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The core annotations are as follows

The follow annotations @Headers, @OutHeaders and @Properties binds to the backing java.util.Map so you can alter the content of these maps directly, for instance using the put method to add a new entry. See the OrderService class at Exception Clause for such an example. You can use @Header("myHeader") and @Property("myProperty") to access the backing java.util.Map.

Example

In this example below we have a @Consume consumer (like message driven) that consumes JMS messages from the activemq queue. We use the @Header and @Body parameter binding annotations to bind from the JMSMessage to the method parameters.For example:

public class Foo {
	
    @MessageDriven@Consume(uri = "activemq:my.queue")
    public void doSomething(@Header('"JMSCorrelationID'") String correlationID, @Body String body) {
		// process the inbound message here
    }

}

In the above you can now pass the Camel will extract the value of Message.getJMSCorrelationID() as a parameter to the method (, then using the Type Converter to adapt the value to the type of the parameter if required - it will inject the parameter value for the parameter). correlationID parameter. Then the payload of the message will be converted to a String and injected into the body parameter.

You Finally you don't necessarily need to use the @MessageDriven annotation; as the Camel route could describe which method to invoke.@Consume annotation if you don't want to as you could also make use of the Camel DSL to route to the bean's method as well.

Using the DSL to invoke the bean method

Here is another example which does not use POJO Consuming annotations but instead uses the DSL to route messages to the bean method

public class Foo {
    public void doSomething(@Header("JMSCorrelationID") String correlationID, @Body String body) {
		// process the inbound message here
    }

}

The routing DSL then looks like thise.g. a route could look like

from("activemq:someQueue").
  to("bean:myBean");

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    public void doSomething(@Header(name = "user") String user, @Body String body, Exchange exchange) {
        exchange.getIn().setBody(body + "MyBean");
    }

Using Expression Languages

You can also use any of the Languages supported in Camel to bind expressions to method parameters when using bean integration. For example you can use any of these annotations:

For example:

public class Foo {
	
    @MessageDriven(uri = "activemq:my.queue")
    public void doSomething(@XPath("/foo/bar/text()") String correlationID, @Body String body) {
		// process the inbound message here
    }
}

Advanced example using @Bean

And an example of using the the @Bean binding annotation, where you can use a POJO where you can do whatever java code you like:

public class Foo {
	
    @MessageDriven(uri = "activemq:my.queue")
    public void doSomething(@Bean("myCorrelationIdGenerator") String correlationID, @Body String body) {
		// process the inbound message here
    }
}

And then we can have a spring bean with the id myCorrelationIdGenerator where we can compute the id.

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public class MyIdGenerator {

    private UserManager userManager;

    public String generate(@Header(name = "user") String user, @Body String payload) throws Exception {
       User user = userManager.lookupUser(user);
       String userId = user.getPrimaryId();
       String id = userId + generateHashCodeForPayload(payload);
       return id;
   }
}

The POJO MyIdGenerator has one public method that accepts two parameters. However we have also annotated this one with the @Header and @Body annotation to help Camel know what to bind here from the Message from the Exchange being processed.

Of course this could be simplified a lot if you for instance just have a simple id generator. But we wanted to demonstrate that you can use the Bean Binding annotations anywhere.

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public class MySimpleIdGenerator {

    public static int generate()  {
       // generate a unique id
       return 123;
   }
}

And finally we just need to remember to have our bean registered in the Spring Registry:

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