EL

Since Camel 1.1

EL

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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

EL Options

The EL language supports 1 options, which are listed below.

Name Default Java Type Description

trim

true

Boolean

Whether to trim the value to remove leading and trailing whitespaces and line breaks

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-juel-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 2 options, which are listed below.

Name Description Default Type

camel.language.el.enabled

Enable el language

true

Boolean

camel.language.el.trim

Whether to trim the value to remove leading and trailing whitespaces and line breaks

true

Boolean

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>x.x.x</version>
</dependency>

Otherwise you’ll also need to include JUEL.