ex6_43.txt

j2ee core design patterns

Example 6.43 	Implementing View Handler Strategy: WebApplicationController
// Application Controller Implementation to handle Web 
// Application Requests
class WebApplicationController implements ApplicationController {

  . . .
  // Handle View Navigation and Dispatching to appropriate View
  public void handleResponse(RequestContext requestContext, 
      ResponseContext responseContext) {
    ViewFactory viewFactory = ViewFactory.getInstance();

    // Identify view template based on logical view name, user agent,
    // locale, etc
    String viewTemplate = viewFactory.getViewTemplate(
        requestContext, responseContext.getLogicalViewName());

    // dispatch to view processor
    dispatch(requestContext.getRequest(), responseContext.getResponse(),
        viewTemplate);      
  }
   
  public void destroy() { }
  
  // dispatcher method  
  private void dispatch(HttpServletRequest request, 
      HttpServletResponse response, String page) {

    try {
      RequestDispatcher dispatcher = request.getRequestDispatcher(page);
      dispatcher.forward(request, response);
    } catch(Exception e) {
      // Handle Exception
    }
  }
}