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Chapter 224. MVEL Language

Available as of Camel version 2.0

Camel allows Mvel to be used as an Expression or Predicate the DSL or Xml Configuration.

You could use Mvel to create an Predicate in a Message Filter or as an Expression for a Recipient List

You can use Mvel 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: 

"request.body.familyName"
   // or
"getRequest().getBody().getFamilyName()"
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224.1. Mvel Options
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The MVEL language supports 1 options which are listed below.

Expand
NameDefaultJava TypeDescription

trim

true

Boolean

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

224.2. Variables
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Expand
VariableTypeDescription

this

Exchange

the Exchange is the root object

exchange

Exchange

the Exchange object

exception

Throwable

the Exchange exception (if any)

exchangeId

String

the exchange id

fault

Message

the Fault message (if any)

request

Message

the exchange.in message

response

Message

the exchange.out message (if any)

properties

Map

the exchange properties

property(name)

Object

the property by the given name

property(name, type)

Type

the property by the given name as the given type

224.3. Samples
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For example you could use Mvel inside a Message Filter in XML 

<route>
  <from uri="seda:foo"/>
  <filter>
    <mvel>request.headers.foo == 'bar'</mvel>
    <to uri="seda:bar"/>
  </filter>
</route>
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And the sample using Java DSL: 

   from("seda:foo").filter().mvel("request.headers.foo == 'bar'").to("seda:bar");
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224.4. Loading script from external resource
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Available as of Camel 2.11

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", eg to refer to a file on the classpath you can do: 

.setHeader("myHeader").mvel("resource:classpath:script.mvel")
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224.5. Dependencies
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To use Mvel in your camel routes you need to add the a dependency on camel-mvel which implements the Mvel 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-mvel</artifactId>
  <version>x.x.x</version>
</dependency>
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