In the example below we use the prop prefix for the namespace
http://camel.apache.org/schema/placeholder by which we can use the prop
prefix in the attributes in the XML DSLs. Notice how we use that in the Multicast to indicate
that the option stopOnException should be the value of the placeholder with the key
"stop".
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In our properties file we have the value defined as
stop=true
Using property placeholder in the Java DSL
Available as of Camel 2.7
Likewise we have added support for defining placeholders in the Java DSL using the new
placeholder DSL as shown in the following equivalent example:
from("direct:start")
// use a property placeholder for the option stopOnException on the Multicast EIP
// which should have the value of {{stop}} key being looked up in the properties
file
.multicast().placeholder("stopOnException", "stop")
.to("mock:a").throwException(new IllegalAccessException("Damn")).to("mock:b");
Using Blueprint property placeholder with Camel routes
Available as of Camel 2.7
Camel supports Blueprint which also offers a property placeholder service. Camel supports
convention over configuration, so all you have to do is to define the OSGi Blueprint property
placeholder in the XML file as shown below:
Listing 77. Using OSGi blueprint property placeholders in Camel routes
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By default Camel detects and uses OSGi blueprint property placeholder service. You can
disable this by setting the attribute useBlueprintPropertyResolver to false on the
definition.
You can also explicit refer to a specific OSGi blueprint property placeholder by its id. For that
you need to use the Camel's as shown in the example below:
Listing 78. Explicit referring to a OSGi blueprint placeholder in Camel
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About placeholder syntaxes
Notice how we can use the Camel syntax for placeholders {{ }} in the Camel route,
which will lookup the value from OSGi blueprint.
The blueprint syntax for placeholders is ${ }. So outside the you
must use the ${ } syntax. Where as inside you must use {{ }}
syntax.
OSGi blueprint allows you to configure the syntax, so you can actually align those if
you want.
Notice how we use the blueprint scheme to refer to the OSGi blueprint placeholder by its
id. This allows you to mix and match, for example you can also have additional schemes in the
location. For example to load a file from the classpath you can do:
location="blueprint:myblueprint.placeholder,classpath:myproperties.properties"
Each location is separated by comma.
See Also
• Configuring Camel
• Component
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• Endpoint
• Getting Started
▪ Jasypt for using encrypted values (eg passwords) in the properties
REF COMPONENT
The ref: component is used for lookup of existing endpoints bound in the Registry.
URI format
ref:someName
Where someName is the name of an endpoint in the Registry (usually, but not always, the
Spring registry). If you are using the Spring registry, someName would be the bean ID of an
endpoint in the Spring registry.
Runtime lookup
This component can be used when you need dynamic discovery of endpoints in the Registry
where you can compute the URI at runtime. Then you can look up the endpoint using the
following code:
// lookup the endpoint
String myEndpointRef = "bigspenderOrder";
Endpoint endpoint = context.getEndpoint("ref:" + myEndpointRef);
Producer producer = endpoint.createProducer();
Exchange exchange = producer.createExchange();
exchange.getIn().setBody(payloadToSend);
// send the exchange
producer.process(exchange);
...
And you could have a list of endpoints defined in the Registry such as:
...
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Sample
In the sample below we use the ref: in the URI to reference the endpoint with the spring ID,
endpoint2:
You could, of course, have used the ref attribute instead:
Which is the more common way to write it.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
RESTLET COMPONENT
The Restlet component provides Restlet based endpoints for consuming and producing
RESTful resources.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-restletx.x.x
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URI format
restlet:restletUrl[?options]
Format of restletUrl:
protocol://hostname[:port][/resourcePattern]
Restlet promotes decoupling of protocol and application concerns. The reference
implementation of Restlet Engine supports a number of protocols. However, we have tested
the HTTP protocol only. The default port is port 80. We do not automatically switch default
port based on the protocol yet.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default Value
Description
headerFilterStrategy=#refName
(2.x or later)
An instance of
RestletHeaderFilterStrategy
Use the # notation (headerFilterStrategy=#refName) to reference a header filter
strategy in the Camel Registry. The strategy will be plugged into the restlet binding if it is
HeaderFilterStrategyAware.
restletBindingRef (1.x),
restletBinding=#refName (2.x or
later)
An instance of
DefaultRestletBinding
The bean ID of a RestletBinding object in the Camel Registry.
restletMethod
GET
On a producer endpoint, specifies the request method to use. On a consumer endpoint,
specifies that the endpoint consumes only restletMethod requests. The string value is
converted to org.restlet.data.Method by the Method.valueOf(String) method.
restletMethods (2.x or later)
None
Consumer only Specify one or more methods separated by commas (e.g.
restletMethods=post,put) to be serviced by a restlet consumer endpoint. If both
restletMethod and restletMethods options are specified, the restletMethod
setting is ignored.
restletRealmRef (1.x),
restletRealm=#refName (2.x or
later)
null
The bean ID of the Realm Map in the Camel Registry.
restletUriPatterns=#refName
(2.x or later)
None
Consumer only Specify one ore more URI templates to be serviced by a restlet
consumer endpoint, using the # notation to reference a List in the Camel
Registry. If a URI pattern has been defined in the endpoint URI, both the URI pattern
defined in the endpoint and the restletUriPatterns option will be honored.
throwExceptionOnFailure (2.6
or later)
true
*Producer only * Throws exception on a producer failure.
Message Headers
Camel 1.x
823
Name
Type
Description
org.apache.camel.restlet.auth.login
String
Login name for basic authentication. It is set on the IN message by the application and gets filtered
before the restlet request header by Camel.
org.apache.camel.restlet.auth.password
String
Password name for basic authentication. It is set on the IN message by the application and gets filtered
before the restlet request header by Camel.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
org.apache.camel.restlet.mediaType
String
Specifies the content type, which can be set on the OUT message by the application/processor. The
value is the content-type of the response message. If this header is not set, the content-type is
set based on the object type of the OUT message body.
org.apache.camel.restlet.queryString
String
The query string of the request URI. It is set on the IN message by DefaultRestletBinding when
the restlet component receives a request.
org.apache.camel.restlet.responseCode
String
or
Integer
The response code can be set on the OUT message by the application/processor. The value is the
response code of the response message. If this header is not set, the response code is set by the restlet
runtime engine.
org.restlet.*
Ê
Attributes of a restlet message that get propagated to Camel IN headers.
Camel 2.x
Name
Type
Description
Content-Type
String
Specifies the content type, which can be set on the OUT message by the application/processor. The value is the content-type
of the response message. If this header is not set, the content type is based on the object type of the OUT message body. In
Camel 2.3 onward, if the Content-Type header is specified in the Camel IN message, the value of the header determine the
content type for the Restlet request message.ÊÊ Otherwise, it is defaulted to "application/x-www-form-urlencoded'. Prior to
release 2.3, it is not possible to change the request content type default.
CamelHttpMethod
String
The HTTP request method. This is set in the IN message header.
CamelHttpQuery
String
The query string of the request URI. It is set on the IN message by DefaultRestletBinding when the restlet component
receives a request.
CamelHttpResponseCode
String
or
Integer
The response code can be set on the OUT message by the application/processor. The value is the response code of the response
message. If this header is not set, the response code is set by the restlet runtime engine.
CamelHttpUri
String
The HTTP request URI. This is set in the IN message header.
CamelRestletLogin
String
Login name for basic authentication. It is set on the IN message by the application and gets filtered before the restlet request
header by Camel.
CamelRestletPassword
String
Password name for basic authentication. It is set on the IN message by the application and gets filtered before the restlet request
header by Camel.
CamelRestletRequest
Request
Camel 2.8: The org.restlet.Request object which holds all request details.
CamelRestletResponse
Response
Camel 2.8: The org.restlet.Response object. You can use this to create responses using the API from Restlet. See
examples below.
org.restlet.*
Ê
Attributes of a Restlet message that get propagated to Camel IN headers.
Message Body
Camel will store the restlet response from the external server on the OUT body. All headers
from the IN message will be copied to the OUT message, so that headers are preserved during
routing.
Samples
Restlet Endpoint with Authentication
The following route starts a restlet consumer endpoint that listens for POST requests on
http://localhost:8080. The processor creates a response that echoes the request body and the
value of the id header.
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from("restlet:http://localhost:" + port +
"/securedOrders?restletMethod=post&restletRealm=#realm").process(new Processor() {
public void process(Exchange exchange) throws Exception {
exchange.getOut().setBody(
"received [" + exchange.getIn().getBody()
+ "] as an order id = "
+ exchange.getIn().getHeader("id"));
}
});
The restletRealm setting (in 2.x, use the # notation, that is,
restletRealm=#refName)in the URI query is used to look up a Realm Map in the registry.
If this option is specified, the restlet consumer uses the information to authenticate user logins.
Only authenticated requests can access the resources. In this sample, we create a Spring
application context that serves as a registry. The bean ID of the Realm Map should match the
restletRealmRef.
The following sample starts a direct endpoint that sends requests to the server on
http://localhost:8080 (that is, our restlet consumer endpoint).
// Note: restletMethod and restletRealmRef are stripped
// from the query before a request is sent as they are
// only processed by Camel.
from("direct:start-auth").to("restlet:http://localhost:" + port +
"/securedOrders?restletMethod=post");
That is all we need. We are ready to send a request and try out the restlet component:
final String id = "89531";
Map headers = new HashMap();
headers.put(RestletConstants.RESTLET_LOGIN, "admin");
headers.put(RestletConstants.RESTLET_PASSWORD, "foo");
headers.put("id", id);
String response = (String)template.requestBodyAndHeaders(
"direct:start-auth", "", headers);
The sample client sends a request to the direct:start-auth endpoint with the following
headers:
• CamelRestletLogin (used internally by Camel)
• CamelRestletPassword (used internally by Camel)
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CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
• id (application header)
The sample client gets a response like the following:
received [] as an order id = 89531
Single restlet endpoint to service multiple methods and URI
templates (2.0 or later)
It is possible to create a single route to service multiple HTTP methods using the
restletMethods option. This snippet also shows how to retrieve the request method from
the header:
from("restlet:http://localhost:" + portNum + "/users/
{username}?restletMethods=post,get")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
// echo the method
exchange.getOut().setBody(exchange.getIn().getHeader(Exchange.HTTP_METHOD,
String.class));
}
});
In addition to servicing multiple methods, the next snippet shows how to create an endpoint
that supports multiple URI templates using the restletUriPatterns option. The request
URI is available in the header of the IN message as well. If a URI pattern has been defined in the
endpoint URI (which is not the case in this sample), both the URI pattern defined in the
endpoint and the restletUriPatterns option will be honored.
from("restlet:http://localhost:" + portNum +
"?restletMethods=post,get&restletUriPatterns=#uriTemplates")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
// echo the method
String uri = exchange.getIn().getHeader(Exchange.HTTP_URI, String.class);
String out = exchange.getIn().getHeader(Exchange.HTTP_METHOD,
String.class);
if (("http://localhost:" + portNum + "/users/homer").equals(uri)) {
exchange.getOut().setBody(out + " " +
exchange.getIn().getHeader("username", String.class));
} else if (("http://localhost:" + portNum + "/atom/collection/foo/
component/bar").equals(uri)) {
exchange.getOut().setBody(out + " " + exchange.getIn().getHeader("id",
String.class)
+ " " + exchange.getIn().getHeader("cid",
String.class));
}
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Note
org.apache.camel.restlet.auth.login and
org.apache.camel.restlet.auth.password will not be propagated as
Restlet header.
}
});
The restletUriPatterns=#uriTemplates option references the List
bean defined in the Spring XML configuration.
/users/{username}/atom/collection/{id}/component/{cid}
Using Restlet API to populate response
Available as of Camel 2.8
You may want to use the org.restlet.Response API to populate the response. This
gives you full access to the Restlet API and fine grained control of the response. See the route
snippet below where we generate the response from an inlined Camel Processor:
Listing 79. Generating response using Restlet Response API
from("restlet:http://localhost:" + portNum + "/users/{id}/like/{beer}")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
// the Restlet request should be available if neeeded
Request request =
exchange.getIn().getHeader(RestletConstants.RESTLET_REQUEST, Request.class);
assertNotNull("Restlet Request", request);
// use Restlet API to create the response
Response response =
exchange.getIn().getHeader(RestletConstants.RESTLET_RESPONSE, Response.class);
assertNotNull("Restlet Response", response);
response.setStatus(Status.SUCCESS_OK);
response.setEntity("Beer is Good",
MediaType.TEXT_XML);
exchange.getOut().setBody(response);
}
});
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Using the Restlet servlet within a webapp
Available as of Camel 2.8
There are three possible ways to configure a Restlet application within a servlet container and
using the subclassed SpringServerServlet enables configuration within Camel by injecting the
Restlet Component.
Use of the Restlet servlet within a servlet container enables routes to be configured with
relative paths in URIs (removing the restrictions of hard-coded absolute URIs) and for the
hosting servlet container to handle incoming requests (rather than have to spawn a separate
server process on a new port).
To configure, add the following to your camel-context.xml;
Request type : ${header.CamelHttpMethod} and ID : ${header.id}
And add this to your web.xml;
RestletServletorg.restlet.ext.spring.SpringServerServletorg.restlet.componentRestletComponentRestletServlet/rs/*
You will then be able to access the deployed route at http://localhost:8080/mywebapp/rs/demo/
1234 where;
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localhost:8080 is the server and port of your servlet container
mywebapp is the name of your deployed webapp
Your browser will then show the following content;
"Request type : GET and ID : 1234"
You will need to add dependency on the Spring extension to restlet which you can do in your
Maven pom.xml file:
org.restlet.jeeorg.restlet.ext.spring${restlet-version}
And you would need to add dependency on the restlet maven repository as well:
maven-restletPublic online Restlet repositoryhttp://maven.restlet.org
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
RMI COMPONENT
The rmi: component binds PojoExchanges to the RMI protocol (JRMP).
Since this binding is just using RMI, normal RMI rules still apply regarding what methods can
be invoked. This component supports only PojoExchanges that carry a method invocation from
an interface that extends the Remote interface. All parameters in the method should be either
Serializable or Remote objects.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-rmi
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x.x.x
URI format
rmi://rmi-regisitry-host:rmi-registry-port/registry-path[?options]
For example:
rmi://localhost:1099/path/to/service
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
method
null
As of Camel 1.3, you can set the name of the method to invoke.
remoteInterfaces
null
Its now possible to use this option from Camel 2.7: in the XML DSL. It can be a list of interface names separated by
comma.
