OGNL

Since Camel 1.1

Camel allows OGNL (Apache Commons OGNL) to be used as an Expression or Predicate in Camel routes.

For example, you can use MVEL in a Predicate with the Content Based Router EIP.

You can use OGNL dot notation to invoke operations. If you for instance have a body that contains a POJO that has a getFamilyName method then you can construct the syntax as follows:

request.body.familyName

Or use similar syntax as in Java:

getRequest().getBody().getFamilyName()

OGNL Options

The OGNL language supports 2 options, which are listed below.

Name Default Java Type Description

resultType

String

Sets the class of the result type (type from output).

trim

true

Boolean

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

Variables

Variable Type Description

this

Exchange

the Exchange is the root object

context

CamelContext

the CamelContext

exchange

Exchange

the Exchange

exchangeId

String

the exchange id

exception

Throwable

the Exchange exception (if any)

request

Message

the message

message

Message

the message

headers

Map

the message headers

header(name)

Object

the message header by the given name

header(name, type)

Type

the message header by the given name as the given type

properties

Map

the exchange properties

property(name)

Object

the exchange property by the given name

property(name, type)

Type

the exchange property by the given name as the given type

Example

For example, you could use OGNL inside a Message Filter

from("seda:foo")
  .filter().ognl("request.headers.foo == 'bar'")
    .to("seda:bar");

And in XML:

<route>
  <from uri="seda:foo"/>
  <filter>
    <ognl>request.headers.foo == 'bar'</ognl>
    <to uri="seda:bar"/>
  </filter>
</route>

Loading script from external resource

You can externalize the script and have Camel load it from a resource such as "classpath:", "file:", or "http:". This is done using the following syntax: "resource:scheme:location", e.g. to refer to a file on the classpath you can do:

.setHeader("myHeader").ognl("resource:classpath:myognl.txt")

Dependencies

To use OGNL in your camel routes you need to add the dependency on camel-ognl which implements the OGNL 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-ognl</artifactId>
  <version>x.x.x</version>
</dependency>