Camel Manual 2.4.0

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Apache Camel
- User Guide
  - Version 2.4.0
Table of Contents
Introduction
Quickstart
Getting Started with Apache Camel
Architecture
- URIs
  - Current Supported URIs
Enterprise Integration Patterns
- Pattern Index
CookBook
Introduction
Using a Producer
Tutorials
Languages Supported Appendix
Pattern Appendix
Component Appendix

Apache Camel

USER GUIDE

Version 2.4.0

Table of Contents

Table of Contents......................................................................... ii

Chapter 1

Introduction ...................................................................................1

Chapter 2

Quickstart.......................................................................................1

Chapter 3

Getting Started..............................................................................7

Chapter 4

Architecture................................................................................ 18

Chapter 5

Enterprise Integration Patterns.............................................. 30

Chapter 6

Cook Book ................................................................................... 35

Chapter 7

Tutorials....................................................................................... 90

Chapter 8

Language Appendix.................................................................. 195

Chapter 9

Pattern Appendix..................................................................... 245

Chapter 10

Component Appendix ............................................................. 361

Index ................................................................................................0

ii APACHE CAMEL

CHAPTER 1

°°°°

Introduction

Apache Camel 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 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 Bus API 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 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)

• Apache MINA a networking framework

So don't get the hump, try Camel today!

CHAPTER 1 - INTRODUCTION 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.

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");

// set up a listener on the file component

from("file://test").process(new Processor() {

public void process(Exchange e) {

System.out.println("Received exchange: " + e.getIn());

}

});

}

});

or explicitly - as we do here when we add the JMS Component:

ConnectionFactory connectionFactory = new

ActiveMQConnectionFactory("vm://localhost?broker.persistent=false");

// Note we can explicity name the component

context.addComponent("test-jms",

JmsComponent.jmsComponentAutoAcknowledge(connectionFactory));

1CHAPTER 2 - QUICKSTART

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

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.

CHAPTER 2 - QUICKSTART 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:

<route>

</pipeline>

</route>

Where as the bean ref is a reference for a spring bean id, so we define our beans using

regular Spring XML as:

3CHAPTER 2 - QUICKSTART

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:

<route>

</route>

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.

<route>

</pipeline>

</multicast>

</route>

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 <pipeline>

<route>

</multicast>

</route>

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

CHAPTER 2 - QUICKSTART 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:

<route>

</route>

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:

5CHAPTER 2 - QUICKSTART

<route>

</route>

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

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Spring 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.

COOKBOOK 62

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;

public void testSendMatchingMessage() throws Exception {

String expectedBody = "<matched/>";

resultEndpoint.expectedBodiesReceived(expectedBody);

template.sendBodyAndHeader(expectedBody, "foo","bar");

resultEndpoint.assertIsSatisfied();

}

public void testSendNotMatchingMessage() throws Exception {

resultEndpoint.expectedMessageCount(0);

template.sendBodyAndHeader("<notMatched/>","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.

Spring Test with XML Config Example

Here is the Spring Testing example using XML Config.

63 COOKBOOK

@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 = "<matched/>";

resultEndpoint.expectedBodiesReceived(expectedBody);

template.sendBodyAndHeader(expectedBody, "foo","bar");

resultEndpoint.assertIsSatisfied();

}

@DirtiesContext

public void testSendNotMatchingMessage() throws Exception {

resultEndpoint.expectedMessageCount(0);

template.sendBodyAndHeader("<notMatched/>","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

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.5.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd

<route>

COOKBOOK 64

</filter>

</route>

</camelContext>

</beans>

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 = "<matched/>";

resultEndpoint.expectedBodiesReceived(expectedBody);

template.sendBodyAndHeader(expectedBody, "foo","bar");

resultEndpoint.assertIsSatisfied();

}

@DirtiesContext

@Test

public void testSendNotMatchingMessage() throws Exception {

resultEndpoint.expectedMessageCount(0);

template.sendBodyAndHeader("<notMatched/>","foo","notMatchedHeaderValue");

resultEndpoint.assertIsSatisfied();

}

@Configuration

public static class ContextConfig extends SingleRouteCamelConfiguration {

65 COOKBOOK

@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.

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

COOKBOOK 66

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

<groupId>org.apache.camel</groupId>

<artifactId>camel-test</artifactId>

<version>${camel-version}</version>

</dependency>

You might also want to add commons-logging and log4j to ensure nice logging messages (and

maybe adding a log4j.properties file into your src/test/resources directory).

67 COOKBOOK

<groupId>commons-logging</groupId>

<artifactId>commons-logging</artifactId>

</dependency>

</dependency>

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.

public class FilterTest extends CamelTestSupport {

@EndpointInject(uri = "mock:result")

protected MockEndpoint resultEndpoint;

@Produce(uri = "direct:start")

protected ProducerTemplate template;

public void testSendMatchingMessage() throws Exception {

String expectedBody = "<matched/>";

resultEndpoint.expectedBodiesReceived(expectedBody);

template.sendBodyAndHeader(expectedBody, "foo","bar");

resultEndpoint.assertIsSatisfied();

}

public void testSendNotMatchingMessage() throws Exception {

resultEndpoint.expectedMessageCount(0);

template.sendBodyAndHeader("<notMatched/>","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");

}

COOKBOOK 68

};

}

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.

Here is an example jndi.properties file

java.naming.factory.initial = org.apache.camel.util.jndi.CamelInitialContextFactory

See Also

• Testing

• Mock

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 org.apache.camel.CamelContext;

import org.apache.camel.component.mock.MockEndpoint;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.test.context.ContextConfiguration;

import org.springframework.test.context.junit38.AbstractJUnit38SpringContextTests;

@ContextConfiguration

public class MyCamelTest extends AbstractJUnit38SpringContextTests {

69 COOKBOOK

@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

You can overload the method createApplicationContext to provide the Spring

ApplicationContext that isn't following the above default. For instance:

protected AbstractXmlApplicationContext createApplicationContext() {

return new ClassPathXmlApplicationContext("/config/MySpringConfig.xml");

}

Then the test method will then run which invokes the

MockEndpoint.assertIsSatisfied(camelContext) method which asserts that all of the Mock and

Test endpoints have their expectations met.

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 =

"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;

COOKBOOK 70

@DirtiesContext

@Test

public void testSendMatchingMessage() throws Exception {

String expectedBody = "<matched/>";

resultEndpoint.expectedBodiesReceived(expectedBody);

template.sendBodyAndHeader(expectedBody, "foo","bar");

resultEndpoint.assertIsSatisfied();

}

@DirtiesContext

@Test

public void testSendNotMatchingMessage() throws Exception {

resultEndpoint.expectedMessageCount(0);

template.sendBodyAndHeader("<notMatched/>","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.

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 {

71 COOKBOOK

@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<Exchange> list = foo.getReceivedExchanges();

for (Exchange exchange : list) {

Message in = exchange.getIn();

...

}

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

COOKBOOK 72

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("<hello>world!</hello>");

}

// 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.

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

73 COOKBOOK

• 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.

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 {

COOKBOOK 74

@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<RouteBuilder> foo(@Named("fooUrl")String fooUrl) {

return Lists.newArrayList(new MyRouteBuilder(fooUrl), new

MyRouteBuilder("activemq:CheeseQueue"));

}

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

75 COOKBOOK

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 you could use

• Freemarker

• Scalate

• StringTemplate

• Velocity

• XQuery

• XSLT

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).

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

COOKBOOK 76

• 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?

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.

77 COOKBOOK

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

from("activemq:a").setHeader("JMSXGroupID", xpath("/invoice/

productCode")).to("activemq:b");

You can of course use the Xml Configuration if you prefer

COOKBOOK 78

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:

• 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.

79 COOKBOOK

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.

• 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.

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 {

COOKBOOK 80

... // 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:

81 COOKBOOK

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:

COOKBOOK 82

from("file:data/in").process(new MyValidator()).thread(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.

83 COOKBOOK

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.

COOKBOOK 84

<!-- If checkException is true , CamelDestination will check the outMessage's

exception and set it into camel exchange. You can also override this value

in CamelDestination's configuration. The default value is false.

This option should be set true when you want to leverage the camel's error

handler to deal with fault message -->

<list>

<value>http://cxf.apache.org/transports/camel</value>

</list>

</property>

</bean>

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 org.apache.cxf.Bus;

import org.apache.cxf.BusFactory;

import org.apache.cxf.transport.ConduitInitiatorManager;

import 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

85 COOKBOOK

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 4.Listing 4. Adding the Configuration NamespaceAdding the Configuration Namespace

<beans ...

xmlns:camel="http://cxf.apache.org/transports/camel

...

xsi:schemaLocation="...

http://cxf.apache.org/transports/camel

http://cxf.apache.org/transports/camel.xsd

...>

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 <port binding="widgetSOAPBinding"

name="widgetSOAPPort> if the endpoint's target namespace was

http://widgets.widgetvendor.net.

Listing 5.Listing 5. camel:destination Elementcamel:destination Element

...

<camel:destination name="{http://widgets/

widgetvendor.net}widgetSOAPPort.http-destination>

<route>

</route>

</camelContext>

</camel:destination>

...

The camel:destination element has a number of child elements that specify configuration

information. They are described below.

Element Description

camel-

spring:camelContext You can specify the camel context in the camel destination

COOKBOOK 86

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 <port binding="widgetSOAPBinding"

name="widgetSOAPPort> if the endpoint's target namespace was

http://widgets.widgetvendor.net.

Listing 6.Listing 6. http-conf:conduit Elementhttp-conf:conduit Element

...

<camelContext id="conduit_context" xmlns="http://activemq.apache.org/camel/schema/

spring">

<route>

</route>

</camelContext>

<camel:conduit name="{http://widgets/widgetvendor.net}widgetSOAPPort.camel-conduit">

<camel:camelContextRef>conduit_context</camel:camelContextRef>

</camel:conduit>

<camel:conduit name="*.camel-conduit">

<!-- you can also using the wild card to specify the camel-conduit that you want to

configure -->

...

</camel:conduit>

...

The camel:conduit element has a number of child elements that specify configuration

information. They are described below.

Element Description

camel-

spring: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

87 COOKBOOK

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"

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:camel="http://cxf.apache.org/transports/camel"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://cxf.apache.org/transports/camel http://cxf.apache.org/transports/

camel.xsd

http://camel.apache.org/schema/cxf http://camel.apache.org/schema/cxf/

cxfEndpoint.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd

<bean id = "roundRobinRef"

class="org.apache.camel.processor.loadbalancer.RoundRobinLoadBalancer" />

<route>

</loadBalance>

</route>

</camelContext>

<camel:destination name="{http://apache.org/

hello_world_soap_http}CamelPort.camel-destination">

<camel:camelContextRef>dest_context</camel:camelContextRef>

</camel:destination>

</beans>

COMPLETE HOWTO AND EXAMPLE FOR ATTACHING

CAMEL TO CXF

Better JMS Transport for CXF Webservice using Apache Camel

COOKBOOK 88

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.

89 INTRODUCTION

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.

TUTORIALS 90

• 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.

• Examples

While not actual tutorials you might find working through the source of the various

Examples useful

TUTORIAL ON SPRING REMOTING WITH JMS

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

• AOP Enabled Server

• 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

• See Also

91 TUTORIALS

Thanks

This tutorial was kindly donated to Apache Camel by Martin Gilday.

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-example-

spring-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:

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.

Point to

Point

Channel

We using JMS queues so there are only one receive of the message exchange

TUTORIALS 92

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.

<groupId>org.apache.camel</groupId>

<artifactId>camel-core</artifactId>

</dependency>

<groupId>org.apache.camel</groupId>

<artifactId>camel-jms</artifactId>

</dependency>

<groupId>org.apache.camel</groupId>

<artifactId>camel-spring</artifactId>

</dependency>

<groupId>org.apache.activemq</groupId>

<artifactId>activemq-camel</artifactId>

</dependency>

As we use spring xml configuration for the ActiveMQ JMS broker we need this dependency:

93 TUTORIALS

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.

<groupId>org.apache.xbean</groupId>

<artifactId>xbean-spring</artifactId>

</dependency>

And dependencies for the AOP enable server example. These dependencies are of course only

needed if you need full blown AOP stuff using AspejctJ with bytecode instrumentation.

<groupId>org.springframework</groupId>

<artifactId>spring-aop</artifactId>

<version>${spring-version}</version>

</dependency>

<groupId>org.aspectj</groupId>

<artifactId>aspectjrt</artifactId>

</dependency>

<groupId>org.aspectj</groupId>

<artifactId>aspectjweaver</artifactId>

</dependency>

<groupId>cglib</groupId>

<artifactId>cglib-nodep</artifactId>

</dependency>

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.

TUTORIALS 94

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.

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 explicity bean bindings to lookup the multiplier bean and

invoke the multiply method

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//from("jms:queue:numbers").beanRef("multiplier","multiply");

// the same as above but expressed as a URI configuration

//from("activemq: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.

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:camel="http://camel.apache.org/schema/spring"

xmlns:broker="http://activemq.apache.org/schema/core"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/context http://www.springframework.org/

schema/context/spring-context-2.5.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd

http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/

activemq-core.xsd">

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:

<context:component-scan base-package="org.apache.camel.example.server"/>

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.

TUTORIALS 96

Notice that we also have enabled the JMXAgent so we will be able to introspect the Camel

Server with a JMX Console.

<!-- declare a camel context that scans for classes that is RouteBuilder

in the package org.apache.camel.example.server -->

<camel:camelContext id="camel">

<camel:package>org.apache.camel.example.server</camel:package>

<!-- Camel will log at INFO level the service URI to use for connecting with

jconsole -->

<camel:jmxAgent id="agent" createConnector="true"/>

</camel:camelContext>

The ActiveMQ JMS broker is also configured in this xml file. We set it up to listen on TCP port

61610.

<broker:broker useJmx="false" persistent="false" brokerName="localhost">

<broker:transportConnectors>

<broker:transportConnector name="tcp" uri="tcp://localhost:61610"/>

</broker:transportConnectors>

</broker:broker>

As this examples uses JMS then Camel needs a JMS component that is connected with the

ActiveMQ broker. This is configured as shown below:

</bean>

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.

component-

scan

Defines the package to be scanned for Spring stereotype annotations, in this

case, to load the "multiplier" bean

camel-

context

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

97 TUTORIALS

AOP Enabled Server

The example has an enhanced Server example that uses fullblown AspejctJ AOP for doing a

audit tracking of invocations of the business service.

We leverage Spring AOP support in the {{camel-server-aop.xml} configuration file. First we

must declare the correct XML schema's to use:

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:aop="http://www.springframework.org/schema/aop"

xmlns:camel="http://camel.apache.org/schema/spring"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:broker="http://activemq.apache.org/schema/core"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/aop http://www.springframework.org/

schema/aop/spring-aop-2.5.xsd

http://www.springframework.org/schema/context http://www.springframework.org/

schema/context/spring-context-2.5.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd

http://activemq.apache.org/schema/core http://activemq.apache.org/schema/core/

activemq-core.xsd">

Then we include all the existing configuration from the normal server example:

<context:component-scan base-package="org.apache.camel.example.server"/>

<broker:broker useJmx="false" persistent="false" brokerName="localhost">

<broker:transportConnectors>

<broker:transportConnector name="tcp" uri="tcp://localhost:61610"/>

</broker:transportConnectors>

</broker:broker>

<!-- lets configure the Camel JMS consumer to use the ActiveMQ broker declared above

-->

</bean>

</property>

</bean>

Then we enable the AspejctJ AOP auto proxy feature of Spring that will scan for classes

annotated with the @Aspect annotation:

TUTORIALS 98

<!-- turn on AspejctJ AOP to weave all @Aspects beans declared in this spring xml file

-->

<aop:aspectj-autoproxy/>

Then we define our Audit tracker bean that does the actual audit logging. It's also the class that

is annotated with the @Aspect so Spring will pick this up, as the aspect.

</bean>

And the gem is that we inject the AuditTracker aspect bean with a Camel endpoint that defines

where the audit should be stored. Noticed how easy it is to setup as we have just defined an

endpoint URI that is file based, meaning that we stored the audit tracks as files. We can change

this tore to any Camel components as we wish. To store it on a JMS queue simply change the

URI to jms:queue:audit.

<!-- declare a camel context that scans for classes that is RouteBuilder

in the package org.apache.camel.example.server -->

<camel:camelContext id="camel">

<camel:package>org.apache.camel.example.server</camel:package>

<!-- Camel will log at INFO level the service URI to use for connecting with

jconsole -->

<camel:jmxAgent id="agent" createConnector="true"/>

<!-- the audit store endpoint is configued as file based.

In Camel 2.0 the endpoint should be defined in camel context -->

<camel:endpoint id="AuditStore" uri="file://target/store"/>

</camel:camelContext>

And the full blown Aspejct for the audit tracker java code:

/**

* For audit tracking of all incoming invocations of our business (Multiplier)

@Aspect

public class AuditTracker {

// endpoint we use for backup store of audit tracks

private Endpoint store;

@Required

public void setStore(Endpoint store) {

this.store = store;

}

99 TUTORIALS

@Before("execution(int org.apache.camel.example.server.Multiplier.multiply(int))

&& args(originalNumber)")

public void audit(int originalNumber) throws Exception {

String msg = "Someone called us with this number " + originalNumber;

System.out.println(msg);

// now send the message to the backup store using the Camel Message Endpoint

pattern

Exchange exchange = store.createExchange();

exchange.getIn().setBody(msg);

store.createProducer().process(exchange);

}

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

Or for the AOP enabled Server example:

mvn compile exec:java -PCamelServerAOP

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

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.

TUTORIALS 100

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:camel="http://camel.apache.org/schema/spring"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.5.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd">

<camel:camelContext id="camel">

<camel:template id="camelTemplate"/>

</camel:camelContext>

</bean>

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 = (ProducerTemplate)

context.getBean("camelTemplate");

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

int response = (Integer)camelTemplate.sendBody("jms:queue:numbers",

ExchangePattern.InOut, 22);

System.out.println("... the result is: " + response);

101 TUTORIALS

System.exit(0);

}

The ProducerTemplate is retrieved from a Spring ApplicationContext and used to

manually place a message on the "numbers" JMS queue. The exchange pattern

(ExchangePattern.InOut) states that the call should be synchronous, and that we will

receive 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.

<!-- Camel proxy for a given service, in this case the JMS queue

In Camel 2.0 , the proxy should be defined in camelContext. -->

<camel:proxy

id="multiplierProxy"

serviceInterface="org.apache.camel.example.server.Multiplier"

serviceUrl="jms:queue:numbers"/>

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!");

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

TUTORIALS 102

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 = (Multiplier)context.getBean("multiplierProxy");

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 = (CamelContext) context.getBean("camel");

// 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 asynchronized exchange where we expect a response

Exchange exchange = endpoint.createExchange(ExchangePattern.InOut);

// set the input on the in body

// must you correct type to match the expected type of an Integer object

exchange.getIn().setBody(11);

103 TUTORIALS

// 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 7.Listing 7. pom.xmlpom.xml

<build>

TUTORIALS 104

<groupId>org.apache.camel</groupId>

<artifactId>camel-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

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:

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

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/

ns/javaee/web-app_2_5.xsd"

version="2.5">

<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

</web-app>

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

177 TUTORIALS

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-2.5.xsd

http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd">

<route>

</route>

</camelContext>

</beans>

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

To enable more rapid development we hightly 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

<build>

<groupId>org.mortbay.jetty</groupId>

<artifactId>maven-jetty-plugin</artifactId>

</webAppConfig>

</configuration>

</plugin>

</plugins>

</build>

TUTORIALS 178

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

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 e-

mail, 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

179 TUTORIALS

Under Construction

This tutorial is a work in progress.

• 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

◦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.

TUTORIALS 180

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:

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

181 TUTORIALS

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<List<String>> 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.

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 8.Listing 8. pom.xmlpom.xml

<?xml version="1.0" encoding="UTF-8"?>

<groupId>org.apache.camel.tutorial</groupId>

<artifactId>business-partners</artifactId>

<version>1.0-SNAPSHOT</version>

<name>Camel Business Partners Tutorial</name>

TUTORIALS 182

<artifactId>camel-core</artifactId>

<groupId>org.apache.camel</groupId>

</dependency>

</dependencies>

<build>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

</configuration>

</plugin>

</plugins>

</build>

</project>

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:

<?xml version="1.0" encoding="UTF-8"?>

<partner-id>2</partner-id>

<date-received>9/12/2008</date-received>

<line-item>

<product-id>134</product-id>

<description>A widget</description>

<item-price>10.45</item-price>

<order-date>6/5/2008</order-date>

</line-item>

183 TUTORIALS

<order-total>218.82</order-total>

</invoice>

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:

<artifactId>camel-jaxb</artifactId>

<groupId>org.apache.camel</groupId>

</dependency>

And a plugin configured:

<groupId>org.codehaus.mojo</groupId>

<artifactId>jaxb2-maven-plugin</artifactId>

<goals>

</goals>

</execution>

</executions>

</plugin>

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/generated-

sources/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

TUTORIALS 184

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 – 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

• 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:

<artifactId>camel-spring</artifactId>

<groupId>org.apache.camel</groupId>

</dependency>

<artifactId>spring-test</artifactId>

<groupId>org.springframework</groupId>

</dependency>

2. Create a new unit test class in src/test/java/your-package-here, perhaps

called XMLInputTest.java

185 TUTORIALS

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.

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<Exchange> 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 <beans> element (including the Camel Namespace) with an empty

<camelContext> element to the Spring context, like this:

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/

spring-beans-2.5.xsd

http://activemq.apache.org/camel/schema/spring

http://activemq.apache.org/camel/schema/spring/

camel-spring-1.4.0.xsd">

TUTORIALS 186

<camelContext id="camel" xmlns="http://activemq.apache.org/camel/schema/

spring">

</camelContext>

</beans>

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

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:

187 TUTORIALS

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 –

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:

◦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<List<String>>, 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:

TUTORIALS 188

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.

1. Create a new class under src/main/java, perhaps called CSVConverterBean.

2. Add a method, with one argument of type List<List<String>> 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

▪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 – 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.

189 TUTORIALS

Create a unit test

Start with a simple test class and test Spring context like last time, perhaps based on the name

CSVInputTest:

Listing 9.Listing 9. CSVInputTest.javaCSVInputTest.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<Exchange> template;

protected void setUp() throws Exception {

super.setUp();

template = camelContext.createProducerTemplate();

}

public void testCSVConversion() {

// TODO

}

Listing 10.Listing 10. CSVInputTest-context.xmlCSVInputTest-context.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/

spring-beans-2.5.xsd

http://activemq.apache.org/camel/schema/spring

http://activemq.apache.org/camel/schema/spring/

camel-spring-1.4.0.xsd">

</camelContext>

</beans>

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:

<artifactId>camel-csv</artifactId>

<groupId>org.apache.camel</groupId>

</dependency>

TUTORIALS 190

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<List<String>> 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)

5. Finally, we need a Spring <bean> element in the Spring context XML file

(but outside the <camelContext> 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:

191 TUTORIALS

◦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 – create

an Excel DataFormat (so Camel can convert Excel spreadsheets to something like the CSV

List<List<String>> 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:

<groupId>org.apache.poi</groupId>

<version>3.1-FINAL</version>

</dependency>

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)

TUTORIALS 192

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 – which probably means

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 <bean> 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

193 TUTORIALS

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.

• 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)

...

Step 8: Create a unit test for the Customer Input Routes

TUTORIALS 194

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

<route>

</filter>

</route>

195 LANGUAGES SUPPORTED APPENDIX

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) {...}

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

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:

LANGUAGES SUPPORTED APPENDIX 196

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:

197 LANGUAGES SUPPORTED APPENDIX

<route>

<constant>the value</constant>

</setHeader>

</route>

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.

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

<route>

<el>${in.headers.foo == 'bar'}</el>

</filter>

</route>

You could also use slightly different syntax, e.g. if the header name is not a valid identifier:

<route>

<el>${in.headers['My Header'] == 'bar'}</el>

</filter>

</route>

You could use EL to create an Predicate in a Message Filter or as an Expression for a Recipient

List

LANGUAGES SUPPORTED APPENDIX 198

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-juel</artifactId>

</dependency>

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:

<route>

199 LANGUAGES SUPPORTED APPENDIX

<header>myHeader</header>

</recipientList>

</route>

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

Variable Type Description

this Exchange the Exchange object

in Message the exchange.in message

out Message the exchange.out message

LANGUAGES SUPPORTED APPENDIX 200

Using XML configuration

If you prefer to configure your routes in your Spring XML file then you can use JXPath

expressions as follows

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.0.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd">

<route>

<jxpath>in/body/name = 'James'</xpath>

</filter>

</route>

</camelContext>

</beans>

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

}

201 LANGUAGES SUPPORTED APPENDIX

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-jxpath</artifactId>

</dependency>

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

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

LANGUAGES SUPPORTED APPENDIX 202

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

<route>

<mvel>request.headers.foo == 'bar'</mvel>

</filter>

</route>

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-mvel</artifactId>

</dependency>

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

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:

203 LANGUAGES SUPPORTED APPENDIX

"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

<route>

<ognl>request.headers.foo = 'bar'</ognl>

</filter>

</route>

And the sample using Java DSL:

from("seda:foo").filter().ognl("request.headers.foo = 'bar'").to("seda:bar");

LANGUAGES SUPPORTED APPENDIX 204

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-ognl</artifactId>

</dependency>

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:

<route>

<property>myProperty</property>

</recipientList>

</route>

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");

Dependencies

The Property language is part of camel-core.

205 LANGUAGES SUPPORTED APPENDIX

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:

• BeanShell

• JavaScript

• Groovy

• Python

• PHP

• Ruby

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:

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

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:

LANGUAGES SUPPORTED APPENDIX 206

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):

<expression language="jaskel">user.firstName</expression>

</setHeader>

Dependencies

To use scripting languages in your camel routes you need to add the a dependency on camel-

script 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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-script</artifactId>

</dependency>

See Also

• BAM

265 CHAPTER 9 - PATTERN APPENDIX

RETURN ADDRESS

Camel supports the Return Address from the EIP patterns by using the JMSReplyTo header.

For example when using JMS with InOut the component will by default return to the address

given in JMSReplyTo.

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.

MESSAGE ROUTING

Content Based Router

The Content Based Router from the EIP patterns allows you to route messages to the correct

destination based on the contents of the message exchanges.

The following example shows how to route a request from an input seda:a endpoint to

either seda:b,seda:c or seda:d depending on the evaluation of various Predicate

expressions

Using the Fluent Builders

RouteBuilder builder = new RouteBuilder() {

public void configure() {

errorHandler(deadLetterChannel("mock:error"));

CHAPTER 9 - PATTERN APPENDIX 266

from("seda:a").choice().when(header("foo").isEqualTo("bar")).to("seda:b")

.when(header("foo").isEqualTo("cheese")).to("seda:c").otherwise().to("seda:d");

}

};

Using the Spring XML Extensions

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

<when>

</when>

<when>

<xpath>$foo = 'cheese'</xpath>

</when>

</otherwise>

</choice>

</route>

</camelContext>

For further examples of this pattern in use you could look at the junit test case

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.

Message Filter

The Message Filter from the EIP patterns allows you to filter messages

The following example shows how to create a Message Filter route consuming messages

from an endpoint called queue:a which if the Predicate is true will be dispatched to queue:b

267 CHAPTER 9 - PATTERN APPENDIX

Using the Fluent Builders

RouteBuilder builder = new RouteBuilder() {

public void configure() {

errorHandler(deadLetterChannel("mock:error"));

from("seda:a").filter(header("foo").isEqualTo("bar")).to("seda:b");

}

};

You can of course use many different Predicate languages such as XPath, XQuery, SQL or

various Scripting Languages. Here is an XPath example

from("direct:start").

filter().xpath("/person[@name='James']").

to("mock:result");

Using the Spring XML Extensions

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

</filter>

</route>

</camelContext>

For further examples of this pattern in use you could look at the junit test case

Using stop

Available as of Camel 2.0

Stop is a bit different than a message filter as it will filter out all messages. Stop is convenient

to use in a Content Based Router when you for example need to stop further processing in one

of the predicates.

In the example below we do not want to route messages any further that has the word Bye

in the message body. Notice how we prevent this in the when predicate by using the

.stop().

from("direct:start")

.choice()

.when(body().contains("Hello")).to("mock:hello")

.when(body().contains("Bye")).to("mock:bye").stop()

CHAPTER 9 - PATTERN APPENDIX 268

.otherwise().to("mock:other")

.end()

.to("mock:result");

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.

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 {

@Consume(uri = "activemq:foo")

@RecipientList

public List<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

...

}

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

• POJO Producing

269 CHAPTER 9 - PATTERN APPENDIX

• 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.

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

CHAPTER 9 - PATTERN APPENDIX 270

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

</multicast>

</route>

</camelContext>

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

271 CHAPTER 9 - PATTERN APPENDIX

Using the Spring XML Extensions

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

</recipientList>

</route>

</camelContext>

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.

<route>

<header>myHeader</header>

</recipientList>

</route>

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"), "#");

CHAPTER 9 - PATTERN APPENDIX 272

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.

from("direct:a").recipientList(header("myHeader")).parallelProcessing();

And in Spring XML its an attribute on the recipient list tag.