Using
To call out to an existing RMI service registered in an RMI registry, create a route similar to the
following:
from("pojo:foo").to("rmi://localhost:1099/foo");
To bind an existing camel processor or service in an RMI registry, define an RMI endpoint as
follows:
RmiEndpoint endpoint= (RmiEndpoint) endpoint("rmi://localhost:1099/bar");
endpoint.setRemoteInterfaces(ISay.class);
from(endpoint).to("pojo:bar");
Note that when binding an RMI consumer endpoint, you must specify the Remote interfaces
exposed.
In XML DSL you can do as follows from Camel 2.7 onwards:
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See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
RSS COMPONENT
Available as of Camel 2.0
The rss: component is used for polling RSS feeds. Camel will default poll the feed every
60th seconds.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-rssx.x.x
Note: The component currently only supports polling (consuming) feeds.
URI format
rss:rssUri
Where rssUri is the URI to the RSS feed to poll.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Property
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Default
Description
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
Using camel-rss in OSGi environment
Camel-rss uses ROME 1.0 and below. This library has class loading issues in OSGi
environment. We submitted issue 142 to ROME.
You can also find patched version in this repository. One thing you have to change
is version - patched version is marked as 1.0-osgi.
splitEntries
true
If true, Camel splits a feed into its individual entries and returns each entry, poll by poll. For example, if a feed contains
seven entries, Camel returns the first entry on the first poll, the second entry on the second poll, and so on. When no
more entries are left in the feed, Camel contacts the remote RSS URI to obtain a new feed. If false, Camel obtains a
fresh feed on every poll and returns all of the feed's entries.
filter
true
Use in combination with the splitEntries option in order to filter returned entries. By default, Camel applies the
UpdateDateFilter filter, which returns only new entries from the feed, ensuring that the consumer endpoint never
receives an entry more than once. The filter orders the entries chronologically, with the newest returned last.
throttleEntries
true
Camel 2.5: Sets whether all entries identified in a single feed poll should be delivered immediately. If true, only one entry
is processed per consumer.delay. Only applicable when splitEntries is set to true.
lastUpdate
null
Use in combination with the filter option to block entries earlier than a specific date/time (uses the
entry.updated timestamp). The format is: yyyy-MM-ddTHH:MM:ss. Example: 2007-12-24T17:45:59.
feedHeader
true
Specifies whether to add the ROME SyndFeed object as a header.
sortEntries
false
If splitEntries is true, this specifies whether to sort the entries by updated date.
consumer.delay
60000
Delay in milliseconds between each poll.
consumer.initialDelay
1000
Milliseconds before polling starts.
consumer.userFixedDelay
false
Set to true to use fixed delay between pools, otherwise fixed rate is used. See ScheduledExecutorService in JDK for
details.
Exchange data types
Camel initializes the In body on the Exchange with a ROME SyndFeed. Depending on the
value of the splitEntries flag, Camel returns either a SyndFeed with one SyndEntry
or a java.util.List of SyndEntrys.
Option
Value
Behavior
splitEntries
true
A single entry from the current feed is set in the exchange.
splitEntries
false
The entire list of entries from the current feed is set in the exchange.
Message Headers
Header
Description
org.apache.camel.component.rss.feed
Camel 1.x: The entire SyncFeed object.
CamelRssFeed
Camel 2.0: The entire SyncFeed object.
RSS Dataformat
The RSS component ships with an RSS dataformat that can be used to convert between String
(as XML) and ROME RSS model objects.
• marshal = from ROME SyndFeed to XML String
• unmarshal = from XML String to ROME SyndFeed
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A route using this would look something like this:
from("rss:file:src/test/data/
rss20.xml?splitEntries=false&consumer.delay=1000").marshal().rss().to("mock:marshal");
The purpose of this feature is to make it possible to use Camel's lovely built-in expressions for
manipulating RSS messages. As shown below, an XPath expression can be used to filter the RSS
message:
// only entries with Camel in the title will get through the filter
from("rss:file:src/test/data/rss20.xml?splitEntries=true&consumer.delay=100")
.marshal().rss().filter().xpath("//item/
title[contains(.,'Camel')]").to("mock:result");
Filtering entries
You can filter out entries quite easily using XPath, as shown in the data format section above.
You can also exploit Camel's Bean Integration to implement your own conditions. For instance,
a filter equivalent to the XPath example above would be:
// only entries with Camel in the title will get through the filter
from("rss:file:src/test/data/rss20.xml?splitEntries=true&consumer.delay=100").
filter().method("myFilterBean", "titleContainsCamel").to("mock:result");
The custom bean for this would be:
public static class FilterBean {
public boolean titleContainsCamel(@Body SyndFeed feed) {
SyndEntry firstEntry = (SyndEntry) feed.getEntries().get(0);
return firstEntry.getTitle().contains("Camel");
}
}
See Also
• Configuring Camel
• Component
• Endpoint
• Getting Started
▪ Atom
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SEDA COMPONENT
The seda: component provides asynchronous SEDA behavior, so that messages are exchanged
on a BlockingQueue and consumers are invoked in a separate thread from the producer.
Note that queues are only visible within a single CamelContext. If you want to communicate
across CamelContext instances (for example, communicating between Web applications),
see the VM component.
This component does not implement any kind of persistence or recovery, if the VM
terminates while messages are yet to be processed. If you need persistence, reliability or
distributed SEDA, try using either JMS or ActiveMQ.
URI format
seda:someName[?options]
Where someName can be any string that uniquely identifies the endpoint within the current
CamelContext.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Description
size
Ê
The maximum size (= capacity of the number of messages it can max hold) of the SEDA queue. The default value in
Camel 2.2 or older is 1000. From Camel 2.3 onwards the size is unbounded by default.
concurrentConsumers
1
Camel 1.6.1/2.0: Number of concurrent threads processing exchanges.
waitForTaskToComplete
IfReplyExpected
Camel 2.0: Option to specify whether the caller should wait for the async task to complete or not before
continuing. The following three options are supported: Always, Never or IfReplyExpected. The first two
values are self-explanatory. The last value, IfReplyExpected, will only wait if the message is Request Reply
based. The default option is IfReplyExpected. See more information about Async messaging.
timeout
30000
Camel 2.0: Timeout in millis a seda producer will at most waiting for an async task to complete. See
waitForTaskToComplete and Async for more details. In Camel 2.2 you can now disable timeout by using 0
or a negative value.
multipleConsumers
false
Camel 2.2: Specifies whether multiple consumers is allowed or not. If enabled you can use SEDA for a pubsub
kinda style messaging. Send a message to a seda queue and have multiple consumers receive a copy of the message.
limitConcurrentConsumers
true
Camel 2.3: Whether to limit the concurrentConsumers to maximum 500. If its configured with a higher number
an exception will be thrown. You can disable this check by turning this option off.
blockWhenFull
false
Camel 2.9: Whether to block the current thread when sending a message to a SEDA endpoint, and the SEDA
queue is full (capacity hit). By default an exception will be thrown stating the queue is full. By setting this option to
true the caller thread will instead block and wait until the message can be delivered to the SEDA queue.
You can set these default value on seda component since Camel 2.9
Name
Default
Description
queueSize
Ê
The maximum size (= capacity of the number of messages it can max hold) of the SEDA queue. It could be override if you
specify the size on the seda endpoint uri
concurrentConsumers
1
Number of concurrent threads processing exchanges. It will be use if you don't specify the option on the seda endpoint uri
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Synchronous
The Direct component provides synchronous invocation of any consumers when a
producer sends a message exchange.
Camel 1.x - Same URI must be used for both producer and
consumer
An exactly identical SEDA endpoint URI must be used for both the producer
endpoint and the consumer endpoint. Otherwise Camel will create a second SEDA
endpoint, even thought the someName portion of the URI is identical. For example:
from("direct:foo").to("seda:bar?concurrentConsumers=5");
from("seda:bar?concurrentConsumers=5").to("file://output");
Notice that we have to use the full URI including options in both the producer and
consumer.
In Camel 2.x this has been fixed so its the queue name that must match, eg in this example
we are using bar as the queue name.
Changes in Camel 2.0
In Camel 2.0 the SEDA component supports using Request Reply, where the caller will wait for
the Async route to complete. For instance:
from("mina:tcp://0.0.0.0:9876?textline=true&sync=true").to("seda:input");
from("seda:input").to("bean:processInput").to("bean:createResponse");
In the route above, we have a TCP listener on port 9876 that accepts incoming requests. The
request is routed to the seda:input queue. As it is a Request Reply message, we wait for
the response. When the consumer on the seda:input queue is complete, it copies the
response to the original message response.
Camel 1.x does not have this feature implemented, the SEDA queues in Camel 1.x will
never wait.
Concurrent consumers
By default, the SEDA endpoint uses a single consumer thread, but you can configure it to use
concurrent consumer threads. So instead of thread pools you can use:
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Camel 2.0 - 2.2: Works only with 2 endpoints
Using Request Reply over SEDA or VM only works with 2 endpoints. You cannot
chain endpoints by sending to A -> B -> C etc. Only between A -> B. The reason is
the implementation logic is fairly simple. To support 3+ endpoints makes the logic
much more complex to handle ordering and notification between the waiting
threads properly.
This has been improved in Camel 2.3 onwards, which allows you to chain as many
endpoints as you like.
from("seda:stageName?concurrentConsumers=5").process(...)
Difference between thread pools and concurrent consumers
The thread pool is a pool that can increase/shrink dynamically at runtime depending on load,
whereas the concurrent consumers are always fixed.
Thread pools
Be aware that adding a thread pool to a SEDA endpoint by doing something like:
from("seda:stageName").thread(5).process(...)
Can wind up with two BlockQueues: one from the SEDA endpoint, and one from the
workqueue of the thread pool, which may not be what you want. Instead, you might want to
consider configuring a Direct endpoint with a thread pool, which can process messages both
synchronously and asynchronously. For example:
from("direct:stageName").thread(5).process(...)
You can also directly configure number of threads that process messages on a SEDA endpoint
using the concurrentConsumers option.
Sample
In the route below we use the SEDA queue to send the request to this async queue to be able
to send a fire-and-forget message for further processing in another thread, and return a
constant reply in this thread to the original caller.
CH APT ER 11 - CO M PO N EN T APPEN DIX
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public void configure() throws Exception {
from("direct:start")
// send it to the seda queue that is async
.to("seda:next")
// return a constant response
.transform(constant("OK"));
from("seda:next").to("mock:result");
}
Here we send a Hello World message and expects the reply to be OK.
Object out = template.requestBody("direct:start", "Hello World");
assertEquals("OK", out);
The "Hello World" message will be consumed from the SEDA queue from another thread for
further processing. Since this is from a unit test, it will be sent to a mock endpoint where we
can do assertions in the unit test.
Using multipleConsumers
Available as of Camel 2.2
In this example we have defined two consumers and registered them as spring beans.
Since we have specified multipleConsumers=true on the seda foo endpoint we can have
those two consumers receive their own copy of the message as a kind of pub-sub style
messaging.
As the beans are part of an unit test they simply send the message to a mock endpoint, but
notice how we can use @Consume to consume from the seda queue.
public class FooEventConsumer {
@EndpointInject(uri = "mock:result")
private ProducerTemplate destination;
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@Consume(ref = "foo")
public void doSomething(String body) {
destination.sendBody("foo" + body);
}
}
Extracting queue information.
If you need it, you can also get information like queue size etc without using JMX like this:
SedaEndpoint seda = context.getEndpoint("seda:xxxx");
int size = seda.getExchanges().size()
See Also
•
•
•
•
▪
▪
▪
Configuring Camel
Component
Endpoint
Getting Started
VM
Direct
Async
SERVLET COMPONENT
Available as of Camel 2.0
The servlet: component provides HTTP based endpoints for consuming HTTP requests
that arrive at a HTTP endpoint and this endpoint is bound to a published Servlet.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-servletx.x.x
<\!-\- use the same version as your Camel core version \-->
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URI format
servlet://relative_path[?options]
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
httpBindingRef
null
Reference to an org.apache.camel.component.http.HttpBinding in the Registry. A HttpBinding
implementation can be used to customize how to write a response.
matchOnUriPrefix
false
Whether or not the CamelServlet should try to find a target consumer by matching the URI prefix, if no exact match is
found.
servletName
CamelServlet
Specifies the servlet name that the servlet endpoint will bind to. This name should match the name you define in web.xml file.
Message Headers
Camel will apply the same Message Headers as the HTTP component.
Camel will also populate all request.parameter and request.headers. For
example, if a client request has the URL, http://myserver/myserver?orderid=123,
the exchange will contain a header named orderid with the value 123.
Usage
You can only consume from endpoints generated by the Servlet component. Therefore, it
should only be used as input into your camel routes. To issue HTTP requests against other
HTTP endpoints, use the HTTP Component
Sample
In this sample, we define a route that exposes a HTTP service at
http://localhost:8080/camel/services/hello.
First, you need to publish the CamelHttpTransportServlet through the normal Web Container,
or OSGi Service.
Use the Web.xml file to publish the CamelHttpTransportServlet as follows:
CamelServletCamel Http Transport Servlet
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From Camel 2.7 onwards its easier to use Servlet in Spring web applications. See
Servlet Tomcat Example for details.
org.apache.camel.component.servlet.CamelHttpTransportServletCamelServlet/services/*
Then you can define your route as follows:
from("servlet:///hello?matchOnUriPrefix=true").process(new Processor() {
public void process(Exchange exchange) throws Exception {
String contentType = exchange.getIn().getHeader(Exchange.CONTENT_TYPE,
String.class);
String path = exchange.getIn().getHeader(Exchange.HTTP_PATH, String.class);
assertEquals("Get a wrong content type", CONTENT_TYPE, contentType);
// assert camel http header
String charsetEncoding =
exchange.getIn().getHeader(Exchange.HTTP_CHARACTER_ENCODING, String.class);
assertEquals("Get a wrong charset name from the message heaer", "UTF-8",
charsetEncoding);
// assert exchange charset
assertEquals("Get a wrong charset naem from the exchange property", "UTF-8",
exchange.getProperty(Exchange.CHARSET_NAME));
exchange.getOut().setHeader(Exchange.CONTENT_TYPE, contentType + ";
charset=UTF-8");
exchange.getOut().setHeader("PATH", path);
exchange.getOut().setBody("Hello World");
}
});
Sample when using Spring 3.x
See Servlet Tomcat Example
Sample when using Spring 2.x
When using the Servlet component in a Camel/Spring application it's often required to load the
Spring ApplicationContext after the Servlet component has started. This can be accomplished
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Specify the relative path for camel-servlet endpoint
Since we are binding the Http transport with a published servlet, and we don't
know the servlet's application context path, the camel-servlet endpoint uses
the relative path to specify the endpoint's URL. A client can access the camelservlet endpoint through the servlet publish address:
("http://localhost:8080/camel/services") +
RELATIVE_PATH("/hello").
by using Spring's ContextLoaderServlet instead of ContextLoaderListener. In
that case you'll need to start ContextLoaderServlet after CamelHttpTransportServlet
like this:
CamelServlet
org.apache.camel.component.servlet.CamelHttpTransportServlet
1SpringApplicationContext
org.springframework.web.context.ContextLoaderServlet
2
Sample when using OSGi
From Camel 2.6.0, you can publish the CamelHttpTransportServlet as an OSGi service with
help of SpringDM like this.
