Processing message body data by using JAXB Java object classes

Use the JAXB object classes generated by a Java™ Architecture for XML Binding (JAXB) compiler by using the JAXB class template.

1. Optional: Modify the onInitialize () method to reference the package or packages that contain your Java object binding classes.

   	public void onInitialize() throws MbException {
   		try {
   			// TODO Update context path "com.example.jaxb" to be the package of your
   			// Java object classes that were generated by a Java Architecture for XML
   			// Binding (JAXB) binding compiler  
   			jxbcntxt = JAXBContext.newInstance("com.example.jaxb");

   Replace com.example.jaxb with your JAXB Java object bindings classes package.

   Note: When you deploy or restart your message flow, the onInitialize () method is called only once, and initializes JAXB context for all processing threads.

   If an error is thrown by the generation of the JAXB context, the code that is provided in the "Process via JAXB class" template throws an MbUserException, and the deployment operation fails. If the deployment operation fails, inspect the error message that is recorded in the host system event log to determine the cause. The most likely cause is that one or more package names cannot be resolved, or that one or more of the packages you specified do not contain the required JAXB object factory or bindings properties.

2. Modify the evaluate() method to process each message that is passed in a MbMessageAssembly object. The MbMessageAssembly object is defined in the Java user-defined node API.
   1. The first section of the evaluate() method extracts the message data from the assembly, creates an output assembly and copies message headers. For more information, see Creating a message processing or output node in Java.

      public void onInitialize() throws MbException {
      try {
      // TODO Update context path "com.example.jaxb" to be the package of your
      // Java object classes that were generated by a Java Architecture for XML
      // Binding (JAXB) binding compiler
      jaxbContext = JAXBContext.newInstance("com.example.jaxb");
      } catch (JAXBException e) {
      // This exception will cause the deploy of this Java compute node to fail
      // Typical cause is the JAXB package above is not available
      MbUserException mbue = new MbUserException(this, "onInitialize()",
      "", "", e.toString(), null);
      throw mbue;
      }
      }

   2. The next part in the evaluate() method unmarshals the input message data into the set of Java objects that are bound from the message schema. Unmarshalling creates a Java object model copy of the message data that is in memory.

      try {
      // unmarshal the input message data from the message tree into your Java object classes
      Object inMsgJavaObj = jaxbContext.createUnmarshaller().unmarshal(inMessage.getDOMDocument());

   3. The next part in the evaluate() method is where you insert your own JAXB code to create or update the output message by processing message data. See external resources for details of how to program transformations by using JAXB Java object classes. For information about debugging in Java, see Java Debugger.

      // ----------------------------------------------------------
      // Add user code below to build the new output data by updating
      // your Java objects or building new Java objects
      Object outMsgJavaObj = inMsgJavaObj;
      // End of user Java object processing
      // ----------------------------------------------------------
      

      The following example shows some JAXB code that adds a record to a CSV message, and sets the value of the three fields in that record:

      // Example: add a record of fixed data
      CsvMsg outMsgJavaObj = (CsvMsg) inMsgJavaObj;
      Record additionalCsvRecord = new Record();
      additionalCsvRecord.setField1("My new field 1 text");
      additionalCsvRecord.setField2("My new field 2 text");
      additionalCsvRecord.setField3("My new field 3 text");
      outMsgJavaObj.getRecord().add(additionalCsvRecord);
      // end example

   4. The next part in the evaluate() method marshals the processed Java object classes back into the Integration node message tree. Modify this code to pass the relevant Java object in place of the template default. If your JAXB transformation code updated the input message, pass the Java object class that was created during unmarshalling into the marshalling code. If you are creating an output message, pass the Java object class for your new output message into the marshalling code.
      The template sets the output domain to XMLNSC; if you require the output message to be in the DFDL or SOAP domains, you must modify this code.

      // TODO set the required
       domain for the output message, eg XMLNSC
      Document outDocument = outMessage.createDOMDocument(MbXMLNSC.PARSER_NAME);
      // marshal the new or updated output Java object class into the message tree
      jaxbContext.createMarshaller().marshal(outMsgJavaObj, outDocument);