<route>

<header>myHeader</header>

</recipientList>

</route>

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.

<route>

<header>myHeader</header>

</recipientList>

</route>

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.

273 CHAPTER 9 - PATTERN APPENDIX

from("direct:a").recipientList(header("myHeader")).ignoreInvalidEndpoints();

And in Spring XML its an attribute on the recipient list tag.

<route>

<header>myHeader</header>

</recipientList>

</route>

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.

<route>

<header>myHeader</header>

</recipientList>

</route>

CHAPTER 9 - PATTERN APPENDIX 274

Using custom thread pool

Available as of Camel 2.2

This is only needed when you use parallelProcessing. By default Camel uses a

thread pool with 10 threads. Notice this is subject to change when we overhaul thread pool

management and configuration later (hopefully in Camel 2.2).

You configure this just as you would with the custom aggregation strategy.

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.

275 CHAPTER 9 - PATTERN APPENDIX

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().

Example

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");

}

};

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

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

CHAPTER 9 - PATTERN APPENDIX 276

What does the splitter return?

The Splitter will by default return the last splitted message. 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.

<split>

<xpath>/invoice/lineItems</xpath>

</split>

</route>

</camelContext>

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.

<route>

<split>

</split>

</route>

</camelContext>

Splitting the body in Spring XML is a bit harder as you need to use the Simple language to

dictate this

<split>

</split>

277 CHAPTER 9 - PATTERN APPENDIX

Message Headers

The following headers is set on each Exchange that are split:

header type description

org.apache.camel.splitCounter int

Camel 1.x: A split counter that

increases for each Exchange being

split. The counter starts from 0.

org.apache.camel.splitSize int

Camel 1.x: The total number of

Exchanges that was splitted. This

header is not applied for stream based

splitting.

Exchange properties

The following properties is set on each Exchange that are split:

header type description

org.apache.camel.splitCounter int

Camel 1.6.2: A split counter that

increases for each Exchange being

split. The counter starts from 0.

org.apache.camel.splitSize int

Camel 1.6.2: The total number of

Exchanges that was splitted. This

header is not applied for stream

based splitting.

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.

CamelSplitComplete boolean Camel 2.4: Whether or not this

Exchange is the last.

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.

CHAPTER 9 - PATTERN APPENDIX 278

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

Available as of Camel 1.5

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");

Specifying a custom aggregation strategy

Available as of Camel 2.0

This is specified similar to the Aggregator.

Specifying a custom ThreadPoolExecutor

You can customize the underlying ThreadPoolExecutor used in the parallel splitter. In the Java

DSL try something like this:

Camel 1.x:

XPathBuilder xPathBuilder = new XPathBuilder("//foo/bar");

ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(8, 16, 0L,

TimeUnit.MILLISECONDS, new LinkedBlockingQueue());

from("activemq:my.queue").split(xPathBuilder, true,

threadPoolExecutor).to("activemq:my.parts");

In the Spring XML try this:

Available as of Camel 1.6.0

Listing 11.Listing 11. Spring DSLSpring DSL

279 CHAPTER 9 - PATTERN APPENDIX

<route>

<xpath>/invoice/lineItems</xpath>

</split>

</route>

</camelContext>

<!-- There's an easier way of specifying constructor args, just can't remember it

at the moment... old Spring syntax will do for now! -->

<constructor-arg index="0" value="8"/>

<constructor-arg index="1" value="16"/>

<constructor-arg index="2" value="0"/>

<constructor-arg index="3" value="MILLISECONDS"/>

<constructor-arg index="4"><bean

class="java.util.concurrent.LinkedBlockingQueue"/></constructor-arg>

</bean>

Camel 2.x:

XPathBuilder xPathBuilder = new XPathBuilder("//foo/bar");

ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(8, 16, 0L,

TimeUnit.MILLISECONDS, new LinkedBlockingQueue());

from("activemq:my.queue").split(xPathBuilder).parallelProcessing().executeService(threadPoolExecutor).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");

CHAPTER 9 - PATTERN APPENDIX 280

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<String> splitBody(String body) {

// since this is based on an unit test you can of cause

// use different logic for splitting as Camel have out

// 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<String> answer = new ArrayList<String>();

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<Message> 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<Message> answer = new ArrayList<Message>();

String[] parts = header.split(",");

for (String part : parts) {

DefaultMessage message = new DefaultMessage();

message.setHeader("user", part);

message.setBody(body);

answer.add(message);

}

return answer;

}

281 CHAPTER 9 - PATTERN APPENDIX

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

// 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

CHAPTER 9 - PATTERN APPENDIX 282

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

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)]

283 CHAPTER 9 - PATTERN APPENDIX

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

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:

<route>

</split>

</route>

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.

CHAPTER 9 - PATTERN APPENDIX 284

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

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

Mandatory AggregationStrategy which is used to merge the incoming Exchange with the existing already merged

exchanges. At first call the oldExchang parameter is null. On subsequent invocations the oldExchnage contains

the merged exchanges and newExchange is of course the new incoming Exchange.

strategyRef A reference to lookup the AggregationStrategy in the Registry.

completionSize

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

Time in millis that an aggregated exchange should be inactive before its complete. Camel has a background task that runs

once a minute to check for inactive aggregated exchanges. 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 can be used.

completionInterval

A repeating period in millis by which the aggregator will complete all current aggregated exchanges. Camel has a

background tasks which is trigger every period. You cannot use this option together with completionTimeout, only one

of the can be used.

completionPredicate A Predicate to indicate when an aggregated exchange is complete.

completionFromBatchConsumer false

This option is if the exchanges is 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.

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 avail 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 incomming 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 thrown an

Exception, but you can enable this option and ignore the situation instead.

closeCorrelationKeyOnCompletion

Whether or not too late Exchange 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 wont grown too big if you use a

log of different correlation keys.

aggregationRepository 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 Reference to lookup a aggregationRepository in the Registry.

285 CHAPTER 9 - PATTERN APPENDIX

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 not custom thread pool has been specified then

Camel creates a default pool with 10 concurrent threads.

executorService 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 Reference to lookup a executorService in the Registry

Exchange Properties

The following properties is set on each Exchange that are aggregated:

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 aggregate 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.

About completion

When aggregation Exchanges at some point you need to indicate that the aggregated exchanges

is complete, so they can be send out of the aggregator. Camel allows you to indicate

completion in various ways as follows:

▪completionTimeout - Is an inactivity timeout in which is triggered if no new exchanges

has been aggregated for that particular correlation key within the period.

▪completionInterval - Once every X period all the current aggregated exchanges is

completed.

▪completionSize - Is a number indicating that after X aggregated exchanges its

complete.

▪completionPredicate - Runs a Predicate when a new exchange is aggregated to

determine if we are complete or not

▪completionFromBatchConsumer - Special option for Batch Consumer which allows

you to complete when all the messages from the batch has been aggregated. |

Notice that all the completion ways are per correlation key. And you can combine them in any

way your like. Its basically the first which triggers that wins. So you can use a completion size

together with a completion timeout. Only completionTimeout and completionInterval cannot

be used at the same time.

CHAPTER 9 - PATTERN APPENDIX 286

Notice the completion is a mandatory option and must be provided to the aggregator. If not

provided Camel will thrown an Exception on startup.

Persistent AggregationRepository

The aggregator provides a pluggable repository which you can implement your own

org.apache.camel.spi.AggregationRepository.

If you need persistent repository then you can use the Camel HawtDB component.

Examples

See some examples from the old Aggregator which is somewhat similar to this new aggregator.

Using completionTimeout

In this example we want to aggregate all incoming messages and after 3 seconds of inactivity we

want the aggregation to complete. This is done using the completionTimeout option as

shown:

from("direct:start")

// aggregate all exchanges correlated by the id header.

// Aggregate them using the BodyInAggregatingStrategy strategy which

// and after 3 seconds of inactivity them timeout and complete the aggregation

// and send it to mock:aggregated

.aggregate(header("id"), new BodyInAggregatingStrategy()).completionTimeout(3000)

.to("mock:aggregated");

And the same example using Spring XML:

<route>

<simple>header.id</simple>

</correlationExpression>

</aggregate>

</route>

</camelContext>

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

287 CHAPTER 9 - PATTERN APPENDIX

Setting options in Spring XML

Many of the options are configurable as attributes on the <aggregate> tag when

using Spring XML.

Using completionSize

In this example we want to aggregate all incoming messages and when we have 3 messages

aggregated (in the same correlation group) we want the aggregation to complete. This is done

using the completionSize option as shown:

from("direct:start")

// aggregate all exchanges correlated by the id header.

// Aggregate them using the BodyInAggregatingStrategy strategy which

// and after 3 messages has been aggregated then complete the aggregation

// and send it to mock:aggregated

.aggregate(header("id"), new BodyInAggregatingStrategy()).completionSize(3)

.to("mock:aggregated");

And the same example using Spring XML:

<route>

<simple>header.id</simple>

</correlationExpression>

</aggregate>

</route>

</camelContext>

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

Using completionPredicate

In this example we want to aggregate all incoming messages and use a Predicate to determine

when we are complete. The Predicate can be evaluated using either the aggregated exchange

(default) or the incoming exchange. We will so both situations as examples. We start with the

default situation as shown:

from("direct:start")

// aggregate all exchanges correlated by the id header.

CHAPTER 9 - PATTERN APPENDIX 288

// Aggregate them using the BodyInAggregatingStrategy strategy which

// and when the aggregated body contains A+B+C then complete the aggregation

// and send it to mock:aggregated

.aggregate(header("id"), new

BodyInAggregatingStrategy()).completionPredicate(body().contains("A+B+C"))

.to("mock:aggregated");

And the same example using Spring XML:

<route>

<simple>header.id</simple>

</correlationExpression>

<simple>${body} contains 'A+B+C'</simple>

</completionPredicate>

</aggregate>

</route>

</camelContext>

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

And the other situation where we use the eagerCheckCompletion option to tell Camel to

use the incoming Exchange. Notice how we can just test in the completion predicate that the

incoming message is the END message:

from("direct:start")

// aggregate all exchanges correlated by the id header.

// Aggregate them using the BodyInAggregatingStrategy strategy

// do eager checking which means the completion predicate will use the incoming

exchange

// which allows us to trigger completion when a certain exchange arrived which is

the

// END message

.aggregate(header("id"), new BodyInAggregatingStrategy())

.eagerCheckCompletion().completionPredicate(body().isEqualTo("END"))

.to("mock:aggregated");

And the same example using Spring XML:

<route>

289 CHAPTER 9 - PATTERN APPENDIX

<simple>header.id</simple>

</correlationExpression>

</completionPredicate>

</aggregate>

</route>

</camelContext>

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

Using dynamic completionTimeout

In this example we want to aggregate all incoming messages and after a period of inactivity we

want the aggregation to complete. The period should be computed at runtime based on the

timeout header in the incoming messages. This is done using the completionTimeout

option as shown:

from("direct:start")

// aggregate all exchanges correlated by the id header.

// Aggregate them using the BodyInAggregatingStrategy strategy which

// and the timeout header contains the timeout in millis of inactivity them

timeout and complete the aggregation

// and send it to mock:aggregated

.aggregate(header("id"), new

BodyInAggregatingStrategy()).completionTimeout(header("timeout"))

.to("mock:aggregated");

And the same example using Spring XML:

<route>

<simple>header.id</simple>

</correlationExpression>

<header>timeout</header>

</completionTimeout>

</aggregate>

</route>

</camelContext>

CHAPTER 9 - PATTERN APPENDIX 290

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

Note: You can also add a fixed timeout value and Camel will fallback to use this value if the

dynamic value was null or 0.

Using dynamic completionSize

In this example we want to aggregate all incoming messages based on a dynamic size per

correlation key. The size is computed at runtime based on the mySize header in the incoming

messages. This is done using the completionSize option as shown:

from("direct:start")

// aggregate all exchanges correlated by the id header.

// Aggregate them using the BodyInAggregatingStrategy strategy which

// and the header mySize determines the number of aggregated messages should

trigger the completion

// and send it to mock:aggregated

.aggregate(header("id"), new

BodyInAggregatingStrategy()).completionSize(header("mySize"))

.to("mock:aggregated");

And the same example using Spring XML:

<route>

<simple>header.id</simple>

</correlationExpression>

<header>mySize</header>

</completionSize>

</aggregate>

</route>

</camelContext>

<bean id="aggregatorStrategy"

class="org.apache.camel.processor.BodyInAggregatingStrategy"/>

Note: You can also add a fixed size value and Camel will fallback to use this value if the

dynamic value was null or 0.

291 CHAPTER 9 - PATTERN APPENDIX

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.

See Also

▪Throttler

▪Aggregator

Delayer

The Delayer Pattern allows you to delay the delivery of messages to some destination.

Using the Fluent Builders

from("seda:b").delay(1000).to("mock:result");

So the above example will delay all messages received on seda:b 1 second before sending

them to mock:result.

You can of course use many different Expression languages such as XPath, XQuery, SQL or

various Scripting Languages. You can just delay things a fixed amount of time from the point at

which the delayer receives the message. For example to delay things 2 seconds

delayer(2000)

The above assume that the delivery order is maintained and that the messages are delivered in

delay order. If you want to reorder the messages based on delivery time, you can use the

Resequencer with this pattern. For example

from("activemq:someQueue").resequencer(header("MyDeliveryTime")).delay("MyRedeliveryTime").to("activemq:aDelayedQueue");

CHAPTER 9 - PATTERN APPENDIX 306

The Delayer in Camel 1.x works a bit differently than Camel 2.0 onwards.

In Camel 1.x the expression is used to calculate an absolute time in millis.

So if you want to wait 3 sec from now and want to use the expression for that you have to

set the absolute time as currentTimeInMillis() + 3000.

In Camel 2.0 the expression is a value in millis to wait from the current time, so the

expression should just be 3000.

However in both Camel 1.x and 2.0 you can use a long value for a fixed value to indicate the

delay in millis.

See the Spring DSL samples for Delayer in Camel 1.x vs. Camel 2.0.

Camel 2.0 - Spring DSL

The sample below demonstrates the delay in Spring DSL:

<route>

<delay>

<header>MyDelay</header>

</delay>

</route>

<route>

<delay>

</delay>

</route>

</camelContext>

Camel 1.x - Spring DSL

The delayer is using slightly different names in Camel 1.x:

</expression>

</delayer>

The empty tag </expression> is needed to fulfill the XSD validation as its an optional

element and we use JAXB annotations to generated the XSD in Camel and some combinations

is hard to auto generate with optional elements.

307 CHAPTER 9 - PATTERN APPENDIX

For further examples of this pattern in use you could look at the junit test case

Asynchronous delaying

Available as of Camel 2.4

You can let the Delayer use non blocking asynchronous delaying, which means Camel will

use a scheduler to schedule a task to be executed in the future. The task will then continue

routing. This allows the caller thread to not block and be able to service other messages etc.

From Java DSL

You use the asyncDelayed() to enable the async behavior.

from("activemq:queue:foo").delay(1000).asyncDelayed().to("activemq:aDelayedQueue");

From Spring XML

You use the asyncDelayed="true" attribute to enable the async behavior.

<route>

</delay>

</route>

Creating a custom delay

You can use an expression to determine when to send a message using something like this

from("activemq:foo").

delay().method("someBean","computeDelay").

to("activemq:bar");

then the bean would look like this...

public class SomeBean {

public long computeDelay() {

long delay = 0;

// use java code to compute a delay value in millis

return delay;

CHAPTER 9 - PATTERN APPENDIX 308

}

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.

Load Balancer

The Load Balancer Pattern allows you to delegate to one of a number of endpoints using a

variety of different load balancing policies.

Build in load balancing policies

Camel has out of the box the following policies:

Policy Description

Round

Robin

The exchanges is selected in a round robin fashion. This is a well known and

classic policy. This spreads the load even.

Random A random endpoint is selected for each exchange

Sticky

Sticky load balancing using an Expression to calculate a correlation key to

perform the sticky load balancing; rather like jsessionid in the web or

JMSXGroupID in JMS.

Topic Topic which sends to all destinations (rather like JMS Topics)

Failover Camel 2.0: In case of failures the exchange is tried on the next endpoint.

Round Robin

Camel 1.x behavior

The round robin load balancer can actually be used to failover with Camel 1.x. This is no longer

possible in Camel 2.x as the underlying Error Handler foundation has been significantly

overhauled in Camel 2.x. Frankly the round robin load balancer in Camel 1.x was not thought

to be used in a failover scenario.

Camel 2.x behavior

The round robin load balancer is not meant to work with failover, for that you should use the

dedicated failover load balancer. The round robin load balancer will only change to next

endpoint per message.

309 CHAPTER 9 - PATTERN APPENDIX

The round robin load balancer is statefull as it keeps state which endpoint to use next time.

Using the Fluent Builders

from("direct:start").loadBalance().

roundRobin().to("mock:x","mock:y","mock:z");

Using the Spring configuration

<route>

</loadBalance>

</route>

</camelContext>

So the above example will load balance requests from direct:start to one of the available

mock endpoint instances, in this case using a round robbin policy.

For further examples of this pattern in use you could look at the junit test case

Failover

Available as of Camel 2.0

The failover load balancer is capable of trying the next processor in case an Exchange failed

with an exception during processing.

You can configure the failover with a list of specific exception to only failover. If you do not

specify any exceptions it will failover over any exceptions. It uses the same strategy for

matching exceptions as the Exception Clause does for the onException.

It has the following options:

Option Type Default Description

CHAPTER 9 - PATTERN APPENDIX 310

inheritErrorHandler boolean true

Camel 2.3: Whether or not the Error

Handler configured on the route should

be used or not. You can disable it if you

want the failover to trigger immediately

and failover to the next endpoint. On

the other hand if you have this option

enabled, then Camel will first let the

Error Handler try to process the

message. The Error Handler may have

been configured to redelivery and use

delays between attempts. If you have

enabled a number of redeliveries then

Camel will try to redeliver to the

same endpoint, and only failover to

the next endpoint, when the Error

Handler is exhausted.

maximumFailoverAttempts int -1

Camel 2.3: A value to indicate after X

failver attempts we should exhaust (give

up). Use -1 to indicate newer give up

and always try to failover. Use 0 to

newer failover. And use e.g. 3 to

failover at most 3 times before giving

up. This option can be used whether or

not round robin is enabled or not.

roundRobin boolean false

Camel 2.3: Whether or not the

failover load balancer should

operate in round robin mode or not. If

not, then it will always start from the

first endpoint when a new message is to

be processed. In other words it restart

from the top for every message. If

round robin is enabled, then it keeps

state and will continue with the next

endpoint in a round robin fashion.

When using round robin it will not stick

to last known good endpoint, it will

always pick the next endpoint to use.

Camel 2.2 or older behavior

The current implement of failover load balancer is a simple logic which always tries the first

endpoint, and in case of an exception being thrown it tries the next in the list, and so forth. It

has no state, and the next message will thus always start with the first endpoint.

311 CHAPTER 9 - PATTERN APPENDIX

Camel 2.3 onwards behavior

The failover load balancer now supports round robin mode, which allows you to failover in

a round robin fashion. See the roundRobin option.

Here is a sample to failover only if a IOException related exception was thrown:

from("direct:start")

// here we will load balance if IOException was thrown

// any other kind of exception will result in the Exchange as failed

// to failover over any kind of exception we can just omit the exception

// in the failOver DSL

.loadBalance().failover(IOException.class)

.to("direct:x","direct:y","direct:z");

You can specify multiple exceptions to failover as the option is varargs, for instance:

// enable redelivery so failover can react

errorHandler(defaultErrorHandler().maximumRedeliveries(5));

from("direct:foo").

loadBalance().failover(IOException.class, MyOtherException.class)

.to("direct:a","direct:b");

Using failover in Spring DSL

Failover can also be used from Spring DSL and you configure it as:

<exception>java.io.IOException</exception>

<exception>com.mycompany.MyOtherException</exception>

</failover>

</loadBalance>

</route>

Using failover in round robin mode

An example using Java DSL:

from("direct:start")

// Use failover load balancer in stateful round robin mode

// which mean it will failover immediately in case of an exception

CHAPTER 9 - PATTERN APPENDIX 312

Redelivery must be enabled

In Camel 2.2 or older the failover load balancer requires you have enabled Camel

Error Handler to use redelivery. In Camel 2.3 onwards this is not required as such,

as you can mix and match. See the inheritErrorHandler option.

// as it does NOT inherit error handler. It will also keep retrying as

// its configured to newer exhaust.

.loadBalance().failover(-1, false,true).

to("direct:bad","direct:bad2","direct:good","direct:good2");

And the same example using Spring XML:

<route>

<!-- failover using stateful round robin,

which will keep retrying forever those 4 endpoints until success.

You can set the maximumFailoverAttempt to break out after X attempts -->

</loadBalance>

</route>

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.

Multicast

The Multicast allows to route the same message to a number of endpoints and process them in

a different way. The main difference between the Multicast and Splitter is that Splitter will split

the message into several pieces but the Multicast will not modify the request message.

Example

The following example shows how to take a request from the direct:a endpoint , then

multicast these request to direct:x,direct:y,direct:z.

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Disabled inheritErrorHandler

You can configure inheritErrorHandler=false if you want to failover to

the next endpoint as fast as possible. By disabling the Error Handler you ensure it

does not intervene which allows the failover load balancer to handle failover

asap. By also enabling roundRobin mode, then it will keep retrying until it

success. You can then configure the maximumFailoverAttempts option to a

high value to let it eventually exhaust (give up) and fail.

Using the Fluent Builders

from("direct:a").multicast().to("direct:x","direct:y","direct:z");

Stop processing in case of exception

Available as of Camel 2.1

The Multicast will by default continue to process the entire Exchange even in case one of the

multicasted messages will thrown an exception during routing.

For example if you want to multicast to 3 destinations and the 2nd destination fails by an

exception. What Camel does by default is to process the remainder destinations. 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")

.multicast()

.stopOnException().to("direct:foo","direct:bar","direct:baz")

.end()

.to("mock:result");

from("direct:foo").to("mock:foo");

from("direct:bar").process(new MyProcessor()).to("mock:bar");

from("direct:baz").to("mock:baz");

And using XML DSL you specify it as follows:

<route>

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</multicast>

</route>

<route>

</route>

<route>

</route>

<route>

</route>

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.

LOOP

The Loop allows to process the a message a number of times and possibly process them in a

different way. Useful mostly for testing.

For each iteration two properties are set on the Exchange that could be used by

processors down the pipeline to process the Message in different ways.

Property Description

CamelIterationCount Camel 1.x: Total number of iterations to be run

CamelIterationIndex Camel 1.x: Index of the current iteration (0 based)

CamelLoopSize Camel 2.0: Total number of loops

CamelLoopIndex Camel 2.0: Index of the current iteration (0 based)

that could be used by processors down the pipeline to process the Message in different ways.

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Examples

The following example shows how to take a request from the direct:x endpoint , then send

the message repetitively to mock:result. The number of times the message is sent is either

passed as an argument to loop(), or determined at runtime by evaluating an expression. The

expression must evaluate to an int, otherwise a RuntimeCamelException is thrown.

Using the Fluent Builders

Pass loop count as an argument

from("direct:a").loop(8).to("mock:result");

Use expression to determine loop count

from("direct:b").loop(header("loop")).to("mock:result");

Use expression to determine loop count

from("direct:c").loop().xpath("/hello/@times").to("mock:result");

Using the Spring XML Extensions

Pass loop count as an argument

<route>

<loop>

</loop>

</route>

Use expression to determine loop count

<route>

<loop>

</loop>

</route>

For further examples of this pattern in use you could look at one of the junit test case

CHAPTER 9 - PATTERN APPENDIX 316

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.

MESSAGE TRANSFORMATION

Content Enricher

Camel supports the Content Enricher from the EIP patterns using a Message Translator, an

artibrary Processor in the routing logic or using the enrich DSL element to enrich the message.

Content enrichment using a Message Translator or a Processor

Using the Fluent Builders

You can use Templating to consume a message from one destination, transform it with

something like Velocity or XQuery and then send it on to another destination. For example

using InOnly (one way messaging)

from("activemq:My.Queue").

to("velocity:com/acme/MyResponse.vm").

to("activemq:Another.Queue");

If you want to use InOut (request-reply) semantics to process requests on the My.Queue

queue on ActiveMQ with a template generated response, then sending responses back to the

JMSReplyTo Destination you could use this.

from("activemq:My.Queue").

to("velocity:com/acme/MyResponse.vm");

Here is a simple example using the DSL directly to transform the message body

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from("direct:start").setBody(body().append(" World!")).to("mock:result");

In this example we add our own Processor using explicit Java code

from("direct:start").process(new Processor() {

public void process(Exchange exchange) {

Message in = exchange.getIn();

in.setBody(in.getBody(String.class) + " World!");

}

}).to("mock:result");

Finally we can use Bean Integration to use any Java method on any bean to act as the

transformer

from("activemq:My.Queue").

beanRef("myBeanName","myMethodName").

to("activemq:Another.Queue");

For further examples of this pattern in use you could look at one of the JUnit tests

• TransformTest

• TransformViaDSLTest

Using Spring XML

<route>

</route>

Content enrichment using the enrich DSL element

Camel comes with two flavors of content enricher in the DSL

▪enrich

▪pollEnrich

enrich is using a Producer to obtain the additional data. It is usually used for Request Reply

messaging, for instance to invoke an external web service.

poolEnrich on the other hand is using a Polling Consumer to obtain the additional data. It is

usually used for Event Message messaging, for instance to read a file or download a FTP file.

This feature is available since Camel 2.0

Using the Fluent Builders

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AggregationStrategy aggregationStrategy = ...

from("direct:start")

.enrich("direct:resource", aggregationStrategy)

.to("direct:result");

from("direct:resource")

...

The content enricher (enrich) retrieves additional data from a resource endpoint in order to

enrich an incoming message (contained in the orginal exchange). An aggregation strategy is used

to combine the original exchange and the resource exchange. The first parameter of the

AggregationStrategy.aggregate(Exchange, Exchange) method corresponds

to the the original exchange, the second parameter the resource exchange. The results from

the resource endpoint are stored in the resource exchange's out-message. Here's an example

template for implementing an aggregation strategy.

public class ExampleAggregationStrategy implements AggregationStrategy {

public Exchange aggregate(Exchange original, Exchange resource) {

Object originalBody = original.getIn().getBody();

Object resourceResponse = resource.getOut().getBody();

Object mergeResult = ... // combine original body and resource response

if (original.getPattern().isOutCapable()) {

original.getOut().setBody(mergeResult);

}else {

original.getIn().setBody(mergeResult);

}

return original;

}

Using this template the original exchange can be of any pattern. The resource exchange created

by the enricher is always an in-out exchange.

Using Spring XML

The same example in the Spring DSL

<route>

</route>

<route>

...

</route>

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</camelContext>

Aggregation strategy is optional

The aggregation strategy is optional. If you do not provide it Camel will by default just use the

body obtained from the resource.

from("direct:start")

.enrich("direct:resource")

.to("direct:result");

In the route above the message send to the direct:result endpoint will contain the

output from the direct:resource as we do not use any custom aggregation.

And in Spring DSL you just omit the strategyRef attribute:

<route>

</route>

Content enrich using pollEnrich

The pollEnrich works just as the enrich however as it uses a Polling Consumer we have

3 methods when polling

▪receive

▪receiveNoWait

▪receive(timeout)

By default Camel will use the receiveNoWait.

If there is no data then the newExchange in the aggregation strategy is null.

You can pass in a timeout value that determines which method to use

▪timeout is -1 or negative then receive is selected

▪timeout is 0 then receiveNoWait is selected

▪otherwise receive(timeout) is selected

The timeout values is in millis.

The sample below reads a file based on a JMS message that contains a header with the filename.

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Data from current Exchange not used

pollEnrich does not access any data from the current Exchange which means

when polling it cannot use any of the existing headers you may have set on the

Exchange. For example you cannot set a filename in the Exchange.FILE_NAME

header and use pollEnrich to consume only that file. For that you must set the

filename in the endpoint URI.

from("activemq:queue:order")

.setHeader(Exchange.FILE_NAME, header("orderId"))

.pollEnrich("file://order/data/additional")

.to("bean:processOrder");

And if we want to wait at most 20 seconds for the file to be ready we can use a timeout:

from("activemq:queue:order")

.setHeader(Exchange.FILE_NAME, header("orderId"))

.pollEnrich("file://order/data/additional", 20000)

.to("bean:processOrder");

And yes pollEnrich also supports the aggregation strategy so we can pass it in as an

argument too:

.pollEnrich("file://order/data/additional", 20000, aggregationStrategy)

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.

Content Filter

Camel supports the Content Filter from the EIP patterns using one of the following mechanisms

in the routing logic to transform content from the inbound message.

• Message Translator

• invoking a Java bean

• Processor object

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A common way to filter messages is to use an Expression in the DSL like XQuery, SQL or

one of the supported Scripting Languages.

