Chapter 24. The Object-Graph Navigation Language(OGNL)
Overview
OGNL is an expression language for getting and setting properties of Java objects. You use the same expression for both getting and setting the value of a property. The OGNL support is in the
camel-ognl module.
Camel on EAP deployment
This component is supported by the Camel on EAP (Wildfly Camel) framework, which offers a simplified deployment model on the Red Hat JBoss Enterprise Application Platform (JBoss EAP) container. For details of this model, see chapter "Apache Camel on Red Hat JBoss EAP" in "Deploying into a Web Server".
Adding the OGNL module
To use OGNL in your routes you need to add a dependency on
camel-ognl to your project as shown in Example 24.1, “Adding the camel-ognl dependency”.
Example 24.1. Adding the camel-ognl dependency
<!-- Maven POM File -->
...
<dependencies>
...
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-ognl</artifactId>
<version>${camel-version}</version>
</dependency>
...
</dependencies>Static import
To use the
ognl() static method in your application code, include the following import statement in your Java source files:
import static org.apache.camel.language.ognl.OgnlExpression.ognl;
Built-in variables
Table 24.1, “OGNL variables” lists the built-in variables that are accessible when using OGNL.
| Name | Type | Description |
|---|---|---|
this | org.apache.camel.Exchange | The current Exchange |
exchange | org.apache.camel.Exchange | The current Exchange |
exception | Throwable | the Exchange exception (if any) |
exchangeID | String | the Exchange ID |
fault | org.apache.camel.Message | The Fault message(if any) |
request | org.apache.camel.Message | The IN message |
response | org.apache.camel.Message | The OUT message |
properties | Map | The Exchange properties |
property(name) | Object | The value of the named Exchange property |
property(name, type) | Type | The typed value of the named Exchange property |
Example
Example 24.2, “Route using OGNL” shows a route that uses OGNL.
Example 24.2. Route using OGNL
<camelContext>
<route>
<from uri="seda:foo"/>
<filter>
<language langauge="ognl">request.headers.foo == 'bar'</language>
<to uri="seda:bar"/>
</filter>
</route>
</camelContext>