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javax.servlet.Servletorg.apache.camel.component.http.CamelServlet
Then use this service in your camel route like this:
CH APT ER 11 - CO M PO N EN T APPEN DIX
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For versions prior to Camel 2.6 you can use an Activator to publish the
CamelHttpTransportServlet on the OSGi platform
import java.util.Dictionary;
import java.util.Hashtable;
import
import
import
import
import
import
import
import
import
org.apache.camel.component.servlet.CamelHttpTransportServlet;
org.osgi.framework.BundleActivator;
org.osgi.framework.BundleContext;
org.osgi.framework.ServiceReference;
org.osgi.service.http.HttpContext;
org.osgi.service.http.HttpService;
org.slf4j.Logger;
org.slf4j.LoggerFactory;
org.springframework.osgi.context.BundleContextAware;
public final class ServletActivator implements BundleActivator, BundleContextAware {
private static final transient Logger LOG =
LoggerFactory.getLogger(ServletActivator.class);
private static boolean registerService;
/**
* HttpService reference.
*/
private ServiceReference httpServiceRef;
/**
* Called when the OSGi framework starts our bundle
*/
public void start(BundleContext bc) throws Exception {
registerServlet(bc);
}
/**
* Called when the OSGi framework stops our bundle
*/
public void stop(BundleContext bc) throws Exception {
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if (httpServiceRef != null) {
bc.ungetService(httpServiceRef);
httpServiceRef = null;
}
}
protected void registerServlet(BundleContext bundleContext) throws Exception {
httpServiceRef =
bundleContext.getServiceReference(HttpService.class.getName());
if (httpServiceRef != null && !registerService) {
LOG.info("Register the servlet service");
final HttpService httpService =
(HttpService)bundleContext.getService(httpServiceRef);
if (httpService != null) {
// create a default context to share between registrations
final HttpContext httpContext = httpService.createDefaultHttpContext();
// register the hello world servlet
final Dictionary initParams = new Hashtable();
initParams.put("matchOnUriPrefix", "false");
initParams.put("servlet-name", "CamelServlet");
httpService.registerServlet("/camel/services", // alias
new CamelHttpTransportServlet(), // register servlet
initParams, // init params
httpContext // http context
);
registerService = true;
}
}
}
public void setBundleContext(BundleContext bc) {
try {
registerServlet(bc);
} catch (Exception e) {
LOG.error("Cannot register the servlet, the reason is " + e);
}
}
}
See Also
•
•
•
•
▪
▪
▪
Configuring Camel
Component
Endpoint
Getting Started
Servlet Tomcat Example
HTTP
Jetty
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SHIRO SECURITY COMPONENT
Available as of Camel 2.5
The shiro-security component in Camel is a security focused component, based on the
Apache Shiro security project.
Apache Shiro is a powerful and flexible open-source security framework that cleanly handles
authentication, authorization, enterprise session management and cryptography. The objective
of the Apache Shiro project is to provide the most robust and comprehensive application
security framework available while also being very easy to understand and extremely simple to
use.
This camel shiro-security component allows authentication and authorization support to be
applied to different segments of a camel route.
Shiro security is applied on a route using a Camel Policy. A Policy in Camel utilizes a strategy
pattern for applying interceptors on Camel Processors. It offering the ability to apply crosscutting concerns (for example. security, transactions etc) on sections/segments of a camel
route.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-shirox.x.x
Shiro Security Basics
To employ Shiro security on a camel route, a ShiroSecurityPolicy object must be instantiated
with security configuration details (including users, passwords, roles etc). This object must then
be applied to a camel route. This ShiroSecurityPolicy Object may also be registered in the
Camel registry (JNDI or ApplicationContextRegistry) and then utilized on other routes in the
Camel Context.
Configuration details are provided to the ShiroSecurityPolicy using an Ini file (properties file)
or an Ini object. The Ini file is a standard Shiro configuration file containing user/role details as
shown below
[users]
# user 'ringo' with password 'starr' and the 'sec-level1' role
ringo = starr, sec-level1
george = harrison, sec-level2
john = lennon, sec-level3
paul = mccartney, sec-level3
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[roles]
# 'sec-level3' role has all permissions, indicated by the
# wildcard '*'
sec-level3 = *
# The 'sec-level2' role can do anything with access of permission
# readonly (*) to help
sec-level2 = zone1:*
# The 'sec-level1' role can do anything with access of permission
# readonly
sec-level1 = zone1:readonly:*
Instantiating a ShiroSecurityPolicy Object
A ShiroSecurityPolicy object is instantiated as follows
private final String iniResourcePath = "classpath:shiro.ini";
private final byte[] passPhrase = {
(byte) 0x08, (byte) 0x09, (byte) 0x0A, (byte) 0x0B,
(byte) 0x0C, (byte) 0x0D, (byte) 0x0E, (byte) 0x0F,
(byte) 0x10, (byte) 0x11, (byte) 0x12, (byte) 0x13,
(byte) 0x14, (byte) 0x15, (byte) 0x16, (byte) 0x17};
List permissionsList = new ArrayList();
Permission permission = new WildcardPermission("zone1:readwrite:*");
permissionsList.add(permission);
final ShiroSecurityPolicy securityPolicy =
new ShiroSecurityPolicy(iniResourcePath, passPhrase, true,
permissionsList);
ShiroSecurityPolicy Options
Name
Default
Value
Type
Description
iniResourcePath or
ini
none
Resource String or Ini Object
A mandatory Resource String for the iniResourcePath or an instance of an Ini object
must be passed to the security policy. Resources can be acquired from the file system,
classpath, or URLs when prefixed with "file:, classpath:, or url:" respectively. For e.g
"classpath:shiro.ini"
passPhrase
An AES 128
based key
byte[]
A passPhrase to decrypt ShiroSecurityToken(s) sent along with Message Exchanges
alwaysReauthenticate
true
boolean
Setting to ensure re-authentication on every individual request. If set to false, the user
is authenticated and locked such than only requests from the same user going forward
are authenticated.
permissionsList
none
List
A List of permissions required in order for an authenticated user to be authorized to
perform further action i.e continue further on the route. If no Permissions list is
provided to the ShiroSecurityPolicy object, then authorization is deemed as not
required
cipherService
AES
org.apache.shiro.crypto.CipherService
Shiro ships with AES & Blowfish based CipherServices. You may use one these or
pass in your own Cipher implementation
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Applying Shiro Authentication on a Camel Route
The ShiroSecurityPolicy, tests and permits incoming message exchanges containing a encrypted
SecurityToken in the Message Header to proceed further following proper authentication. The
SecurityToken object contains a Username/Password details that are used to determine where
the user is a valid user.
protected RouteBuilder createRouteBuilder() throws Exception {
final ShiroSecurityPolicy securityPolicy =
new ShiroSecurityPolicy("classpath:shiro.ini", passPhrase);
return new RouteBuilder() {
public void configure() {
onException(UnknownAccountException.class).
to("mock:authenticationException");
onException(IncorrectCredentialsException.class).
to("mock:authenticationException");
onException(LockedAccountException.class).
to("mock:authenticationException");
onException(AuthenticationException.class).
to("mock:authenticationException");
from("direct:secureEndpoint").
to("log:incoming payload").
policy(securityPolicy).
to("mock:success");
}
};
}
Applying Shiro Authorization on a Camel Route
Authorization can be applied on a camel route by associating a Permissions List with the
ShiroSecurityPolicy. The Permissions List specifies the permissions necessary for the user to
proceed with the execution of the route segment. If the user does not have the proper
permission set, the request is not authorized to continue any further.
protected RouteBuilder createRouteBuilder() throws Exception {
final ShiroSecurityPolicy securityPolicy =
new ShiroSecurityPolicy("./src/test/resources/securityconfig.ini",
passPhrase);
return new RouteBuilder() {
public void configure() {
onException(UnknownAccountException.class).
to("mock:authenticationException");
onException(IncorrectCredentialsException.class).
to("mock:authenticationException");
onException(LockedAccountException.class).
to("mock:authenticationException");
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onException(AuthenticationException.class).
to("mock:authenticationException");
from("direct:secureEndpoint").
to("log:incoming payload").
policy(securityPolicy).
to("mock:success");
}
};
}
Creating a ShiroSecurityToken and injecting it into a Message Exchange
A ShiroSecurityToken object may be created and injected into a Message Exchange using a
Shiro Processor called ShiroSecurityTokenInjector. An example of injecting a
ShiroSecurityToken using a ShiroSecurityTokenInjector in the client is shown below
ShiroSecurityToken shiroSecurityToken = new ShiroSecurityToken("ringo", "starr");
ShiroSecurityTokenInjector shiroSecurityTokenInjector =
new ShiroSecurityTokenInjector(shiroSecurityToken, passPhrase);
from("direct:client").
process(shiroSecurityTokenInjector).
to("direct:secureEndpoint");
Sending Messages to routes secured by a ShiroSecurityPolicy
Messages and Message Exchanges sent along the camel route where the security policy is
applied need to be accompanied by a SecurityToken in the Exchange Header. The
SecurityToken is an encrypted object that holds a Username and Password. The SecurityToken
is encrypted using AES 128 bit security by default and can be changed to any cipher of your
choice.
Given below is an example of how a request may be sent using a ProducerTemplate in
Camel along with a SecurityToken
@Test
public void testSuccessfulShiroAuthenticationWithNoAuthorization() throws
Exception {
//Incorrect password
ShiroSecurityToken shiroSecurityToken = new ShiroSecurityToken("ringo",
"stirr");
// TestShiroSecurityTokenInjector extends ShiroSecurityTokenInjector
TestShiroSecurityTokenInjector shiroSecurityTokenInjector =
new TestShiroSecurityTokenInjector(shiroSecurityToken, passPhrase);
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848
successEndpoint.expectedMessageCount(1);
failureEndpoint.expectedMessageCount(0);
template.send("direct:secureEndpoint", shiroSecurityTokenInjector);
successEndpoint.assertIsSatisfied();
failureEndpoint.assertIsSatisfied();
}
SIP COMPONENT
Available as of Camel 2.5
The sip component in Camel is a communication component, based on the Jain SIP
implementation (available under the JCP license).
Session Initiation Protocol (SIP) is an IETF-defined signaling protocol, widely used for
controlling multimedia communication sessions such as voice and video calls over Internet
Protocol (IP).The SIP protocol is an Application Layer protocol designed to be independent of
the underlying transport layer; it can run on Transmission Control Protocol (TCP), User
Datagram Protocol (UDP) or Stream Control Transmission Protocol (SCTP).
The Jain SIP implementation supports TCP and UDP only.
The Camel SIP component only supports the SIP Publish and Subscribe capability as
described in the RFC3903 - Session Initiation Protocol (SIP) Extension for Event
This camel component supports both producer and consumer endpoints.
Camel SIP Producers (Event Publishers) and SIP Consumers (Event Subscribers)
communicate event & state information to each other using an intermediary entity called a SIP
Presence Agent (a stateful brokering entity).
For SIP based communication, a SIP Stack with a listener must be instantiated on both the
SIP Producer and Consumer (using separate ports if using localhost). This is necessary in order
to support the handshakes & acknowledgements exchanged between the SIP Stacks during
communication.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-sipx.x.x
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URI format
The URI scheme for a sip endpoint is as follows:
sip://johndoe@localhost:99999[?options]
sips://johndoe@localhost:99999/[?options]
This component supports producer and consumer endpoints for both TCP and UDP.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
The SIP Component offers an extensive set of configuration options & capability to create
custom stateful headers needed to propagate state via the SIP protocol.
Name
Default
Value
Description
stackName
NAME_NOT_SET
Name of the SIP Stack instance associated with an SIP Endpoint.
transport
tcp
Setting for choice of transport potocol. Valid choices are "tcp" or "udp".
fromUser
Ê
Username of the message originator. Mandatory setting unless a registry based custom FromHeader is
specified.
fromHost
Ê
Hostname of the message originator. Mandatory setting unless a registry based FromHeader is specified
fromPort
Ê
Port of the message originator. Mandatory setting unless a registry based FromHeader is specified
toUser
Ê
Username of the message receiver. Mandatory setting unless a registry based custom ToHeader is
specified.
toHost
Ê
Hostname of the message receiver. Mandatory setting unless a registry based ToHeader is specified
toPort
Ê
Portname of the message receiver. Mandatory setting unless a registry based ToHeader is specified
maxforwards
0
the number of intermediaries that may forward the message to the message receiver. Optional setting. May
alternatively be set using as registry based MaxForwardsHeader
eventId
Ê
Setting for a String based event Id. Mandatory setting unless a registry based FromHeader is specified
eventHeaderName
Ê
Setting for a String based event Id. Mandatory setting unless a registry based FromHeader is specified
maxMessageSize
1048576
Setting for maximum allowed Message size in bytes.
cacheConnections
false
Should connections be cached by the SipStack to reduce cost of connection creation. This is useful if the connection is
used for long running conversations.
consumer
false
This setting is used to determine whether the kind of header (FromHeader,ToHeader etc) that needs to be created for
this endpoint
automaticDialogSupport
off
Setting to specify whether every communication should be associated with a dialog.
contentType
text
Setting for contentType can be set to any valid MimeType.
contentSubType
xml
Setting for contentSubType can be set to any valid MimeSubType.
receiveTimeoutMillis
10000
Setting for specifying amount of time to wait for a Response and/or Acknowledgement can be received from another SIP
stack
useRouterForAllUris
false
This setting is used when requests are sent to the Presence Agent via a proxy.
msgExpiration
3600
The amount of time a message received at an endpoint is considered valid
presenceAgent
false
This setting is used to distingish between a Presence Agent & a consumer. This is due to the fact that the SIP Camel
component ships with a basic Presence Agent (for testing purposes only). Consumers have to set this flag to true.
Registry based Options
SIP requires a number of headers to be sent/received as part of a request. These SIP header can
be enlisted in the Registry, such as in the Spring XML file.