Using the Fluent Builders

Here is a simple example using the DSL directly

from("direct:start").setBody(body().append(" World!")).to("mock:result");

In this example we add our own Processor

from("direct:start").process(new Processor() {

public void process(Exchange exchange) {

Message in = exchange.getIn();

in.setBody(in.getBody(String.class) + " World!");

}

}).to("mock:result");

For further examples of this pattern in use you could look at one of the JUnit tests

• TransformTest

• TransformViaDSLTest

Using Spring XML

<route>

</route>

You can also use XPath to filter out part of the message you are interested in:

<route>

</route>

CHAPTER 9 - PATTERN APPENDIX 322

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.

Claim Check

The Claim Check from the EIP patterns allows you to replace message content with a claim

check (a unique key), which can be used to retrieve the message content at a later time. The

message content is stored temporarily in a persistent store like a database or file system. This

pattern is very useful when message content is very large (thus it would be expensive to send

around) and not all components require all information.

It can also be useful in situations where you cannot trust the information with an outside

party; in this case, you can use the Claim Check to hide the sensitive portions of data.

Available in Camel 1.5.

Example

In this example we want to replace a message body with a claim check, and restore the body at

a later step.

from("direct:start").to("bean:checkLuggage","mock:testCheckpoint",

"bean:dataEnricher","mock:result");

The example route is pretty simple - its just a Pipeline. In a real application you would have

some other steps where the mock:testCheckpoint endpoint is in the example.

The message is first sent to the checkLuggage bean which looks like

public static final class CheckLuggageBean {

public void checkLuggage(Exchange exchange, @Body String body, @XPath("/order/

@custId")String custId) {

// store the message body into the data store, using the custId as the claim

check

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dataStore.put(custId, body);

// add the claim check as a header

exchange.getIn().setHeader("claimCheck", custId);

// remove the body from the message

exchange.getIn().setBody(null);

}

This bean stores the message body into the data store, using the custId as the claim check. In

this example, we're just using a HashMap to store the message body; in a real application you

would use a database or file system, etc. Next the claim check is added as a message header for

use later. Finally we remove the body from the message and pass it down the pipeline.

The next step in the pipeline is the mock:testCheckpoint endpoint which is just used

to check that the message body is removed, claim check added, etc.

To add the message body back into the message, we use the dataEnricher bean which

looks like

public static final class DataEnricherBean {

public void addDataBackIn(Exchange exchange, @Header("claimCheck")String

claimCheck) {

// query the data store using the claim check as the key and add the data

// back into the message body

exchange.getIn().setBody(dataStore.get(claimCheck));

// remove the message data from the data store

dataStore.remove(claimCheck);

// remove the claim check header

exchange.getIn().removeHeader("claimCheck");

}

This bean queries the data store using the claim check as the key and then adds the data back

into the message. The message body is then removed from the data store and finally the claim

check is removed. Now the message is back to what we started with!

For full details, check the example source here:

camel-core/src/test/java/org/apache/camel/processor/ClaimCheckTest.java

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.

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Normalizer

Camel supports the Normalizer from the EIP patterns by using a Message Router in front of a

number of Message Translator instances.

Example

This example shows a Message Normalizer that converts two types of XML messages into a

common format. Messages in this common format are then filtered.

Using the Fluent Builders

// we need to normalize two types of incoming messages

from("direct:start")

.choice()

.when().xpath("/employee").to("bean:normalizer?method=employeeToPerson")

.when().xpath("/customer").to("bean:normalizer?method=customerToPerson")

.end()

.to("mock:result");

In this case we're using a Java bean as the normalizer. The class looks like this

public class MyNormalizer {

public void employeeToPerson(Exchange exchange, @XPath("/employee/name/text()")

String name) {

exchange.getOut().setBody(createPerson(name));

}

public void customerToPerson(Exchange exchange, @XPath("/customer/@name")String

name) {

exchange.getOut().setBody(createPerson(name));

}

private String createPerson(String name) {

return "<person name=\"" + name + "\"/>";

}

Using the Spring XML Extensions

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The same example in the Spring DSL

<route>

<when>

<xpath>/employee</xpath>

</when>

<when>

<xpath>/customer</xpath>

</when>

</choice>

</route>

</camelContext>

See Also

• Message Router

• Content Based Router

• Message Translator

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.

SORT

Available as of Camel 2.0

Sort can be used to sort a message. Imagine you consume text files and before processing

each file you want to be sure the content is sorted.

Sort will by default sort the body using a default comparator that handles numeric values or

uses the string representation. You can provide your own comparator, and even an expression

to return the value to be sorted. Sort requires the value returned from the expression

evaluation is convertible to java.util.List as this is required by the JDK sort operation.

CHAPTER 9 - PATTERN APPENDIX 326

Using from Java DSL

In the route below it will read the file content and tokenize by line breaks so each line can be

sorted.

from("file://inbox").sort(body().tokenize("\n")).to("bean:MyServiceBean.processLine");

You can pass in your own comparator as a 2nd argument:

from("file://inbox").sort(body().tokenize("\n"), new

MyReverseComparator()).to("bean:MyServiceBean.processLine");

Using from Spring DSL

In the route below it will read the file content and tokenize by line breaks so each line can be

sorted.

<route>

<sort>

</sort>

</route>

And to use our own comparator we can refer to it as a spring bean:

<route>

</sort>

</route>

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.

327 CHAPTER 9 - PATTERN APPENDIX

MESSAGING ENDPOINTS

Messaging Mapper

Camel supports the Messaging Mapper from the EIP patterns by using either Message Translator

pattern or the Type Converter module.

See Also

▪POJO Consuming

▪Batch Consumer

Competing Consumers

Camel supports the Competing Consumers from the EIP patterns using a few different

components.

You can use the following components to implement competing consumers:-

• SEDA for SEDA based concurrent processing using a thread pool

• JMS for distributed SEDA based concurrent processing with queues which support

reliable load balancing, failover and clustering.

Enabling Competing Consumers with JMS

To enable Competing Consumers you just need to set the concurrentConsumers

property on the JMS endpoint.

For example

335 CHAPTER 9 - PATTERN APPENDIX

from("jms:MyQueue?concurrentConsumers=5").bean(SomeBean.class);

Or just run multiple JVMs of any ActiveMQ or JMS route

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.

Message Dispatcher

Camel supports the Message Dispatcher from the EIP patterns using various approaches.

You can use a component like JMS with selectors to implement a Selective Consumer as the

Message Dispatcher implementation. Or you can use an Endpoint as the Message Dispatcher

itself and then use a Content Based Router as the Message Dispatcher.

See Also

• JMS

• Selective Consumer

• Content Based Router

• Endpoint

CHAPTER 9 - PATTERN APPENDIX 336

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.

Selective Consumer

The Selective Consumer from the EIP patterns can be implemented in two ways

The first solution is to provide a Message Selector to the underlying URIs when creating

your consumer. For example when using JMS you can specify a selector parameter so that the

message broker will only deliver messages matching your criteria.

The other approach is to use a Message Filter which is applied; then if the filter matches the

message your consumer is invoked as shown in the following example

Using the Fluent Builders

RouteBuilder builder = new RouteBuilder() {

public void configure() {

errorHandler(deadLetterChannel("mock:error"));

from("seda:a").filter(header("foo").isEqualTo("bar")).process(myProcessor);

}

};

Using the Spring XML Extensions

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

</filter>

</route>

</camelContext>

337 CHAPTER 9 - PATTERN APPENDIX

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.

Durable Subscriber

Camel supports the Durable Subscriber from the EIP patterns using the JMS component which

supports publish & subscribe using Topics with support for non-durable and durable

subscribers.

Another alternative is to combine the Message Dispatcher or Content Based Router with

File or JPA components for durable subscribers then something like Queue for non-durable.

See Also

• JMS

• File

• JPA

• Message Dispatcher

• Selective Consumer

• Content Based Router

• Endpoint

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.

CHAPTER 9 - PATTERN APPENDIX 338

Idempotent Consumer

The Idempotent Consumer from the EIP patterns is used to filter out duplicate messages.

This pattern is implemented using the IdempotentConsumer class. This uses an Expression

to calculate a unique message ID string for a given message exchange; this ID can then be

looked up in the MessageIdRepository to see if it has been seen before; if it has the message is

consumed; if its not then the message is processed and the ID is added to the repository.

The Idempotent Consumer essentially acts like a Message Filter to filter out duplicates.

Camel will add the message id eagerly to the repository to detect duplication also for

Exchanges currently in progress.

On completion Camel will remove the message id from the repository if the Exchange failed,

otherwise it stays there.

Options

The Idempotent Consumer has the following options:

Option Default Description

eager true

Camel 2.0: Eager controls whether Camel adds the message to the

repository before or after the exchange has been processed. If

enabled before then Camel will be able to detect duplicate messages

even when messages are currently in progress. By disabling Camel

will only detect duplicates when a message has successfully been

processed.

Using the Fluent Builders

The following example will use the header myMessageId to filter out duplicates

RouteBuilder builder = new RouteBuilder() {

public void configure() {

errorHandler(deadLetterChannel("mock:error"));

from("seda:a").idempotentConsumer(header("myMessageId"),

MemoryIdempotentRepository.memoryIdempotentRepository(200))

.to("seda:b");

}

};

The above example will use an in-memory based MessageIdRepository which can easily run out

of memory and doesn't work in a clustered environment. So you might prefer to use the JPA

based implementation which uses a database to store the message IDs which have been

processed

from("direct:start").idempotentConsumer(

header("messageId"),

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jpaMessageIdRepository(lookup(JpaTemplate.class), PROCESSOR_NAME)

).to("mock:result");

In the above example we are using the header messageId to filter out duplicates and using

the collection myProcessorName to indicate the Message ID Repository to use. This name

is important as you could process the same message by many different processors; so each may

require its own logical Message ID Repository.

For further examples of this pattern in use you could look at the junit test case

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.

Transactional Client

Camel recommends supporting the Transactional Client from the EIP patterns using spring

transactions.

Transaction Oriented Endpoints (Camel Toes) like JMS support using a transaction for both

inbound and outbound message exchanges. Endpoints that support transactions will participate

in the current transaction context that they are called from.

You should use the SpringRouteBuilder to setup the routes since you will need to setup the

spring context with the TransactionTemplates that will define the transaction manager

configuration and policies.

For inbound endpoint to be transacted, they normally need to be configured to use a Spring

PlatformTransactionManager. In the case of the JMS component, this can be done by looking it

up in the spring context.

You first define needed object in the spring configuration.

<bean id="jmsTransactionManager"

class="org.springframework.jms.connection.JmsTransactionManager">

</bean>

<bean id="jmsConnectionFactory"

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Convention over configuration

In Camel 2.0 onwards we have improved the default configuration reducing the

number of Spring XML gobble you need to configure.

In this wiki page we provide the Camel 1.x examples and the same 2.0 example that

requires less XML setup.

Configuration of Redelivery

The redelivery in transacted mode is not handled by Camel but by the backing

system (the transaction manager). In such cases you should resort to the backing

system how to configure the redelivery.

class="org.apache.activemq.ActiveMQConnectionFactory">

</bean>

Then you look them up and use them to create the JmsComponent.

PlatformTransactionManager transactionManager = (PlatformTransactionManager)

spring.getBean("jmsTransactionManager");

ConnectionFactory connectionFactory = (ConnectionFactory)

spring.getBean("jmsConnectionFactory");

JmsComponent component = JmsComponent.jmsComponentTransacted(connectionFactory,

transactionManager);

component.getConfiguration().setConcurrentConsumers(1);

ctx.addComponent("activemq", component);

Transaction Policies

Outbound endpoints will automatically enlist in the current transaction context. But what if you

do not want your outbound endpoint to enlist in the same transaction as your inbound

endpoint? The solution is to add a Transaction Policy to the processing route. You first have to

define transaction policies that you will be using. The policies use a spring TransactionTemplate

under the covers for declaring the transaction demarcation to use. So you will need to add

something like the following to your spring xml:

<bean id="PROPAGATION_REQUIRED"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

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<bean id="PROPAGATION_REQUIRES_NEW"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

Then in your SpringRouteBuilder, you just need to create new SpringTransactionPolicy objects

for each of the templates.

public void configure() {

...

Policy requried = bean(SpringTransactionPolicy.class, "PROPAGATION_REQUIRED"));

Policy requirenew = bean(SpringTransactionPolicy.class,

"PROPAGATION_REQUIRES_NEW"));

...

}

Once created, you can use the Policy objects in your processing routes:

// Send to bar in a new transaction

from("activemq:queue:foo").policy(requirenew).to("activemq:queue:bar");

// Send to bar without a transaction.

from("activemq:queue:foo").policy(notsupported ).to("activemq:queue:bar");

Camel 1.x - Database Sample

In this sample we want to ensure that two endpoints is under transaction control. These two

endpoints inserts data into a database.

The sample is in its full as a unit test.

First of all we setup the usual spring stuff in its configuration file. Here we have defined a

DataSource to the HSQLDB and a most importantly

the Spring DataSoruce TransactionManager that is doing the heavy lifting of ensuring our

transactional policies. You are of course free to use any

of the Spring based TransactionMananger, eg. if you are in a full blown J2EE container you could

use JTA or the WebLogic or WebSphere specific managers.

We use the required transaction policy that we define as the PROPOGATION_REQUIRED

spring bean. And as last we have our book service bean that does the business logic

and inserts data in the database as our core business logic.

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<bean id="dataSource"

class="org.springframework.jdbc.datasource.DriverManagerDataSource">

</bean>

<bean id="txManager"

class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

</bean>

<bean id="PROPAGATION_REQUIRED"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

</bean>

In our Camel route that is Java DSL based we setup the transactional policy, wrapped as a

Policy.

// Notice that we use the SpringRouteBuilder that has a few more features than

// the standard RouteBuilder

return new SpringRouteBuilder() {

public void configure() throws Exception {

// lookup the transaction policy

SpringTransactionPolicy required = lookup("PROPAGATION_REQUIRED",

SpringTransactionPolicy.class);

// use this error handler instead of DeadLetterChannel that is the default

// Notice: transactionErrorHandler is in SpringRouteBuilder

if (isUseTransactionErrorHandler()) {

// useTransactionErrorHandler is only used for unit testing to reuse code

// for doing a 2nd test without this transaction error handler, so ignore

// this. For spring based transaction, end users are encouraged to use the

// transaction error handler instead of the default DeadLetterChannel.

errorHandler(transactionErrorHandler(required));

}

Then we are ready to define our Camel routes. We have two routes: 1 for success conditions,

and 1 for a forced rollback condition.

This is after all based on a unit test.

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// set the required policy for this route

from("direct:okay").policy(required).

setBody(constant("Tiger in Action")).beanRef("bookService").

setBody(constant("Elephant in Action")).beanRef("bookService");

// set the required policy for this route

from("direct:fail").policy(required).

setBody(constant("Tiger in Action")).beanRef("bookService").

setBody(constant("Donkey in Action")).beanRef("bookService");

As its a unit test we need to setup the database and this is easily done with Spring JdbcTemplate

Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20

And our core business service, the book service, will accept any books except the Donkeys.

public class BookService {

private SimpleJdbcTemplate jdbc;

public BookService() {

}

public void setDataSource(DataSource ds) {

jdbc = new SimpleJdbcTemplate(ds);

}

public void orderBook(String title) throws Exception {

if (title.startsWith("Donkey")) {

throw new IllegalArgumentException("We don't have Donkeys, only Camels");

}

// create new local datasource to store in DB

jdbc.update("insert into books (title) values (?)", title);

}

Then we are ready to fire the tests. First to commit condition:

public void testTransactionSuccess() throws Exception {

template.sendBody("direct:okay","Hello World");

int count = jdbc.queryForInt("select count(*) from books");

assertEquals("Number of books", 3, count);

}

And lastly the rollback condition since the 2nd book is a Donkey book:

public void testTransactionRollback() throws Exception {

try {

template.sendBody("direct:fail","Hello World");

CHAPTER 9 - PATTERN APPENDIX 344

}catch (RuntimeCamelException e) {

// expected as we fail

assertIsInstanceOf(RuntimeCamelException.class, e.getCause());

assertTrue(e.getCause().getCause() instanceof IllegalArgumentException);

assertEquals("We don't have Donkeys, only Camels",

e.getCause().getCause().getMessage());

}

int count = jdbc.queryForInt("select count(*) from books");

assertEquals("Number of books", 1, count);

}

Camel 1.x - JMS Sample

In this sample we want to listen for messages on a queue and process the messages with our

business logic java code and send them along. Since its based on a unit test the destination is a

mock endpoint.

This time we want to setup the camel context and routes using the Spring XML syntax.

<camel:camelContext id="myroutes">

<camel:route errorHandlerRef="errorHandler">

<camel:from uri="activemq:queue:okay"/>

<camel:transacted ref="PROPAGATION_REQUIRED"/>

<camel:process ref="myProcessor"/>

<camel:to uri="mock:result"/>

</camel:route>

</camel:camelContext>

<bean id="myProcessor"

class="org.apache.camel.component.jms.tx.JMSTransactionalClientTest$MyProcessor"/>

Since the rest is standard XML stuff its nothing fancy now for the reader:

<bean id="errorHandler"

class="org.apache.camel.spring.spi.TransactionErrorHandlerBuilder">

</bean>

<property name="brokerURL"

value="vm://localhost?broker.persistent=false&broker.useJmx=false"/>

345 CHAPTER 9 - PATTERN APPENDIX

</bean>

<bean id="jmsTransactionManager"

class="org.springframework.jms.connection.JmsTransactionManager">

</bean>

</bean>

</bean>

<bean id="PROPAGATION_REQUIRED"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

Our business logic is set to handle the incomming messages and fail the first two times. When

its a success it responds with a Bye World message.

public static class MyProcessor implements Processor {

private int count;

public void process(Exchange exchange) throws Exception {

if (++count <= 2) {

throw new IllegalArgumentException("Forced Exception number " + count + ",

please retry");

}

exchange.getIn().setBody("Bye World");

exchange.getIn().setHeader("count", count);

}

And our unit test is tested with this java code. Notice that we expect the Bye World

message to be delivered at the 3rd attempt.

MockEndpoint mock = getMockEndpoint("mock:result");

mock.expectedMessageCount(1);

mock.expectedBodiesReceived("Bye World");

// success at 3rd attempt

mock.message(0).header("count").isEqualTo(3);

template.sendBody("activemq:queue:okay","Hello World");

mock.assertIsSatisfied();

CHAPTER 9 - PATTERN APPENDIX 346

Camel 1.x - Spring based configuration

In Camel 1.4 we have introduced the concept of configuration of the error handlers using

spring XML configuration. The sample below demonstrates that you can configure transaction

error handlers in Spring XML as spring beans. These can then be set as global, per route based

or per policy based error handler. The latter has been demonstrated in the samples above. This

sample is the database sample configured in Spring XML.

Notice that we have defined two error handler, one per route. The first route uses the

transaction error handler, and the 2nd uses no error handler at all.

<camel:camelContext id="myroutes">

<!-- here we refer to our transaction error handler we define in this Spring XML

file -->

<camel:route errorHandlerRef="transactionErrorHandler">

<camel:from uri="activemq:queue:okay"/>

<camel:transacted ref="required"/>

<camel:process ref="myProcessor"/>

<camel:to uri="mock:result"/>

</camel:route>

<!-- this route doens't use error handler, in fact the spring bean with id

noErrorHandler -->

<camel:route errorHandlerRef="noErrorHandler">

<camel:from uri="activemq:queue:bad"/>

<camel:to uri="log:bad"/>

</camel:route>

</camel:camelContext>

The following snippet is the Spring XML configuration to setup the error handlers in pure

spring XML:

</bean>

<bean id="PROPAGATION_REQUIRED"

class="org.springframework.transaction.support.TransactionTemplate">

</bean>

347 CHAPTER 9 - PATTERN APPENDIX

<bean id="transactionErrorHandler"

class="org.apache.camel.spring.spi.TransactionErrorHandlerBuilder">

</bean>

DelayPolicy (@deprecated)

DelayPolicy is a new policy introduced in Camel 1.5, to replaces the RedeliveryPolicy used in

Camel 1.4. Notice the transactionErrorHandler can be configured with a DelayPolicy

to set a fixed delay in millis between each redelivery attempt. Camel does this by sleeping the

delay until transaction is marked for rollback and the caused exception is rethrown.

This allows a simple redelivery interval that can be configured for development mode or

light production to avoid a rapid redelivery strategy that can exhaust a system that constantly

fails.

The DelayPolicy is @deprecated and removed in Camel 2.0. All redelivery configuration

should be configured on the back system.

We strongly recommend that you configure the backing system for

correct redelivery policy in your environment.

Camel 2.0 - Database Sample

In this sample we want to ensure that two endpoints is under transaction control. These two

endpoints inserts data into a database.

The sample is in its full as a unit test.

First of all we setup the usual spring stuff in its configuration file. Here we have defined a

DataSource to the HSQLDB and a most importantly

the Spring DataSoruce TransactionManager that is doing the heavy lifting of ensuring our

transactional policies. You are of course free to use any

of the Spring based TransactionMananger, eg. if you are in a full blown J2EE container you could

use JTA or the WebLogic or WebSphere specific managers.

As we use the new convention over configuration we do not need to configure a

transaction policy bean, so we do not have any PROPAGATION_REQUIRED beans.

All the beans needed to be configured is standard Spring beans only, eg. there are no Camel

specific configuration at all.

<bean id="dataSource"

CHAPTER 9 - PATTERN APPENDIX 348

class="org.springframework.jdbc.datasource.DriverManagerDataSource">

</bean>

<bean id="txManager"

class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

</bean>

</bean>

Then we are ready to define our Camel routes. We have two routes: 1 for success conditions,

and 1 for a forced rollback condition.

This is after all based on a unit test. Notice that we mark each route as transacted using the

transacted tag.

<route>

<!-- we mark this route as transacted. Camel will lookup the spring

transaction manager

and use it by default. We can optimally pass in arguments to specify a

policy to use

that is configured with a spring transaction manager of choice. However

Camel supports

convention over configuration as we can just use the defaults out of the

box and Camel

that suites in most situations -->

<constant>Tiger in Action</constant>

</setBody>

<constant>Elephant in Action</constant>

</setBody>

</route>

<route>

349 CHAPTER 9 - PATTERN APPENDIX

<constant>Tiger in Action</constant>

</setBody>

<constant>Donkey in Action</constant>

</setBody>

</route>

</camelContext>

That is all that is needed to configure a Camel route as being transacted. Just remember to use

the transacted DSL. The rest is standard Spring XML to setup the transaction manager.

Camel 2.0 - JMS Sample

In this sample we want to listen for messages on a queue and process the messages with our

business logic java code and send them along. Since its based on a unit test the destination is a

mock endpoint.

First we configure the standard Spring XML to declare a JMS connection factory, a JMS

transaction manager and our ActiveMQ component that we use in our routing.

<property name="brokerURL"

value="vm://localhost?broker.persistent=false&broker.useJmx=false"/>

</bean>

<bean id="jmsTransactionManager"

class="org.springframework.jms.connection.JmsTransactionManager">

</bean>

<!-- if not provided then Camel will automatic use a JmsTransactionManager,

however if you

for instance use a JTA transaction manager then you must configure it -->

</bean>

And then we configure our routes. Notice that all we have to do is mark the route as

transacted using the transacted tag.

CHAPTER 9 - PATTERN APPENDIX 350

<route>

</route>

</camelContext>

<bean id="myProcessor"

class="org.apache.camel.component.jms.tx.JMSTransactionalClientTest$MyProcessor"/>

USING MULTIPLE ROUTES WITH DIFFERENT

PROPAGATION BEHAVIORS

Available as of Camel 2.2

Suppose you want to route a message through two routes and by which the 2nd route should

run in its own transaction. How do you do that? You use propagation behaviors for that where

you configure it as follows:

▪The first route use PROPAGATION_REQUIRED

▪The second route use PROPAGATION_REQUIRES_NEW

This is configured in the Spring XML file:

<bean id="PROPAGATION_REQUIRED"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

<bean id="PROPAGATION_REQUIRES_NEW"

class="org.apache.camel.spring.spi.SpringTransactionPolicy">

</bean>

Then in the routes you use transacted DSL to indicate which of these two propagations it uses.

from("direct:mixed")

// using required

.transacted("PROPAGATION_REQUIRED")

// all these steps will be okay

.setBody(constant("Tiger in Action")).beanRef("bookService")

.setBody(constant("Elephant in Action")).beanRef("bookService")

351 CHAPTER 9 - PATTERN APPENDIX

Transaction error handler

When a route is marked as transacted using transacted Camel will automatic use

the TransactionErrorHandler as Error Handler. It supports basically the same

feature set as the DefaultErrorHandler, so you can for instance use Exception

Clause as well.

.setBody(constant("Lion in Action")).beanRef("bookService")

// continue on route 2

.to("direct:mixed2");

from("direct:mixed2")

// using a different propagation which is requires new

.transacted("PROPAGATION_REQUIRES_NEW")

// tell Camel that if this route fails then only rollback this last route

// by using (rollback only *last*)

.onException(Exception.class).markRollbackOnlyLast().end()

// this step will be okay

.setBody(constant("Giraffe in Action")).beanRef("bookService")

// this step will fail with donkey

.setBody(constant("Donkey in Action")).beanRef("bookService");

Notice how we have configured the onException in the 2nd route to indicate in case of any

exceptions we should handle it and just rollback this transaction.

This is done using the markRollbackOnlyLast which tells Camel to only do it for the

current transaction and not globally.

See Also

• Error handling in Camel

• TransactionErrorHandler

• Error Handler

• JMS

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.

CHAPTER 9 - PATTERN APPENDIX 352

Messaging Gateway

Camel has several endpoint components that support the Messaging Gateway from the EIP

patterns.

Components like Bean and CXF provide a a way to bind a Java interface to the message

exchange.

However you may want to read the Using CamelProxy documentation as a true Messaging

Gateway EIP solution.

Another approach is to use @Produce which you can read about in POJO Producing which

also can be used as a Messaging Gateway EIP solution.

See Also

• Bean

• CXF

• Using CamelProxy

• POJO Producing

• Spring Remoting

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.

Service Activator

Camel has several endpoint components that support the Service Activator from the EIP

patterns.

353 CHAPTER 9 - PATTERN APPENDIX

Components like Bean, CXF and Pojo provide a a way to bind the message exchange to a

Java interface/service where the route defines the endpoints and wires it up to the bean.

In addition you can use the Bean Integration to wire messages to a bean using annotation.

See Also

• Bean

• Pojo

• CXF

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.

SYSTEM MANAGEMENT

Detour

The Detour from the EIP patterns allows you to send messages through additional steps if a

control condition is met. It can be useful for turning on extra validation, testing, debugging code

when needed.

Available in Camel 1.5.

CHAPTER 9 - PATTERN APPENDIX 354

Example

In this example we essentially have a route like

from("direct:start").to("mock:result") with a conditional detour to the

mock:detour endpoint in the middle of the route..

from("direct:start").choice()

.when().method("controlBean","isDetour").to("mock:detour").end()

.to("mock:result");

whether the detour is turned on or off is decided by the ControlBean. So, when the detour

is on the message is routed to mock:detour and then mock:result. When the detour is

off, the message is routed to mock:result.

For full details, check the example source here:

camel-core/src/test/java/org/apache/camel/processor/DetourTest.java

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.

Wire Tap

The Wire Tap from the EIP patterns allows you to route messages to a separate tap location

while it is forwarded to the ultimate destination.

WireTap node

Available as of Camel 2.0

In Camel 2.0 we have introduced a new wireTap node for properly doing wire taps.

Camel will copy the original Exchange and set its Exchange Pattern to InOnly as we want the

tapped Exchange to be sent as a fire and forget style. The tapped Exchange is then send in a

separate thread so it can run in parallel with the original

We have extended the wireTap to support two flavors when tapping an Exchange

355 CHAPTER 9 - PATTERN APPENDIX

▪send a copy of the original Exchange (the traditional wire tap)

▪send a new Exchange, allowing you to populate the Exchange beforehand

Sending a copy (traditional wire tap)

Using the Fluent Builders

from("direct:start")

.to("log:foo")

.wireTap("direct:tap")

.to("mock:result");

Using the Spring XML Extensions

<route>

</route>

Sending a new Exchange

Using the Fluent Builders

Camel supports either a processor or an Expression to populate the new Exchange. Using

processor gives you full power how the Exchange is populated as you can set properties,

headers etc. The Expression can only be used to set the IN body.

From Camel 2.3 onwards the Expression or Processor is pre populated with a copy of the

original Exchange which allows you to access the original message when you prepare the new

Exchange to be sent. You can use the copy option to indicate if you want this or not (default is

enabled). If your turn copy=false then it works as in Camel 2.2 or older, where the

Exchange always will be empty.

