EL

Camel supports the unified JSP and JSF Expression Language via the JUEL to allow an Expression or Predicate to be used in the DSL or Xml Configuration.

For example you could use EL inside a Message Filter in XML

<route>
  <from uri="seda:foo"/>
  <filter>
    <el>${in.headers.foo == 'bar'}</el>
    <to uri="seda:bar"/>
  </filter>
</route>

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

<route>
  <from uri="seda:foo"/>
  <filter>
    <el>${in.headers['My Header'] == 'bar'}</el>
    <to uri="seda:bar"/>
  </filter>
</route>

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

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).

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-juel</artifactId>
  <version>1.6.1</version>
</dependency>

Otherwise you'll also need to include JUEL.