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The values that could be passed in, are the following:
Name
Description
fromHeader
a custom Header object containing message originator settings. Must implement the type javax.sip.header.FromHeader
toHeader
a custom Header object containing message receiver settings. Must implement the type javax.sip.header.ToHeader
viaHeaders
List of custom Header objects of the type javax.sip.header.ViaHeader. Each ViaHeader containing a proxy address for request forwarding. (Note this
header is automatically updated by each proxy when the request arrives at its listener)
contentTypeHeader
a custom Header object containing message content details. Must implement the type javax.sip.header.ContentTypeHeader
callIdHeader
a custom Header object containing call details. Must implement the type javax.sip.header.CallIdHeader
maxForwardsHeader
a custom Header object containing details on maximum proxy forwards. This header places a limit on the viaHeaders possible. Must implement the
type javax.sip.header.MaxForwardsHeader
eventHeader
a custom Header object containing event details. Must implement the type javax.sip.header.EventHeader
contactHeader
an optional custom Header object containing verbose contact details (email, phone number etc). Must implement the type
javax.sip.header.ContactHeader
expiresHeader
a custom Header object containing message expiration details. Must implement the type javax.sip.header.ExpiresHeader
extensionHeader
a custom Header object containing user/application specific details. Must implement the type javax.sip.header.ExtensionHeader
Sending Messages to/from a SIP endpoint
Creating a Camel SIP Publisher
In the example below, a SIP Publisher is created to send SIP Event publications to
a user "agent@localhost:5152". This is the address of the SIP Presence Agent which acts as a
broker between the SIP Publisher and Subscriber
• using a SIP Stack named client
• using a registry based eventHeader called evtHdrName
• using a registry based eventId called evtId
• from a SIP Stack with Listener set up as user2@localhost:3534
• The Event being published is EVENT_A
• A Mandatory Header called REQUEST_METHOD is set to Request.Publish thereby
setting up the endpoint as a Event publisher"
producerTemplate.sendBodyAndHeader(
"sip://agent@localhost:5152?stackName=client&eventHeaderName=evtHdrName&eventId=evtid&fromUser=user2&f
"EVENT_A",
"REQUEST_METHOD",
Request.PUBLISH);
Creating a Camel SIP Subscriber
In the example below, a SIP Subscriber is created to receive SIP Event publications sent to
a user "johndoe@localhost:5154"
• using a SIP Stack named Subscriber
• registering with a Presence Agent user called agent@localhost:5152
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• using a registry based eventHeader called evtHdrName. The evtHdrName contains
the Event which is se to "Event_A"
• using a registry based eventId called evtId
@Override
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
@Override
public void configure() throws Exception {
// Create PresenceAgent
from("sip://agent@localhost:5152?stackName=PresenceAgent&presenceAgent=true&eventHeaderName=evtHdrName
.to("mock:neverland");
// Create Sip Consumer(Event Subscriber)
from("sip://johndoe@localhost:5154?stackName=Subscriber&toUser=agent&toHost=localhost&toPort=5152&even
.to("log:ReceivedEvent?level=DEBUG")
.to("mock:notification");
}
};
}
The Camel SIP component also ships with a Presence Agent that is meant to
be used for Testing and Demo purposes only. An example of instantiating a Presence
Agent is given above.
Note that the Presence Agent is set up as a user agent@localhost:5152 and is capable of
communicating with both Publisher as well as Subscriber. It has a separate SIP stackName
distinct from Publisher as well as Subscriber. While it is set up as a Camel Consumer, it does
not actually send any messages along the route to the endpoint "mock:neverland".
SMPP COMPONENT
Available as of Camel 2.2
This component provides access to an SMSC (Short Message Service Center) over the SMPP
protocol to send and receive SMS. The JSMPP is used.
Starting with Camel 2.9, you are also able to execute ReplaceSm, QuerySm,
SubmitMulti, CancelSm and DataSm.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-smppx.x.x
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URI format
smpp://[username@]hostname[:port][?options]
smpps://[username@]hostname[:port][?options]
If no username is provided, then Camel will provide the default value smppclient.
If no port number is provided, then Camel will provide the default value 2775.
Camel 2.3: If the protocol name is "smpps", camel-smpp with try to use SSLSocket to init a
connection to the server.
You can append query options to the URI in the following format,
?option=value&option=value&...
URI Options
853
Name
Default
Value
Description
password
password
Specifies the password to use to log in to the SMSC.
systemType
cp
This parameter is used to categorize the type of ESME (External Short Message Entity) that is binding to the SMSC (max. 13
characters).
dataCoding
0
Camel 2.5 onwarts until Camel 2.8.x Defines encoding of data according the SMPP 3.4 specification, section 5.2.19.
Example data encodings are:
0: SMSC Default Alphabet
4: 8 bit Alphabet
8: UCS2 Alphabet
alphabet
0
Camel 2.9 onwarts Defines the alphabet of the data according the SMPP 3.4 specification, section 5.2.19. Example
alphabet encodings are:
-1: The SMPP component will try to determine the actual alphabet to be used. The message will be sent using UCS2
encoding if it contains non standard GSM characters.
0: SMSC Default Alphabet
4: 8 bit Alphabet
8: UCS2 Alphabet
encoding
ISO-8859-1
only for SubmitSm, ReplaceSm and SubmitMulti Defines the encoding scheme of the short message user data.
enquireLinkTimer
5000
Defines the interval in milliseconds between the confidence checks. The confidence check is used to test the communication
path between an ESME and an SMSC.
transactionTimer
10000
Defines the maximum period of inactivity allowed after a transaction, after which an SMPP entity may assume that the
session is no longer active. This timer may be active on either communicating SMPP entity (i.e. SMSC or ESME).
initialReconnectDelay
5000
Defines the initial delay in milliseconds after the consumer/producer tries to reconnect to the SMSC, after the connection
was lost.
reconnectDelay
5000
Defines the interval in milliseconds between the reconnect attempts, if the connection to the SMSC was lost and the
previous was not succeed.
registeredDelivery
1
only for SubmitSm, ReplaceSm, SubmitMulti and DataSm Is used to request an SMSC delivery receipt and/or
SME originated acknowledgements. The following values are defined:
0: No SMSC delivery receipt requested.
1: SMSC delivery receipt requested where final delivery outcome is success or failure.
2: SMSC delivery receipt requested where the final delivery outcome is delivery failure.
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serviceType
CMT
The service type parameter can be used to indicate the SMS Application service associated with the message. The following
generic service_types are defined:
CMT: Cellular Messaging
CPT: Cellular Paging
VMN: Voice Mail Notification
VMA: Voice Mail Alerting
WAP: Wireless Application Protocol
USSD: Unstructured Supplementary Services Data
sourceAddr
1616
Defines the address of SME (Short Message Entity) which originated this message.
destAddr
1717
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the destination SME address. For mobile
terminated messages, this is the directory number of the recipient MS.
0
Defines the type of number (TON) to be used in the SME originator address parameters. The following TON values are
defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
0
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the type of number (TON) to be used in the
SME destination address parameters. The following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
0
Defines the numeric plan indicator (NPI) to be used in the SME originator address parameters. The following NPI values are
defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
0
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the numeric plan indicator (NPI) to be used
in the SME destination address parameters. The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
priorityFlag
1
only for SubmitSm and SubmitMulti Allows the originating SME to assign a priority level to the short message.
Four Priority Levels are supported:
0: Level 0 (lowest) priority
1: Level 1 priority
2: Level 2 priority
3: Level 3 (highest) priority
replaceIfPresentFlag
0
only for SubmitSm and SubmitMulti Used to request the SMSC to replace a previously submitted message, that is
still pending delivery. The SMSC will replace an existing message provided that the source address, destination address and
service type match the same fields in the new message. The following replace if present flag values are defined:
0: Don't replace
1: Replace
0
Defines the type of number (TON) to be used in the SME. The following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
sourceAddrTon
destAddrTon
sourceAddrNpi
destAddrNpi
typeOfNumber
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numberingPlanIndicator
0
Defines the numeric plan indicator (NPI) to be used in the SME. The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
lazySessionCreation
false
Camel 2.8 onwarts Sessions can be lazily created to avoid exceptions, if the SMSC is not available when the Camel
producer is started.
You can have as many of these options as you like.
smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&systemT
Message Headers
The following message headers can be used to affect the behavior of the SMPP producer
855
Header
Description
CamelSmppDestAddr
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the destination SME address. For mobile terminated
messages, this is the directory number of the recipient MS.
CamelSmppDestAddrTon
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the type of number (TON) to be used in the SME
destination address parameters. The following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
CamelSmppDestAddrNpi
only for SubmitSm, SubmitMulti, CancelSm and DataSm Defines the numeric plan indicator (NPI) to be used in the
SME destination address parameters. The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
CamelSmppSourceAddr
Defines the address of SME (Short Message Entity) which originated this message.
CamelSmppSourceAddrTon
Defines the type of number (TON) to be used in the SME originator address parameters. The following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
CamelSmppSourceAddrNpi
Defines the numeric plan indicator (NPI) to be used in the SME originator address parameters. The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
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CamelSmppServiceType
The service type parameter can be used to indicate the SMS Application service associated with the message. The following generic
service_types are defined:
CMT: Cellular Messaging
CPT: Cellular Paging
VMN: Voice Mail Notification
VMA: Voice Mail Alerting
WAP: Wireless Application Protocol
USSD: Unstructured Supplementary Services Data
CamelSmppRegisteredDelivery
only for SubmitSm, ReplaceSm, SubmitMulti and DataSm Is used to request an SMSC delivery receipt and/or SME
originated acknowledgements. The following values are defined:
0: No SMSC delivery receipt requested.
1: SMSC delivery receipt requested where final delivery outcome is success or failure.
2: SMSC delivery receipt requested where the final delivery outcome is delivery failure.
CamelSmppPriorityFlag
only for SubmitSm and SubmitMulti Allows the originating SME to assign a priority level to the short message. Four Priority
Levels are supported:
0: Level 0 (lowest) priority
1: Level 1 priority
2: Level 2 priority
3: Level 3 (highest) priority
CamelSmppScheduleDeliveryTime
only for SubmitSm, SubmitMulti and ReplaceSm This parameter specifies the scheduled time at which the message
delivery should be first attempted. It defines either the absolute date and time or relative time from the current SMSC time at which
delivery of this message will be attempted by the SMSC. It can be specified in either absolute time format or relative time format.
The encoding of a time format is specified in chapter 7.1.1. in the smpp specification v3.4.
CamelSmppValidityPeriod
only for SubmitSm, SubmitMulti and ReplaceSm The validity period parameter indicates the SMSC expiration time, after
which the message should be discarded if not delivered to the destination. It can be defined in absolute time format or relative time
format. The encoding of absolute and relative time format is specified in chapter 7.1.1 in the smpp specification v3.4.
CamelSmppReplaceIfPresentFlag
only for SubmitSm and SubmitMulti The replace if present flag parameter is used to request the SMSC to replace a
previously submitted message, that is still pending delivery. The SMSC will replace an existing message provided that the source
address, destination address and service type match the same fields in the new message. The following values are defined:
0: Don't replace
1: Replace
CamelSmppDataCoding
Camel 2.5 onwarts until Camel 2.8.x The data coding according to the SMPP 3.4 specification, section 5.2.19:
0: SMSC Default Alphabet
4: 8 bit Alphabet
8: UCS2 Alphabet
CamelSmppAlphabet
Camel 2.9 onwarts only for SubmitSm, SubmitMulti and ReplaceSm The data coding according to the SMPP 3.4
specification, section 5.2.19:
-1: The SMPP component will try to determine the actual alphabet to be used. The message will be sent using UCS2 encoding if it
contains non standard GSM characters.
0: SMSC Default Alphabet
4: 8 bit Alphabet
8: UCS2 Alphabet
The following message headers are used by the SMPP producer to set the response from the
SMSC in the message header
Header
Description
CamelSmppId
The id to identify the submitted short message(s) for later use (delivery receipt, query sm, cancel sm, replace sm). From Camel 2.9: In
case of a ReplaceSm, QuerySm, CancelSm and DataSm, this header vaule is a String. In case of a SubmitSm or SubmitMultiSm this
header vaule is a List.
CamelSmppSentMessageCount
From Camel 2.9 onwarts only for SubmitSm and SubmitMultiSm The total number of messages which has been sent.
CamelSmppError
From Camel 2.9 onwarts only for SubmitMultiSm The errors which occurred by sending the short message(s) the form
Map>> (messageID : (destAddr : address, error : errorCode)).
The following message headers are used by the SMPP consumer to set the request data from
the SMSC in the message header
Header
Description
CamelSmppSequenceNumber
only for AlertNotification, DeliverSm and DataSm A sequence number allows a response PDU to be correlated with a
request PDU. The associated SMPP response PDU must preserve this field.
CamelSmppCommandId
only for AlertNotification, DeliverSm and DataSm The command id field identifies the particular SMPP PDU. For the
complete list of defined values see chapter 5.1.2.1 in the smpp specification v3.4.
CamelSmppSourceAddr
only for AlertNotification, DeliverSm and DataSm Defines the address of SME (Short Message Entity) which originated
this message.
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857
CamelSmppSourceAddrNpi
only for AlertNotification and DataSm Defines the numeric plan indicator (NPI) to be used in the SME originator address
parameters. The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
CamelSmppSourceAddrTon
only for AlertNotification and DataSm Defines the type of number (TON) to be used in the SME originator address
parameters. The following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
CamelSmppEsmeAddr
only for AlertNotification Defines the destination ESME address. For mobile terminated messages, this is the directory
number of the recipient MS.
CamelSmppEsmeAddrNpi
only for AlertNotification Defines the numeric plan indicator (NPI) to be used in the ESME originator address parameters.
The following NPI values are defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
CamelSmppEsmeAddrTon
only for AlertNotification Defines the type of number (TON) to be used in the ESME originator address parameters. The
following TON values are defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
CamelSmppId
only for smsc DeliveryReceipt and DataSm The message ID allocated to the message by the SMSC when originally
submitted.
CamelSmppDelivered
only for smsc DeliveryReceipt Number of short messages delivered. This is only relevant where the original message was
submitted to a distribution list.The value is padded with leading zeros if necessary.
CamelSmppDoneDate
only for smsc DeliveryReceipt The time and date at which the short message reached it's final state. The format is as follows:
YYMMDDhhmm.
CamelSmppStatus
only for smsc DeliveryReceipt and DataSm The final status of the message. The following values are defined:
DELIVRD: Message is delivered to destination
EXPIRED: Message validity period has expired.
DELETED: Message has been deleted.
UNDELIV: Message is undeliverable
ACCEPTD: Message is in accepted state (i.e. has been manually read on behalf of the subscriber by customer service)
UNKNOWN: Message is in invalid state
REJECTD: Message is in a rejected state
CamelSmppError
only for smsc DeliveryReceipt Where appropriate this may hold a Network specific error code or an SMSC error code for
the attempted delivery of the message. These errors are Network or SMSC specific and are not included here.