Below is the processor variation shown. This example is from Camel 2.3, where we disable

copy by passing in false. This will create a new empty Exchange.

from("direct:start")

.wireTap("direct:foo",false,new Processor() {

public void process(Exchange exchange) throws Exception {

exchange.getIn().setBody("Bye World");

exchange.getIn().setHeader("foo","bar");

}

}).to("mock:result");

CHAPTER 9 - PATTERN APPENDIX 356

from("direct:foo").to("mock:foo");

And the Expression variation. This example is from Camel 2.3, where we disable copy by

passing in false. This will create a new empty Exchange.

from("direct:start")

.wireTap("direct:foo",false, constant("Bye World"))

.to("mock:result");

from("direct:foo").to("mock:foo");

Using the Spring XML Extensions

The processor variation, notice we use a processorRef attribute to refer to a spring bean

with this id:

<route>

</route>

And the Expression variation, where the expression is defined in the body tag:

<route>

<body><constant>Bye World</constant></body>

</wireTap>

</route>

And this variation accesses the body of the original message and creates a new Exchange which

is based on the Expression.

It will create a new Exchange and have the body contain "Bye ORIGINAL BODY MESSAGE

HERE"

<route>

</wireTap>

</route>

357 CHAPTER 9 - PATTERN APPENDIX

Camel 1.x

The following example shows how to route a request from an input queue:a endpoint to the

wire tap location queue:tap it is received by queue:b

Using the Fluent Builders

RouteBuilder builder = new RouteBuilder() {

public void configure() {

errorHandler(deadLetterChannel("mock:error"));

from("seda:a").multicast().to("seda:tap","seda:b");

}

};

Using the Spring XML Extensions

<camelContext errorHandlerRef="errorHandler" streamCache="false" id="camel"

xmlns="http://camel.apache.org/schema/spring">

<route>

</multicast>

</route>

</camelContext>

Further Example

For another example of this pattern in use you could look at the wire tap test case.

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.

LOG

How can I log processing a Message?

Camel provides many ways to log processing a message. Here is just some examples:

▪You can use the Log component which logs the Message content.

▪You can use the Tracer which trace logs message flow.

▪You can also use a Processor or Bean and log from Java code.

CHAPTER 9 - PATTERN APPENDIX 358

▪You can use the log DSL.

Using log DSL

And in Camel 2.2 you can use the log DSL which allows you to use Simple language to

construct a dynamic message which gets logged.

For example you can do

from("direct:start").log("Processing ${id}").to("bean:foo");

Which will construct a String message at runtime using the Simple language. The log message

will by logged at INFO level using the route id as the log name. By default a route is named

route-1,route-2 etc. But you can use the routeId("myCoolRoute") to set a route

name of choice.

The log DSL have overloaded methods to set the logging level and/or name as well.

from("direct:start").log(LoggingLevel.DEBUG, "Processing ${id}").to("bean:foo");

For example you can use this to log the file name being processed if you consume files.

from("file://target/files").log(LoggingLevel.DEBUG, "Processing file

${file:name}").to("bean:foo");

Using log DSL from Spring

In Spring DSL its also easy to use log DSL as shown below:

</route>

The log tag has attributes to set the message,loggingLevel and logName. For example:

</route>

359 CHAPTER 9 - PATTERN APPENDIX

Difference between log in the DSL and Log component

The log DSL is much lighter and meant for logging human logs such as Starting

to do ... etc. It can only log a message based on the Simple language. On the

other hand Log component is a full fledged component which involves using

endpoints and etc. The Log component is meant for logging the Message itself and

you have many URI options to control what you would like to be logged.

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.

CHAPTER 9 - PATTERN APPENDIX 360

CHAPTER 10

°°°°

Component Appendix

There now follows the documentation on each Camel component.

ACTIVEMQ COMPONENT

The ActiveMQ component allows messages to be sent to a JMS Queue or Topic; or messages

to be consumed from a JMS Queue or Topic using Apache ActiveMQ.

This component is based on the JMS Component and uses Spring's JMS support for

declarative transactions, using Spring's JmsTemplate for sending and a

MessageListenerContainer for consuming. All the options from the JMS component

also applies for this component.

To use this component make sure you have the activemq.jar or activemq-

core.jar on your classpath along with any Camel dependencies such as camel-core.jar,

camel-spring.jar and camel-jms.jar.

URI format

activemq:[queue:|topic:]destinationName

Where destinationName is an ActiveMQ queue or topic name. By default, the

destinationName is interpreted as a queue name. For example, to connect to the queue,

FOO.BAR, use:

activemq:FOO.BAR

You can include the optional queue: prefix, if you prefer:

activemq:queue:FOO.BAR

To connect to a topic, you must include the topic: prefix. For example, to connect to the

topic, Stocks.Prices, use:

361 CHAPTER 10 - COMPONENT APPENDIX

activemq:topic:Stocks.Prices

Options

See Options on the JMS component as all these options also apply for this component.

Configuring the Connection Factory

The following test case shows how to add an ActiveMQComponent to the CamelContext using

the activeMQComponent() method while specifying the brokerURL used to connect to

ActiveMQ

camelContext.addComponent("activemq",

activeMQComponent("vm://localhost?broker.persistent=false"));

Configuring the Connection Factory using Spring XML

You can configure the ActiveMQ broker URL on the ActiveMQComponent as follows

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.0.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd">

</camelContext>

</bean>

</beans>

Using connection pooling

When sending to an ActiveMQ broker using Camel it's recommended to use a pooled

connection factory to handle efficient pooling of JMS connections, sessions and producers. This

is documented in the page ActiveMQ Spring Support .

You can grab ActiveMQ's

org.apache.activemq.pool.PooledConnectionFactory with maven:

CHAPTER 10 - COMPONENT APPENDIX 362

<groupId>org.apache.activemq</groupId>

<artifactId>activemq-pool</artifactId>

</dependency>

And then setup the activemq Camel component as follows:

<bean id="jmsConnectionFactory"

class="org.apache.activemq.ActiveMQConnectionFactory">

</bean>

<bean id="pooledConnectionFactory"

class="org.apache.activemq.pool.PooledConnectionFactory">

</bean>

</bean>

<bean id="activemq"

class="org.apache.activemq.camel.component.ActiveMQComponent">

</bean>

Invoking MessageListener POJOs in a Camel route

The ActiveMQ component also provides a helper Type Converter from a JMS MessageListener

to a Processor. This means that the Bean component is capable of invoking any JMS

MessageListener bean directly inside any route.

So for example you can create a MessageListener in JMS like this....

public class MyListener implements MessageListener {

public void onMessage(Message jmsMessage) {

// ...

}

Then use it in your Camel route as follows

363 CHAPTER 10 - COMPONENT APPENDIX

from("file://foo/bar").

bean(MyListener.class);

That is, you can reuse any of the Camel Components and easily integrate them into your JMS

MessageListener POJO!

Consuming Advisory Messages

ActiveMQ can generates Advisory messages which are put in topics that you can consume. Such

messages can help you to send alarm in case you detect slow consumers

or to build statistics (nber of messages/produced per day, ...). The following Spring DSL example

shows you how to read messages from Connection Topic :

The route start by reading the topic : ActiveMQ.Advisory.Connection. To watch another

topic, simply change the name according to the name provided in ActiveMQ Advisory Messages

documentation. The parameter mapJmsMessage=false allows to convert the

org.apache.activemq.command.ActiveMqMessage object from the jms queue.

Next, the body received is converted into a String for the example purpose and a carriage

return is added. Finally, the string is added to a file

<route>

</transform>

<to uri="file://data/activemq/

?fileExist=Append&fileName=advisoryConnection-${date:now:yyyyMMdd}.txt" />

</route>

If you produce consume a message on a queue, you should see the following files under data/

activemq folder :

advisoryConnection-20100312.txt

advisoryProducer-20100312.txt

and containing string :

ActiveMQMessage {commandId = 0, responseRequired = false, messageId =

ID:dell-charles-3258-1268399815140-1:0:0:0:221, originalDestination = null,

originalTransactionId = null, producerId = ID:dell-charles-3258-1268399815140-1:0:0:0,

destination = topic://ActiveMQ.Advisory.Connection,

transactionId = null, expiration = 0, timestamp = 0, arrival = 0, brokerInTime =

1268403383468, brokerOutTime = 1268403383468, correlationId = null,

replyTo = null, persistent = false, type = Advisory, priority = 0, groupID = null,

groupSequence = 0, targetConsumerId = null, compressed = false,

userID = null, content = null, marshalledProperties =

org.apache.activemq.util.ByteSequence@17e2705, dataStructure =

CHAPTER 10 - COMPONENT APPENDIX 364

ConnectionInfo {commandId = 1, responseRequired = true, connectionId =

ID:dell-charles-3258-1268399815140-2:50, clientId =

ID:dell-charles-3258-1268399815140-14:0, userName = , password = *****, brokerPath =

null, brokerMasterConnector = false, manageable = true,

clientMaster = true}, redeliveryCounter = 0, size = 0, properties =

{originBrokerName=master, originBrokerId=ID:dell-charles-3258-1268399815140-0:0,

originBrokerURL=vm://master}, readOnlyProperties = true, readOnlyBody = true,

droppable = false}

Getting Component JAR

You need these dependencies

▪camel-jms

▪activemq-camel

camel-jms

You must have the camel-jms as dependency as ActiveMQ is an extension to the JMS

component.

<groupId>org.apache.camel</groupId>

<artifactId>camel-jms</artifactId>

</dependency>

The ActiveMQ Camel component is released with the ActiveMQ project itself.

For Maven 2 users you simply just need to add the following dependency to your project.

ActiveMQ 5.2 or later

<groupId>org.apache.activemq</groupId>

<artifactId>activemq-camel</artifactId>

</dependency>

ActiveMQ 5.1.0

For 5.1.0 its in the activemq-core library

365 CHAPTER 10 - COMPONENT APPENDIX

<groupId>org.apache.activemq</groupId>

<artifactId>activemq-core</artifactId>

</dependency>

Alternatively you can download the component jar directly from the Maven repository:

• activemq-camel-5.2.0.jar

• activemq-core-5.1.0.jar

ActiveMQ 4.x

For this version you must use the JMS component instead. Please be careful to use a pooling

connection factory as described in the JmsTemplate Gotchas

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

ACTIVEMQ JOURNAL COMPONENT

The ActiveMQ Journal Component allows messages to be stored in a rolling log file and then

consumed from that log file. The journal aggregates and batches up concurrent writes so that to

overhead of writing and waiting for the disk sync is relatively constant regardless of how many

concurrent writes are being done. Therefore, this component supports and encourages you to

use multiple concurrent producers to the same journal endpoint.

Each journal endpoint uses a different log file and therefore write batching (and the

associated performance boost) does not occur between multiple endpoints.

This component only supports 1 active consumer on the endpoint. After the message is

processed by the consumer's processor, the log file is marked and only subsequent messages in

the log file will get delivered to consumers.

URI format

activemq.journal:directoryName[?options]

So for example, to send to the journal located in the /tmp/data directory you would use the

following URI:

CHAPTER 10 - COMPONENT APPENDIX 366

activemq.journal:/tmp/data

Options

Name Default

Value Description

syncConsume false

If set to true, when the journal is marked after a message is

consumed, wait till the Operating System has verified the

mark update is safely stored on disk.

syncProduce true If set to true, wait till the Operating System has verified the

message is safely stored on disk.

You can append query options to the URI in the following format,

?option=value&option=value&...

Expected Exchange Data Types

The consumer of a Journal endpoint generates DefaultExchange objects with the in message :

• header "journal" : set to the endpoint uri of the journal the message came from

• header "location" : set to a Location which identifies where the recored was stored

on disk

• body : set to ByteSequence which contains the byte array data of the stored message

The producer to a Journal endpoint expects an Exchange with an In message where the body

can be converted to a ByteSequence or a byte[].

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

AMQP

The AMQP component supports the AMQP protocol via the Qpid project.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

367 CHAPTER 10 - COMPONENT APPENDIX

<artifactId>camel-ampq</artifactId>

</dependency>

URI format

amqp:[queue:|topic:]destinationName[?options]

You can specify all of the various configuration options of the JMS component after the

destination name.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

ATOM COMPONENT

The atom: component is used for polling atom feeds.

Camel will default poll the feed every 60th seconds.

Note: The component currently only supports polling (consuming) feeds.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-atom</artifactId>

</dependency>

URI format

atom://atomUri[?options]

Where atomUri is the URI to the atom feed to poll.

CHAPTER 10 - COMPONENT APPENDIX 368

Options

Property Default Description

splitEntries true

If true Camel will poll the feed and for the

subsequent polls return each entry poll by

poll. If the feed contains 7 entries then

Camel will return the first entry on the first

poll, the 2nd entry on the next poll, until no

more entries where as Camel will do a new

update on the feed. If false then Camel

will poll a fresh feed on every invocation.

filter true

Is only used by the split entries to filter the

entries to return. Camel will default use the

UpdateDateFilter that only return

new entries from the feed. So the client

consuming from the feed never receives the

same entry more than once. The filter will

return the entries ordered by the newest

last.

lastUpdate null

Is only used by the filter, as the starting

timestamp for selection never entries (uses

the entry.updated timestamp). Syntax

format is: yyyy-MM-ddTHH:MM:ss.

Example: 2007-12-24T17:45:59.

feedHeader true Sets whether to add the Abdera Feed

object as a header.

sortEntries false

If splitEntries is true, this sets

whether to sort those entries by updated

date.

consumer.delay 60000 Delay in millis between each poll.

consumer.initialDelay 1000 Millis before polling starts.

consumer.userFixedDelay false

If true, use fixed delay between pools,

otherwise fixed rate is used. See

ScheduledExecutorService in JDK for

details.

You can append query options to the URI in the following format,

?option=value&option=value&...

369 CHAPTER 10 - COMPONENT APPENDIX

Exchange data format

Camel will set the In body on the returned Exchange with the entries. Depending on the

splitEntries flag Camel will either return one Entry or a List<Entry>.

Option Value Behavior

splitEntries true Only a single entry from the currently being processed feed is

set: exchange.in.body(Entry)

splitEntries false The entire list of entries from the feed is set:

exchange.in.body(List<Entry>)

Camel can set the Feed object on the In header (see feedHeader option to disable this):

Message Headers

Camel atom uses these headers.

Header Description

org.apache.camel.component.atom.feed

Camel 1.x: When consuming the

org.apache.abdera.model.Feed

object is set to this header.

CamelAtomFeed

Camel 2.0: When consuming the

org.apache.abdera.model.Feed

object is set to this header.

Samples

In this sample we poll James Strachan's blog.

from("atom://http://macstrac.blogspot.com/feeds/posts/default").to("seda:feeds");

In this sample we want to filter only good blogs we like to a SEDA queue. The sample also

shows how to setup Camel standalone, not running in any Container or using Spring.

// This is the CamelContext that is the heart of Camel

private CamelContext context;

@Override

protected CamelContext createCamelContext() throws Exception {

// We initialize Camel

SimpleRegistry registry = new SimpleRegistry();

// First we register a blog service in our bean registry

registry.put("blogService",new BlogService());

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// Then we create the camel context with our bean registry

context = new DefaultCamelContext(registry);

// Then we add all the routes we need using the route builder DSL syntax

context.addRoutes(createRouteBuilder());

// And finally we must start Camel to let the magic routing begins

context.start();

return context;

}

/**

* This is the route builder where we create our routes in the advanced Camel DSL

syntax

protected RouteBuilder createRouteBuilder() throws Exception {

return new RouteBuilder() {

public void configure() throws Exception {

// We pool the atom feeds from the source for further processing in the

seda queue

// we set the delay to 1 second for each pool as this is a unit test also

and we can

// not wait the default poll interval of 60 seconds.

// Using splitEntries=true will during polling only fetch one Atom Entry

at any given time.

// As the feed.atom file contains 7 entries, using this will require 7

polls to fetch the entire

// content. When Camel have reach the end of entries it will refresh the

atom feed from URI source

// and restart - but as Camel by default uses the UpdatedDateFilter it

will only deliver new

// blog entries to "seda:feeds". So only when James Straham updates his

blog with a new entry

// Camel will create an exchange for the seda:feeds.

from("atom:file:src/test/data/

feed.atom?splitEntries=true&consumer.delay=1000").to("seda:feeds");

// From the feeds we filter each blot entry by using our blog service class

from("seda:feeds").filter().method("blogService",

"isGoodBlog").to("seda:goodBlogs");

// And the good blogs is moved to a mock queue as this sample is also used

for unit testing

// this is one of the strengths in Camel that you can also use the mock

endpoint for your

// unit tests

from("seda:goodBlogs").to("mock:result");

}

};

}

/**

* This is the actual junit test method that does the assertion that our routes is

371 CHAPTER 10 - COMPONENT APPENDIX

working

* as expected

@Test

public void testFiltering() throws Exception {

// Get the mock endpoint

MockEndpoint mock = context.getEndpoint("mock:result", MockEndpoint.class);

// There should be two good blog entries from the feed

mock.expectedMinimumMessageCount(2);

// Asserts that the above expectations is true, will throw assertions exception if

it failed

// Camel will default wait max 20 seconds for the assertions to be true,if the

conditions

// is true sooner Camel will continue

mock.assertIsSatisfied();

}

/**

* Services for blogs

public class BlogService {

/**

* Tests the blogs if its a good blog entry or not

public boolean isGoodBlog(Exchange exchange) {

Entry entry = exchange.getIn().getBody(Entry.class);

String title = entry.getTitle();

// We like blogs about Camel

boolean good = title.toLowerCase().contains("camel");

return good;

}

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

BEAN COMPONENT

The bean: component binds beans to Camel message exchanges.

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URI format

bean:beanID[?options]

Where beanID can be any string which is used to look up the bean in the 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.

cache boolean false

If enabled, Camel will cache the

result of the first Registry look-up.

Cache can be enabled if the bean in

the Registry is defined as a singleton

scope.

multiParameterArray boolean false

Camel 1.5: 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&...

Using

The object instance that is used to consume messages must be explicitly registered with the

Registry. For example, if you are using Spring you must define the bean in the Spring

configuration, spring.xml; or if you don't use Spring, put the bean in JNDI.

// lets populate the context with the services we need

// note that we could just use a spring.xml file to avoid this step

JndiContext context = new JndiContext();

context.bind("bye",new SayService("Good Bye!"));

CamelContext camelContext = new DefaultCamelContext(context);

Once an endpoint has been registered, you can build Camel routes that use it to process

exchanges.

373 CHAPTER 10 - COMPONENT APPENDIX

// lets add simple route

camelContext.addRoutes(new RouteBuilder() {

public void configure() {

from("direct:hello").to("bean:bye");

}

});

Abean: endpoint cannot be defined as the input to the route; i.e. you cannot consume from it,

you can only route from some inbound message Endpoint to the bean endpoint as output. So

consider using a direct: or queue: endpoint as the input.

You can use the createProxy() methods on ProxyHelper to create a proxy that will

generate BeanExchanges and send them to any endpoint:

Endpoint endpoint = camelContext.getEndpoint("direct:hello");

ISay proxy = ProxyHelper.createProxy(endpoint, ISay.class);

String rc = proxy.say();

assertEquals("Good Bye!", rc);

And the same route using Spring DSL:

<route>

</route>

Bean as endpoint

Camel also supports invoking Bean as an Endpoint. In the route below:

<route>

</route>

</camelContext>

What happens is that when the exchange is routed to the myBean Camel will use the Bean

Binding to invoke the bean.

The source for the bean is just a plain POJO:

public class ExampleBean {

CHAPTER 10 - COMPONENT APPENDIX 374

public String sayHello(String name) {

return "Hello " + name + "!";

}

Camel will use Bean Binding to invoke the sayHello method, by converting the Exchange's In

body to the String type and storing the output of the method on the Exchange Out body.

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.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Class component

• Bean Binding

• Bean Integration

BEAN VALIDATION COMPONENT

Available as of Camel 2.3

The Validation component performs bean validation of the message body using the Java Bean

Validation API (JSR 303). Camel uses the reference implementation, which is Hibernate

Validator.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-bean-validator</artifactId>

</dependency>

375 CHAPTER 10 - COMPONENT APPENDIX

URI format

bean-validator:something[?options]

bean-validator://something[?options]

Where something must be present to provide a valid url

You can append query options to the URI in the following format,

?option=value&option=value&...

URI Options

Option Default Description

group javax.validation.groups.Default The custom validation group to use.

messageInterpolator org.hibernate.validator.engine.

ResourceBundleMessageInterpolator

Reference to a custom

javax.validation.MessageInterpolator in the Registry.

traversableResolver org.hibernate.validator.engine.resolver.

DefaultTraversableResolver

Reference to a custom

javax.validation.TraversableResolver in the Registry.

constraintValidatorFactory org.hibernate.validator.engine.

ConstraintValidatorFactoryImpl

Reference to a custom

javax.validation.ConstraintValidatorFactory in the

Registry.

Example

Assumed we have a java bean with the following annotations

Listing 12.Listing 12. Car.javaCar.java

public class Car {

@NotNull

private String manufacturer;

@NotNull

@Size(min = 5, max = 14, groups = OptionalChecks.class)

private String licensePlate;

// getter and setter

}

and an interface definition for our custom validation group

Listing 13.Listing 13. OptionalChecks.javaOptionalChecks.java

public interface OptionalChecks {

}

CHAPTER 10 - COMPONENT APPENDIX 376

with the following Camel route, only the @NotNull constraints on the attributes

manufacturer and licensePlate will be validated (Camel uses the default group

javax.validation.groups.Default).

from("direct:start")

.to("bean-validator://x")

.to("mock:end")

If you want to check the constraints from the group OptionalChecks, you have to define

the route like this

from("direct:start")

.to("bean-validator://x?group=OptionalChecks")

.to("mock:end")

If you want to check the constraints from both groups, you have to define a new interface first

Listing 14.Listing 14. AllChecks.javaAllChecks.java

@GroupSequence({Default.class, OptionalChecks.class})

public interface AllChecks {

}

and then your route definition should looks like this

from("direct:start")

.to("bean-validator://x?group=AllChecks")

.to("mock:end")

And if you have to provide your own message interpolator, traversable resolver and constraint

validator factory, you have to write a route like this

from("direct:start")

.to("bean-validator://x?group=AllChecks&messageInterpolator=#myMessageInterpolator&traversableResolver=#myTraversableResolver&constraintValidatorFactory=#myConstraintValidatorFactory")

.to("mock:end")

It's also possible to describe your constraints as XML and not as Java annotations. In this case,

you have to provide the file META-INF/validation.xml which could looks like this

Listing 15.Listing 15. validation.xmlvalidation.xml

<?xml version="1.0" encoding="UTF-8"?>

<validation-config

xmlns="http://jboss.org/xml/ns/javax/validation/configuration"

377 CHAPTER 10 - COMPONENT APPENDIX

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/configuration">

<default-provider>org.hibernate.validator.HibernateValidator</default-provider>

<message-interpolator>org.hibernate.validator.engine.ResourceBundleMessageInterpolator</message-interpolator>

<traversable-resolver>org.hibernate.validator.engine.resolver.DefaultTraversableResolver</traversable-resolver>

<constraint-validator-factory>org.hibernate.validator.engine.ConstraintValidatorFactoryImpl</constraint-validator-factory>

<constraint-mapping>/constraints-car.xml</constraint-mapping>

</validation-config>

and the constraints-car.xml file

Listing 16.Listing 16. constraints-car.xmlconstraints-car.xml

<?xml version="1.0" encoding="UTF-8"?>

<constraint-mappings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/mapping

validation-mapping-1.0.xsd"

xmlns="http://jboss.org/xml/ns/javax/validation/mapping">

<default-package>org.apache.camel.component.bean.validator</default-package>

<constraint annotation="javax.validation.constraints.NotNull"

</field>

<constraint annotation="javax.validation.constraints.NotNull"

<value>org.apache.camel.component.bean.validator.OptionalChecks</value>

</groups>

</constraint>

</field>

</bean>

</constraint-mappings>

See Also

• Configuring Camel

• Component

• Endpoint

CHAPTER 10 - COMPONENT APPENDIX 378

• Getting Started

BROWSE COMPONENT

Available as of Camel 2.0

The Browse component 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.

URI format

browse:someName

Where someName can be any string to uniquely identify the endpoint.

Sample

In the route below, we insert a browse: component to be able to browse the Exchanges that

are passing through:

from("activemq:order.in").to("browse:orderReceived").to("bean:processOrder");

We can now inspect the received exchanges from within the Java code:

private CamelContext context;

public void inspectRecievedOrders() {

BrowsableEndpoint browse = context.getEndpoint("browse:orderReceived",

BrowsableEndpoint.class);

List<Exchange> exchanges = browse.getExchanges();

...

// then we can inspect the list of received exchanges from Java

for (Exchange exchange : exchanges) {

String payload = exchange.getIn().getBody();

...

}

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

379 CHAPTER 10 - COMPONENT APPENDIX

CACHE COMPONENT

Available as of Camel 2.1

The cache component enables you to perform caching operations using EHCache as the

Cache Implementation. The cache itself is created on demand or if a cache of that name already

exists then it is simply utilized with its original settings.

This component supports producer and event based consumer endpoints.

The Cache consumer is an event based consumer and can be used to listen and respond to

specific cache activities. If you need to perform selections from a pre-existing cache, used the

processors defined for the cache component.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-cache</artifactId>

</dependency>

URI format

cache://cacheName[?options]

You can append query options to the URI in the following format,

?option=value&option=value&...

Options

Name Default Value Description

maxElementsInMemory 1000 The numer of elements that may be stored in the defined cache

memoryStoreEvictionPolicy MemoryStoreEvictionPolicy.LFU

The number of elements that may be stored in the defined cache. Options include

▪MemoryStoreEvictionPolicy.LFU - Least frequently used

▪MemoryStoreEvictionPolicy.LRU - Least recently used

▪MemoryStoreEvictionPolicy.FIFO - first in first out, the oldest

element by creation time

overflowToDisk true Specifies whether cache may overflow to disk

eternal false Sets whether elements are eternal. If eternal, timeouts are ignored and the

element is never expired.

timeToLiveSeconds 300 The maximum time between creation time and when an element expires.

Is only used if the element is not eternal

timeToIdleSeconds 300 The maximum amount of time between accesses before an element expires

diskPersistent true Whether the disk store persists between restarts of the Virtual Machine.

The default value is false.

diskExpiryThreadIntervalSeconds 120 The number of seconds between runs of the disk expiry thread. The default value

is 120 seconds

CHAPTER 10 - COMPONENT APPENDIX 380

cacheManagerFactory null Camel 2.3: If you want to use a custom factory which instantiates and creates the

EHCache net.sf.ehcache.CacheManager.

Sending/Receiving Messages to/from the cache

Message Headers

Header Description

CACHE_OPERATION

The operation to be performed on the cache. The valid options are

▪GET

▪CHECK

▪ADD

▪UPDATE

▪DELETE

▪DELETEALL

The GET and CHECK requires Camel 2.3 onwards.

CACHE_KEY The cache key used to store the Message in the cache. The cache key is optional if the CACHE_OPERATION is DELETEALL

Cache Producer

Sending data to the cache involves the ability to direct payloads in exchanges to be stored in a

pre-existing or created-on-demand cache. The mechanics of doing this involve

▪setting the Message Exchange Headers shown above.

▪ensuring that the Message Exchange Body contains the message directed to the cache

Cache Consumer

Receiving data from the cache involves the ability of the CacheConsumer to listen on a pre-

existing or created-on-demand Cache using an event Listener and receive automatic

notifications when any cache activity take place (i.e ADD/UPDATE/DELETE/DELETEALL). Upon

such an activity taking place

▪an exchange containing Message Exchange Headers and a Message Exchange Body

containing the just added/updated payload is placed and sent.

▪in case of a DELETEALL operation, the Message Exchange Header CACHE_KEY and

the Message Exchange Body are not populated.

Cache Processors

There are a set of nice processors with the ability to perform cache lookups and selectively

replace payload content at the

▪body

▪token

▪xpath level

381 CHAPTER 10 - COMPONENT APPENDIX

Cache Usage Samples

Example 1: Configuring the cache

from("cache://MyApplicationCache" +

"?maxElementsInMemory=1000" +

"&memoryStoreEvictionPolicy=" +

"MemoryStoreEvictionPolicy.LFU" +

"&overflowToDisk=true"+

"&eternal=true"+

"&timeToLiveSeconds=300" +

"&timeToIdleSeconds=true"+

"&diskPersistent=true"+

"&diskExpiryThreadIntervalSeconds=300")

Example 2: Adding keys to the cache

RouteBuilder builder = new RouteBuilder() {

public void configure() {

from("direct:start")

.setHeader("CACHE_OPERATION", constant("ADD"))

.setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))

.to("cache://TestCache1")

}

};

Example 2: Updating existing keys in a cache

RouteBuilder builder = new RouteBuilder() {

public void configure() {

from("direct:start")

.setHeader("CACHE_OPERATION", constant("UPDATE"))

.setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))

.to("cache://TestCache1")

}

};

CHAPTER 10 - COMPONENT APPENDIX 382

Example 3: Deleting existing keys in a cache

RouteBuilder builder = new RouteBuilder() {

public void configure() {

from("direct:start")

.setHeader("CACHE_OPERATION", constant("DELETE"))

.setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))

.to("cache://TestCache1")

}

};

Example 4: Deleting all existing keys in a cache

RouteBuilder builder = new RouteBuilder() {

public void configure() {

from("direct:start")

.setHeader("CACHE_OPERATION", constant("DELETEALL"))

.to("cache://TestCache1");

}

};

Example 5: Notifying any changes registering in a Cache to

Processors and other Producers

RouteBuilder builder = new RouteBuilder() {

public void configure() {

from("cache://TestCache1")

.process(new Processor() {

public void process(Exchange exchange)

throws Exception {

String operation = (String) exchange.getIn().getHeader("CACHE_OPERATION");

String key = (String) exchange.getIn().getHeader("CACHE_KEY");

Object body = exchange.getIn().getBody();

// Do something

}

})

}

};

383 CHAPTER 10 - COMPONENT APPENDIX

Example 6: Using Processors to selectively replace payload with

cache values

RouteBuilder builder = new RouteBuilder() {

public void configure() {

//Message Body Replacer

from("cache://TestCache1")

.filter(header("CACHE_KEY").isEqualTo("greeting"))

.process(new CacheBasedMessageBodyReplacer("cache://TestCache1","farewell"))

.to("direct:next");

//Message Token replacer

from("cache://TestCache1")

.filter(header("CACHE_KEY").isEqualTo("quote"))

.process(new CacheBasedTokenReplacer("cache://TestCache1","novel","#novel#"))

.process(new CacheBasedTokenReplacer("cache://TestCache1","author","#author#"))

.process(new CacheBasedTokenReplacer("cache://TestCache1","number","#number#"))

.to("direct:next");

//Message XPath replacer

from("cache://TestCache1").

