Example 6.17 Request Context Map Strategy
public class FrontController extends HttpServlet {
. . .
  private void processRequest(HttpServletRequest request, 
      HttpServletResponse response) throws ServletException,
          java.io.IOException {

    // create RequestContext object using Map Strategy
    Map requestContextMap = new HashMap(request.getParameterMap());
    Dispatcher dispatcher = new Dispatcher(request, response);
    requestContextMap.put("dispatcher", dispatcher);

    // Create ApplicationController instance
    ApplicationController applicationController = 
        new ApplicationControllerImpl();

    // Request processing
    ResponseContext responseContext =
        applicationController.handleRequest(requestContextMap);

    // Response processing
    applicationController.handleResponse(requestContextMap,
        responseContext);
  }
  . . .
}