CamelSmppSubmitDate
only for smsc DeliveryReceipt The time and date at which the short message was submitted. In the case of a message which
has been replaced, this is the date that the original message was replaced. The format is as follows: YYMMDDhhmm.
CamelSmppSubmitted
only for smsc DeliveryReceipt Number of short messages originally submitted. This is only relevant when the original
message was submitted to a distribution list.The value is padded with leading zeros if necessary.
CamelSmppDestAddr
only for DeliverSm and DataSm Defines the destination SME address. For mobile terminated messages, this is the directory
number of the recipient MS.
CamelSmppScheduleDeliveryTime
only for DeliverSm and DataSm This parameter specifies the scheduled time at which the message delivery should be first
attempted. It defines either the absolute date and time or relative time from the current SMSC time at which delivery of this
message will be attempted by the SMSC. It can be specified in either absolute time format or relative time format. The encoding of a
time format is specified in Section 7.1.1. in the smpp specification v3.4.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
CamelSmppValidityPeriod
only for DeliverSm The validity period parameter indicates the SMSC expiration time, after which the message should be
discarded if not delivered to the destination. It can be defined in absolute time format or relative time format. The encoding of
absolute and relative time format is specified in Section 7.1.1 in the smpp specification v3.4.
CamelSmppServiceType
only for DeliverSm and DataSm The service type parameter indicates the SMS Application service associated with the
message.
CamelSmppRegisteredDelivery
only for DataSm Is used to request an delivery receipt and/or SME originated acknowledgements. The following values are
defined:
0: No SMSC delivery receipt requested.
1: SMSC delivery receipt requested where final delivery outcome is success or failure.
2: SMSC delivery receipt requested where the final delivery outcome is delivery failure.
CamelSmppDestAddrNpi
only for DataSm Defines the numeric plan indicator (NPI) in the destination address parameters. The following NPI values are
defined:
0: Unknown
1: ISDN (E163/E164)
2: Data (X.121)
3: Telex (F.69)
6: Land Mobile (E.212)
8: National
9: Private
10: ERMES
13: Internet (IP)
18: WAP Client Id (to be defined by WAP Forum)
CamelSmppDestAddrTon
only for DataSm Defines the type of number (TON) in the destination address parameters. The following TON values are
defined:
0: Unknown
1: International
2: National
3: Network Specific
4: Subscriber Number
5: Alphanumeric
6: Abbreviated
CamelSmppMessageType
Camel 2.6 onwarts: Identifies the type of an incoming message:
AlertNotification: an SMSC alert notification
DataSm: an SMSC data short message
DeliveryReceipt: an SMSC delivery receipt
DeliverSm: an SMSC deliver short message
Exception handling
This component supports the general Camel exception handling capabilities.
Camel 2.8 onwarts: When the SMPP consumer receives a DeliverSm or DataSm short
message and the processing of these messages fails, you can also throw a
ProcessRequestException instead of handle the failure. In this case, this exception is
forwarded to the underlying JSMPP library which will return the included error code to the
SMSC. This feature is useful to e.g. instruct the SMSC to resend the short message at a later
time. This could be done with the following lines of code:
from("smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&s
.doTry()
.to("bean:dao?method=updateSmsState")
.doCatch(Exception.class)
.throwException(new ProcessRequestException("update of sms state failed", 100))
.end();
Please refer to the SMPP specification for the complete list of error codes and their meanings.
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JSMPP library
See the documentation of the JSMPP Library for more details about the underlying
library.
Samples
A route which sends an SMS using the Java DSL:
from("direct:start")
.to("smpp://smppclient@localhost:2775?
password=password&enquireLinkTimer=3000&transactionTimer=5000&systemType=producer");
A route which sends an SMS using the Spring XML DSL:
A route which receives an SMS using the Java DSL:
from("smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&s
.to("bean:foo");
A route which receives an SMS using the Spring XML DSL:
Debug logging
This component has log level DEBUG, which can be helpful in debugging problems. If you use
log4j, you can add the following line to your configuration:
log4j.logger.org.apache.camel.component.smpp=DEBUG
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CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
SMSC simulator
If you need an SMSC simulator for your test, you can use the simulator provided by
Logica.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
SNMP COMPONENT
Available as of Camel 2.1
The snmp: component gives you the ability to poll SNMP capable devices or receiving
traps.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-snmpx.x.x
URI format
snmp://hostname[:port][?Options]
The component supports polling OID values from an SNMP enabled device and receiving traps.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
type
none
The type of action you want to perform. Actually you can enter here POLL or TRAP. The value POLL will instruct the endpoint to poll a
given host for the supplied OID keys. If you put in TRAP you will setup a listener for SNMP Trap Events.
address
none
This is the IP address and the port of the host to poll or where to setup the Trap Receiver. Example: 127.0.0.1:162
CH APT ER 11 - CO M PO N EN T APPEN DIX
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protocol
udp
Here you can select which protocol to use. You can use either udp or tcp.
retries
2
Defines how often a retry is made before canceling the request.
timeout
1500
Sets the timeout value for the request in millis.
snmpVersion
0 (which means
SNMPv1)
Sets the snmp version for the request.
snmpCommunity
public
Sets the community octet string for the snmp request.
delay
60 seconds
Defines the delay in seconds between to poll cycles.
oids
none
Defines which values you are interested in. Please have a look at the Wikipedia to get a better understanding. You may provide a single
OID or a coma separated list of OIDs. Example:
oids="1.3.6.1.2.1.1.3.0,1.3.6.1.2.1.25.3.2.1.5.1,1.3.6.1.2.1.25.3.5.1.1.1,1.3.6.1.2.1.43.5.1.1.11.1"
The result of a poll
Given the situation, that I poll for the following OIDs:
Listing 80. OIDs
1.3.6.1.2.1.1.3.0
1.3.6.1.2.1.25.3.2.1.5.1
1.3.6.1.2.1.25.3.5.1.1.1
1.3.6.1.2.1.43.5.1.1.11.1
The result will be the following:
Listing 81. Result of toString conversion
1.3.6.1.2.1.1.3.06 days, 21:14:28.001.3.6.1.2.1.25.3.2.1.5.121.3.6.1.2.1.25.3.5.1.1.131.3.6.1.2.1.43.5.1.1.11.161.3.6.1.2.1.1.1.0My Very Special Printer Of Brand Unknown
As you maybe recognized there is one more result than requested....1.3.6.1.2.1.1.1.0.
This one is filled in by the device automatically in this special case. So it may absolutely happen,
that you receive more than you requested...be prepared.
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CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
Examples
Polling a remote device:
snmp:192.168.178.23:161?protocol=udp&type=POLL&oids=1.3.6.1.2.1.1.5.0
Setting up a trap receiver (Note that no OID info is needed here!):
snmp:127.0.0.1:162?protocol=udp&type=TRAP
Routing example in Java: (converts the SNMP PDU to XML String)
from("snmp:192.168.178.23:161?protocol=udp&type=POLL&oids=1.3.6.1.2.1.1.5.0").
convertBodyTo(String.class).
to("activemq:snmp.states");
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
SPRING INTEGRATION COMPONENT
The spring-integration: component provides a bridge for Camel components to talk to
spring integration endpoints.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-spring-integrationx.x.x
URI format
spring-integration:defaultChannelName[?options]
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Where defaultChannelName represents the default channel name which is used by the
Spring Integration Spring context. It will equal to the inputChannel name for the Spring
Integration consumer and the outputChannel name for the Spring Integration provider.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Type
Description
inputChannel
String
The Spring integration input channel name that this endpoint wants to consume from, where the specified channel name is defined in the
Spring context.
outputChannel
String
The Spring integration output channel name that is used to send messages to the Spring integration context.
inOut
String
The exchange pattern that the Spring integration endpoint should use. If inOut=true then a reply channel is expected, either from the
Spring Integration Message header or configured on the endpoint.
Usage
The Spring integration component is a bridge that connects Camel endpoints with Spring
integration endpoints through the Spring integration's input channels and output channels. Using
this component, we can send Camel messages to Spring Integration endpoints or receive
messages from Spring integration endpoints in a Camel routing context.
Examples
Using the Spring integration endpoint
You can set up a Spring integration endpoint using a URI, as follows:
Or directly using a Spring integration channel name:
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The Source and Target adapter
Spring integration also provides the Spring integration's source and target adapters, which can
route messages from a Spring integration channel to a Camel endpoint or from a Camel
endpoint to a Spring integration channel.
This example uses the following namespaces:
You can bind your source or target to a Camel endpoint as follows:
camelTargetContextcamelTargetContextcamelTargetContextcamelSourceContext
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camelSourceContext
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
SPRING WEB SERVICES COMPONENT
Available as of Camel 2.6
The spring-ws: component allows you to integrate with Spring Web Services. It offers
both client-side support, for accessing web services, and server-side support for creating your
own contract-first web services.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-spring-wsx.x.x
URI format
The URI scheme for this component is as follows
spring-ws:[mapping-type:]address[?options]
To expose a web service mapping-type needs to be set to any of the following:
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Mapping
type
Description
rootqname
Offers the option to map web service requests based on the qualified name of the root element contained in the message.
soapaction
Used to map web service requests based on the SOAP action specified in the header of the message.
uri
In order to map web service requests that target a specific URI.
CH A PTE R 1 1 - C OMP ONE NT A P P E ND I X
Dependencies
As of Camel 2.8 this component ships with Spring-WS 2.0.x which (like the rest of
Camel) requires Spring 3.0.x.
Earlier Camel versions shipped Spring-WS 1.5.9 which is compatible with Spring 2.5.x and
3.0.x. In order to run earlier versions of camel-spring-ws on Spring 2.5.x you need to
add the spring-webmvc module from Spring 2.5.x. In order to run Spring-WS 1.5.9 on
Spring 3.0.x you need to exclude the OXM module from Spring 3.0.x as this module is also
included in Spring-WS 1.5.9 (see this post)
xpathresult
Used to map web service requests based on the evaluation of an XPath expression against the incoming message. The result of the evaluation should
match the XPath result specified in the endpoint URI.
beanname
Allows you to reference a org.apache.camel.component.spring.ws.bean.CamelEndpointDispatcher in order to integrate with existing
(legacy) endpoint mappings like PayloadRootQNameEndpointMapping, SoapActionEndpointMapping, etc
As a consumer the address should contain a value relevant to the specified mapping-type (e.g.
a SOAP action, XPath expression). As a producer the address should be set to the URI of the
web service your calling upon.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Required?
Description
soapAction
No
SOAP action to include inside a SOAP request when accessing remote web services
wsAddressingAction
No
WS-Addressing 1.0 action header to include when accessing web services. The To header is set to the address of the
web service as specified in the endpoint URI (default Spring-WS behavior).
expression
Only when mapping-type is
xpathresult
XPath expression to use in the process of mapping web service requests, should match the result specified by
xpathresult
Registry based options
The following options can be specified in the registry (most likely a Spring ApplicationContext)
and referenced from the endpoint URI using the # notation.
Name
Required?
Description
webServiceTemplate
No
Option to provide a custom WebServiceTemplate. This allows for full control over client-side web services handling; like
adding a custom interceptor or specifying a fault resolver, message sender or message factory.
messageSender
No
Option to provide a custom WebServiceMessageSender. For example to perform authentication or use alternative
transports
messageFactory
No
Option to provide a custom WebServiceMessageFactory. For example when you want Apache Axiom to handle web
service messages instead of SAAJ
transformerFactory
No
Option to override default TransformerFactory. The provided transformer factory must be of type
javax.xml.transform.TransformerFactory
endpointMapping
Only when mappingtype is rootqname,
soapaction, uri
or xpathresult
Reference to org.apache.camel.component.spring.ws.bean.CamelEndpointMapping in the Registry/
ApplicationContext. Only one bean is required in the registry to serve all Camel/Spring-WS endpoints. This bean is autodiscovered by the MessageDispatcher and used to map requests to Camel endpoints based on characteristics specified on
the endpoint (like root QName, SOAP action, etc)
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Message headers
Name
Type
Description
CamelSpringWebserviceEndpointUri
String
URI of the web service your accessing as a client, overrides address part of the endpoint URI
CamelSpringWebserviceSoapAction
String
Header to specify the SOAP action of the message, overrides soapAction option if present
CamelSpringWebserviceAddressingAction
URI
Use this header to specify the WS-Addressing action of the message, overrides wsAddressingAction
option if present
ACCESSING WEB SERVICES
To call a web service at http://foo.com/bar simply define a route:
from("direct:example").to("spring-ws:http://foo.com/bar")
And sent a message:
template.requestBody("direct:example", "test
message");
Remember if it's a SOAP service you're calling you don't have to include SOAP tags. Spring-WS
will perform the XML-to-SOAP marshaling.
Sending SOAP and WS-Addressing action headers
When a remote web service requires a SOAP action or use of the WS-Addressing standard
you define your route as:
from("direct:example")
.to("spring-ws:http://foo.com/
bar?soapAction=http://foo.com&wsAddressingAction=http://bar.com")
Optionally you can override the endpoint options with header values:
template.requestBodyAndHeader("direct:example",
"test message",
SpringWebserviceConstants.SPRING_WS_SOAP_ACTION, "http://baz.com");
Using a custom MessageSender and MessageFactory
A custom message sender or factory in the registry can be referenced like this:
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from("direct:example")
.to("spring-ws:http://foo.com/
bar?messageFactory=#messageFactory&messageSender=#messageSender")
Spring configuration:
EXPOSING WEB SERVICES
In order to expose a web service using this component you first need to set-up a
MessageDispatcher to look for endpoint mappings in a Spring XML file. If you plan on running
inside a servlet container you probably want to use a MessageDispatcherServlet
configured in web.xml.
By default the MessageDispatcherServlet will look for a Spring XML named /WEBINF/spring-ws-servlet.xml. To use Camel with Spring-WS the only mandatory bean
in that XML file is CamelEndpointMapping. This bean allows the MessageDispatcher
to dispatch web service requests to your routes.
web.xml
spring-wsorg.springframework.ws.transport.http.MessageDispatcherServlet1
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spring-ws/*
spring-ws-servlet.xml
More information on setting up Spring-WS can be found in Writing Contract-First Web
Services. Basically paragraph 3.6 "Implementing the Endpoint" is handled by this component
(specifically paragraph 3.6.2 "Routing the Message to the Endpoint" is where
CamelEndpointMapping comes in). Also don't forget to check out the Spring Web
Services Example included in the Camel distribution.