.filter(header("CACHE_KEY").isEqualTo("XML_FRAGMENT"))

.process(new CacheBasedXPathReplacer("cache://TestCache1","book1","/books/book1"))

.process (new CacheBasedXPathReplacer("cache://TestCache1","book2","/books/book2"))

.to("direct:next");

}

};

Example 7: Getting an entry from the Cache

from("direct:start")

// Prepare headers

.setHeader(CacheConstants.CACHE_OPERATION,

constant(CacheConstants.CACHE_OPERATION_GET))

.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson")).

.to("cache://TestCache1").

// Check if entry was not found

.choice().when(header(CacheConstants.CACHE_ELEMENT_WAS_FOUND).isNull()).

// If not found, get the payload and put it to cache

.to("cxf:bean:someHeavyweightOperation").

.setHeader(CacheConstants.CACHE_OPERATION,

constant(CacheConstants.CACHE_OPERATION_ADD))

.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))

.to("cache://TestCache1")

.end()

.to("direct:nextPhase");

CHAPTER 10 - COMPONENT APPENDIX 384

Example 8: Checking for an entry in the Cache

Note: CHECK command tests existence of the entry in the cache but doesn't place message to

the body.

from("direct:start")

// Prepare headers

.setHeader(CacheConstants.CACHE_OPERATION,

constant(CacheConstants.CACHE_OPERATION_CHECK))

.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson")).

.to("cache://TestCache1").

// Check if entry was not found

.choice().when(header(CacheConstants.CACHE_ELEMENT_WAS_FOUND).isNull()).

// If not found, get the payload and put it to cache

.to("cxf:bean:someHeavyweightOperation").

.setHeader(CacheConstants.CACHE_OPERATION,

constant(CacheConstants.CACHE_OPERATION_ADD))

.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))

.to("cache://TestCache1")

.end();

COMETD COMPONENT

The cometd: component is a transport for working with the jetty implementation of the

cometd/bayeux protocol.

Using this component in combination with the dojo toolkit library it's possible to push Camel

messages directly into the browser using an AJAX based mechanism.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-cometd</artifactId>

</dependency>

URI format

cometd://host:port/channelName[?options]

The channelName represents a topic that can be subscribed to by the Camel endpoints.

385 CHAPTER 10 - COMPONENT APPENDIX

Examples

cometd://localhost:8080/service/mychannel

cometds://localhost:8443/service/mychannel

where cometds: represents an SSL configured endpoint.

See this blog entry by David Greco who contributed this component to Apache Camel, for a

full sample.

Options

Name Default

Value Description

resourceBase

The root directory for the web resources or

classpath. Use the protocol file: or classpath:

depending if you want that the component loads

the resource from file system or classpath.

Classpath is required for OSGI deployment where

the resources are packaged in the jar

timeout 240000

The server side poll timeout in milliseconds. This is

how long the server will hold a reconnect request

before responding.

interval 0 The client side poll timeout in milliseconds. How

long a client will wait between reconnects

maxInterval 30000

The max client side poll timeout in milliseconds. A

client will be removed if a connection is not

received in this time.

multiFrameInterval 1500 The client side poll timeout, if multiple connections

are detected from the same browser.

jsonCommented true

If true, the server will accept JSON wrapped in a

comment and will generate JSON wrapped in a

comment. This is a defence against Ajax Hijacking.

logLevel 1 0=none, 1=info, 2=debug.

You can append query options to the URI in the following format,

?option=value&option=value&...

Here is some examples on How to pass the parameters

For file (for webapp resources located in the Web Application directory -->

cometd://localhost:8080?resourceBase=file./webapp

CHAPTER 10 - COMPONENT APPENDIX 386

For classpath (when by example the web resources are packaged inside the webapp folder -->

cometd://localhost:8080?resourceBase=classpath:webapp

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-crypto</artifactId>

</dependency>

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

387 CHAPTER 10 - COMPONENT APPENDIX

▪Beginning Cryptography with Java by David Hook

▪The ever insightful, Wikipedia Digital_signatures

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.

CHAPTER 10 - COMPONENT APPENDIX 388

from("direct:keypair").to("crypto:sign://basic?privateKey=#myPrivateKey",

"crypto:verify://basic?publicKey=#myPublicKey", "mock:result");

The same can be achieved with the Spring XML Extensions using references to keys

<route>

</route>

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.

<route>

<to

uri="crypto:sign://keystore?keystore=#keystore&alias=bob&password=letmein" />

</route>

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.

389 CHAPTER 10 - COMPONENT APPENDIX

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");

keyGen.initialize(512, new SecureRandom());

keyPair = keyGen.generateKeyPair();

PrivateKey privateKey = keyPair.getPrivate();

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");

<route>

</route>

<route>

</route>

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=AnotherDigitalSignature",

"crypto:verify://another?publicKey=#myPublicKey&signatureHeader=AnotherDigitalSignature",

"mock:result");

CHAPTER 10 - COMPONENT APPENDIX 390

<route>

<to

uri="crypto:sign://another?privateKey=#myPrivateKey&signatureHeader=AnotherDigitalSignature"

<to

uri="crypto:verify://another?publicKey=#myPublicKey&signatureHeader=AnotherDigitalSignature"

</route>

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");

<route>

</route>

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");

391 CHAPTER 10 - COMPONENT APPENDIX

<route>

</route>

<route>

</route>

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");

<route>

</route>

<route>

</route>

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

CHAPTER 10 - COMPONENT APPENDIX 392

• 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

• 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

• CXF Bean Component ( 2.0 or later)

• URI format

• Options

• Headers

• A Working Sample

• See Also

Maven users will need to add the following dependency to their pom.xml for this component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-cxf</artifactId>

</dependency>

393 CHAPTER 10 - COMPONENT APPENDIX

CXF dependencies

If you want to learn about CXF dependencies you can checkout the WHICH-JARS

text file.

URI format

cxf:bean:cxfEndpoint[?options]

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 Description Example Required? Default Value

wsdlURL The location of the WSDL. file://local/wsdl/hello.wsdl or wsdl/

hello.wsdl No WSDL is obtained from endpoint address by default.

serviceClass

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.

Since 2.0, it is possible to use #notation to reference a

serviceClass object instance from the registry. E.g.

serviceClass=#beanName.

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.

org.apache.camel.Hello Yes

serviceClassInstance

In 1.6 or later (will be deprecated in 2.0),

serviceClassInstance works like

serviceClass=#beanName, which looks up a

serviceObject instance from the registry.

serviceClassInstance=beanName

No (use either

serviceClass or

serviceClassInstance)

serviceName The service name this service is implementing, it maps to the

wsdl:service@name.{http:¬≠//org.apache.camel}ServiceName

Only if more than one

serviceName in WSDL

present, and it is required for

camel-cxf consumer since

camel 2.2

CHAPTER 10 - COMPONENT APPENDIX 394

portName The port name this service is implementing, it maps to the

wsdl:port@name.{http:¬≠//org.apache.camel}PortName

Only if more than one

portName under the

serviceName is present,

and it is required for camel-

cxf consumer since camel 2.2

dataFormat Which data type messages the CXF endpoint supports POJO,PAYLOAD,MESSAGE No POJO

relayHeaders

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

true,false No true

wrapped Which kind of operation that CXF endpoint producer will

invoke true,false No false

setDefaultBus Will set the default bus when CXF endpoint create a bus by

itself true,false No false

bus

New in 2.0, 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 Default bus created by CXF Bus Factory

cxfBinding

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.

cxfBinding=#bindingName No An instance of

org.apache.camel.component.cxf.DefaultCxfBinding

headerFilterStrategy

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.

headerFilterStrategy=#strategyName No An instance of

org.apache.camel.component.cxf.CxfHeaderFilterStrategy

loggingFeatureEnabled New in 2.3, this option enables CXF Logging Feature which

writes inbound and outbound SOAP messages to log. loggingFeatureEnabled=true No false

defaultOperationName

New in 2.4, this option will set the default operationName

that will be used by the CxfProducer which invokes the

remote service.

defaultOperationName=greetMe No null

defaultOperationNameSpace

New in 2.4, this option will set the default

operationNamespace that will be used by the CxfProducer

which invokes the remote service.

defaultOperationNamespace{{=

http://apache.org/hello_world_soap_http

}} No null

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 JAX-

WS handler is supported. Logical JAX-WS handler is not supported.

MESSAGE MESSAGE is the raw message that is received from the transport layer. 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

395 CHAPTER 10 - COMPONENT APPENDIX

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.

<bean id="loggingOutInterceptor"

class="org.apache.cxf.interceptor.LoggingOutInterceptor">

<!-- it really should have been user-prestream but CXF does have such phase!

-->

<constructor-arg value="write"/>

</bean>

<cxf:cxfEndpoint id="serviceEndpoint" address="http://localhost:9002/helloworld"

serviceClass="org.apache.camel.component.cxf.HelloService">

<cxf:outInterceptors>

</cxf:outInterceptors>

<cxf:properties>

</cxf:properties>

</cxf:cxfEndpoint>

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

CHAPTER 10 - COMPONENT APPENDIX 396

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.

<cxf:cxfEndpoint ...>

<cxf:properties>

<list>

</list>

</entry>

</cxf:properties>

</cxf:cxfEndpoint>

<bean id="customHeadersRelay"

class="org.apache.camel.component.cxf.soap.headers.CustomHeadersRelay"/>

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.

397 CHAPTER 10 - COMPONENT APPENDIX

<bean id="dropAllMessageHeadersStrategy"

class="org.apache.camel.component.cxf.CxfHeaderFilterStrategy">

</bean>

Then, your endpoint can reference the CxfHeaderFilterStrategy.

<route>

<from

uri="cxf:bean:routerNoRelayEndpoint?headerFilterStrategy=#dropAllMessageHeadersStrategy"/>

<to

uri="cxf:bean:serviceNoRelayEndpoint?headerFilterStrategy=#dropAllMessageHeadersStrategy"/>

</route>

• 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:

<bean id="customMessageFilterStrategy"

class="org.apache.camel.component.cxf.CxfHeaderFilterStrategy">

<list>

<!-- SoapMessageHeaderFilter is the built in filter. It can be

removed by omitting it. -->

<bean

class="org.apache.camel.component.cxf.SoapMessageHeaderFilter"/>

<bean

class="org.apache.camel.component.cxf.soap.headers.CustomHeaderFilter"/>

</list>

</property>

</bean>

• Other than relayHeaders, there are new properties that can be configured in

CxfHeaderFilterStrategy.

Name Description type Required? Default

value

relayHeaders All message headers will be processed by Message Header

Filters boolean No true (1.6.1

behavior)

relayAllMessageHeaders All message headers will be propagated (without processing by

Message Header Filters) boolean No false (1.6.1

behavior)

allowFilterNamespaceClash

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

boolean No false (1.6.1

behavior)

CHAPTER 10 - COMPONENT APPENDIX 398

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.

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:cxf="http://activemq.apache.org/camel/schema/cxfEndpoint"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.0.xsd

http://activemq.apache.org/camel/schema/cxfEndpoint

http://activemq.apache.org/camel/schema/cxf/camel-cxf-1.6.0.xsd

http://activemq.apache.org/camel/schema/spring

http://activemq.apache.org/camel/schema/spring/camel-spring.xsd ">

<cxf:cxfEndpoint id="routerEndpoint" address="http://localhost:9003/CamelContext/

RouterPort"

serviceClass="org.apache.hello_world_soap_http.GreeterImpl"/>

<cxf:cxfEndpoint id="serviceEndpoint" address="http://localhost:9000/SoapContext/

SoapPort"

wsdlURL="testutils/hello_world.wsdl"

serviceClass="org.apache.hello_world_soap_http.Greeter"

endpointName="s:SoapPort"

serviceName="s:SOAPService"

xmlns:s="http://apache.org/hello_world_soap_http" />

<route>

</route>

</camelContext>

</beans>

NOTE In Camel 2.x we change to use {{http:¬≠//camel.apache.org/schema/cxf}} as the CXF

endpoint's target namespace.

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:cxf="http://camel.apache.org/schema/cxf"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

schema/beans/spring-beans-2.0.xsd

http://camel.apache.org/schema/cxf http://camel.apache.org/schema/cxf/

camel-cxf.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd ">

...

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

399 CHAPTER 10 - COMPONENT APPENDIX

declarations at the end of the <cxf:cxfEndpoint/> 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 Value

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 <bean> or <ref>.

cxf:inFaultInterceptors The incoming fault interceptors for this endpoint. A list of <bean> or <ref>.

cxf:outInterceptors The outgoing interceptors for this endpoint. A list of <bean> or <ref>.

cxf:outFaultInterceptors The outgoing fault interceptors for this endpoint. A list of <bean> or <ref>.

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 <bean

class="MyDataBinding"/> syntax.

cxf:binding You can specify the BindingFactory for this endpoint to use. This can be supplied using the Spring <bean

class="MyBindingFactory"/> syntax.

cxf:features The features that hold the interceptors for this endpoint. A list of {{<bean>}}s or {{<ref>}}s

cxf:schemaLocations The schema locations for endpoint to use. A list of {{<schemaLocation>}}s

cxf:serviceFactory The service factory for this endpoint to use. This can be supplied using the Spring <bean class="MyServiceFactory"/> 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.

<cxf:cxfEndpoint id="testEndpoint" address="http://localhost:9000/router"

serviceClass="org.apache.camel.component.cxf.HelloService"

endpointName="s:PortName"

serviceName="s:ServiceName"

xmlns:s="http://www.example.com/test">

<cxf:properties>

</cxf:properties>

</cxf:cxfEndpoint>

CHAPTER 10 - COMPONENT APPENDIX 400

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 "<?xml version="1.0" encoding="utf-8"?>"

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<SoapMessage> {

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);

}

You can add a customer interceptor like this and configure it into you camel-cxf endpont

<cxf:cxfEndpoint id="routerEndpoint" address="http://localhost:9003/CamelContext/

RouterPort"

serviceClass="org.apache.hello_world_soap_http.GreeterImpl">

<cxf:outInterceptors>

<!-- This interceptor will force the CXF server send the XML start document

to client -->

</cxf:outInterceptors>

</cxf:cxfEndpoint>

Or adding a message header for it like this if you are using Camel 2.4.

401 CHAPTER 10 - COMPONENT APPENDIX

// set up the response context which force start document

Map<String,Object> map = new HashMap<String,Object>();

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 Log LOG = LogFactory.getLog(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());

}

// Get the parameters list which element is the holder.

MessageContentsList msgList = (MessageContentsList)exchange.getIn().getBody();

Holder<String> personId = (Holder<String>)msgList.get(0);

Holder<String> ssn = (Holder<String>)msgList.get(1);

Holder<String> name = (Holder<String>)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";

CHAPTER 10 - COMPONENT APPENDIX 402

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<String> params = new ArrayList<String>();

// Prepare the request message for the camel-cxf procedure

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<String,Object> 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));

403 CHAPTER 10 - COMPONENT APPENDIX

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<Element> to set or get SOAP body elements.

Camel 1.x branch, you can get the List<Element> 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<Element> inElements =

cxfInMessage.getMessage().get(List.class);

List<Element> outElements = new ArrayList<Element>();

XmlConverter converter = new XmlConverter();

String documentString = ECHO_RESPONSE;

if (inElements.get(0).getLocalName().equals("echoBoolean")) {

documentString = ECHO_BOOLEAN_RESPONSE;

}

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.

CHAPTER 10 - COMPONENT APPENDIX 404

protected RouteBuilder createRouteBuilder() {

return new RouteBuilder() {

public void configure() {

from(SIMPLE_ENDPOINT_URI +

"&dataFormat=PAYLOAD").to("log:info").process(new Processor() {

@SuppressWarnings("unchecked")

public void process(final Exchange exchange) throws Exception {

CxfPayload<SoapHeader> requestPayload =

exchange.getIn().getBody(CxfPayload.class);

List<Element> inElements = requestPayload.getBody();

List<Element> outElements = new ArrayList<Element>();

// 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;

if (inElements.get(0).getLocalName().equals("echoBoolean")) {

documentString = ECHO_BOOLEAN_RESPONSE;

assertEquals("Get a wrong request", ECHO_BOOLEAN_REQUEST,

request);

}else {

assertEquals("Get a wrong request", ECHO_REQUEST, request);

}

Document outDocument = converter.toDOMDocument(documentString);

outElements.add(outDocument.getDocumentElement());

// set the payload header with null

CxfPayload<SoapHeader> responsePayload = new

CxfPayload<SoapHeader>(null, outElements);

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:

405 CHAPTER 10 - COMPONENT APPENDIX

<route>

</route>

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")

public void process(Exchange exchange) throws Exception {

List<SoapHeader> soapHeaders =

(List)exchange.getIn().getHeader(Header.HEADER_LIST);

// Insert a new header

String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><outofbandHeader "

+"xmlns=\"http://cxf.apache.org/outofband/Header\"

hdrAttribute=\"testHdrAttribute\" "

+"xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"

soap:mustUnderstand=\"1\">"

"<name>New_testOobHeader</name><value>New_testOobHeaderValue</value></outofbandHeader>";

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.

CHAPTER 10 - COMPONENT APPENDIX 406

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<SoapHeader> soapHeaders = (List)cxf.get(Header.HEADER_LIST);

// Insert a new header

String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><outofbandHeader "

+"xmlns=\"http://cxf.apache.org/outofband/Header\"

hdrAttribute=\"testHdrAttribute\" "

+"xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"

soap:mustUnderstand=\"1\">"

"<name>New_testOobHeader</name><value>New_testOobHeaderValue</value></outofbandHeader>";

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);

}

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<SoapHeader> soapHeaders = (List)responseContext.get(Header.HEADER_LIST);

// Insert a new header

String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><outofbandHeader "

+"xmlns=\"http://cxf.apache.org/outofband/Header\"

hdrAttribute=\"testHdrAttribute\" "

+"xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\"

soap:mustUnderstand=\"1\">"

"<name>New_testOobHeader</name><value>New_testOobHeaderValue</value></outofbandHeader>";

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);

}

407 CHAPTER 10 - COMPONENT APPENDIX

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(routerEndpointURI).process(new Processor() {

@SuppressWarnings("unchecked")

public void process(Exchange exchange) throws Exception {

CxfPayload<SoapHeader> payload = exchange.getIn().getBody(CxfPayload.class);

List<Element> elements = payload.getBody();

assertNotNull("We should get the elements here", elements);

assertEquals("Get the wrong elements size", 1, elements.size());

assertEquals("Get the wrong namespace URI","http://camel.apache.org/pizza/

types",

elements.get(0).getNamespaceURI());

List<SoapHeader> headers = payload.getHeaders();

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);

*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<Element> 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<SoapHeader> 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");

}

CHAPTER 10 - COMPONENT APPENDIX 408

})

.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

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

409 CHAPTER 10 - COMPONENT APPENDIX

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:

CxfExchange exchange = (CxfExchange)template.send(getJaxwsEndpointUri(), new

Processor() {

public void process(final Exchange exchange) {

final List<String> params = new ArrayList<String>();

params.add(TEST_MESSAGE);

// Set the request context to the inMessage

Map<String,Object> requestContext = new HashMap<String,Object>();

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<String,Object> 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). However, SOAP with Attachment is not tested. Since

attachments are marshalled and unmarshalled into POJOs, users typically do not need to deal

with the attachment themself. Attachments are propagated to Camel message's attachments

since 2.1. 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 retrieve by Camel

Message APIs mentioned above. SOAP with Attachment is not supported as there is no SOAP

processing in this mode.

CHAPTER 10 - COMPONENT APPENDIX 410

To enable MTOM, set the CXF endpoint property "mtom_enabled" to true. (I believe you

can only do it with Spring.)

<cxf:cxfEndpoint id="routerEndpoint" address="http://localhost:9091/jaxws-mtom/hello"

wsdlURL="mtom.wsdl"

serviceName="ns:HelloService"

endpointName="ns:HelloPort"

xmlns:ns="http://apache.org/camel/cxf/mtom_feature">

<cxf:properties>

</cxf:properties>

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<Element> elements = new ArrayList<Element>();

elements.add(DOMUtils.readXml(new

StringReader(MtomTestHelper.REQ_MESSAGE)).getDocumentElement());

CxfPayload<SoapHeader> body = new CxfPayload<SoapHeader>(new

ArrayList<SoapHeader>(),

elements);

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<SoapHeader> out = exchange.getOut().getBody(CxfPayload.class);

Assert.assertEquals(1, out.getBody().size());

Map<String,String> ns = new HashMap<String,String>();

ns.put("ns", MtomTestHelper.SERVICE_TYPES_NS);

411 CHAPTER 10 - COMPONENT APPENDIX

ns.put("xop", MtomTestHelper.XOP_NS);

XPathUtils xu = new XPathUtils(ns);

Element ele = (Element)xu.getValue("//ns:DetailResponse/ns:photo/xop:Include",

out.getBody().get(0),

XPathConstants.NODE);

String photoId = ele.getAttribute("href").substring(4); // skip "cid:"

ele = (Element)xu.getValue("//ns:DetailResponse/ns:image/xop:Include",

out.getBody().get(0),

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<SoapHeader> in = exchange.getIn().getBody(CxfPayload.class);

// verify request

Assert.assertEquals(1, in.getBody().size());

Map<String,String> ns = new HashMap<String,String>();

ns.put("ns", MtomTestHelper.SERVICE_TYPES_NS);

ns.put("xop", MtomTestHelper.XOP_NS);

XPathUtils xu = new XPathUtils(ns);

Element ele = (Element)xu.getValue("//ns:Detail/ns:photo/xop:Include",

in.getBody().get(0),

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",

in.getBody().get(0),

XPathConstants.NODE);

String imageId = ele.getAttribute("href").substring(4); // skip "cid:"

Assert.assertEquals(MtomTestHelper.REQ_IMAGE_CID, imageId);

CHAPTER 10 - COMPONENT APPENDIX 412

DataHandler dr = exchange.getIn().getAttachment(photoId);

Assert.assertEquals("application/octet-stream", dr.getContentType());

MtomTestHelper.assertEquals(MtomTestHelper.REQ_PHOTO_DATA,

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<Element> elements = new ArrayList<Element>();

elements.add(DOMUtils.readXml(new

StringReader(MtomTestHelper.RESP_MESSAGE)).getDocumentElement());

CxfPayload<SoapHeader> body = new CxfPayload<SoapHeader>(new

ArrayList<SoapHeader>(),

elements);

exchange.getOut().setBody(body);

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.

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.)

Note:CxfBeanEndpoint is a ProcessorEndpoint so it has no consumers. It works

similarly to a Bean component.

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.

413 CHAPTER 10 - COMPONENT APPENDIX

Options

Name Description Example Required? Default Value

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 An instance of

org.apache.camel.component.cxf.cxfbean.DefaultCxfBeanBinding

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 created by CXF Bus 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 An instance of

org.apache.camel.component.cxf.CxfHeaderFilterStrategy

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 to 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

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

Note: Currently, CXF Bean component has (only) been tested with Jetty

HTTP component it can understand headers from Jetty HTTP component

without requiring conversion.

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.

<route>

</route>

CHAPTER 10 - COMPONENT APPENDIX 414

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.

<util:list id="customerServiceBean">

</util:list>

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.

url = new URL("http://localhost:9000/customerservice/orders/223/products/323");

in = url.openStream();

assertEquals("{\"Product\":{\"description\":\"product 323\",\"id\":323}}",

CxfUtils.getStringFromInputStream(in));

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-cxf</artifactId>

</dependency>

415 CHAPTER 10 - COMPONENT APPENDIX

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

Options

Name Description Example Required? default

value

resourcesClass

The resource classes

which you want to

export as REST service

resourcesClass=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

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.

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.

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:cxf="http://camel.apache.org/schema/cxf"

xmlns:jaxrs="http://cxf.apache.org/jaxrs"

xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/

CHAPTER 10 - COMPONENT APPENDIX 416

schema/beans/spring-beans-2.5.xsd

http://camel.apache.org/schema/cxf http://camel.apache.org/schema/cxf/

camel-cxf.xsd

http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs.xsd

http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/

camel-spring.xsd

<jaxrs:server id="restService"

address="http://localhost:9002/rest"

staticSubresourceResolution="true">

<jaxrs:serviceBeans>

</jaxrs:serviceBeans>

</jaxrs:server>

<bean id="customerService"

class="org.apache.camel.component.cxf.jaxrs.testbean.CustomerService" />

<cxf:rsServer id="rsServer" address="http://localhost:9000/route"

serviceClass="org.apache.camel.component.cxf.jaxrs.testbean.CustomerService" />

<cxf:rsClient id="rsClient" address="http://localhost:9002/rest"

serviceClass="org.apache.camel.component.cxf.jaxrs.testbean.CustomerService"/>

<route>

<!-- We can remove this configure as the CXFRS producer is using the HttpAPI by

default -->

</setHeader>

</route>

</camelContext>

</beans>

How to consumer 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

417 CHAPTER 10 - COMPONENT APPENDIX

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

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));

customer.setName("Willem");

// We just put the response Object into the out message

body

exchange.getOut().setBody(customer);

}else {

Response r = Response.status(404).entity("Can't found the

customer with uri " + path).build();

throw new WebApplicationException(r);

}

if ("updateCustomer".equals(operationName)) {

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());

}

});

CHAPTER 10 - COMPONENT APPENDIX 418

}

};

}

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();

// 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");

}

});

// 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");

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 {

419 CHAPTER 10 - COMPONENT APPENDIX

exchange.setPattern(ExchangePattern.InOut);

Message inMessage = exchange.getIn();

// 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");

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:9003/

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<String,String> queryMap = new LinkedHashMap<String,String>();

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.

CHAPTER 10 - COMPONENT APPENDIX 420

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.

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 0Allows a delay in ms to be specified, which causes

consumers to pause in order to simulate slow consumers.

preloadSize 0Sets 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 till that the minimum rate of messages is raised

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

421 CHAPTER 10 - COMPONENT APPENDIX

</bean>

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.

Load testing ActiveMQ with Camel

There is an example of load testing an ActiveMQ queue using Camel in the ActiveMQ source

code repository. The code lives at this location:

• https://svn.apache.org/repos/asf/activemq/trunk/activemq-camel-loadtest/

You can grab the code as follows:

CHAPTER 10 - COMPONENT APPENDIX 422

svn co https://svn.apache.org/repos/asf/activemq/trunk/activemq-camel-loadtest/

Then try running the test case:

cd activemq-camel-loadtest

mvn clean install

To see how the test is defined, see the Spring XML file

Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Spring Testing

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.

423 CHAPTER 10 - COMPONENT APPENDIX

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.

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");

And the sample using spring DSL:

<route>

</route>

<route>

</route>

See also samples from the SEDA component, how they can be used together.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

CHAPTER 10 - COMPONENT APPENDIX 424

▪SEDA

▪VM

ESPER

The Esper component supports the Esper Library for Event Stream Processing. The camel-

esper 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 The Esper Pattern expression as a String to filter events

eql 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

• Configuring Camel

• Component

• Endpoint

• Getting Started

425 CHAPTER 10 - COMPONENT APPENDIX

• Esper Camel Demo

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]

file://directoryName[?options]

Where directoryName represents the underlying file directory.

CHAPTER 10 - COMPONENT APPENDIX 426

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.

You can append query options to the URI in the following format,

?option=value&option=value&...

URI Options

Common

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 to where the files should be written.

bufferSize 128kb Write buffer sized in bytes.

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.

Consumer only

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 false Set to true to use fixed delay between pools, otherwise fixed rate is used. See ScheduledExecutorService in JDK

for details.

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 Use Expression such as File Language 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 Use Expression such as File Language to dynamically set the filename when moving it after processing. To move files

into a .done subdirectory just enter .done.

moveFailed null

Use Expression such as File Language to dynamically set the filename when moving failed files after processing.

To move files into a error subdirectory just enter error.Note: When moving the files to another location it

can/will handle the error when you move it to another location so Camel cannot 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.

