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- if the body of the message can be converted to a BeanInvocation (the default payload used by the ProxyHelper) - then that its used to invoke the method and pass the arguments
- if the message contains the header org.apache.camel.MethodName then that method is invoked, converting the body to whatever the argument is to the method
- otherwise the type of the method body is used to try find a method which matches; an error is thrown if a single method cannot be chosen unambiguously.
You can also use the @Property and @Header annotations on method parameters to tell Camel which method parameters bind to some header/property value and which parameter binds to the message body. You can use @Body to be precise about which parameter is the By default the return value is set on the outbound message body.
For example you could write a method like this
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Here Camel with subscribe to an ActiveMQ queue, then convert the message payload to a String (so dealing with TextMessage, ObjectMessage and BytesMessage in JMS), then process this method.
Using Annotations to bind parameters to expresions
You can also use the following annotations to bind paramters to different kinds of Expression
Annotation | Meaning |
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To bind to an inbound message body | |
To bind to an inbound message header | |
To bind to the Map of the inbound message headers | |
To bind to an outbound message header | |
To bind to the Map of the outbound message headers | |
To bind to a named property on the exchange | |
To bind to the property map on the exchange |
For exampleYou could process some headers if you wish like this
Code Block |
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public class Foo { @MessageDriven(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 Message.getJMSCorrelationID() as a parameter to the method (again with possible type conversion toousing the Type Converter to adapt the value to the type of the parameter).
Finally you don't need the @MessageDriven annotation; as the Camel route could describe which method to invoke.
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