Endpoint mapping in routes
With the XML configuration in-place you can now use Camel's DSL to define what web service
requests are handled by your endpoint:
The following route will receive all web service requests that have a root element named
"GetFoo" within the http://example.com/ namespace.
from("spring-ws:rootqname:{http://example.com/
}GetFoo?endpointMapping=#endpointMapping")
.convertBodyTo(String.class).to(mock:example)
The following route will receive web service requests containing the
http://example.com/GetFoo SOAP action.
from("spring-ws:soapaction:http://example.com/GetFoo?endpointMapping=#endpointMapping")
.convertBodyTo(String.class).to(mock:example)
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The following route will receive all requests sent to http://example.com/foobar.
from("spring-ws:uri:http://example.com/foobar?endpointMapping=#endpointMapping")
.convertBodyTo(String.class).to(mock:example)
The route below will receive requests that contain the element abc
anywhere inside the message (and the default namespace).
from("spring-ws:xpathresult:abc?expression=//foobar&endpointMapping=#endpointMapping")
.convertBodyTo(String.class).to(mock:example)
Alternative configuration, using existing endpoint mappings
For every endpoint with mapping-type beanname one bean of type
CamelEndpointDispatcher with a corresponding name is required in the Registry/
ApplicationContext. This bean acts as a bridge between the Camel endpoint and an existing
endpoint mapping like PayloadRootQNameEndpointMapping.
An example of a route using beanname:
FutureEndpointDispatcherQuoteEndpointDispatcher
POJO (UN)MARSHALLING
Camel's pluggable data formats offer support for pojo/xml marshalling using libraries such as
JAXB, XStream, JibX, Castor and XMLBeans. You can use these data formats in your route to
sent and receive pojo's, to and from web services.
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The use of the beanname mapping-type is primarily meant for (legacy) situations
where you're already using Spring-WS and have endpoint mappings defined in a
Spring XML file. The beanname mapping-type allows you to wire your Camel
route into an existing endpoint mapping. When you're starting from scratch it's
recommended to define your endpoint mappings as Camel URI's (as illustrated
above with endpointMapping) since it requires less configuration and is more
expressive. Alternatively you could use vanilla Spring-WS with the help of
annotations.
When accessing web services you can marshal the request and unmarshal the response
message:
JaxbDataFormat jaxb = new JaxbDataFormat(false);
jaxb.setContextPath("com.example.model");
from("direct:example").marshal(jaxb).to("spring-ws:http://foo.com/
bar").unmarshal(jaxb);
Similarly when providing web services, you can unmarshal XML requests to POJO's and marshal
the response message back to XML:
from("spring-ws:rootqname:{http://example.com/
}GetFoo?endpointMapping=#endpointMapping").unmarshal(jaxb)
.to("mock:example").marshal(jaxb);
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
STREAM COMPONENT
The stream: component provides access to the System.in, System.out and
System.err streams as well as allowing streaming of file and URL.
Maven users will need to add the following dependency to their pom.xml for this
component:
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org.apache.camelcamel-streamx.x.x
URI format
stream:in[?options]
stream:out[?options]
stream:err[?options]
stream:header[?options]
In addition, the file and url endpoint URIs are supported in Camel 2.0:
stream:file?fileName=/foo/bar.txt
stream:url[?options]
If the stream:header URI is specified, the stream header is used to find the stream to
write to. This option is available only for stream producers (that is, it cannot appear in
from()).
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Name
Default
Value
Description
delay
0
Initial delay in milliseconds before consuming or producing the stream.
encoding
JVM Default
As of 1.4, you can configure the encoding (is a charset name) to use text-based streams (for example, message body is a String
object). If not provided, Camel uses the JVM default Charset.
promptMessage
null
Camel 2.0: Message prompt to use when reading from stream:in; for example, you could set this to Enter a command:
promptDelay
0
Camel 2.0: Optional delay in milliseconds before showing the message prompt.
initialPromptDelay
2000
Camel 2.0: Initial delay in milliseconds before showing the message prompt. This delay occurs only once. Can be used during
system startup to avoid message prompts being written while other logging is done to the system out.
fileName
null
Camel 2.0: When using the stream:file URI format, this option specifies the filename to stream to/from.
scanStream
false
Camel 2.0: To be used for continuously reading a stream such as the unix tail command.
Camel 2.4 to Camel 2.6: will retry opening the file if it is overwritten, somewhat like tail --retry
retry
false
Camel 2.7: will retry opening the file if it's overwritten, somewhat like tail --retry
scanStreamDelay
0
Camel 2.0: Delay in milliseconds between read attempts when using scanStream.
groupLines
0
Camel 2.5: To group X number of lines in the consumer. For example to group 10 lines and therefore only spit out an
Exchange with 10 lines, instead of 1 Exchange per line.
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Message content
The stream: component supports either String or byte[] for writing to streams. Just add
either String or byte[] content to the message.in.body.
The special stream:header URI is used for custom output streams. Just add a
java.io.OutputStream object to message.in.header in the key header.
See samples for an example.
Samples
In the following sample we route messages from the direct:in endpoint to the
System.out stream:
@Test
public void testStringContent() throws Exception {
template.sendBody("direct:in", "Hello Text World\n");
}
@Test
public void testBinaryContent() {
template.sendBody("direct:in", "Hello Bytes World\n".getBytes());
}
protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from("direct:in").to("stream:out");
}
};
}
The following sample demonstrates how the header type can be used to determine which
stream to use. In the sample we use our own output stream, MyOutputStream.
private OutputStream mystream = new MyOutputStream();
private StringBuffer sb = new StringBuffer();
@Test
public void testStringContent() {
template.sendBody("direct:in", "Hello");
// StreamProducer appends \n in text mode
assertEquals("Hello\n", sb.toString());
}
@Test
public void testBinaryContent() {
template.sendBody("direct:in", "Hello".getBytes());
// StreamProducer is in binary mode so no \n is appended
assertEquals("Hello", sb.toString());
}
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protected RouteBuilder createRouteBuilder() {
return new RouteBuilder() {
public void configure() {
from("direct:in").setHeader("stream", constant(mystream)).
to("stream:header");
}
};
}
private class MyOutputStream extends OutputStream {
public void write(int b) throws IOException {
sb.append((char)b);
}
}
The following sample demonstrates how to continuously read a file stream (analogous to the
UNIX tail command):
from("stream:file?fileName=/server/logs/
server.log&scanStream=true&scanStreamDelay=1000").to("bean:logService?method=parseLogLine");
One gotcha with scanStream (pre Camel 2.7) or scanStream + retry is the file will be re-opened
and scanned with each iteration of scanStreamDelay. Until NIO2 is available we cannot reliably
detect when a file is deleted/recreated.
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
STRING TEMPLATE
The string-template: component allows you to process a message using a String Template.
This can be ideal when using Templating to generate responses for requests.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-stringtemplatex.x.x
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URI format
string-template:templateName[?options]
Where templateName is the classpath-local URI of the template to invoke; or the complete
URL of the remote template.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
contentCache
false
New option in Camel 1.4. Cache for the resource content when its loaded.
Note : as of Camel 2.9 cached resource content can be cleared via JMX using the endpoint's clearContentCache operation.
Headers
Camel will store a reference to the resource in the message header with key,
org.apache.camel.stringtemplate.resource. The Resource is an
org.springframework.core.io.Resource object.
Hot reloading
The string template resource is by default hot-reloadable for both file and classpath resources
(expanded jar). If you set contentCache=true, Camel loads the resource only once and
hot-reloading is not possible. This scenario can be used in production when the resource never
changes.
StringTemplate Attributes
Camel will provide exchange information as attributes (just a java.util.Map) to the string
template. The Exchange is transfered as:
877
key
value
exchange
The Exchange itself.
headers
The headers of the In message.
camelContext
The Camel Context.
request
The In message.
in
The In message.
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body
The In message body.
out
The Out message (only for InOut message exchange pattern).
response
The Out message (only for InOut message exchange pattern).
Samples
For example you could use a string template as follows in order to formulate a response to a
message:
from("activemq:My.Queue").
to("string-template:com/acme/MyResponse.tm");
The Email Sample
In this sample we want to use a string template to send an order confirmation email. The email
template is laid out in StringTemplate as:
Dear $headers.lastName$, $headers.firstName$
Thanks for the order of $headers.item$.
Regards Camel Riders Bookstore
$body$
And the java code is as follows:
private Exchange createLetter() {
Exchange exchange = context.getEndpoint("direct:a").createExchange();
Message msg = exchange.getIn();
msg.setHeader("firstName", "Claus");
msg.setHeader("lastName", "Ibsen");
msg.setHeader("item", "Camel in Action");
msg.setBody("PS: Next beer is on me, James");
return exchange;
}
@Test
public void testVelocityLetter() throws Exception {
MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedMessageCount(1);
mock.expectedBodiesReceived("Dear Ibsen, Claus! Thanks for the order of Camel in
Action. Regards Camel Riders Bookstore PS: Next beer is on me, James");
template.send("direct:a", createLetter());
mock.assertIsSatisfied();
}
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protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
from("direct:a").to("string-template:org/apache/camel/component/
stringtemplate/letter.tm").to("mock:result");
}
};
}
See Also
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
SQL COMPONENT
The sql: component allows you to work with databases using JDBC queries. The difference
between this component and JDBC component is that in case of SQL the query is a property of
the endpoint and it uses message payload as parameters passed to the query.
This component uses spring-jdbc behind the scenes for the actual SQL handling.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-sqlx.x.x
The SQL component also supports:
▪ a JDBC based repository for the Idempotent Consumer EIP pattern. See further
below.
▪ a JDBC based repository for the Aggregator EIP pattern. See further below.
URI format
The SQL component uses the following endpoint URI notation:
sql:select * from table where id=# order by name[?options]
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The SQL component can only be used to define producer endpoints. In other
words, you cannot define an SQL endpoint in a from() statement.
This component can be used as a Transactional Client.
Notice that the standard ? symbol that denotes the parameters to an SQL query is substituted
with the # symbol, because the ? symbol is used to specify options for the endpoint. The ?
symbol replacement can be configured on endpoint basis.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Type
Default
Description
batch
boolean
false
Camel 2.7.5, 2.8.4 and 2.9: Execute
SQL batch update statements. See notes
below on how the treatment of the
inbound message body changes if this is set
to true.
dataSourceRef
String
null
Camel 1.5.1 and 2.0: Reference to a
DataSource to look up in the registry.
#
Camel 2.4: Specifies a character that will
be replaced to ? in SQL query. Notice, that
it is simple String.replaceAll()
operation and no SQL parsing is involved
(quoted strings will also change)
null
Sets additional options on the Spring
JdbcTemplate that is used behind the
scenes to execute the queries. For instance,
template.maxRows=10. For detailed
documentation, see the JdbcTemplate
javadoc documentation.
placeholder
template.
String
Ê
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Treatment of the message body
The SQL component tries to convert the message body to an object of
java.util.Iterator type and then uses this iterator to fill the query parameters (where
each query parameter is represented by a # symbol (or configured placeholder) in the endpoint
URI). If the message body is not an array or collection, the conversion results in an iterator that
iterates over only one object, which is the body itself.
For example, if the message body is an instance of java.util.List, the first item in the
list is substituted into the first occurrence of # in the SQL query, the second item in the list is
substituted into the second occurrence of #, and so on.
If batch is set to true, then the interpretation of the inbound message body changes
slightly Ð instead of an iterator of parameters, the component expects an iterator that contains
the parameter iterators; the size of the outer iterator determines the batch size.
Result of the query
For select operations, the result is an instance of List> type,
as returned by the JdbcTemplate.queryForList() method. For update operations, the result is
the number of updated rows, returned as an Integer.
Header values
When performing update operations, the SQL Component stores the update count in the
following message headers:
Header
Description
SqlProducer.UPDATE_COUNT
Camel 1.x: The number of rows updated for
update operations, returned as an Integer object.
CamelSqlUpdateCount
Camel 2.0: The number of rows updated for
update operations, returned as an Integer object.
CamelSqlRowCount
Camel 2.0: The number of rows returned for
select operations, returned as an Integer object.
CamelSqlQuery
Camel 2.8: Query to execute. This query takes
precedence over the query specified in the endpoint
URI. Note that query parameters in the header are
represented by a ? instead of a # symbol
Configuration in Camel 1.5.0 or lower
The SQL component must be configured before it can be used. In Spring, you can configure it as
follows:
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Configuration in Camel 1.5.1 or higher
You can now set a reference to a DataSource in the URI directly:
sql:select * from table where id=# order by name?dataSourceRef=myDS
Sample
In the sample below we execute a query and retrieve the result as a List of rows, where each
row is a Map instead containing each binding value.
template.sendBody("direct:simple", "XXX");
mock.assertIsSatisfied();
// the result is a List
List received = assertIsInstanceOf(List.class,
mock.getReceivedExchanges().get(0).getIn().getBody());
// and each row in the list is a Map
Map row = assertIsInstanceOf(Map.class, received.get(0));
// and we should be able the get the project from the map that should be Linux
assertEquals("Linux", row.get("PROJECT"));
We could configure the DataSource in Spring XML as follows:
Using the JDBC based idempotent repository
Available as of Camel 2.7: In this section we will use the JDBC based idempotent
repository.
First we have to create the database table which will be used by the idempotent repository. For
Camel 2.7, we use the following schema:
CREATE TABLE CAMEL_MESSAGEPROCESSED (
processorName VARCHAR(255),
messageId VARCHAR(100)
)
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Abstract class
From Camel 2.9 onwards there is an abstract class
org.apache.camel.processor.idempotent.jdbc.AbstractJdbcMessageIdReposi
you can extend to build custom JDBC idempotent repository.
In Camel 2.8, we added the createdAt column:
CREATE TABLE CAMEL_MESSAGEPROCESSED (
processorName VARCHAR(255),
messageId VARCHAR(100),
createdAt TIMESTAMP
)
We recommend to have a unique constraint on the columns processorName and messageId.
Because the syntax for this constraint differs for database to database, we do not show it here.
Second we need to setup a javax.sql.DataSource in the spring XML file:
And finally we can create our JDBC idempotent repository in the spring XML file as well:
messageId
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Customize the JdbcMessageIdRepository
Starting with Camel 2.9.1 you have a few options to tune the
org.apache.camel.processor.idempotent.jdbc.JdbcMessageIdRepository
for your needs:
Parameter
Default Value
Description
createTableIfNotExists
true
Defines whether or not Camel
should try to create the table if
it doesn't exist.
tableExistsString
SELECT 1 FROM
CAMEL_MESSAGEPROCESSED
WHERE 1 = 0
This query is used to figure out
whether the table already exists
or not. It must throw an
exception to indicate the table
doesn't exist.
createString
CREATE TABLE
CAMEL_MESSAGEPROCESSED
(processorName
VARCHAR(255), messageId
VARCHAR(100), createdAt
TIMESTAMP)
The statement which is used to
create the table.