427 CHAPTER 10 - COMPONENT APPENDIX

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 that you can use. See also the section

Consuming files from folders where others drop files directly.

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<org.apache.camel.component.file.GenericFile> 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.

readLock markerFile

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 not avail for the FTP component.

▪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.

CHAPTER 10 - COMPONENT APPENDIX 428

readLockTimeout ▪

Optional timeout in milliseconds 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.

exclusiveReadLockStrategy null Pluggable read-lock as a

org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy implementation.

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.

maxMessagesPerPoll 0

An integer that defines 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 having the server read thousands of files as it starts up. Set a value of 0 or

negative to disabled it.

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.

• Only files (not directories) are matched for valid filename, if options such as:

include or exclude are used.

Producer only

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.

Default behavior for file producer

• By default it will override any existing file, if one exist with the same name.

429 CHAPTER 10 - COMPONENT APPENDIX

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.

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.

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.

CHAPTER 10 - COMPONENT APPENDIX 430

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:

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.

File consumer only

Header Description

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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).

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.

CamelFileAbsolute

Aboolean 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 Along value containing the file size.

CamelFileLastModified ADate value containing the last modified timestamp of

the file.

Batch Consumer

This component implements the Batch Consumer.

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.

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CamelBatchIndex The current index of the batch. Starts from 0.

CamelBatchComplete Aboolean 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

Aggregator 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: ID-

MACHINENAME-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.

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

433 CHAPTER 10 - COMPONENT APPENDIX

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.

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.

Reading recursive from a directory and write the 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 sub-

directories. 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:

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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

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.

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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 contents what is probably what you want.

The route above using Spring DSL:

<route>

</route>

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 processes 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");

}

};

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}

private 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");

}

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:

<route>

</route>

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 sub-

folder name:

from("file://inbox?move=backup/${date:now:yyyyMMdd}/${file:name}").to("...");

See File Language for more samples.

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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 storing 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.

<route>

</route>

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 store the key in separate lines in the file. By default, the file store

has a size limit of 1mb when the file grew larger Camel will truncate the file store be rebuilding

the content by flushing the 1st level cache in 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:

<!-- this is our file based idempotent store configured to use the .filestore.dat as

file -->

<bean id="fileStore"

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class="org.apache.camel.processor.idempotent.FileIdempotentRepository">

<!-- the max filesize in bytes for the file. Camel will trunk and flush the cache

if the file gets bigger -->

</bean>

<route>

<from uri="file://target/fileidempotent/

?idempotent=true&idempotentRepository=#fileStore&move=done/${file:name}"/>

</route>

</camelContext>

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.

<persistence-unit name="idempotentDb" transaction-type="RESOURCE_LOCAL">

<class>org.apache.camel.processor.idempotent.jpa.MessageProcessed</class>

<property name="openjpa.ConnectionURL" value="jdbc:derby:target/

idempotentTest;create=true"/>

<property name="openjpa.ConnectionDriverName"

value="org.apache.derby.jdbc.EmbeddedDriver"/>

</properties>

</persistence-unit>

Then we need to setup a Spring jpaTemplate in the spring XML file:

</bean>

<bean id="entityManagerFactory"

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class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">

<!-- we use idempotentDB as the persitence unit name defined in the

persistence.xml file -->

</bean>

And finally we can create our JPA idempotent repository in the spring XML file as well:

<!-- we define our jpa based idempotent repository we want to use in the file consumer

-->

<bean id="jpaStore"

class="org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository">

<constructor-arg index="0" ref="jpaTemplate"/>

<!-- This 2nd parameter is the name (= a cateogry name).

You can have different repositories with different names -->

<constructor-arg index="1" value="FileConsumer"/>

</bean>

And yes then we just need to refer to the jpaStore bean in the file consumer endpoint using

the [[idempotentRepository}} using the #syntax option:

<route>

</route>

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 build 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 defines in the spring XML file:

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<route>

</route>

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:

<!-- use myFilter as filter to allow setting ANT paths for which files to scan for

-->

<endpoint id="myFileEndpoint" uri="file://target/

antpathmatcher?recursive=true&filter=#myAntFilter"/>

<route>

</route>

</camelContext>

<bean id="myAntFilter"

class="org.apache.camel.component.file.AntPathMatcherGenericFileFilter">

<!-- exclude all files with bad in name or .xml files. Use comma to seperate

multiple excludes -->

</bean>

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.

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In the sample we have built our own comparator that just sorts by file name:

public class MyFileSorter implements Comparator<GenericFile> {

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:

<route>

</route>

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:size

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:

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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.

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

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.

443 CHAPTER 10 - COMPONENT APPENDIX

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 have 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

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪File Language

▪FTP2

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-flatpack</artifactId>

</dependency>

URI format

flatpack:[delim|fixed]:flatPackConfig.pzmap.xml[?options]

Or for a delimited file handler with no configuration file just use

CHAPTER 10 - COMPONENT APPENDIX 444

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.

•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

445 CHAPTER 10 - COMPONENT APPENDIX

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.

</RECORD>

</RECORD>

Using the endpoint

A common use case is sending a file to this endpoint for further processing in a separate route.

For example:

CHAPTER 10 - COMPONENT APPENDIX 446

<route>

</route>

<route>

...

</route>

</camelContext>

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<Map<String, Object>> 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.

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)

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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.

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-flatpack</artifactId>

</dependency>

CHAPTER 10 - COMPONENT APPENDIX 448

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-freemarker</artifactId>

</dependency>

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&...

Options

Option Default Description

contentCache true Cache for the resource content when its loaded.

encoding null Character encoding of the resource content.

Headers

Camel will store a reference to the resource in the message header in the key

org.apache.camel.freemarker.resource. The Resource is an

449 CHAPTER 10 - COMPONENT APPENDIX

org.springframework.core.io.Resource object. And the key

org.apache.camel.freemarker.resourceUri holds the templateName as a

String object.

Note From Camel 2.1 and Camel 1.6.2, freemarker endpoint will not store these headers

into to message, as these header will cause some side effect on the dynamic templates feature.

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.

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

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

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CamelFreemarkerResourceUri String Camel 2.1: A URI for the template resource to

use instead of the endpoint configured.

CamelFreemarkerTemplate 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("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("CamelFreemarkerResourceUri").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

• Component

• Endpoint

• Getting Started

CHAPTER 10 - COMPONENT APPENDIX 452

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-ftp</artifactId>

</dependency>

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.

The username is currently only possible to provide in the hostname parameter.

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&...

URI Options

The options below are exclusive for the FTP2 component.

Name Default

Value Description

password null Specifies the password to use to log in to the remote file system.

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.

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.

453 CHAPTER 10 - COMPONENT APPENDIX

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.

Using FTPS

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.

Libraries used

This component uses two different libraries for the actual FTP work. FTP and FTPS

uses Apache Commons Net while SFTP uses JCraft JSCH.

execProt null

Camel 2.4: FTPS only: This option specifies the protection level. If option useSecureDataChannel

has been enabled and this option has not been explicit set, then value Pis used. 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 0is 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.

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.

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.

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.

CHAPTER 10 - COMPONENT APPENDIX 454

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.

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:

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.serverLanguageCode=fr").to("bean:foo");

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:

</bean>

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

ftp://someoneelse@someotherftpserver.co.uk:12049/reports/2008/

455 CHAPTER 10 - COMPONENT APPENDIX

FTPS component default trust store

By default, the FTPS component 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.

See File2 as all the options there also applies for this component.

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 explicit 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. And there is only a few options supported for FTP.

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

CHAPTER 10 - COMPONENT APPENDIX 456

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.

In the future we will add consumer pooling to Camel to allow this consumer to support

concurrency as well.

More information

This component is an extension of the File2 component. So there are more samples

and details on the File2 component page.

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 end-

users 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.

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

457 CHAPTER 10 - COMPONENT APPENDIX

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");

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

// notice that the FTPConsumer properties must be prefixed with

"consumer." in the URL

// the delay parameter is from the FileConsumer component so we should use

consumer.delay as

// the URI parameter name. The FTP Component is an extension of the File

Component.

from("ftp://scott@localhost/public/reports?password=tiger&binary=true&consumer.delay="

+ delay).

to("file://target/test-reports");

}

};

}

And the route using Spring DSL:

<route>

<from uri="ftp://scott@localhost/public/

reports?password=tiger&binary=true&delay=60000"/>

</route>

CHAPTER 10 - COMPONENT APPENDIX 458

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.

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 build 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");

}

459 CHAPTER 10 - COMPONENT APPENDIX

And then we can configure our route using the filter attribute to reference our filter (using #

notation) that we have defines in the spring XML file:

<route>

</route>

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:

<!-- use myFilter as filter to allow setting ANT paths for which files to scan for

-->

<endpoint id="myFTPEndpoint" uri="ftp://admin@localhost:20123/

antpath?password=admin&recursive=true&delay=10000&initialDelay=2000&filter=#myAntFilter"/>

<route>

</route>

</camelContext>

<!-- we use the AntPathMatcherRemoteFileFilter to use ant paths for includes and

exlucde -->

<bean id="myAntFilter"

class="org.apache.camel.component.file.AntPathMatcherGenericFileFilter">

<!-- exclude all files with bad in name or .xml files. Use comma to seperate

multiple excludes -->

</bean>

CHAPTER 10 - COMPONENT APPENDIX 460

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 Not supported yet.

XMPP

service Not supported yet.

Images

service Not supported yet.

Datastore

service Not supported yet.

461 CHAPTER 10 - COMPONENT APPENDIX

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.

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.

Camel context

Setting up a SpringCamelContext on Google App Engine differs between Camel 2.1 and

Camel 2.2. 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.

• Camel 2.1 depends on the Google App Engine SDK 1.2.6 which doesn't support

JAXB. Refer to the Camel 2.1 subsection for instructions how to set up a

SpringCamelContext with Camel 2.1 on GAE.

• Camel 2.2 depends on the Google App Engine SDK 1.2.8, the first version that

introduces support for JAXB. Refer to the Camel 2.2 or higher subsection for

instructions how to set up a SpringCamelContext with Camel 2.2 on GAE.

• Camel 2.3 depends on the Google App Engine SDK 1.3.2.

In all versions, JMX must be disabled 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)

CHAPTER 10 - COMPONENT APPENDIX 462

•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 17.Listing 17. appctx.xmlappctx.xml

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<bean id="camelContext"

class="org.apache.camel.component.gae.context.GaeSpringCamelContext">

</bean>

<bean id="myRouteBuilder"

class="org.example.MyRouteBuilder">

</bean>

</beans>

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, 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 18.Listing 18. appctx.xmlappctx.xml

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:camel="http://camel.apache.org/schema/spring"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd">

<camel:camelContext id="camelContext">

<camel:jmxAgent id="agent" disabled="true" />

<camel:routeBuilder ref="myRouteBuilder"/>

</camel:camelContext>

463 CHAPTER 10 - COMPONENT APPENDIX

<bean id="myRouteBuilder"

class="org.example.MyRouteBuilder">

</bean>

</beans>

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 19.Listing 19. web.xmlweb.xml

<web-app

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="

http://java.sun.com/xml/ns/javaee

http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">

<servlet-name>CamelServlet</servlet-name>

<servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class>

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>appctx.xml</param-value>

</init-param>

</servlet>

<!--

Mapping used for external requests

-->

<servlet-mapping>

<servlet-name>CamelServlet</servlet-name>

<url-pattern>/camel/*</url-pattern>

</servlet-mapping>

<!--

Mapping used for web hooks accessed by task queueing service.

-->

<servlet-mapping>

<servlet-name>CamelServlet</servlet-name>

<url-pattern>/worker/*</url-pattern>

</servlet-mapping>

</web-app>

CHAPTER 10 - COMPONENT APPENDIX 464

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://<appname>.appspot.com/camel/... when deployed to Google App Engine

where <appname> 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.

HDFS COMPONENT

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.

It can only be built using JDK1.6 or later because this is a strict requirement for Hadoop itself.

This component is hosted at http://github.com/dgreco/camel-hdfs. We decided to put it

temporarily on this github because currently Camel is being built and tested using JDK1.5 and

for this reason we couldn't put that component into the Camel official distribution. Hopefully,

as soon Camel will allow to use JDK1.6 for building and testing we will put it into the trunk.

This component is developed and tested using the latest Camel snapshot, but it should work

seamlessly with the latest Camel GA version (at the time of writing 2.1.0)

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

Name Default

Value Description

overwrite true The file can be overwritten

bufferSize 4096 The buffer size used by HDFS

465 CHAPTER 10 - COMPONENT APPENDIX

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

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

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:

469 CHAPTER 10 - COMPONENT APPENDIX

<groupId>org.apache.camel</groupId>

<artifactId>camel-hl7</artifactId>

</dependency>

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:

<endpoint id="hl7listener"

uri="mina:tcp://localhost:8888?sync=true&codec=hl7codec"/>

CHAPTER 10 - COMPONENT APPENDIX 470

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:

</bean>

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:

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:

<bean id="patientLookupService"

class="com.mycompany.healtcare.service.PatientLookupService"/>

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.

471 CHAPTER 10 - COMPONENT APPENDIX

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||

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");

CHAPTER 10 - COMPONENT APPENDIX 472

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:

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

473 CHAPTER 10 - COMPONENT APPENDIX

Camel 2.0

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

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

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).

<groupId>org.apache.camel</groupId>

<artifactId>camel-hl7</artifactId>

</dependency>

CHAPTER 10 - COMPONENT APPENDIX 474

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:

<artifactId>hapi-structures-v24</artifactId>

</dependency>

<artifactId>hapi-structures-v25</artifactId>

</dependency>

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.

</dependency>

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||";

475 CHAPTER 10 - COMPONENT APPENDIX

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();

}

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

// make the routing much easier (see below)

.unmarshal(hl7)

// using choice as the content base router

CHAPTER 10 - COMPONENT APPENDIX 476

.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.

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:

477 CHAPTER 10 - COMPONENT APPENDIX

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-http</artifactId>

</dependency>

URI format

http:hostname[:port][/resourceUri][?options]

Will by default use port 80 for HTTP and 443 for HTTPS.

You can append query options to the URI in the following format,

?option=value&option=value&...

CHAPTER 10 - COMPONENT APPENDIX 478

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

HttpEndpoint Options

Name Default

Value Description

throwExceptionOnFailure true Camel 2.0: 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

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 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

Camel 2.3: 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 Camel 2.3: 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 Camel 2.3: 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 Camel 2.3: To use a custom org.apache.http.conn.ClientConnectionManager.

The following authentication options can also be set on the HttpEndpoint:

Camel 2.2 or older: Setting Authentication and Proxy

Name Default Value Description

username null Username for authentication.

password null Password for authentication.

domain null Camel 2.1: Domain for NTML Authentication. This option must be used to force NTML authentication.

proxyHost null Camel 1.6.2: The proxy host name

proxyPort null Camel 1.6.2: The proxy port number

proxyUsername null Camel 1.6.2: Username for proxy authentication

proxyPassword null Camel 1.6.2: Password for proxy authentication

Camel 2.3 or newer: HttpConfiguration - Setting

Authentication and Proxy

Name Default Value Description

479 CHAPTER 10 - COMPONENT APPENDIX

authMethod null Authentication method, either as Basic,Digest or NTLM.

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 Camel 2.3: 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

Camel 1.x

Name Type Description

HttpProducer.HTTP_URI String Camel 1.6.0: URI to call. Will override existing URI set directly on the endpoint. Is set on the In message.

HttpProducer.HTTP_RESPONSE_CODE int The HTTP response code from the external server. Is 200 for OK. Is set on the Out message.

HttpProducer.QUERY String URI parameters. Will override existing URI parameters set directly on the endpoint. Is set on the In message.

CHAPTER 10 - COMPONENT APPENDIX 480

Camel 2.x

Name Type Description

Exchange.HTTP_URI String URI to call. Will override existing URI set directly on the endpoint.

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.

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 Camel 2.3: The HttpServletRequest object.

Exchange.HTTP_SERVLET_RESPONSE HttpServletResponse Camel 2.3: The HttpServletResponse object.

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

In Camel 1.5 the following algorithm is used to determine if either GET or POST HTTP

method should be used:

1. Use method provided in header.

481 CHAPTER 10 - COMPONENT APPENDIX

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.

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.

How to get access to HttpServletRequest and HttpServletResponse

Available as of Camel 2.0

You can get access to these two using the Camel type converter system using

NOTE from Camel 2.3.0 you can get the request and response not just from the processor

after the camel-jetty or camel-cxf endpoint.

HttpServletRequest request = exchange.getIn().getBody(HttpServletRequest.class);

HttpServletRequest response = exchange.getIn().getBody(HttpServletResponse.class);

Configuring URI to call

You can set the HTTP producer's URI directly form the endpoint URI. In the route below,

Camel will call out to the external server, oldhost, using HTTP.

from("direct:start")

.to("http://oldhost");

And the equivalent Spring sample:

<route>

</route>

</camelContext>

In Camel 1.5.1 you can override the HTTP endpoint URI by adding a header with the key,

HttpProducer.HTTP_URI, on the message.

CHAPTER 10 - COMPONENT APPENDIX 482

from("direct:start")

.setHeader(org.apache.camel.component.http.HttpProducer.HTTP_URI,

constant("http://newhost"))

.to("http://oldhost");

In the sample above Camel will call the http://newhost despite the endpoint is configured with

http://oldhost.

And the same code in Camel 2.0:

from("direct:start")

.setHeader(HttpConstants.HTTP_URI, constant("http://newhost"))

.to("http://oldhost");

Where Constants is the class, org.apache.camel.component.http.Constants.

Configuring URI Parameters

Camel 1.x

The http producer supports URI parameters to be sent to the HTTP server. The URI

parameters can either be set directly on the endpoint URI or as a header with the key

HttpProducer.QUERY on the message.

from("direct:start")

.to("http://oldhost?order=123&detail=short");

Or options provided in a header:

from("direct:start")

.setHeader(HttpConstants.HTTP_QUERY, constant("order=123&detail=short"))

.to("http://oldhost");

Camel 2.x

The http producer supports URI parameters to be sent to the HTTP server. The URI

parameters can either be set directly on the endpoint URI or as a header with the key

Exchange.HTTP_QUERY on the message.

from("direct:start")

.to("http://oldhost?order=123&detail=short");

Or options provided in a header:

483 CHAPTER 10 - COMPONENT APPENDIX

from("direct:start")

.setHeader(Exchange.HTTP_QUERY, constant("order=123&detail=short"))

.to("http://oldhost");

How to set the http method (GET/POST/PUT/DELETE/HEAD/OPTIONS/

TRACE) to the HTTP producer

The HTTP component provides a way to set the HTTP request method by setting the message

header. Here is an example;

Camel 1.x

from("direct:start")

.setHeader(HttpConstants.HTTP_METHOD,

constant(org.apache.camel.component.http.HttpMethods.POST))

.to("http://www.google.com")

.to("mock:results");

Camel 2.x

from("direct:start")

.setHeader(Exchange.HTTP_METHOD,

constant(org.apache.camel.component.http.HttpMethods.POST))

.to("http://www.google.com")

.to("mock:results");

The method can be written a bit shorter using the string constants:

.setHeader("CamelHttpMethod", constant("POST"))

And the equivalent Spring sample:

<route>

</setHeader>

</route>

</camelContext>

Using client tineout - SO_TIMEOUT

See the unit test in this link

CHAPTER 10 - COMPONENT APPENDIX 484

Configuring a Proxy

Only for >= Camel 1.6.2

The HTTP component provides a way to configure a proxy.

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

*Only for >= Camel 1.6.2 and < Camel 2.2.0 *

The HTTP component will detect Java System Properties for http.proxyHost and

http.proxyPort and use them if provided.

See more at SUN http proxy documentation.

To avoid the System properties conflicts, from Camel 2.2.0 you can only set the proxy

configure from CameContext or URI.

Java DSL :

context.getProperties().put("http.proxyHost","172.168.18.9");

context.getProperties().put("http.proxyPort" "8080");

Spring XML

</properties>

</camelContext>

Camel will first set the settings from Java System or CamelContext Properties and then the

endpoint proxy options if provided.

So you can override the system properties with the endpoint options.

Configuring charset

If you are using POST to send data you can configure the charset using the Exchange

property:

exchange.setProperty(Exchange.CHARSET_NAME, "iso-8859-1");

485 CHAPTER 10 - COMPONENT APPENDIX

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");

URI Parameters from the endpoint URI

In this sample we have the complete URI endpoint that is just what you would have typed in a

web browser. Multiple URI parameters can of course be set using the &character as separator,

just as you would in the web browser. Camel does no tricks here.

// we query for Camel at the Google page

template.sendBody("http://www.google.com/search?q=Camel",null);

URI Parameters from the Message

Map headers = new HashMap();

headers.put(HttpProducer.QUERY, "q=Camel&lr=lang_en");

// we query for Camel and English language at Google

template.sendBody("http://www.google.com/search",null, headers);

In the header value above notice that it should not be prefixed with ?and you can separate

parameters as usual with the &char.

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(HttpProducer.QUERY,

constant("hl=en&q=activemq"));

}

});

CHAPTER 10 - COMPONENT APPENDIX 486

Message out = exchange.getOut();

int responseCode = out.getHeader(HttpProducer.HTTP_RESPONSE_CODE, Integer.class);

Using throwExceptionOnFailure=false to get any response back

Available as of Camel 2.0

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:8222/

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:8222/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

487 CHAPTER 10 - COMPONENT APPENDIX

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

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.

</bean>

<bean id="myHttpConnectionManager"

class="org.apache.commons.httpclient.MultiThreadedHttpConnectionManager">

</bean>

<bean id="myHttpConnectionManagerParams"

class="org.apache.commons.httpclient.params.HttpConnectionManagerParams">

</bean>

And then we can just use it as we normally do in our routes:

<route>

</route>

</camelContext>

CHAPTER 10 - COMPONENT APPENDIX 488

Using HTTPS to authenticate gotchas

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

Accepting self signed certifications 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

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:

<bean id="myHttpClientConfigurer"

class="my.https.HttpClientConfigurer">

</bean>

<to uri="https://myhostname.com:443/

myURL?httpClientConfigurerRef=myHttpClientConfigurer"/>

489 CHAPTER 10 - COMPONENT APPENDIX

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

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-ibatis</artifactId>

</dependency>

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.

CHAPTER 10 - COMPONENT APPENDIX 490

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

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.

491 CHAPTER 10 - COMPONENT APPENDIX

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.

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.

CHAPTER 10 - COMPONENT APPENDIX 492

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

)

values (

#id#, #firstName#, #lastName#, #emailAddress#

)

</insert>

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:

493 CHAPTER 10 - COMPONENT APPENDIX

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").to("activemq:queue:allAccounts");

And the iBatis SQL map file used:

select * from ACCOUNT

</select>

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:

CHAPTER 10 - COMPONENT APPENDIX 494

select * from ACCOUNT where PROCESSED = false

</select>

update ACCOUNT set PROCESSED = true where ACC_ID = #id#

</update>

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-irc</artifactId>

</dependency>

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&...

495 CHAPTER 10 - COMPONENT APPENDIX

Options

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.

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

SSL Support

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.

CHAPTER 10 - COMPONENT APPENDIX 496

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

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-javaspace</artifactId>

</dependency>

URI format

javaspace:jini://host[?options]

497 CHAPTER 10 - COMPONENT APPENDIX

You can append query options to the URI in the following format,

?option=value&option=value&...

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")

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.

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:

from("direct:input").to("javaspace:jini://localhost?spaceName=mySpace");

//Client side

from("javaspace:jini://localhost?concurrentConsumers=10&spaceName=mySpace").to("pojo:pojo");

//Server side

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.

Options

Name Default Value Description

CHAPTER 10 - COMPONENT APPENDIX 498

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.

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 URI-

format).

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.

499 CHAPTER 10 - COMPONENT APPENDIX

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

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,robust-

in-out and in-optional-out.

CHAPTER 10 - COMPONENT APPENDIX 500

operation

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.

serialization 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.

convertException 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 non-

serializable 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");

501 CHAPTER 10 - COMPONENT APPENDIX

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:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/

XMLSchema-instance"

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/

maven-v4_0_0.xsd">

<groupId>myGroupId</groupId>

<artifactId>myArtifactId</artifactId>

<packaging>jbi-service-unit</packaging>

<version>1.0-SNAPSHOT</version>

<name>A Camel based JBI Service Unit</name>

<url>http://www.myorganization.org</url>

<camel-version>1.0.0</camel-version>

<servicemix-version>3.3</servicemix-version>

</properties>

<groupId>org.apache.servicemix</groupId>

<artifactId>servicemix-camel</artifactId>

<version>${servicemix-version}</version>

</dependency>

<groupId>org.apache.servicemix</groupId>

<artifactId>servicemix-core</artifactId>

<version>${servicemix-version}</version>

CHAPTER 10 - COMPONENT APPENDIX 502

<scope>provided</scope>

</dependency>

</dependencies>

<build>

<defaultGoal>install</defaultGoal>

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-compiler-plugin</artifactId>

</configuration>

</plugin>

<groupId>org.apache.servicemix.tooling</groupId>

<artifactId>jbi-maven-plugin</artifactId>

<version>${servicemix-version}</version>

</plugin>

</plugins>

</build>

</project>

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 (JSR-170) compliant content repository

(for example, Apache Jackrabbit ).

Maven users will need to add the following dependency to their pom.xml for this

component:

503 CHAPTER 10 - COMPONENT APPENDIX

<groupId>org.apache.camel</groupId>

<artifactId>camel-jcr</artifactId>

</dependency>

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

CHAPTER 10 - COMPONENT APPENDIX 504

• 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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-jdbc</artifactId>

</dependency>

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 Default

Value Description

readSize 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.

505 CHAPTER 10 - COMPONENT APPENDIX

This component can only be used to define producer endpoints, which means that

you cannot use the JDBC component in a from() statement.

statement.<xxx> 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.

useJDBC4ColumnNameAndLabelSemantics 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).

Result

The result is returned in the OUT body as an ArrayList<HashMap<String,

Object>>. 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.

CHAPTER 10 - COMPONENT APPENDIX 506

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:

JndiRegistry reg = super.createRegistry();

reg.bind("testdb", ds);

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:

<route>

<constant>select * from customer</constant>

</setBody>

</route>

</camelContext>

</bean>

507 CHAPTER 10 - COMPONENT APPENDIX

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<HashMap<String,Object>> data = out.getOut().getBody(ArrayList.class);

assertNotNull("out body could not be converted to an ArrayList - was: "

+ out.getOut().getBody(), data);

assertEquals(2, data.size());

HashMap<String,Object> row = data.get(0);

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

CHAPTER 10 - COMPONENT APPENDIX 508

• Component

• Endpoint

• Getting Started

▪SQL

JETTY COMPONENT

Supports non blocking Request Reply producer in Camel 2.1 onwards

The jetty component provides HTTP-based endpoints for consuming HTTP requests. That

is, the Jetty component behaves as a simple Web server.

In Camel 2.1 the jetty component also provides non blocking Request Reply for

producing HTTP requests. That is it can also acts as HTTP client sending to a remote HTTP

server and use non blocking in this process. See more at ToAsync and the HTTP Async

Example.

URI format

jetty:http://hostname[:port][/resourceUri][?options]

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.

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.

509 CHAPTER 10 - COMPONENT APPENDIX

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.

disableStreamCache 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. |

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

CHAPTER 10 - COMPONENT APPENDIX 510

Sample

In this sample we define a route that exposes a HTTP service at

http://localhost:8080/myapp/myservice:

from("jetty:http://localhost:9080/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

HttpServletRequest req = exchange.getIn().getBody(HttpServletRequest.class);

assertNotNull(req);

// for unit testing

assertEquals("bookid=123", body);

// send a html response

exchange.getOut().setBody("<html><body>Book 123 is Camel in

Action</body></html>");

}

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("in.header.one").to("mock:one")

.otherwise()

.to("mock:other");

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.

511 CHAPTER 10 - COMPONENT APPENDIX

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.

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:

<route><from uri="jetty:http://0.0.0.0/myapp/myservice/

?sessionSupport=true"/><processRef ref="myCode"/><route>

The myCode Processor can be instantiated by a Spring bean element:

Where the processor implementation can access the HttpSession as follows:

publicvoid process(Exchange exchange)throwsException { HttpSession session =

((HttpExchange)exchange).getRequest().getSession(); ... }

SSL Support (HTTPS)

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:

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.

