ex6_50.txt

j2ee core design patterns

Example 6.50 WebServiceApplicationController
// Application Controller implementation to handle Web Service Request
class WebServiceApplicationController implements ApplicationController {

  HandlerChain handlerChain;

  public WebServiceApplicationController() { }

  public void init() {
    handlerChain = new HandlerChain();
    handlerChain.addHandler(new AuditHandler());
    handlerChain.addHandler(new AuthenticationHandler());
  }

  public ResponseContext handleRequest(RequestContext requestContext) {
    ResponseContext responseContext = null;
    try {
      SOAPRequestContext soapRequestContext = 
          (SOAPRequestContext)requestContext;

      // create a SOAPMessage from incoming HTTP stream
      SOAPMessage soapMessage = soapRequestContext.getSOAPMessage();

      // pre-process SOAPMessage by Message Handlers
      handlerChain.handleRequest(soapMessage);

      // Identify Command Name from protocol-specific request
      String commandName = soapRequestContext.getCommandName();

      // resolve command name to Command Object
      CommandFactory commandFactory = CommandFactory.getInstance();
      Command command = commandFactory.getCommand(commandName);

      // Invoke Command using a CommandProcessor               
      CommandProcessor commandProcessor = new CommandProcessor();
      Object result = commandProcessor.invoke(command, requestContext);

      // Create Response context based on Command results
      responseContext = ResponseContextFactory.getInstance().
          createResponseContext(result, null);
    } catch(java.lang.InstantiationException e) {
      // Handle Exception
    } catch(java.lang.IllegalAccessException e ) {
      // Handle Exception
    }
    return responseContext;
  }

  public void handleResponse(
    RequestContext requestContext, ResponseContext responseContext) {
    try {

      // create response SOAPResponse message from
      // previously-obtained Command result
      SOAPMessage soapMessage = null;
      Object payload = responseContext.getData();

      soapMessage = SOAPHttpFacade.createSOAPMessage(payload);
      if (soapMessage != null) {
        // post-process Response Message by SOAP Message Handlers
        handlerChain.handleResponse(soapMessage);

        // Need to saveChanges because we're going to use the
        // MimeHeaders to set HTTP response information. These
        // MimeHeaders are generated as part of the save.

        if (soapMessage.saveRequired()) {
          soapMessage.saveChanges();
        }

        HttpServletResponse response = (HttpServletResponse)
        responseContext.getResponse();
        response.setStatus(HttpServletResponse.SC_OK);

        SOAPHttpFacade.putHeaders(
            soapMessage.getMimeHeaders(), response);
        writeResponse(
            (HttpServletResponse)responseContext.
                getResponse(), soapMessage);
      }
    } catch (SOAPException e) {
      // Handle Exception
    }
  }

  public void destroy() { }

  private void writeResponse(
      HttpServletResponse response, SOAPMessage soapResponse) {
    try {
      // Write out the message on the response stream.
      response.setContentType("text/xml"); // SOAP 1.1 Message
      OutputStream outputStream = response.getOutputStream();
      soapResponse.writeTo(outputStream);
      outputStream.flush();                
    } catch(SOAPException e) {
      // Handle Exception
      response.setStatus(HttpServletResponse.SC_NO_CONTENT);
    } catch(java.io.IOException e) {
      // Handle Exception
      response.setStatus(HttpServletResponse.SC_NO_CONTENT);
    }
  }
  . . .
}