SELECT COUNT(*) FROM
CAMEL_MESSAGEPROCESSED
WHERE processorName = ?
AND messageId = ?
The query which is used to
figure out whether the message
already exists in the repository
(the result is not equals to '0').
It takes two parameters. This
first one is the processor name
(String) and the second one
is the message id (String).
INSERT INTO
CAMEL_MESSAGEPROCESSED
(processorName, messageId,
createdAt) VALUES (?, ?, ?)
The statement which is used to
add the entry into the table. It
takes three parameter. The first
one is the processor name
(String), the second one is
the message id (String) and
the third one is the timestamp
(java.sql.Timestamp)
when this entry was added to
the repository.
queryString
insertString
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deleteString
DELETE FROM
CAMEL_MESSAGEPROCESSED
WHERE processorName = ?
AND messageId = ?
The statement which is used to
delete the entry from the
database. It takes two
parameter. This first one is the
processor name (String) and
the second one is the message
id (String).
A customized
org.apache.camel.processor.idempotent.jdbc.JdbcMessageIdRepository
could look like:
Using the JDBC based aggregation repository
Available as of Camel 2.6
JdbcAggregationRepository is an AggregationRepository which on the fly
persists the aggregated messages. This ensures that you will not loose messages, as the default
aggregator will use an in memory only AggregationRepository.
The JdbcAggregationRepository allows together with Camel to provide persistent
support for the Aggregator.
It has the following options:
Option
Type
Description
dataSource
DataSource
Mandatory: The javax.sql.DataSource
repositoryName
String
Mandatory: The name of the repository.
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Using JdbcAggregationRepository in Camel 2.6
In Camel 2.6, the JdbcAggregationRepository is provided in the camel-jdbcaggregator component. From Camel 2.7 onwards, the
JdbcAggregationRepository is provided in the camel-sql component.
transactionManager
TransactionManager
Mandatory: The
org.springframework.transaction.Pl
to mange transactions for the database. The Trans
support databases.
lobHandler
LobHandler
A org.springframework.jdbc.support
Lob types in the database. Use this option to use
example when using Oracle.
returnOldExchange
boolean
Whether the get operation should return the old
default this option is false to optimize as we do
aggregating.
useRecovery
boolean
Whether or not recovery is enabled. This option
the Camel Aggregator automatic recover failed ag
resubmitted.
recoveryInterval
long
If recovery is enabled then a background task is ru
exchanges to recover and resubmit. By default thi
maximumRedeliveries
int
Allows you to limit the maximum number of rede
exchange. If enabled then the Exchange will be mo
redelivery attempts failed. By default this option is
the deadLetterUri option must also be provi
deadLetterUri
String
An endpoint uri for a Dead Letter Channel where
will be moved. If this option is used then the max
must also be provided.
What is preserved when persisting
JdbcAggregationRepository will only preserve any Serializable compatible data
types. If a data type is not such a type its dropped and a WARN is logged. And it only persists the
Message body and the Message headers. The Exchange properties are not persisted.
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Recovery
The JdbcAggregationRepository will by default recover any failed Exchange. It does
this by having a background tasks that scans for failed Exchanges in the persistent store. You
can use the checkInterval option to set how often this task runs. The recovery works as
transactional which ensures that Camel will try to recover and redeliver the failed Exchange.
Any Exchange which was found to be recovered will be restored from the persistent store and
resubmitted and send out again.
The following headers is set when an Exchange is being recovered/redelivered:
Header
Type
Description
Exchange.REDELIVERED
Boolean
Is set to true to indicate the Exchange
is being redelivered.
Exchange.REDELIVERY_COUNTER
Integer
The redelivery attempt, starting from
1.
Only when an Exchange has been successfully processed it will be marked as complete which
happens when the confirm method is invoked on the AggregationRepository. This
means if the same Exchange fails again it will be kept retried until it success.
You can use option maximumRedeliveries to limit the maximum number of redelivery
attempts for a given recovered Exchange. You must also set the deadLetterUri option so
Camel knows where to send the Exchange when the maximumRedeliveries was hit.
You can see some examples in the unit tests of camel-sql, for example this test.
Database
To be operational, each aggregator uses two table: the aggregation and completed one. By
convention the completed has the same name as the aggregation one suffixed with
"_COMPLETED". The name must be configured in the Spring bean with the
RepositoryName property. In the following example aggregation will be used.
The table structure definition of both table are identical: in both case a String value is used as
key (id) whereas a Blob contains the exchange serialized in byte array.
However one difference should be remembered: the id field does not have the same content
depending on the table.
In the aggregation table id holds the correlation Id used by the component to aggregate the
messages. In the completed table, id holds the id of the exchange stored in corresponding the
blob field.
Here is the SQL query used to create the tables, just replace "aggregation" with your
aggregator repository name.
CREATE TABLE aggregation (
id varchar(255) NOT NULL,
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exchange blob NOT NULL,
constraint aggregation_pk PRIMARY KEY (id)
);
CREATE TABLE aggregation_completed (
id varchar(255) NOT NULL,
exchange blob NOT NULL,
constraint aggregation_completed_pk PRIMARY KEY (id)
);
Codec (Serialization)
Since they can contain any type of payload, Exchanges are not serializable by design. It is
converted into a byte array to be stored in a database BLOB field. All those conversions are
handled by the JdbcCodec class. One detail of the code requires your attention: the
ClassLoadingAwareObjectInputStream.
The ClassLoadingAwareObjectInputStream has been reused from the Apache
ActiveMQ project. It wraps an ObjectInputStream and use it with the
ContextClassLoader rather than the currentThread one. The benefit is to be able to
load classes exposed by other bundles. This allows the exchange body and headers to have
custom types object references.
Transaction
A Spring PlatformTransactionManager is required to orchestrate transaction.
Service (Start/Stop)
The start method verify the connection of the database and the presence of the required
tables. If anything is wrong it will fail during starting.
Aggregator configuration
Depending on the targeted environment, the aggregator might need some configuration. As you
already know, each aggregator should have its own repository (with the corresponding pair of
table created in the database) and a data source. If the default lobHandler is not adapted to
your database system, it can be injected with the lobHandler property.
Here is the declaration for Oracle:
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See Also
•
•
•
•
▪
Configuring Camel
Component
Endpoint
Getting Started
JDBC
TEST COMPONENT
Testing of distributed and asynchronous processing is notoriously difficult. The Mock, Test and
DataSet endpoints work great with the Camel Testing Framework to simplify your unit and
integration testing using Enterprise Integration Patterns and Camel's large range of Components
together with the powerful Bean Integration.
The test component extends the Mock component to support pulling messages from another
endpoint on startup to set the expected message bodies on the underlying Mock endpoint. That
is, you use the test endpoint in a route and messages arriving on it will be implicitly compared
to some expected messages extracted from some other location.
So you can use, for example, an expected set of message bodies as files. This will then set up
a properly configured Mock endpoint, which is only valid if the received messages match the
number of expected messages and their message payloads are equal.
Maven users will need to add the following dependency to their pom.xml for this
component when using Camel 2.8 or older:
org.apache.camelcamel-springx.x.x
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From Camel 2.9 onwards the Test component is provided directly in the camel-core.
URI format
test:expectedMessagesEndpointUri
Where expectedMessagesEndpointUri refers to some other Component URI that the
expected message bodies are pulled from before starting the test.
Example
For example, you could write a test case as follows:
from("seda:someEndpoint").
to("test:file://data/expectedOutput?noop=true");
If your test then invokes the MockEndpoint.assertIsSatisfied(camelContext) method, your test
case will perform the necessary assertions.
To see how you can set other expectations on the test endpoint, see the Mock component.
See Also
•
•
•
•
•
Configuring Camel
Component
Endpoint
Getting Started
Spring Testing
TIMER COMPONENT
The timer: component is used to generate message exchanges when a timer fires You can
only consume events from this endpoint.
URI format
timer:name[?options]
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Where name is the name of the Timer object, which is created and shared across endpoints.
So if you use the same name for all your timer endpoints, only one Timer object and thread
will be used.
You can append query options to the URI in the following format,
?option=value&option=value&...
Note: The IN body of the generated exchange is null. So
exchange.getIn().getBody() returns null.
Options
Name
Default
Value
Description
time
null
A java.util.Date the first event should be generated. If using the URI, the pattern expected is: yyyy-MM-dd HH:mm:ss or
yyyy-MM-dd'T'HH:mm:ss.
pattern
null
Allows you to specify a custom Date pattern to use for setting the time option using URI syntax.
period
1000
If greater than 0, generate periodic events every period milliseconds.
delay
0
The number of milliseconds to wait before the first event is generated. Should not be used in conjunction with the time option.
fixedRate
false
Events take place at approximately regular intervals, separated by the specified period.
daemon
true
Specifies whether or not the thread associated with the timer endpoint runs as a daemon.
repeatCount
0
Camel 2.8: Specifies a maximum limit of number of fires. So if you set it to 1, the timer will only fire once. If you set it to 5, it will only
fire five times. A value of zero or negative means fire forever.
Exchange Properties
When the timer is fired, it adds the following information as properties to the Exchange:
Name
Type
Description
Exchange.TIMER_NAME
String
The value of the name option.
Exchange.TIMER_TIME
Date
The value of the time option.
Exchange.TIMER_PERIOD
long
The value of the period option.
Exchange.TIMER_FIRED_TIME
Date
The time when the consumer fired.
Exchange.TIMER_COUNTER
Long
Camel 2.8: The current fire counter. Starts from 1.
Message Headers
When the timer is fired, it adds the following information as headers to the IN message
Name
Type
Description
Exchange.TIMER_FIRED_TIME
java.util.Date
The time when the consumer fired
Sample
To set up a route that generates an event every 60 seconds:
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Advanced Scheduler
See also the Quartz component that supports much more advanced scheduling.
Specify time in human friendly format
In Camel 2.3 onwards you can specify the time in human friendly syntax.
from("timer://foo?fixedRate=true&period=60000").to("bean:myBean?method=someMethodName");
The above route will generate an event and then invoke the someMethodName method on
the bean called myBean in the Registry such as JNDI or Spring.
And the route in Spring DSL:
Firing only once
Available as of Camel 2.8
You may want to fire a message in a Camel route only once, such as when starting the
route. To do that you use the repeatCount option as shown:
See Also
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Getting Started
Quartz
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Instead of 60000 you can use period=60s which is more friendly to read.
VALIDATION COMPONENT
The Validation component performs XML validation of the message body using the JAXP
Validation API and based on any of the supported XML schema languages, which defaults to
XML Schema
Note that the Jing component also supports the following useful schema languages:
• RelaxNG Compact Syntax
• RelaxNG XML Syntax
The MSV component also supports RelaxNG XML Syntax.
URI format
validator:someLocalOrRemoteResource
Where someLocalOrRemoteResource is some URL to a local resource on the classpath
or a full URL to a remote resource or resource on the file system which contains the XSD to
validate against. For example:
• msv:org/foo/bar.xsd
• msv:file:../foo/bar.xsd
• msv:http://acme.com/cheese.xsd
• validator:com/mypackage/myschema.xsd
Maven users will need to add the following dependency to their pom.xml for this component
when using Camel 2.8 or older:
org.apache.camelcamel-springx.x.x
From Camel 2.9 onwards the Validation component is provided directly in the camel-core.
Options
Option
Default
Description
resourceResolver
null
Camel 2.9: Reference to a org.w3c.dom.ls.LSResourceResolver in the Registry.
useDom
false
Camel 2.0: Whether DOMSource/DOMResult or SaxSource/SaxResult should be used by the validator.
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useSharedSchema
true
Camel 2.3: Whether the Schema instance should be shared or not. This option is introduced to work around a JDK 1.6.x bug.
Xerces should not have this issue.
Example
The following example shows how to configure a route from endpoint direct:start which
then goes to one of two endpoints, either mock:valid or mock:invalid based on whether
or not the XML matches the given schema (which is supplied on the classpath).
org.apache.camel.ValidationException
See Also
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Configuring Camel
Component
Endpoint
Getting Started
VELOCITY
The velocity: component allows you to process a message using an Apache Velocity template.
This can be ideal when using Templating to generate responses for requests.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-velocityx.x.x
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URI format
velocity:templateName[?options]
Where templateName is the classpath-local URI of the template to invoke; or the complete
URL of the remote template (eg: file://folder/myfile.vm).
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
Option
Default
Description
loaderCache
true
Velocity based file loader cache.
contentCache
Ê
New option in Camel 1.4: Cache for the resource content when it is loaded. By default, it's false in Camel 1.x. By default, it's true
in Camel 2.x.
Note : as of Camel 2.9 cached resource content can be cleared via JMX using the endpoint's clearContentCache operation.
encoding
null
New option in Camel 1.6: Character encoding of the resource content.
propertiesFile
null
New option in Camel 2.1: The URI of the properties file which is used for VelocityEngine initialization.
Message Headers
The velocity component sets a couple headers on the message (you can't set these yourself and
from Camel 2.1 velocity component will not set these headers which will cause some side effect
on the dynamic template support):
Header
Description
org.apache.camel.velocity.resource
Camel 1.x: The resource as an org.springframework.core.io.Resource object.
org.apache.camel.velocity.resourceUri
Camel 1.x: The templateName as a String object.
CamelVelocityResource
Camel 2.0: The resource as an org.springframework.core.io.Resource object.
CamelVelocityResourceUri
Camel 2.0: The templateName as a String object.
In Camel 1.4 headers set during the Velocity evaluation are returned to the message and added
as headers. Then its kinda possible to return values from Velocity to the Message.
For example, to set the header value of fruit in the Velocity template .tm:
$in.setHeader('fruit', 'Apple')
The fruit header is now accessible from the message.out.headers.
Velocity Context
Camel will provide exchange information in the Velocity context (just a Map). The Exchange
is transfered as:
key
value
exchange
The Exchange itself.
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exchange.properties
The Exchange properties.
headers
The headers of the In message.
camelContext
The Camel Context intance.
request
The In message.
in
The In message.
body
The In message body.
out
The Out message (only for InOut message exchange pattern).
response
The Out message (only for InOut message exchange pattern).
Hot reloading
The Velocity template resource is, by default, hot reloadable for both file and classpath
resources (expanded jar). If you set contentCache=true, Camel will only load the
resource once, and thus hot reloading is not possible. This scenario can be used in production,
when the resource never changes.
Dynamic templates
Available as of Camel 2.1
Camel provides two headers by which you can define a different resource location for a
template or the template content itself. If any of these headers is set then Camel uses this over
the endpoint configured resource. This allows you to provide a dynamic template at runtime.
Header
Type
Description
CamelVelocityResourceUri
String
Camel 2.1: A URI for the template resource to use instead of the endpoint configured.
