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Chapter 39. Payload-Based Route

39.1. Processing Messages in PAYLOAD Format


Select the PAYLOAD format, if you want to access the SOAP message body in XML format, encoded as a DOM object (that is, of org.w3c.dom.Node type). One of the advantages of the PAYLOAD format is that no JAX-WS and JAXB stub code is required, which allows your application to be dynamic, potentially handling many different WSDL interfaces.
Having a message body in XML format enables you to parse the request using XML languages such as XPath and to generate responses using templating languages, such as Velocity.
The DOM format is not the optimal type to use for large XML message bodies. For large messages, consider using the techniques described in Chapter 40, Provider-Based Route.

Demonstration location

The code presented in this chapter is taken from the following demonstration:
For details of how to download and install the demonstration code, see Chapter 34, Demonstration Code for Camel/CXF

Camel CXF component

The Camel CXF component is an Apache CXF component that integrates Web services with routes. You can use it either to instantiate consumer endpoints (at the start of a route), which behave like Web service instances, or to instantiate producer endpoints (at any other points in the route), which behave like WS clients.
Came CXF endpoints—which are instantiated using the cxf:cxfEndpoint XML element and are implemented by the Apache Camel project—are not to be confused with the Apache CXF JAX-WS endpoints—which are instantiated using the jaxws:endpoint XML element and are implemented by the Apache CXF project.

PAYLOAD data format

The PAYLOAD data format is selected by setting the dataFormat=PAYLOAD option on a Camel CXF endpoint URI and it has the following characteristics:
  • Enables you to access the message body as a DOM object (XML payload).
  • No JAX-WS or JAXB stub code required.
  • The SOAP body is marshalled as follows:
    • The message body is effectively an XML payload of org.w3c.dom.Node type (wrapped in a CxfPayload object).
    • The type of the message body is org.apache.camel.component.cxf.CxfPayload.
  • The SOAP headers are converted into headers in the exchange's In message, of org.apache.cxf.binding.soap.SoapHeader type.

Implementing and building a PAYLOAD route

To implement and build the demonstration PAYLOAD-based route, starting from scratch, you would perform the following steps:
  1. Instantiate the Camel CXF endpoint in Spring, using the cxf:cxfEndpoint element.
  2. Implement the route in XML, where you can use the content-based router to sort requests by operation name.
  3. For each operation, define a processor bean to process the request.
  4. Define velocity templates for generating the reponse messages.

Sample PAYLOAD route

Figure 39.1, “Sample PAYLOAD Route” shows an outline of the route that is used to process the operations of the CustomerService Web service using the PAYLOAD data format. After sorting the request messages by operation name, an operation-specific processor bean reads the incoming request parameters. Finally, the response messages are generated using Velocity templates.

Figure 39.1. Sample PAYLOAD Route

Sample PAYLOAD Route