CHAPTER 10 - COMPONENT APPENDIX 512

•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:

Error formatting macro: clickable: java.lang.AbstractMethodError 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

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property

name="sslSocketConnector"> <bean

class="org.mortbay.jetty.security.SslSocketConnector"> <property

name="password"value="..."/> <property name="keyPassword"value="..."/> <property

name="keystore"value="..."/> <property name="wantClientAuth"value="..."/> <property

name="truststore"value="..."/> </bean> </property> </bean>

until Camel 2.2

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property

name="sslSocketConnectors"> <map> <entry key="8043"> <bean

class="org.mortbay.jetty.security.SslSocketConnector"> <property

name="password"value="..."/> <property name="keyPassword"value="..."/> <property

name="keystore"value="..."/> <property name="needClientAuth"value="..."/> <property

name="truststore"value="..."/> </bean> </entry> </map> </property> </bean>

from Camel 2.3 onwards

513 CHAPTER 10 - COMPONENT APPENDIX

<bean id="jetty"class="org.apache.camel.component.jetty.JettyHttpComponent"> <property

name="sslSocketConnectors"> <map> <entry key="8043"> <bean

class="org.eclipse.jetty.server.ssl.SslSocketConnector"> <property

name="password"value="..."/> <property name="keyPassword"value="..."/> <property

name="keystore"value="..."/> <property name="needClientAuth"value="..."/> <property

name="truststore"value="..."/> </bean> </entry> </map> </property> </bean>

The value you use as keys in the above map is the port you configure Jetty to listen on.

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 MyHttpBinding extends DefaultHttpBinding {

@Override

public void doWriteExceptionResponse(Throwable exception, HttpServletResponse

response) throws IOException {

// we override the doWriteExceptionResponse as we only want to alter the

binding how exceptions is

// written back to the client.

// we just return HTTP 200 so the client thinks its okay

response.setStatus(200);

// and we return this fixed text

response.getWriter().write("Something went wrong but we dont care");

}

CHAPTER 10 - COMPONENT APPENDIX 514

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:

<route><from uri="jetty:http://0.0.0.0:8080/myapp/

myservice?httpBindingRef=mybinding"/><to uri="bean:doSomething"/></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 --><bean

id="userRealm"class="org.mortbay.jetty.plus.jaas.JAASUserRealm"><property

name="name"value="tracker-users"/><property

name="loginModuleName"value="ldaploginmodule"/></bean><bean

id="constraint"class="org.mortbay.jetty.security.Constraint"><property

name="name"value="BASIC"/><property name="roles"value="tracker-users"/><property

name="authenticate"value="true"/></bean><bean

id="constraintMapping"class="org.mortbay.jetty.security.ConstraintMapping"><property

name="constraint"ref="constraint"/><property name="pathSpec"value="/*"/></bean><bean

id="securityHandler"class="org.mortbay.jetty.security.SecurityHandler"><property

name="userRealm"ref="userRealm"/><property

name="constraintMappings"ref="constraintMapping"/></bean>

And from Camel 2.3 onwards you can configure a list of Jetty handlers as follows:

<-- Jetty Security handling --><bean

id="constraint"class="org.eclipse.jetty.http.security.Constraint"><property

name="name"value="BASIC"/><property name="roles"value="tracker-users"/><property

name="authenticate"value="true"/></bean><bean

id="constraintMapping"class="org.eclipse.jetty.security.ConstraintMapping"><property

name="constraint"ref="constraint"/><property name="pathSpec"value="/*"/></bean><bean

id="securityHandler"class="org.eclipse.jetty.security.ConstraintSecurityHandler"><property

name="authenticator"><bean

class="org.eclipse.jetty.security.authentication.BasicAuthenticator"/></property><property

name="constraintMappings"><list><ref

bean="constraintMapping"/></list></property></bean>

You can then define the endpoint as:

from("jetty:http://0.0.0.0:9080/myservice?handlers=securityHandler")

515 CHAPTER 10 - COMPONENT APPENDIX

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:8234/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"));

Multi-part Form support

From Camel 2.3.0, camel-jetty support to multipart form post out of box. The submitted form-

data 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.

// 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:9080/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);

assertEquals("Get a wrong content type","text/plain", data.getContentType());

CHAPTER 10 - COMPONENT APPENDIX 516

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

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

517 CHAPTER 10 - COMPONENT APPENDIX

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-jing</artifactId>

</dependency>

Note that the MSV component can also support RelaxNG XML syntax.

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

CHAPTER 10 - COMPONENT APPENDIX 518

or not the XML matches the given RelaxNG Compact Syntax schema (which is supplied on the

classpath).

<route>

<doTry>

<exception>org.apache.camel.ValidationException</exception>

</doCatch>

</doFinally>

</doTry>

</route>

</camelContext>

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-jms</artifactId>

</dependency>

519 CHAPTER 10 - COMPONENT APPENDIX

Using ActiveMQ

If you are using Apache ActiveMQ, you should prefer the ActiveMQ component as

it has been particularly optimized for ActiveMQ. All of the options and samples on

this page are also valid for the ActiveMQ component.

URI format

jms:[temp:][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

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 can append query options to the URI in the following format,

?option=value&option=value&...

Using Temporary Destinations

As of Camel 1.4.0, you can access temporary queues using the following URL format:

jms:temp:queue:foo

Or temporary topics using the following URL format:

jms:temp:topic:bar

CHAPTER 10 - COMPONENT APPENDIX 520

This URL format enables multiple routes or processors or beans to refer to the same

temporary destination. For example, you can create three temporary destinations and use them

in routes as inputs or outputs by referring to them by name.

Notes

If you wish to use durable topic subscriptions, you need to specify both clientId and

durableSubscriptionName. Note that 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.

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:

▪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. Note: 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.

The options is divided into two tables, the first one with the most common options used.

The latter contains the rest.

521 CHAPTER 10 - COMPONENT APPENDIX

If you are using ActiveMQ

Note that 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 performance being lousy.

So 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 configured to use

ActiveMQ efficiently, or

• Use the PoolingConnectionFactory in ActiveMQ.

For Consuming Messages cacheLevelName settings are vital!

If you are using Spring before 2.5.1 and Camel before 1.3.0, you might want to set

the cacheLevelName to be CACHE_CONSUMER for maximum performance.

Due to a bug in earlier Spring versions causing a lack of transactional integrity, previous

versions of Camel and Camel versions from 1.3.0 onwwards when used with Spring versions

earlier than 2.5.1 will default to using CACHE_CONNECTION. See the JIRAs CAMEL-163 and

CAMEL-294.

Also, if you are using XA resources or running in a J2EE container, you may want to set

the cacheLevelName to be CACHE_NONE as we have found that when using JBoss with

TibCo EMS and JTA/XA you must disable caching.

Another user reports problems using WebSphere MQ 6.0.2.5, Camel 1.6.0 and Spring

2.5.6. The application does not use XA and is not running inside a J2EE Container, but the

cacheLevelName=CACHE_NONE setting seems to solve the problem with WebSphere

MQ.

See also more about JmsTemplate gotchas.

Most commonly used options

Option Default

Value Description

autoStartup true Specifies whether the consumer container should auto-startup.

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.

CHAPTER 10 - COMPONENT APPENDIX 522

For users with Camel 1.6.1 or older

JMS consumers have a bad default in Camel 1.6.1 or older. The

maxMessagesPerTask is set to 1, whereas it really should be -1.

This issue causes Spring to create a new thread after it has processed a message,

causing the thread count to rise continuously. You can see this in the log where a

new thread name is used.

To remedy this, change a route such as:

By adding the maxMessagesPerTask option and setting its value to -1, as follows:

This has been fixed in Camel 1.6.2/2.0.

durableSubscriptionName null The durable subscriber name for specifying durable topic subscriptions.

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().

requestTimeout 20000 The timeout for sending messages (in milliseconds). The default is 20 seconds.

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).

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.

All the other options

Option Default

Value Description

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.

523 CHAPTER 10 - COMPONENT APPENDIX

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)

cacheLevelName CACHE_CONSUMER 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. See the Spring documentation and see the warning above.

cacheLevel -1 Sets the cache level by ID for the underlying JMS resources.

consumerType Default

The consumer type to use, which can be one of: Simple,Default or ServerSessionPool. 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, and ServerSessionPool

will use

org.springframework.jms.listener.serversession.ServerSessionMessageListenerContainer.

If the option, useVersion102=true, Camel will use the JMS 1.0.2 Spring classes instead. ServerSessionPool is

@deprecated and will be removed in Camel 2.0.

connectionFactory null The default JMS connection factory to use for the listenerConnectionFactory and

templateConnectionFactory, if neither is specified.

deliveryMode 2 Specifies the delivery mode when sending, where 1 = non-persistent, and 2 = persistent.

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).

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.

exceptionListener null Specifies the JMS Exception Listener that is to be notified of any underlying JMS exceptions.

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.

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).

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.

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).

CHAPTER 10 - COMPONENT APPENDIX 524

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.

replyToTempDestinationAffinity producer

Defines the component-created temporary replyTo destination sharing strategy. Possible values are: component,

endpoint or producer.component = a single temp queue is shared among all producers for a given component

instance; endpoint = a single temp queue is shared among all producers for a given endpoint instance; producer = a

single temp queue is created for each producer.

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.

serverSessionFactory null @deprecated - will be removed in Camel 2.0. The JMS ServerSessionFactory, if you wish to use

ServerSessionFactory for consumption

subscriptionDurable false Enabled by default, if you specify a durableSubscriberName and a clientId.

taskExecutor null 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 null 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. Be careful:

When this option is set camel will ignore the incoming correlation id and always use the message id instead. Camel will by

default use a GUID.

useVersion102 false @deprecated: Specifies whether the old JMS API should be used. Will be removed in Camel 2.2, as JMS API 1.0.2 is no

longer provided in Spring 3.0.

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

org.w3c.dom.Node javax.jms.TextMessage The DOM will be

converted to String.

Map javax.jms.MapMessage

java.io.Serializable javax.jms.ObjectMessage

byte[] javax.jms.BytesMessage

525 CHAPTER 10 - COMPONENT APPENDIX

java.io.File javax.jms.BytesMessage

java.io.Reader javax.jms.BytesMessage

java.io.InputStream javax.jms.BytesMessage

java.nio.ByteBuffer javax.jms.BytesMessage

When receiving a JMS message, Camel converts the JMS message to the following body type:

JMS Message Body Type

javax.jms.TextMessage String

javax.jms.BytesMessage byte[]

javax.jms.MapMessage Map<String, Object>

javax.jms.ObjectMessage Object

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

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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.

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:

527 CHAPTER 10 - COMPONENT APPENDIX

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:

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.

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:

CHAPTER 10 - COMPONENT APPENDIX 528

▪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

Camel sees this as a contradiction and will suppress the

JMSReplyTo. In fact, Camel will disable it by clearing it

before sending. Camel will send the message and not

expect a reply. Camel logs this in the log at WARN level and

you should see: WARN JmsProducer - Disabling

JMSReplyTo as this Exchange is not OUT

capable with JMSReplyTo: myReplyQueue to

destination: myQueue.Note: You can use the

preserveMessageQos=true setting or the

explicitQosEnabled=true setting to force Camel to

send the JMSReplyTo anyway, and the WARN log will

disappear.

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.

529 CHAPTER 10 - COMPONENT APPENDIX

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.

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:

CHAPTER 10 - COMPONENT APPENDIX 530

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.

Configuring different JMS providers

You can configure your JMS provider in Spring XML as follows:

</camelContext>

</bean>

</property>

</bean>

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 <bean> mechanism in Spring. You can do

this using Spring's factory bean or the new Spring XML namespace. For example:

531 CHAPTER 10 - COMPONENT APPENDIX

</bean>

<jee:jndi-lookup id="myConnectionFactory" jndi-name="jms/connectionFactory"/>

See The jee schema in the Spring reference documentation for more details about JNDI lookup.

Using JNDI to lookup the physical queues

You need to use the destinationResolver option to use the Spring JNDI resolver that

can lookup in the JNDI, or use your own custom implementation.

See this nabble post for more details: http://www.nabble.com/JMS-queue---JNDI-instead-of-

physical-name-td24484994.html

Using WebSphere MQ

See this link at nabble for details of how a Camel user configured JMS to connect to remote

WebSphere MQ brokers.

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.

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

CHAPTER 10 - COMPONENT APPENDIX 532

See also 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.");

}

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");

533 CHAPTER 10 - COMPONENT APPENDIX

Transaction and Request Reply over JMS

Note that when using Request Reply over JMS you cannot use a single transaction;

as JMS will not send any messages until a commit is performed, the server side

won't receive anything at all until the transaction commits. So, with request/

response you must commit a transaction after sending the first request and then use

a separate transaction for receiving the response.

This is why the transacted property applies only to the InOnly message Exchange Pattern

(MEP). If you want to use transactions for the InOut MEP as well, you must set

transactedInOut=true.

To recap: if you have transacted=true,transactedInOut=false and are

sending an InOut, the Exchange will not use transactions.

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");

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:

CHAPTER 10 - COMPONENT APPENDIX 534

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:

<route>

</filter>

</route>

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.

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:

535 CHAPTER 10 - COMPONENT APPENDIX

// 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.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪Transactional Client

▪Bean Integration

▪Tutorial-JmsRemoting

▪JMSTemplate gotchas

CHAPTER 10 - COMPONENT APPENDIX 536

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-jpa</artifactId>

</dependency>

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).

If the body does not contain an entity bean, 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.

537 CHAPTER 10 - COMPONENT APPENDIX

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.

CHAPTER 10 - COMPONENT APPENDIX 538

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 JPA consumer only: To use a

custom query when consuming data.

consumer.namedQuery JPA consumer only: To use a

named query when consuming data.

consumer.nativeQuery

JPA consumer only: To use a

custom native query when consuming

data.

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.

For example, you can instantiate a JPA component that references the myEMFactory

entity manager factory, as follows:

539 CHAPTER 10 - COMPONENT APPENDIX

</bean>

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:

</bean>

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");

CHAPTER 10 - COMPONENT APPENDIX 540

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.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪Tracer Example

JT/400 COMPONENT

The jt400 component allows you to exchanges messages with an AS/400 system using data

queues. This components is only available in Camel 1.5 and above.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-jt400</artifactId>

541 CHAPTER 10 - COMPONENT APPENDIX

</dependency>

URI format

jt400://user:password@system/QSYS.LIB/LIBRARY.LIB/QUEUE.DTAQ[?options]

You can append query options to the URI in the following format,

?option=value&option=value&...

URI options

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.

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.

CHAPTER 10 - COMPONENT APPENDIX 542

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");

}

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-ldap</artifactId>

</dependency>

URI format

ldap:ldapServerBean[?options]

543 CHAPTER 10 - COMPONENT APPENDIX

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.

Result

The result is returned in the Out body as a

ArrayList<javax.naming.directory.SearchResult> object.

DirContext

The URI, ldap:ldapserver, references a Spring bean with the ID, ldapserver. The

ldapserver bean may be defined as follows:

<bean id="ldapserver" class="javax.naming.directory.InitialDirContext"

scope="prototype">

<constructor-arg>

<props>

<prop key="java.naming.factory.initial">com.sun.jndi.ldap.LdapCtxFactory</prop>

<prop key="java.naming.provider.url">ldap://localhost:10389</prop>

</props>

</constructor-arg>

</bean>

The preceding example declares a regular Sun based LDAP DirContext that connects

anonymously to a locally hosted LDAP server.

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.

CHAPTER 10 - COMPONENT APPENDIX 544

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.

ProducerTemplate<Exchange> 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=*)

See Also

• Configuring Camel

545 CHAPTER 10 - COMPONENT APPENDIX

• Component

• Endpoint

• Getting Started

LOG COMPONENT

The log: component logs message exchanges to the underlying logging mechanism.

Camel uses commons-logging which allows you to configure logging via

• Log4j

• JDK 1.4 logging

• Avalon

• 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

groupSize null Integer

An integer that specifies a group size for

throughput logging. By default, regular logging is

used.

CHAPTER 10 - COMPONENT APPENDIX 546

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 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.

547 CHAPTER 10 - COMPONENT APPENDIX

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.

multiline false If true, each piece of information is logged on a

new line.

maxChars Camel 2.0: Limits the number of characters

logged per line.

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:

<route>

</route>

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 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");

CHAPTER 10 - COMPONENT APPENDIX 548

See Also

• Configuring Camel

• Component

• Endpoint

• 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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-lucene</artifactId>

</dependency>

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&...

549 CHAPTER 10 - COMPONENT APPENDIX

Insert 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

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

CHAPTER 10 - COMPONENT APPENDIX 550

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.

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",

551 CHAPTER 10 - COMPONENT APPENDIX

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);

}

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) {

CHAPTER 10 - COMPONENT APPENDIX 552

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");

}

};

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-mail</artifactId>

</dependency>

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]

553 CHAPTER 10 - COMPONENT APPENDIX

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.

The mail component also supports secure variants of these protocols (layered over SSL). You

can enable the secure protocols by adding sto 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):

CHAPTER 10 - COMPONENT APPENDIX 554

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

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

POP3S 995

IMAP 143

IMAPS 993

Options

Property Default Description

host The host name or IP address to connect to.

port See DefaultPorts The TCP port number to connect on.

username 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.

555 CHAPTER 10 - COMPONENT APPENDIX

from camel@localhost The FROM email address.

subject 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.

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.

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.

dummyTrustManager false

As of Camel 1.4, when testing SSL connections, you can enable the dummy trust manager by

setting this option to true. When the dummy trust manager is enabled, the mail client skips the

server certificate check.

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).

CHAPTER 10 - COMPONENT APPENDIX 556

Warning

Enabling this option makes the email connection completely insecure. The connection

becomes vulnerable to a man-in-the-middle attack, which implies that your login

credentials can be stolen. Do not use this option in a production environment.

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:

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<String,Object> map = new HashMap<String,Object>();

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);

557 CHAPTER 10 - COMPONENT APPENDIX

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 pre-

configured settings. It is not possible to mix and match headers and pre-configured settings.

Map<String,Object> headers = new HashMap<String,Object>();

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<String,Object> headers = new HashMap<String,Object>();

headers.put("to","davsclaus@apache.org ; jstrachan@apache.org ;

ningjiang@apache.org");

The preceding example uses a semicolon, ;, as the separator character.

Setting sender name and email

You can specify recipients in the format, name <email>, 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 <davsclaus@apache.org>");

map.put("From","James Strachan <jstrachan@apache.org>");

map.put("Subject","Camel is cool");

CHAPTER 10 - COMPONENT APPENDIX 558

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&processOnlyUnseenMessages=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";

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");

559 CHAPTER 10 - COMPONENT APPENDIX

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.

// 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"

"&deleteProcessedMessages=false&processOnlyUnseenMessages=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:

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

CHAPTER 10 - COMPONENT APPENDIX 560

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"

"&deleteProcessedMessages=false&processOnlyUnseenMessages=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<String, DataHandler> 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);

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

561 CHAPTER 10 - COMPONENT APPENDIX

• 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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-mina</artifactId>

</dependency>

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.

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 content—message 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&...

CHAPTER 10 - COMPONENT APPENDIX 562

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<org.apache.mina.common.IoFilter>.

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.

decorderMaxLineLength -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.

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.

563 CHAPTER 10 - COMPONENT APPENDIX

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:6200?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:6200?textline=true&sync=false", "Hello World");

assertMockEndpointsSatisfied();

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:9201?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.

CHAPTER 10 - COMPONENT APPENDIX 564

String response =

(String)template.requestBody("mina:tcp://localhost:9201?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:

<route>

</route>

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

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:

<!-- Creating mina endpoints is a bit complex so we reuse MinaComponnet

as a factory bean to create our endpoint, this is the easiest to do -->

<constructor-arg index="0" ref="myCamel"/>

</bean>

565 CHAPTER 10 - COMPONENT APPENDIX

<!-- This is our mina endpoint configured with spring, we will use the factory above

to create it for us. The goal is to invoke the createEndpoint method with the

mina configuration parameter we defined using the constructor-arg option -->

<bean id="myMinaEndpoint"

factory-bean="myMinaFactory"

factory-method="createEndpoint">

<constructor-arg index="0" ref="myMinaConfig"/>

</bean>

</bean>

And then we can refer to our endpoint directly in the route, as follows:

<route>

</route>

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.

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(MinaConsumer.HEADER_CLOSE_SESSION_WHEN_COMPLETE, true);

}

});

CHAPTER 10 - COMPONENT APPENDIX 566

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);

}

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)

567 CHAPTER 10 - COMPONENT APPENDIX

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:

<constructor-arg index="0" ref="camelContext" />

</bean>

<bean id="myMinaEndpoint"

factory-bean="myMinaFactory"

factory-method="createEndpoint">

<constructor-arg index="0" ref="myMinaConfig"/>

</bean>

</bean>

<constructor-arg>

</list>

</constructor-arg>

</bean>

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪Camel Netty

CHAPTER 10 - COMPONENT APPENDIX 568

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

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.

569 CHAPTER 10 - COMPONENT APPENDIX

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 20 seconds when the assertIsSatisfied() is invoked. This

can be configured by setting the setResultWaitTime(millis) method.

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:

CHAPTER 10 - COMPONENT APPENDIX 570

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 zero-

based 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.

A Spring Example

First, here's the spring.xml file

<route>

<xpath>/person/city = 'London'</xpath>

</filter>

</route>

</camelContext>

As you can see, it defines a simple routing rule which consumes messages from the local src/

test/data directory. The noop flag just means not to delete or move the file after its been

processed.

Also note we instantiate a bean called myBean, here is the source of the MyAssertions

bean.

public class MyAssertions implements InitializingBean {

@EndpointInject(uri = "mock:matched")

private MockEndpoint matched;

@EndpointInject(uri = "mock:notMatched")

private MockEndpoint notMatched;

public void afterPropertiesSet() throws Exception {

571 CHAPTER 10 - COMPONENT APPENDIX

// lets add some expectations

matched.expectedMessageCount(1);

notMatched.expectedMessageCount(0);

}

public void assertEndpointsValid() throws Exception {

// now lets perform some assertions that the test worked as we expect

Assert.assertNotNull("Should have a matched endpoint", matched);

Assert.assertNotNull("Should have a notMatched endpoint", notMatched);

MockEndpoint.assertIsSatisfied(matched, notMatched);

}

The bean is injected with a bunch of Mock endpoints using the @EndpointInject annotation, it

then sets a bunch of expectations on startup (using Spring's InitializingBean interface

and afterPropertiesSet() method) before the CamelContext starts up.

Then in our test case (which could be JUnit or TesNG) we lookup myBean in Spring (or

have it injected into our test) and then invoke the assertEndpointsValid() method on

it to verify that the mock endpoints have their assertions met. You could then inspect the

message exchanges that were delivered to any of the endpoints using the

getReceivedExchanges() method on the Mock endpoint and perform further assertions or

debug logging.

Here is the actual JUnit test case we use.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Spring 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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-msv</artifactId>

CHAPTER 10 - COMPONENT APPENDIX 572

</dependency>

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).

<route>

<doTry>

<exception>org.apache.camel.ValidationException</exception>

</doCatch>

573 CHAPTER 10 - COMPONENT APPENDIX

</doFinally>

</doTry>

</route>

</camelContext>

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-nagios</artifactId>

</dependency>

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 The port number of the host.

CHAPTER 10 - COMPONENT APPENDIX 574

password Password to be authenticated when sending checks to Nagios.

connectionTimeout 5000 Connection timeout in millis.

timeout 5000 Sending timeout in millis.

nagiosSettings To use an already configured com.googlecode.jsendnsca.core.NagiosSettings object.

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.

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.

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 = ...

575 CHAPTER 10 - COMPONENT APPENDIX

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

• Configuring Camel

• Component

• Endpoint

• Getting Started

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-netty</artifactId>

</dependency>

URI format

The URI scheme for a netty component is as follows

CHAPTER 10 - COMPONENT APPENDIX 576

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.

timeout 30000 Time to wait for a response to be received on a connection. Value is in millis.

reuseAddress true Setting to facilitate socket multiplexing

sync true Setting to set endpoint as one-way or request-response

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.

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:

577 CHAPTER 10 - COMPONENT APPENDIX

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.

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")

CHAPTER 10 - COMPONENT APPENDIX 578

.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);

}

};

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 Request-

Reply communication

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:5150sync=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);

}

579 CHAPTER 10 - COMPONENT APPENDIX

}

});

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.

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<ChannelUpstreamHandler> decoders = new ArrayList<ChannelUpstreamHandler>();

decoders.add(lengthDecoder);

decoders.add(stringDecoder);

List<ChannelDownstreamHandler> encoders = new ArrayList<ChannelDownstreamHandler>();

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

<util:list id="decoders" list-class="java.util.LinkedList">

<constructor-arg value="1048576"/>

<constructor-arg value="0"/>

<constructor-arg value="4"/>

<constructor-arg value="0"/>

<constructor-arg value="4"/>

CHAPTER 10 - COMPONENT APPENDIX 580

</bean>

</util:list>

<util:list id="encoders" list-class="java.util.LinkedList">

<constructor-arg value="4"/>

</bean>

</util:list>

<bean id="length-encoder"

class="org.jboss.netty.handler.codec.frame.LengthFieldPrepender">

<constructor-arg value="4"/>

</bean>

<bean id="string-encoder"

class="org.jboss.netty.handler.codec.string.StringEncoder"/>

<bean id="length-decoder"

class="org.jboss.netty.handler.codec.frame.LengthFieldBasedFrameDecoder">

<constructor-arg value="1048576"/>

<constructor-arg value="0"/>

<constructor-arg value="4"/>

<constructor-arg value="0"/>

<constructor-arg value="4"/>

</bean>

<bean id="string-decoder"

class="org.jboss.netty.handler.codec.string.StringDecoder"/>

</beans>

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:5150?encoders=#encoders&sync=false");

from("netty:tcp://localhost:5150?decoders=#length-decoder,#string-decoder&sync=false").to("mock:multiple-codec");

}

};

}

or via spring.

<camelContext id="multiple-netty-codecs-context" xmlns="http://camel.apache.org/schema/

spring">

<route>

581 CHAPTER 10 - COMPONENT APPENDIX

</route>

<route>

<from

uri="netty:tcp://localhost:5150?decoders=#length-decoder,#string-decoder&sync=false"/>

</route>

</camelContext>

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.

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);

}

});

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪MINA

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. By

CHAPTER 10 - COMPONENT APPENDIX 582

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:

...

<osgi:reference interface="org.apache.servicemix.nmr.api.NMR" />

</property>

</bean>

...

</beans>

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.

URI format

nmr:endpointName

583 CHAPTER 10 - COMPONENT APPENDIX

URI Options

Option Default

Value Description

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

Examples

from("nmr:MyServiceEndpoint")

from("nmr:MyServiceEndpoint?synchronous=true").to("nmr:AnotherEndpoint")

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.

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.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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).

CHAPTER 10 - COMPONENT APPENDIX 584

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-quartz</artifactId>

</dependency>

URI format

quartz://timerName?options

quartz://groupName/timerName?options

quartz://groupName/timerName/cronExpression (@deprecated)

quartz://groupName/timerName/?cron=expression (Camel 2.0)

quartz://timerName?cron=expression (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.

585 CHAPTER 10 - COMPONENT APPENDIX

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.

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:

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

</bean>

CHAPTER 10 - COMPONENT APPENDIX 586

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

</bean>

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.

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

Avaiable 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:

587 CHAPTER 10 - COMPONENT APPENDIX

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

+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

$ ?

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Timer

CHAPTER 10 - COMPONENT APPENDIX 588

QUICKFIX COMPONENT

Available as of Camel 2.0

The quickfix component is an implementation of the QuickFix engine for Java . This engine

allows to connect to a FIX server which is used to exchange financial messages according to FIX

protocol standard.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-quickfix</artifactId>

</dependency>

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 QuickFixJ 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.

Warning: You cannot use a quickfix engine to send or receive messages in both direction

as the FIX protocol handle logon/logout sessions with heartbeat messages which are send to

verify if the server or client is still alive in only one direction.

Exchange data format

The QuickFixJ engine is like CXF component a messaging bus using MINA as protocol layer to

create the socket connection with the FIX engine gateway.

When QuickFixJ 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

589 CHAPTER 10 - COMPONENT APPENDIX

When a message must be send to QuickFix, then you must create a QuickFix.Message

instance.

Samples

Direction : to FIX gateway

<route>

<bean ref="fixService" method="createFixMessage" /> // bean method in charge to

transform message into a QuickFix.Message

<to uri="quickfix-client:META-INF/quickfix/client.cfg" /> // Quickfix engine who will

send the FIX messages to the gateway

Direction : from FIX gateway

<from uri="quickfix-server:META-INF/quickfix/server.cfg"/> // QuickFix engine who will

receive the message from FIX gateway

<bean ref="fixService" method="parseFixMessage" /> // 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:

CHAPTER 10 - COMPONENT APPENDIX 590

<groupId>org.apache.camel</groupId>

<artifactId>camel-printer</artifactId>

</dependency>

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.

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

591 CHAPTER 10 - COMPONENT APPENDIX

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")

}};

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() {

CHAPTER 10 - COMPONENT APPENDIX 592

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.

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 <property-placeholder> 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

593 CHAPTER 10 - COMPONENT APPENDIX

▪additional supported in Spring XML (see below in examples)

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)

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");

Configuring in Java DSL

You have to create and register the PropertiesComponent under the name

properties such as:

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

<propertyPlaceholder> tag.

CHAPTER 10 - COMPONENT APPENDIX 594

<bean id="properties"

class="org.apache.camel.component.properties.PropertiesComponent">

</bean>

Using the <propertyPlaceholder> tag makes the configuration a bit more fresh such as:

</camelContext>

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

// 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.

595 CHAPTER 10 - COMPONENT APPENDIX

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

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");

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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

<package>, <packageScan>, <contextScan>, <jmxAgent>, <endpoint>,

<routeBuilder>, <proxy> and the others.