CamelVelocityTemplate
String
Camel 2.1: The template to use instead of the endpoint configured.
Samples
For example you could use something like
from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm");
To use a Velocity template to formulate a response to a message for InOut message exchanges
(where there is a JMSReplyTo header).
If you want to use InOnly and consume the message and send it to another destination, you
could use the following route:
from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm").
to("activemq:Another.Queue");
And to use the content cache, e.g. for use in production, where the .vm template never
changes:
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from("activemq:My.Queue").
to("velocity:com/acme/MyResponse.vm?contentCache=true").
to("activemq:Another.Queue");
And a file based resource:
from("activemq:My.Queue").
to("velocity:file://myfolder/MyResponse.vm?contentCache=true").
to("activemq:Another.Queue");
In Camel 2.1 it's possible to specify what template the component should use dynamically via
a header, so for example:
from("direct:in").
setHeader("CamelVelocityResourceUri").constant("path/to/my/template.vm").
to("velocity:dummy");
In Camel 2.1 it's possible to specify a template directly as a header the component should use
dynamically via a header, so for example:
from("direct:in").
setHeader("CamelVelocityTemplate").constant("Hi this is a velocity template that can
do templating ${body}").
to("velocity:dummy");
The Email Sample
In this sample we want to use Velocity templating for an order confirmation email. The email
template is laid out in Velocity as:
Dear ${headers.lastName}, ${headers.firstName}
Thanks for the order of ${headers.item}.
Regards Camel Riders Bookstore
${body}
And the java code:
private Exchange createLetter() {
Exchange exchange = context.getEndpoint("direct:a").createExchange();
Message msg = exchange.getIn();
msg.setHeader("firstName", "Claus");
msg.setHeader("lastName", "Ibsen");
msg.setHeader("item", "Camel in Action");
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msg.setBody("PS: Next beer is on me, James");
return exchange;
}
@Test
public void testVelocityLetter() throws Exception {
MockEndpoint mock = getMockEndpoint("mock:result");
mock.expectedMessageCount(1);
mock.expectedBodiesReceived("Dear Ibsen, Claus\n\nThanks for the order of Camel in
Action.\n\nRegards Camel Riders Bookstore\nPS: Next beer is on me, James");
template.send("direct:a", createLetter());
mock.assertIsSatisfied();
}
protected RouteBuilder createRouteBuilder() throws Exception {
return new RouteBuilder() {
public void configure() throws Exception {
from("direct:a").to("velocity:org/apache/camel/component/velocity/
letter.vm").to("mock:result");
}
};
}
See Also
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Configuring Camel
Component
Endpoint
Getting Started
VM COMPONENT
The vm: component provides asynchronous SEDA behavior, exchanging messages on a
BlockingQueue and invoking consumers in a separate thread pool.
This component differs from the SEDA component in that VM supports communication
across CamelContext instances - so you can use this mechanism to communicate across web
applications (provided that camel-core.jar is on the system/boot classpath).
VM is an extension to the SEDA component.
URI format
vm:queueName[?options]
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Where queueName can be any string to uniquely identify the endpoint within the JVM (or at
least within the classloader that loaded camel-core.jar)
You can append query options to the URI in the following format:
?option=value&option=value&...
Options
See the SEDA component for options and other important usage details as the same rules apply
to the VM component.
Samples
In the route below we send exchanges across CamelContext instances to a VM queue named
order.email:
from("direct:in").bean(MyOrderBean.class).to("vm:order.email");
And then we receive exchanges in some other Camel context (such as deployed in another
.war application):
from("vm:order.email").bean(MyOrderEmailSender.class);
See Also
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Configuring Camel
Component
Endpoint
Getting Started
SEDA
XMPP COMPONENT
The xmpp: component implements an XMPP (Jabber) transport.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-xmppx.x.x
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Camel 1.x to 2.3 - Same URI must be used for both producer and
consumer
An exactly identical VM endpoint URI must be used for both the producer and the
consumer endpoint. Otherwise, Camel will create a second VM endpoint despite
that the queueName portion of the URI is identical. For example:
from("direct:foo").to("vm:bar?concurrentConsumers=5");
from("vm:bar?concurrentConsumers=5").to("file://output");
Notice that we have to use the full URI, including options in both the producer and
consumer.
In Camel 2.4 this has been fixed so that only the queue name must match. Using the
queue name bar, we could rewrite the previous exmple as follows:
from("direct:foo").to("vm:bar");
from("vm:bar?concurrentConsumers=5").to("file://output");
URI format
xmpp://[login@]hostname[:port][/participant][?Options]
The component supports both room based and private person-person conversations.
The component supports both producer and consumer (you can get messages from XMPP or
send messages to XMPP). Consumer mode supports rooms starting from camel-1.5.0.
You can append query options to the URI in the following format,
?option=value&option=value&...
Options
901
Name
Description
room
If this option is specified, the component will connect to MUC (Multi User Chat). Usually, the domain name for MUC is different from the login domain. For
example, if you are superman@jabber.org and want to join the krypton room, then the room URL is krypton@conference.jabber.org.
Note the conference part.
Starting from camel-1.5.0, it is not a requirement to provide the full room JID. If the room parameter does not contain the @ symbol, the domain part will
be discovered and added by Camel
user
User name (without server name). If not specified, anonymous login will be attempted.
password
Password.
resource
XMPP resource. The default is Camel.
createAccount
If true, an attempt to create an account will be made. Default is false.
participant
JID (Jabber ID) of person to receive messages. room parameter has precedence over participant.
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nickname
Use nickname when joining room. If room is specified and nickname is not, user will be used for the nickname.
serviceName
Camel 1.6/2.0 The name of the service you are connecting to. For Google Talk, this would be gmail.com.
Headers and setting Subject or Language
Camel sets the message IN headers as properties on the XMPP message. You can configure a
HeaderFilterStategy if you need custom filtering of headers.
In Camel 1.6.2/2.0 the Subject and Language of the XMPP message are also set if they
are provided as IN headers.
Examples
User superman to join room krypton at jabber server with password, secret:
xmpp://superman@jabber.org/?room=krypton@conference.jabber.org&password=secret
User superman to send messages to joker:
xmpp://superman@jabber.org/joker@jabber.org?password=secret
Routing example in Java:
from("timer://kickoff?period=10000").
setBody(constant("I will win!\n Your Superman.")).
to("xmpp://superman@jabber.org/joker@jabber.org?password=secret");
Consumer configuration, which writes all messages from joker into the queue, evil.talk.
from("xmpp://superman@jabber.org/joker@jabber.org?password=secret").
to("activemq:evil.talk");
Consumer configuration, which listens to room messages (supported from camel-1.5.0):
from("xmpp://superman@jabber.org/?password=secret&room=krypton@conference.jabber.org").
to("activemq:krypton.talk");
Room in short notation (no domain part; for camel-1.5.0+):
from("xmpp://superman@jabber.org/?password=secret&room=krypton").
to("activemq:krypton.talk");
When connecting to the Google Chat service, you'll need to specify the serviceName as well
as your credentials (as of Camel 1.6/2.0):
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// send a message from fromuser@gmail.com to touser@gmail.com
from("direct:start").
to("xmpp://talk.google.com:5222/
touser@gmail.com?serviceName=gmail.com&user=fromuser&password=secret").
to("mock:result");
See Also
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Configuring Camel
Component
Endpoint
Getting Started
XQUERY
The xquery: component allows you to process a message using an XQuery template. This can
be ideal when using Templating to generate respopnses for requests.
Maven users will need to add the following dependency to their pom.xml for this
component:
org.apache.camelcamel-saxonx.x.x
URI format
xquery:templateName
Where templateName is the classpath-local URI of the template to invoke; or the complete
URL of the remote template.
For example you could use something like this:
from("activemq:My.Queue").
to("xquery:com/acme/mytransform.xquery");
To use an XQuery template to formulate a response to a message for InOut message
exchanges (where there is a JMSReplyTo header).
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If you want to use InOnly, consume the message, and send it to another destination, you
could use the following route:
from("activemq:My.Queue").
to("xquery:com/acme/mytransform.xquery").
to("activemq:Another.Queue");
See Also
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Configuring Camel
Component
Endpoint
Getting Started
XSLT
The xslt: component allows you to process a message using an XSLT template. This can be
ideal when using Templating to generate respopnses for requests.
URI format
xslt:templateName[?options]
Where templateName is the classpath-local URI of the template to invoke; or the complete
URL of the remote template. Refer to the Spring Documentation for more detail of the URI
syntax
You can append query options to the URI in the following format,
?option=value&option=value&...
Here are some example URIs
URI
Description
xslt:com/acme/mytransform.xsl
refers to the file com/acme/mytransform.xsl on the classpath
xslt:file:///foo/bar.xsl
refers to the file /foo/bar.xsl
xslt:http://acme.com/cheese/foo.xsl
refers to the remote http resource
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Maven users will need to add the following dependency to their pom.xml for this component
when using Camel 2.8 or older:
org.apache.camelcamel-springx.x.x
From Camel 2.9 onwards the XSLT component is provided directly in the camel-core.
Options
Name
Default
Value
Description
converter
null
Option to override default XmlConverter. Will lookup for the converter in the Registry. The provided converted must be
of type org.apache.camel.converter.jaxp.XmlConverter.
transformerFactory
null
Camel 1.6 Option to override default TransformerFactory. Will lookup for the transformerFactory in the Registry. The
provided transformer factory must be of type javax.xml.transform.TransformerFactory.
transformerFactoryClass
null
Camel 1.6 Option to override default TransformerFactory. Will create a TransformerFactoryClass instance and set it to
the converter.
uriResolver
null
Camel 2.3: Allows you to use a custom javax.xml.transformation.URIResolver. Camel will by default use
its own implementation org.apache.camel.builder.xml.XsltUriResolver which is capable of loading from
classpath.
resultHandlerFactory
null
Camel 2.3: Allows you to use a custom org.apache.camel.builder.xml.ResultHandlerFactory which
is capable of using custom org.apache.camel.builder.xml.ResultHandler types.
failOnNullBody
true
Camel 2.3: Whether or not to throw an exception if the input body is null.
deleteOutputFile
false
Camel 2.6: If you have output=file then this option dictates whether or not the output file should be deleted when
the Exchange is done processing. For example suppose the output file is a temporary file, then it can be a good idea to
delete it after use.
output
string
Camel 2.3: Option to specify which output type to use. Possible values are: string, bytes, DOM, file. The
first three options are all in memory based, where as file is streamed directly to a java.io.File. For file you
must specify the filename in the IN header with the key Exchange.XSLT_FILE_NAME which is also
CamelXsltFileName. Also any paths leading to the filename must be created beforehand, otherwise an exception is
thrown at runtime.
contentCache
true
Camel 2.6: Cache for the resource content (the stylesheet file) when it is loaded. If set to false Camel will reload the
stylesheet file on each message processing. This is good for development.
Note: from Camel 2.9 a cached stylesheet can be forced to reload at runtime via JMX using the
clearCachedStylesheet operation.
allowStAX
false
Camel 2.8.3/2.9: Whether to allow using StAX as the javax.xml.transform.Source.
Using XSLT endpoints
For example you could use something like
from("activemq:My.Queue").
to("xslt:com/acme/mytransform.xsl");
To use an XSLT template to formulate a response for a message for InOut message exchanges
(where there is a JMSReplyTo header).
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If you want to use InOnly and consume the message and send it to another destination you
could use the following route:
from("activemq:My.Queue").
to("xslt:com/acme/mytransform.xsl").
to("activemq:Another.Queue");
Getting Parameters into the XSLT to work with
By default, all headers are added as parameters which are available in the XSLT.
To do this you will need to declare the parameter so it is then useable.
42
And the XSLT just needs to declare it at the top level for it to be available:
Spring XML versions
To use the above examples in Spring XML you would use something like
There is a test case along with its Spring XML if you want a concrete example.
Using xsl:include
Camel 1.6.2/2.2 or older
If you use xsl:include in your XSL files then in Camel 2.2 or older it uses the default
javax.xml.transform.URIResolver which means it can only lookup files from file
system, and its does that relative from the JVM starting folder.
For example this include:
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Will lookup the staff_tempkalte.xsl file from the starting folder where the application
was started.
Camel 1.6.3/2.3 or newer
Now Camel provides its own implementation of URIResolver which allows Camel to load
included files from the classpath and more intelligent than before.
For example this include:
Will now be located relative from the starting endpoint, which for example could be:
.to("xslt:org/apache/camel/component/xslt/staff_include_relative.xsl")
Which means Camel will locate the file in the classpath as org/apache/camel/
component/xslt/staff_template.xsl.
This allows you to use xsl include and have xsl files located in the same folder such as we do in
the example org/apache/camel/component/xslt.
You can use the following two prefixes classpath: or file: to instruct Camel to look
either in classpath or file system. If you omit the prefix then Camel uses the prefix from the
endpoint configuration. If that neither has one, then classpath is assumed.
You can also refer back in the paths such as
Which then will resolve the xsl file under org/apache/camel/component.
Dynamic stylesheets
Available as of Camel 2.9
Camel provides the CamelXsltResourceUri header which you can use to define a
stylesheet to use instead of what is configured on the endpoint URI. This allows you to provide
a dynamic stylesheet at runtime.
Notes on using XSLT and Java Versions
Here are some observations from Sameer, a Camel user, which he kindly shared with us:
In case anybody faces issues with the XSLT endpoint please review these points.
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I was trying to use an xslt endpoint for a simple transformation from one xml to
another using a simple xsl. The output xml kept appearing (after the xslt processor
in the route) with outermost xml tag with no content within.
No explanations show up in the DEBUG logs. On the TRACE logs however I did
find some error/warning indicating that the XMLConverter bean could no be
initialized.
After a few hours of cranking my mind, I had to do the following to get it to work
(thanks to some posts on the users forum that gave some clue):
1. Use the transformerFactory option in the route ("xslt:mytransformer.xsl?transformerFactory=tFactory") with the
tFactory bean having bean defined in the spring context for
class="org.apache.xalan.xsltc.trax.TransformerFactoryImpl".
2. Added the Xalan jar into my maven pom.
My guess is that the default xml parsing mechanism supplied within the JDK (I am
using 1.6.0_03) does not work right in this context and does not throw up any error
either. When I switched to Xalan this way it works. This is not a Camel issue, but
might need a mention on the xslt component page.
Another note, jdk 1.6.0_03 ships with JAXB 2.0 while Camel needs 2.1. One
workaround is to add the 2.1 jar to the jre/lib/endorsed directory for the
jvm or as specified by the container.
Hope this post saves newbie Camel riders some time.
See Also
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Configuring Camel
Component
Endpoint
Getting Started
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