Model 2 - ServletRequestWrapper & Forwards

Question

Hello Folks,
My last (none portal) project allow a better separation of business logic and display logic by allowing a HTTP request to be submitted to a servlet and then have the servlet extract the data and forward on to a JSP which built the view.
I would like to be able to do the same with my Portlets so a request will come into my servlet and I can forward to the appropriate JSP (Edit,Full Screen, ...)
The API for the Servlet20RequestWrapper has :
"Wraps the servlet Request so we can "forward" requests to a servlet/jsp and respond to that "forwarded" servlet with the proper paths "
Does anyone have an example of this ?
Is there any more documentation ?
A normal forward to required the RequestDispatcher but the Portal API sits about this.
Cheers
JonK

Answer 1

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by David Knox ([email protected]):
// in the appropriate method, just forward to your JSP
public void render(PortletRenderRequest pr) throws PortletException, AccessControlException {
switch (pr.getMode()) {
case PortletRenderer.MODE_SHOW:
renderShow(pr);
break;
case PortletRenderer.MODE_EDIT:
renderEdit(pr);
break;
case PortletRenderer.MODE_EDIT_DEFAULTS:
break; // nothing
default:
throw new PortletException(" Invalid render mode "
+ pr.getMode());
}<HR></BLOCKQUOTE>
I am not sure you have understood what I am trying to do, The render method sits in the servlet you write for the Portlet. The renderShow is another method within the servlet which contains the code to generate HTML, you have given no example of how to forward to a JSP. ie pass control to JSP compiled servlet to perform HTML generation.
I understand that you can determine the Page Mode, and that in your servlet you would write a method for each mode. The bit I am try to find out is how to do the "forward" under the control of the Portal. For a forward I mean pass control from my portlet servlet that processes the request to another portlet servlet or JSP that generates the HTML.
I need to know if the Portlet API has a method for one of it's classes to perform the forward.
In the old days :
In My Servlet
HttpServletRequest request;
HttpServletResponse response
String url = "/jsp/myPage.jsp";
RequestDispatcher rd = request.getRequestDispatcher(url);
rd.forward(request,response);
Within the servlet I would do my processing and then pass control to another servlet which is generated from the JSP page. That way the JSP page could stick to creating the HTML and the Servlet would stick to extracting data and updating the model.
The Portal works by having a central Servlet or Portal Servlet which controls all other servlets or JSP generated servlets. Instead of writing a servlet for a whole page we write a servlet for part of the page. The Portal Servlet can then call the sub-servlets in parallel to build the page. If I call the Request Dispatcher's forward routine I will replace the Portal Servlet with my own servlet thus taking out the PORTAL.
The Serlvet technology was replaced by JSP as they felt that embedding HTML within Java Code lead to un-maintainable Java. Instead you embed java in HTML, but embedding logic within in the JSP lead to un-maintainable HTML(JSP). Then came Tag Libraries, this allows you to extend the tags within HTML with your own tags to take the complex logic out of the JSP and back into the java making JSP look more like HTML and allowing designers to do their thing. This is known as Model 2.
Model 1 is where you just have a JSP file with all the logic required to process a request and generate the HTML.
The whole thing will be replaced by XML / XSL but currently it is too slow.
I expect I might as well stick to servlets as you don't have to generate a full HTML page but a component within a page, which means the HTML embedded within the servlet never be too complicated.