The example below has property placeholder in the <jmxAgent> tag:

<propertyPlaceholder id="properties" location="org/apache/camel/spring/

jmx.properties"/>

<jmxAgent id="agent" registryPort="{{myjmx.port}}"

usePlatformMBeanServer="{{myjmx.usePlatform}}"

createConnector="true"

statisticsLevel="RoutesOnly"

<route>

</route>

</camelContext>

You can also define property placeholders in the various attributes on the <camelContext> tag

such as trace as shown here:

597 CHAPTER 10 - COMPONENT APPENDIX

<propertyPlaceholder id="properties" location="org/apache/camel/spring/processor/

myprop.properties"/>

<route>

<simple>${in.body} World!</simple>

</setHeader>

</route>

</camelContext>

Unit tests

See the unit tests in camel-core and camel-spring

▪PropertiesComponentTest.java

▪PropertiesComponentEndpointTest.java

▪PropertiesComponentSimpleLanguageTest.java

▪SpringPropertiesComponentTest.xml

▪SpringPropertiesComponent2Test.xml

▪SpringPropertiesComponent3Test.xml

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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.

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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:

...

</camelContext>

Sample

In the sample below we use the ref: in the URI to reference the endpoint with the spring ID,

endpoint2:

</bean>

<route>

</route>

</camelContext>

You could, of course, have used the ref attribute instead:

599 CHAPTER 10 - COMPONENT APPENDIX

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-restlet</artifactId>

</dependency>

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

CHAPTER 10 - COMPONENT APPENDIX 600

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<String> 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.

Message Headers

Camel 1.x

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.

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

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.* 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. 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.

CamelHttpRsponseCode

String

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.

601 CHAPTER 10 - COMPONENT APPENDIX

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.

org.restlet.* 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.

from("restlet:http://localhost:9080/

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.

<util:map id="realm">

</util:map>

The following sample starts a direct endpoint that sends requests to the server on

http://localhost:8080 (that is, our restlet consumer endpoint).

CHAPTER 10 - COMPONENT APPENDIX 602

// 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:9080/

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<String,Object> headers = new HashMap<String,Object>();

headers.put(RestletConstants.RESTLET_LOGIN, "admin");

headers.put(RestletConstants.RESTLET_PASSWORD, "foo");

headers.put("id", id);

String response = (String) template.requestBodyAndHeaders("direct:start-auth",

"<order foo='1'/>", 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)

•id (application header)

The sample client gets a response like the following:

received [<order foo='1'/>] 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:9080/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

603 CHAPTER 10 - COMPONENT APPENDIX

Note

org.apache.camel.restlet.auth.login and

org.apache.camel.restlet.auth.password will not be propagated as

Restlet header.

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:9080?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:9080/users/homer".equals(uri)) {

exchange.getOut().setBody(out + " " +

exchange.getIn().getHeader("username",String.class));

}else if ("http://localhost:9080/atom/collection/foo/component/

bar".equals(uri)) {

exchange.getOut().setBody(out + " " + exchange.getIn().getHeader("id",

String.class)

+" " + exchange.getIn().getHeader("cid",

String.class));

}

});

The restletUriPatterns=#uriTemplates option references the List<String>

bean defined in the Spring XML configuration.

<list>

<value>/users/{username}</value>

<value>/atom/collection/{id}/component/{cid}</value>

</list>

</bean>

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

CHAPTER 10 - COMPONENT APPENDIX 604

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-rmi</artifactId>

</dependency>

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.

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:

605 CHAPTER 10 - COMPONENT APPENDIX

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.

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

RSS COMPONENT

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-rss</artifactId>

</dependency>

Note: The component currently only supports polling (consuming) feeds.

New in Camel 2.0

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&...

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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.

Options

Property Default Description

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.

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.

607 CHAPTER 10 - COMPONENT APPENDIX

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

A route using this would look something like this:

CHAPTER 10 - COMPONENT APPENDIX 608

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");

Merging multiple incoming feeds

To merge multiple incoming feeds into a single feed, you can apply the custom aggregator,

AggregationCollection, provided with camel-rss. For example:

Error formatting macro: snippet: java.lang.IndexOutOfBoundsException: Index: 20, Size: 20

Here we use a SEDA queue to gather up entries from two RSS feeds. The entries are then fed

into the custom aggregator which combines these entries into a single ROME SyndFeed

object.

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

609 CHAPTER 10 - COMPONENT APPENDIX

• Component

• Endpoint

• Getting Started

SCALATE

Available as of Camel 2.3

The scalate: component allows you to process a message using Scalate template, which

supports either SSP or Scaml format templates. 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:

<groupId>org.fusesource.scalate</groupId>

<artifactId>scalate-camel</artifactId>

</dependency>

URI format

scalate: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.ssp).

You can append query options to the URI in the following format,

?option=value&option=value&...

Message Headers

The scalate component sets a couple headers on the message (you can't set these yourself and

from Camel 2.1 scalate component will not set these headers which will cause some side effect

on the dynamic template support):

Header Description

CamelScalateResource

The resource as an

org.springframework.core.io.Resource

object.

CamelScalateResourceUri The templateName as a String object.

Headers set during the Scalate evaluation are returned to the message and added as headers.

Then its kinda possible to return values from Scalate to the Message.

CHAPTER 10 - COMPONENT APPENDIX 610

For example, to set the header value of fruit in the Scalate template .tm:

<% in.setHeader('fruit', 'Apple') %>

The fruit header is now accessible from the message.out.headers.

Scalate Context

Camel will provide exchange information in the Scalate context (just a Map). The Exchange is

transfered as:

key value

exchange The Exchange itself.

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 Scalate template resource is, by default, hot reloadable for both file and classpath resources

(expanded jar).

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.

Header Type Description

CamelScalateResourceUri String An URI for the template resource to use instead of

the endpoint configured.

CamelScalateTemplate String The template to use instead of the endpoint

configured.

611 CHAPTER 10 - COMPONENT APPENDIX

Samples

For example you could use something like

from("activemq:My.Queue").

to("scalate:com/acme/MyResponse.ssp");

To use a Scalate 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("scalate:com/acme/MyResponse.scaml").

to("activemq:Another.Queue");

It's possible to specify what template the component should use dynamically via a header, so for

example:

from("direct:in").

setHeader("CamelScalateResourceUri").constant("path/to/my/template.scaml").

to("scalate:dummy");

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("CamelScalateTemplate").constant("<%@ attribute body: Object %>\nHi this

is a scalate template that can do templating ${body}").

to("scalate:dummy");

The Email Sample

In this sample we want to use Scalate templating for an order confirmation email. The email

template is laid out in Scalate as:

<%@ attribute in: org.apache.camel.scala.RichMessage %>

Dear ${in("lastName"}, ${in("firstName")}

Thanks for the order of ${in("item")}.

Regards Camel Riders Bookstore

${in.body}

CHAPTER 10 - COMPONENT APPENDIX 612

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

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

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.

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Synchronous

The Direct component provides synchronous invocation of any consumers when a

producer sends a message exchange.

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.

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.

CHAPTER 10 - COMPONENT APPENDIX 614

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.

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.

615 CHAPTER 10 - COMPONENT APPENDIX

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.

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:

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.

CHAPTER 10 - COMPONENT APPENDIX 616

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.

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.

<!-- define a shared endpoint which the consumers can refer to instead of using

url -->

</camelContext>

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.

617 CHAPTER 10 - COMPONENT APPENDIX

public class FooEventConsumer {

@EndpointInject(uri = "mock:result")

private ProducerTemplate destination;

@Consume(ref = "foo")

public void doSomething(String body) {

destination.sendBody("foo" + body);

}

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪VM

▪Direct

▪Async

SERVLET COMPONENT

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.

Note: This component is new to Camel 2.0-M3.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-servlet</artifactId>

<\!-\- use the same version as your Camel core version \-->

</dependency>

URI format

servlet://relative_path[?options]

You can append query options to the URI in the following format,

?option=value&option=value&...

CHAPTER 10 - COMPONENT APPENDIX 618

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 null

Specifies the servlet name that the servlet endpoint will bind

to. If there is no servlet name specified, the servlet endpoint

will be bind to first published Servlet

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:

<web-app>

<servlet-name>CamelServlet</servlet-name>

<display-name>Camel Http Transport Servlet</display-name>

<servlet-class>

619 CHAPTER 10 - COMPONENT APPENDIX

org.apache.camel.component.servlet.CamelHttpTransportServlet

</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>CamelServlet</servlet-name>

<url-pattern>/services/*</url-pattern>

</servlet-mapping>

</web-app>

Use an Activator to publish the CamelHttpTransportServlet on the OSGi platform

import java.util.Dictionary;

import java.util.Hashtable;

import javax.servlet.Servlet;

import org.apache.camel.component.servlet.CamelHttpTransportServlet;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.osgi.framework.BundleActivator;

import org.osgi.framework.BundleContext;

import org.osgi.framework.ServiceReference;

import org.osgi.service.http.HttpContext;

import org.osgi.service.http.HttpService;

import org.springframework.osgi.context.BundleContextAware;

public final class ServletActivator implements BundleActivator, BundleContextAware {

private static final transient Log LOG = LogFactory.getLog(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 {

if (httpServiceRef != null) {

bc.ungetService(httpServiceRef);

httpServiceRef = null;

CHAPTER 10 - COMPONENT APPENDIX 620

}

protected void registerServlet(BundleContext bundleContext) throws Exception {

httpServiceRef =

bundleContext.getServiceReference(HttpService.class.getName());

if (httpServiceRef != null && !registerService) {

LOG.info("Regist 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<String,String> initParams = new Hashtable<String,

String>();

initParams.put("matchOnUriPrefix","false");

initParams.put("servlet-name","camelServlet");

httpService.registerServlet("/camel/services",// alias

(Servlet)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("Can't register the servlet, the reason is " + e);

}

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);

String charsetEncoding =

exchange.getIn().getHeader(Exchange.HTTP_CHARACTER_ENCODING, String.class);

assertEquals("Get a wrong charset name","UTF-8", charsetEncoding);

exchange.getOut().setHeader(Exchange.CONTENT_TYPE, contentType + ";

charset=UTF-8");

exchange.getOut().setHeader("PATH", path);

621 CHAPTER 10 - COMPONENT APPENDIX

exchange.getOut().setBody("<b>Hello World</b>");

}

});

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 camel-servlet endpoint through the

servlet publish address: ("http://localhost:8080/camel/services") +

RELATIVE_PATH("/hello").

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪HTTP

SMOOKS

The smooks component supports the Smooks Library for EDI parsing. The camel-smooks

library is provided by the Camel Extra project which hosts all *GPL related components for

Camel.

It is only the EDI parsing feature that is implemented in this component. The other features

from Smooks are covered in existing camel components.

Parsing from any given data source to EDI is implemented using Camel Data Format.

EDI DATAFORMAT

This component ships with a EDI dataformat that can be used to format from a

java.io.InputStream to XML as a org.w3c.Document Object.

• marshal = currently not supported by Smooks

• unmarshal = from stream to XML (can be used when reading EDI files)

The EDIDataFormat must be configued with either a:

•setSmooksConfig(configfile) = a fully Smooks configuration file

•setMappingModel(modelfile) = just the mapping model xml file and Camel

will use a default Smooks configuration

To use the data format simply instantiate an instance, set the configuration (above) and invoke

the unmarshal operation in the route builder:

CHAPTER 10 - COMPONENT APPENDIX 622

Specify the relative path for camel-servlet endpoint

DataFormat edi = new EDIDataFormat();

edi.setMappingModel("my-order-mapping.xml");

...

from("file://edi/in").

unmarshal(edi).

to("jms:queue:edi");

And you can also provide the full Smooks configuration file where you can configure Smooks as

you want, in case the default configuration isn't useful:

DataFormat edi = new EDIDataFormat();

edi.setSmooksConfig("my-smooks-config.xml");

...

from("file://edi/in").

unmarshal(edi).

to("jms:queue:edi");

Dependencies

To use EDI in your camel routes you need to add the a dependency on camel-smooks

which implements this data format.

This component is hosted at the Camel Extra project since the Smooks library uses a

licenses which cant be included directly in an Apache project.

SMPP COMPONENT

This component provides access to an SMSC (Short Message Service Center) over the SMPP

protocol to send and receive SMS. The JSMPP is used.

Maven users will need to add the following dependency to their pom.xml for this

component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-smpp</artifactId>

</dependency>

623 CHAPTER 10 - COMPONENT APPENDIX

Using Camel 2.2 onwards

This component is only available for Camel 2.2 or newer.

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

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).

encoding ISO-8859-1 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

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.

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 Defines the destination SME address. For mobile terminated messages, this is the directory number of the recipient MS.

CHAPTER 10 - COMPONENT APPENDIX 624

sourceAddrTon 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

destAddrTon 0

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

sourceAddrNpi 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)

destAddrNpi 0

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

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

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

typeOfNumber 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

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)

You can have as many of these options as you like.

625 CHAPTER 10 - COMPONENT APPENDIX

smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&systemType=consumer

Message Headers

The following message headers can be used to affect the behavior of the SMPP producer

Header Description

CamelSmppDestAddr

Defines the destination SME address. For

mobile terminated messages, this is the

directory number of the recipient MS.

CamelSmppDestAddrTon

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

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.

CHAPTER 10 - COMPONENT APPENDIX 626

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)

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

627 CHAPTER 10 - COMPONENT APPENDIX

CamelSmppRegisteredDelivery

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

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

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

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.

CHAPTER 10 - COMPONENT APPENDIX 628

CamelSmppReplaceIfPresentFlag

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

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 for later use (delivery

receipt, query sm, cancel sm, replace sm).

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 alert notification, deliver sm

and data sm: 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 alert notification, deliver sm

and data sm: 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 alert notification, deliver sm

and data sm: Defines the address of SME

(Short Message Entity) which originated this

message.

629 CHAPTER 10 - COMPONENT APPENDIX

CamelSmppSourceAddrNpi

only for alert notification and data

sm: 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 alert notification and data

sm: 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 alert notification: Defines the

destination ESME address. For mobile

terminated messages, this is the directory

number of the recipient MS.

CHAPTER 10 - COMPONENT APPENDIX 630

CamelSmppEsmeAddrNpi

only for alert notification: 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 alert notification: 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 delivery receipt and

data sm: The message ID allocated to the

message by the SMSC when originally

submitted.

CamelSmppDelivered

only for smsc delivery receipt: 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 delivery receipt: The time

and date at which the short message reached

it's final state. The format is as follows:

YYMMDDhhmm.

631 CHAPTER 10 - COMPONENT APPENDIX

CamelSmppStatus

only for smsc delivery receipt and

data sm: 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 delivery receipt: 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 delivery receipt: 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 delivery receipt: 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 deliver sm and data sm:

Defines the destination SME address. For

mobile terminated messages, this is the

directory number of the recipient MS.

CHAPTER 10 - COMPONENT APPENDIX 632

CamelSmppScheduleDeliveryTime

only for deliver sm and data sm: 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.

CamelSmppValidityPeriod

only for deliver sm: 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 deliver sm and data sm: The

service type parameter indicates the SMS

Application service associated with the

message.

CamelSmppRegisteredDelivery

only for data sm: 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.

633 CHAPTER 10 - COMPONENT APPENDIX

CamelSmppDestAddrNpi

only for data sm: 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 data sm: 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

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:

<route>

<to

uri="smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&systemType=producer"/>

</route>

CHAPTER 10 - COMPONENT APPENDIX 634

JSMPP library

See the documentation of the JSMPP Library for more details about the underlying

library.

A route which receives an SMS using the Java DSL:

from("smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&systemType=consumer")

.to("bean:foo");

A route which receives an SMS using the Spring XML DSL:

<route>

<from

uri="smpp://smppclient@localhost:2775?password=password&enquireLinkTimer=3000&transactionTimer=5000&systemType=consumer"/>

</route>

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

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:

635 CHAPTER 10 - COMPONENT APPENDIX

SMSC simulator

If you need an SMSC simulator for your test, you can use the simulator provided by

Logica.

<groupId>org.apache.camel</groupId>

<artifactId>camel-snmp</artifactId>

</dependency>

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

protocol none Here you can select which protocol to use. By default it will be udp protocol but you may want to use tcp as well

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 20.Listing 20. oidsoids

CHAPTER 10 - COMPONENT APPENDIX 636

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 21.Listing 21. Result of toString conversionResult of toString conversion

<?xml version="1.0" encoding="UTF-8"?>

<snmp>

<entry>

</entry>

<entry>

</entry>

<entry>

</entry>

<entry>

</entry>

<entry>

<value>My Very Special Printer Of Brand Unknown</value>

</entry>

</snmp>

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.

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)

637 CHAPTER 10 - COMPONENT APPENDIX

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-spring-integration</artifactId>

</dependency>

URI format

spring-integration:defaultChannelName[?options]

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 Description Example Required Default

Value

CHAPTER 10 - COMPONENT APPENDIX 638

inputChannel

The Spring integration input channel name

that this endpoint wants to consume from,

where the specified channel name is

defined in the Spring context.

inputChannel=requestChannel No

outputChannel

The Spring integration output channel

name that is used to send messages to the

Spring integration context.

outputChannel=replyChannel No

inOut The exchange pattern that the Spring

integration endpoint should use. inOut=true No

inOnly for the Spring

integration consumer and

outOnly for the Spring

integration provider

consumer.delay Delay in milliseconds between each poll. consumer.delay=60000 No 500

consumer.initialDelay Milliseconds before polling starts. consumer.initialDelay=10000 No 1000

consumer.userFixedDelay

Specify true to use fixed delay between

polls, otherwise fixed rate is used. See the

JavaScheduledExecutorService class for

details.

consumer.userFixedDelay=false No false

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:

<beans:beans xmlns="http://www.springframework.org/schema/integration"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:beans="http://www.springframework.org/schema/beans"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/

spring-beans-2.5.xsd

http://www.springframework.org/schema/integration

http://www.springframework.org/schema/integration/

spring-integration-1.0.xsd

http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd">

<service-activator input-channel="inputChannel"

ref="helloService"

method="sayHello"/>

<service-activator input-channel="onewayChannel"

639 CHAPTER 10 - COMPONENT APPENDIX

ref="helloService"

method="greet"/>

<beans:bean id="helloService"

class="org.apache.camel.component.spring.integration.HelloWorldService"/>

<route>

<to

uri="spring-integration:inputChannel?inOut=true&inputChannel=outputChannel"/>

</route>

<route>

</route>

</camelContext>

<beans:bean id="myProcessor"

class="org.apache.camel.component.spring.integration.MyProcessor"/>

<route>

<from

uri="spring-integration://requestChannel?outputChannel=responseChannel&inOut=true"/>

</route>

</camelContext>

Or directly using a Spring integration channel name:

<beans:beans xmlns="http://www.springframework.org/schema/integration"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:beans="http://www.springframework.org/schema/beans"

xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/

spring-beans-2.5.xsd

http://www.springframework.org/schema/integration

http://www.springframework.org/schema/integration/

spring-integration-1.0.xsd

http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd">

<route>

CHAPTER 10 - COMPONENT APPENDIX 640

</route>

</camelContext>

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:

<beans:beans xmlns="http://www.springframework.org/schema/integration"

xmlns:beans="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:camel-si="http://camel.apache.org/schema/spring/integration"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/integration

http://www.springframework.org/schema/integration/spring-integration-1.0.xsd

http://camel.apache.org/schema/spring/integration

http://camel.apache.org/schema/spring/integration/camel-spring-integration.xsd

http://camel.apache.org/schema/spring

http://camel.apache.org/schema/spring/camel-spring.xsd

You can bind your source or target to a Camel endpoint as follows:

<route>

</route>

<route>

</route>

</camelContext>

<!-- We can bind the camelTarget to the camel context's endpoint by specifying the

camelEndpointUri attribute -->

<camel-si:camelTarget id="camelTargetA" camelEndpointUri="direct:EndpointA"

expectReply="false">

<camel-si:camelContextRef>camelTargetContext</camel-si:camelContextRef>

</camel-si:camelTarget>

641 CHAPTER 10 - COMPONENT APPENDIX

<camel-si:camelTarget id="camelTargetB" camelEndpointUri="direct:EndpointC"

replyChannel="channelC" expectReply="true">

<camel-si:camelContextRef>camelTargetContext</camel-si:camelContextRef>

</camel-si:camelTarget>

<camel-si:camelTarget id="camelTargetD" camelEndpointUri="direct:EndpointC"

expectReply="true">

<camel-si:camelContextRef>camelTargetContext</camel-si:camelContextRef>

</camel-si:camelTarget>

<beans:bean id="myProcessor"

class="org.apache.camel.component.spring.integration.MyProcessor"/>

<route>

</route>

<route>

</route>

</camelContext>

<!-- camelSource will redirect the message coming for direct:EndpointB to the spring

requestChannel channelA -->

<camel-si:camelSource id="camelSourceA" camelEndpointUri="direct:EndpointB"

requestChannel="channelA" expectReply="false">

<camel-si:camelContextRef>camelSourceContext</camel-si:camelContextRef>

</camel-si:camelSource>

<!-- camelSource will redirect the message coming for direct:EndpointC to the spring

requestChannel channelB

then it will pull the response from channelC and put the response message back to

direct:EndpointC -->

<camel-si:camelSource id="camelSourceB" camelEndpointUri="direct:EndpointC"

requestChannel="channelB" replyChannel="channelC" expectReply="true">

<camel-si:camelContextRef>camelSourceContext</camel-si:camelContextRef>

</camel-si:camelSource>

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

CHAPTER 10 - COMPONENT APPENDIX 642

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-stream</artifactId>

</dependency>

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.

643 CHAPTER 10 - COMPONENT APPENDIX

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: will retry opening the file if it is

overwritten, like tail --retry

scanStreamDelay 0 Camel 2.0: Delay in milliseconds between read

attempts when using scanStream.

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() {

CHAPTER 10 - COMPONENT APPENDIX 644

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());

}

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):

645 CHAPTER 10 - COMPONENT APPENDIX

from("stream:file?fileName=/server/logs/

server.log&scanStream=true&scanStreamDelay=1000").to("bean:logService?method=parseLogLine");

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-stringtemplate</artifactId>

</dependency>

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.

CHAPTER 10 - COMPONENT APPENDIX 646

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:

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.

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");

647 CHAPTER 10 - COMPONENT APPENDIX

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();

}

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

CHAPTER 10 - COMPONENT APPENDIX 648

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-sql</artifactId>

</dependency>

URI format

The SQL component uses the following endpoint URI notation:

sql:select * from table where id=# order by name[?options]

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

dataSourceRef String null Camel 1.5.1/2.0: Reference to a

DataSource to look up in the registry.

placeholder String #

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)

649 CHAPTER 10 - COMPONENT APPENDIX

The SQL component can only be used to define producer endpoints. In other

words, you cannot define an SQL endpoint in a from() statement.

template.<xxx> 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.

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.

Result of the query

For select operations, the result is an instance of List<Map<String, Object>> 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.

CHAPTER 10 - COMPONENT APPENDIX 650

CamelSqlRowCount Camel 2.0: The number of rows returned for

select operations, returned as an Integer object.

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:

</bean>

</bean>

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<String, Object and the key is the column name.

First, we set up a table to use for our sample. As this is based on an unit test, we do it java

code:

// this is the database we create with some initial data for our unit test

jdbcTemplate.execute("create table projects (id integer primary key,"

+"project varchar(10), license varchar(5))");

jdbcTemplate.execute("insert into projects values (1, 'Camel', 'ASF')");

jdbcTemplate.execute("insert into projects values (2, 'AMQ', 'ASF')");

jdbcTemplate.execute("insert into projects values (3, 'Linux', 'XXX')");

Then we configure our route and our sql component. Notice that we use a direct endpoint

in front of the sql endpoint. This allows us to send an exchange to the direct endpoint with

the URI, direct:simple, which is much easier for the client to use than the long sql: URI.

651 CHAPTER 10 - COMPONENT APPENDIX

Note that the DataSource is looked up up in the registry, so we can use standard Spring

XML to configure our DataSource.

from("direct:simple")

.to("sql:select * from projects where license = # order by id?dataSourceRef=jdbc/

myDataSource")

.to("mock:result");

And then we fire the message into the direct endpoint that will route it to our sql

component that queries the database.

MockEndpoint mock = getMockEndpoint("mock:result");

mock.expectedMessageCount(1);

// send the query to direct that will route it to the sql where we will execute the

query

// and bind the parameters with the data from the body. The body only contains one

value

// in this case (XXX) but if we should use multi values then the body will be iterated

// so we could supply a List<String> 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:

<jee:jndi-lookup id="myDS" jndi-name="jdbc/myDataSource"/>

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪JDBC

CHAPTER 10 - COMPONENT APPENDIX 652

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.

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.

Here is a real example test case using Mock and Spring along with its Spring XML.

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

653 CHAPTER 10 - COMPONENT APPENDIX

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]

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

Ajava.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 Camel 1.6.2/2.0: 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.

CHAPTER 10 - COMPONENT APPENDIX 654

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.

Exchange Properties

When the timer is fired, it adds the following information as properties to the Exchange:

Name Type Description

org.apache.camel.timer.name String The value of the name option.

org.apache.camel.timer.time Date The value of the time option.

org.apache.camel.timer.period long The value of the period

option.

org.apache.camel.timer.firedTime Date Camel 1.5: The time when

the consumer fired.

Message Headers

When the timer is fired, it adds the following information as headers to the IN message

Name Type Description

firedTime java.util.Date Camel 1.5: The time when the consumer fired

Sample

To set up a route that generates an event every 60 seconds:

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:

655 CHAPTER 10 - COMPONENT APPENDIX

<route>

</route>

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

• Quartz

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

Options

Option Default Description

CHAPTER 10 - COMPONENT APPENDIX 656

useDom false

Camel 2.0: Whether DOMSource/DOMResult or

SaxSource/SaxResult should be used by the

validator.

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).

<route>

<doTry>

<exception>org.apache.camel.ValidationException</exception>

</doCatch>

</doFinally>

</doTry>

</route>

</camelContext>

See Also

• 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:

657 CHAPTER 10 - COMPONENT APPENDIX

<groupId>org.apache.camel</groupId>

<artifactId>camel-velocity</artifactId>

</dependency>

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 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.

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.

CHAPTER 10 - COMPONENT APPENDIX 658

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.

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");

659 CHAPTER 10 - COMPONENT APPENDIX

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:

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}

CHAPTER 10 - COMPONENT APPENDIX 660

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 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

• Configuring Camel

• Component

• Endpoint

• Getting Started

661 CHAPTER 10 - COMPONENT APPENDIX

VM COMPONENT

The vm: component provides asynchronous SEDA behavior so that messages are exchanged

on a BlockingQueue and consumers are invoked in a separate thread pool to the producer.

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 the camel-core.jar is on the system/boot classpath.

This component is an extension to the SEDA component.

URI format

vm:someName[?options]

Where someName can be any string to uniquely identify the endpoint within the JVM (or at

least within the classloader which loaded the 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 as the same rules applies for

this VM component.

Samples

In the route below we send the exchange to the VM queue that is working across

CamelContext instances:

from("direct:in").bean(MyOrderBean.class).to("vm:order.email");

And then in another Camel context such as deployed as in another .war application:

from("vm:order.email").bean(MyOrderEmailSender.class);

See Also

• Configuring Camel

• Component

• Endpoint

• Getting Started

▪SEDA

CHAPTER 10 - COMPONENT APPENDIX 662

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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-xmpp</artifactId>

</dependency>

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

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

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.

663 CHAPTER 10 - COMPONENT APPENDIX

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.

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):

CHAPTER 10 - COMPONENT APPENDIX 664

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):

// 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

• 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:

<groupId>org.apache.camel</groupId>

<artifactId>camel-saxon</artifactId>

</dependency>

URI format

xquery:templateName

665 CHAPTER 10 - COMPONENT APPENDIX

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).

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

• 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

CHAPTER 10 - COMPONENT APPENDIX 666

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

Maven users will need to add the following dependency to their pom.xml for this component:

<groupId>org.apache.camel</groupId>

<artifactId>camel-spring</artifactId>

</dependency>

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.

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.

Using XSLT endpoints

For example you could use something like

from("activemq:My.Queue").

to("xslt:com/acme/mytransform.xsl");

667 CHAPTER 10 - COMPONENT APPENDIX

To use an XSLT 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 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.

And the XSLT just needs to declare it at the top level for it to be available:

<xsl: ...... >

<xsl:param name="myParam"/>

<xsl:template ...>

Spring XML versions

To use the above examples in Spring XML you would use something like

<route>

</route>

</camelContext>

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

CHAPTER 10 - COMPONENT APPENDIX 668

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:

<xsl:include href="staff_template.xsl"/>

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:

<xsl:include href="staff_template.xsl"/>

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

<xsl:include href="../staff_other_template.xsl"/>

Which then will resolve the xsl file under org/apache/camel/component.

Notes on using XSTL 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.

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.

669 CHAPTER 10 - COMPONENT APPENDIX

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:my-

transformer.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

• Configuring Camel

• Component

• Endpoint

• Getting Started

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