Data Format

Camel supports a pluggable DataFormat to allow messages to be marshalled to and from binary or text formats to support a kind of Message Translator.

The following data formats are currently supported:

And related is the following:

Unmarshalling

If you receive a message from one of the Camel Components such as File, HTTP or JMS you often want to unmarshal the payload into some bean so that you can process it using some Bean Integration or perform Predicate evaluation and so forth. To do this use the unmarshal word in the DSL in Java or the XML Configuration.

For example:

DataFormat jaxb = new JaxbDataFormat("com.acme.model");

from("activemq:My.Queue").
  unmarshal(jaxb).
  to("mqseries:Another.Queue");

The above uses a named DataFormat of jaxb which is configured with a number of Java package names. You can if you prefer use a named reference to a data format which can then be defined in your Registry such as via your Spring XML file.

You can also use the DSL itself to define the data format as you use it. For example the following uses Java serialization to unmarshal a binary file then send it as an ObjectMessage to ActiveMQ

from("file://foo/bar").
  unmarshal().serialization().
  to("activemq:Some.Queue");

Marshalling

Marshalling is the opposite of unmarshalling, where a bean is marshalled into some binary or textual format for transmission over some transport via a Camel Component. Marshalling is used in the same way as unmarshalling above; in the DSL you can use a DataFormat instance, you can configure the DataFormat dynamically using the DSL or you can refer to a named instance of the format in the Registry.

The following example unmarshals via serialization then marshals using a named JAXB data format to perform a kind of Message Translator:

from("file://foo/bar").
  unmarshal().serialization().
  marshal("jaxb").
  to("activemq:Some.Queue");

Using Spring XML

This example shows how to configure the data type just once and reuse it on multiple routes:

<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
  <dataFormats>
    <jaxb id="myJaxb" prettyPrint="true" contextPath="org.apache.camel.example"/>
  </dataFormats>

  <route>
    <from uri="direct:start"/>
    <marshal ref="myJaxb"/>
    <to uri="direct:marshalled"/>
  </route>
  <route>
    <from uri="direct:marshalled"/>
    <unmarshal ref="myJaxb"/>
    <to uri="mock:result"/>
  </route>

</camelContext>

You can also define reusable data formats as Spring beans:

<bean id="myJaxb" class="org.apache.camel.model.dataformat.JaxbDataFormat">
  <property name="prettyPrint" value="true"/>
  <property name="contextPath" value="org.apache.camel.example"/>
</bean>
Back to top