EL was originally specified as part of the JSP 2.1 standard (JSR-245), but it is now available as a standalone language. Apache Camel integrates with JUEL (http://juel.sourceforge.net/), which is an open source implementation of the EL language.
To use EL in your routes you need to add a dependency on
camel-juel
to your project as shown in
Example 2, “Adding the camel-juel dependency”.
Example 2. Adding the camel-juel dependency
<!-- Maven POM File --> <properties> <camel-version>2.11.0-fuse-00-xx</camel-version> ... </properties> <dependencies> ... <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-juel</artifactId> <version>${camel-version}</version> </dependency> ... </dependencies>
Table 2, “EL variables” lists the variables that are accessible when using EL.
Table 2. EL variables
Variable | Type | Value |
---|---|---|
exchange | org.apache.camel.Exchange | The current Exchange |
in | org.apache.camel.Message | The IN message |
out | org.apache.camel.Message | The OUT message |
Example 3, “Routes using EL” shows two routes that use EL.
Example 3. Routes using EL
<camelContext> <route> <from uri="seda:foo"/> <filter> <language language="el">${in.headers.foo == 'bar'}</language> <to uri="seda:bar"/> </filter> </route> <route> <from uri="seda:foo2"/> <filter> <language language="el">${in.headers['My Header'] == 'bar'}</language> <to uri="seda:bar"/> </filter> </route> </camelContext>