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.

Using a Message Translator
Invoking a Bean with the filtering programmed in Java
Using a Processor with the filtering programmed in Java
Using an Expression

Message Content filtering using a Processor

In this example, we add our own Processor using explicit Java to filter the message:

from("direct:start")
    .process(new Processor() {
        public void process(Exchange exchange) {
            String body = exchange.getMessage().getBody(String.class);
            // do something with the body
            // and replace it back
            exchange.getMessage().setBody(body);
        }
    })
    .to("mock:result");

In the Java code above we used an inlined Processor which is harder to do with XML or YAML DSL. A good practice is to use a class for your custom Processor which can then be referenced in the DSL:

@BindToRegistry("myProcessor")
public class MyProcessor implements Processor {

    @Override
    public void process(Exchange exchange) {
        String body = exchange.getMessage().getBody(String.class);
        // do something with the body
        // and replace it back
        exchange.getMessage().setBody(body);
    }
}

Then you can refer to this processor by its id.

Java
XML
YAML

from("direct:start")
    .process("myProcessor")
    .to("mock:result");

<route>
    <from uri="direct:start"/>
    <process ref="myProcessor"/>
    <to uri="mock:result"/>
</route>

- route:
    from:
      uri: direct
      parameters:
        name: start
      steps:
        - process:
            ref: myProcessor
        - to:
            uri: mock
            parameters:
              name: result

Message Content filtering using a Bean EIP

We can use Bean EIP to use any Java method on any bean to act as a content filter:

Java
XML
YAML

from("activemq:My.Queue")
    .bean("myBeanName", "doFilter")
    .to("activemq:Another.Queue");

<route>
    <from uri="activemq:Input"/>
    <bean ref="myBeanName" method="doFilter"/>
    <to uri="activemq:Output"/>
</route>

- from:
    uri: activemq:Input
    steps:
      - bean:
          ref: myBeanName
          method: doFilter
      - to:
          uri: activemq:Output

Message Content filtering using expression

Some languages like XPath, and XQuery can be used to transform and filter content from messages.

In the example we use xpath to filter a XML message to select all the <foo><bar> elements:

Java
XML
YAML

from("activemq:Input")
  .setBody().xpath("//foo:bar")
  .to("activemq:Output");

<route>
  <from uri="activemq:Input"/>
  <setBody>
    <xpath>//foo:bar</xpath>
  </setBody>
  <to uri="activemq:Output"/>
</route>

- from:
    uri: activemq:Input
    steps:
      - setBody:
          expression:
            xpath: //foo:bar
      - to:
          uri: activemq:Output