Re: Populating a Form with values

[Sid Stuart <si...@aynot.com>]

Hi all,

I also initially wrote two action classes for each JSP page, one to 
intialize it and the other to process the form. This got a bit messy, so 
I wrote template that looks at the HTTP method and calls an 
initialization method if it is a "GET" or calls a form processing method 
if it is "POST". A class extending the template can be used both to 
initialize the form needed by a JSP page as well as process the form. An 
excerpt of the code is below.

Sid

public abstract class ActionTemplate extends Action {

    private final String GET = "GET";
    private final String POST = "POST";

    //----------------------------------------------------------------- 
Public Methods
    /**
     * Override the Action method's perform method. This looks at the 
HTTP method used to initiate the
     * transaction and calls one of two abstract methods, depending on 
whether a get or post
     * was sent.
     *
     * @return An ActionForward object.
     */
    public ActionForward perform(ActionMapping mapping, ActionForm form,
                                 HttpServletRequest request, 
HttpServletResponse response)   {
        log.info ("Entering perform:");
        // The result is returned at the end.
        ActionForward result = null;

        // Get the session
        final HttpSession session = request.getSession ();

        // At this point, the perform method calls one of two abstract 
methods.
        // One does initialization and displays the JSP page. The other 
processes
        // a form submitted by the JSP page. Which method to call is 
decided by whether the
        // action was initiated by a get or a post.
        //
        final String method = request.getMethod ();
        // Initialize a JSP page.
        if (method.compareToIgnoreCase(GET) == 0 ) {
            result = initializeJSP (mapping, form, request, response, 
session);
        }
        // Process a form.
        else if (method.compareToIgnoreCase(POST) == 0) {
            result = processForm (mapping, form, request, response, 
session);
        }
        else {
            log.error("Unknown method received by Action: " + method);
        }
        log.info ("Leaving perform");
        return result;
      }


    
//------------------------------------------------------------------- 
Abstract Methods
    /**
     * The initializeJSP method is called before the JSP page is 
displayed. It should
     * initialize any objects needed by the page.
     * @return An ActionForward object
     */
    protected abstract ActionForward initializeJSP (ActionMapping 
mapping, ActionForm form,
     HttpServletRequest request, HttpServletResponse response, 
HttpSession session);

    /**
     * The processForm method is called when the form is submitted from 
the JSP page. It should contain
     * the code needed to process the form.
     * @return An ActionForward object
     */
     protected abstract ActionForward processForm (ActionMapping 
mapping, ActionForm form,
              HttpServletRequest request,  HttpServletResponse response, 
HttpSession session);
    }


Keith Bacon wrote:

>Most people say best practice is to always start your jsp from the struts action. (always use the
>/myAction.do not /myAction.jsp).
>
>I think you need to do a lot of studying & messing around to get the hang of struts, it's not
>totally simple - but web apps never were.
>Try http://husted.com/struts/resources.htm
>
>Keith.
>  
>




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