Dieser Inhalt ist in der von Ihnen ausgewählten Sprache nicht verfügbar.
Chapter 15. EL
Overview
The Unified Expression Language (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.
Adding JUEL package
To use EL in your routes you need to add a dependency on camel-juel to your project as shown in Example 15.1, “Adding the camel-juel dependency”.
Example 15.1. Adding the camel-juel dependency
<!-- Maven POM File -->
<properties>
<camel-version>2.23.2.fuse-7_13_0-00013-redhat-00001</camel-version>
...
</properties>
<dependencies>
...
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-juel</artifactId>
<version>${camel-version}</version>
</dependency>
...
</dependencies>Static import
To use the el() static method in your application code, include the following import statement in your Java source files:
import static org.apache.camel.language.juel.JuelExpression.el;
Variables
Table 15.1, “EL variables” lists the variables that are accessible when using EL.
| Variable | Type | Value |
|---|---|---|
|
|
| The current Exchange |
|
|
| The IN message |
|
|
| The OUT message |
Example
Example 15.2, “Routes using EL” shows two routes that use EL.
Example 15.2. Routes using EL
<camelContext>
<route>
<from uri="seda:foo"/>
<filter>
<language language="el">${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>