Re: AW: AW: AW: using multiple action forms in one action. Best practice?

[Bill Keese]

Hi Martin,
I see what you mean about the "wizard" metaphor being inappropriate for 
your case.  Maybe "tabbed dialog box" is a closer analogy.  But I guess 
that doesn't match exactly either, because the contents of tab B change 
according to the contents of tab A.  Anyway, there are many ways to 
implement something like that and I guess each has advantages/disadvantages.

By the way, in our application, we have a few cases where we process the 
data entered on multiple forms in one final action.  Specifically we do 
this when we use popup windows, since the concept of "ordering of pages" 
becomes more complicated / impossible when there are multiple windows 
displayed on the screen at a single time.  So we save the information 
from the popup window in the session context, and then reference it when 
the user hits "submit" on the "main" form.   By the way, does anyone 
have experience using popup windows in this way without resorting to 
using session variables?

Anyway, good luck!
Bill
Martin Kindler wrote:
Bill,
you seem to understand my application quite well. The metaphor of
region/shops is excellent.
What adds a bit of complexity is that the "shop"-module is just one of
several. There might be an additional
"people"-module, a "statistical data"-module, etc. Thus serializing the
editing process in a wizard style would impose an order on the process which
is not very pleasant. Also, I would like to reuse the forms/action for
editing already existing objects/regions, where the order enforced by a
wizard is not appropriate.
But I think I have learned fromthis discussion how it could be implemented
reasonably.
The only exception being the question of scope which is not that important
in my case.
Martin
 

-----Ursprüngliche Nachricht-----
Von: Bill Keese [mailto:[EMAIL PROTECTED] 
Gesendet: Mittwoch, 17. November 2004 01:48
An: Struts Users Mailing List
Betreff: Re: AW: AW: using multiple action forms in one 
action. Best practice?

It's hard for me to answer because I don't really understand your 
application.  JSP1 is for picking a region, and then JSP2 is 
for picking 
stores within that region, right? And then after picking the 
stores, you 
display a confirmation page with the map and the list of 
picked stores?

When you hit the "save" button on the confirmation page, the input to 
the SaveAction is both the selected region and the selected stores, 
right?  So you are combining the information entered on two 
previous forms.

If it was me, I would have 3 separate actions and 3 separate 
action-forms:
  1. select-region
  2. select-stores
  3. confirm-dialog

The confirm-dialog ActionForm would contain both the region 
information 
and the list of stores.  Thus I would only use one ActionForm per 
Action, and I wouldn't use session variables.

Bill
Martin Kindler wrote:
   

Hi Bill,
so you say, it is good practice to use the two forms in one 
     

action as I 
   

do in my current solution? Sure, one has to hide the 
     

internals from AF1 
   

to an action primarily designed to use AF2 to keep the 
     

address module 
   

generic. Perhaps I should make the calling ActionForms implement a 
specific interface. If I really want a fully generic address 
     

module I 
   

would have to split the
action(s) in two, simply because the actions designed for 
     

the address 
   

module need a generic API. I cannot rely (for full genericity) on a 
"calling" module to use AF1. In my current situation I will probably 
ignore this as it is a straightforward refactoring which can be done 
when need occurs. As to the question request vs. session scope I 
understand the problems which might occur using session 
     

scope. I do not 
   

see a solution which would also fulfil the modularization 
     

requirement.
   

Thanks!
Martin

     

-----Ursprüngliche Nachricht-----
Von: Bill Keese [mailto:[EMAIL PROTECTED]
Gesendet: Dienstag, 16. November 2004 02:10
An: Struts Users Mailing List
Betreff: Re: AW: using multiple action forms in one action. 
Best practice?

Hi Martin,
  

From this JSP I want to access a (hopefully) generic module
       

    

         

to get the
  

       

access points. This "module" has to get some information (e. g. a
region to prefilter the addresses or access points already 
    

         

existing)
  

from JSP1.
       

    

         

I think you should  generate the input to the generic module, rather
than passing the ActionForm directly:
 // get data from ActionForm1 needed to look up addresses
 AddressLookupInfo info = getAddressInfoFromActionForm1(AF1);
 // lookup addresses
 List res = AddressLookup.getAddresses(info);
  ...
Then your module can still be generic.
  

       

I could take the necessary information from AF1 to some
    

         

POJO (or bean)
  

       

on model level (or controller level) and transfer it to
    

         

AF2. This is
  

       

probably the "cleanest" solution but means to split each
    

         

action into
  

       

two, just to do
the data transfer.
    

         

You shouldn't need to split each action into two.  Action1's
job is to 
handle the input from ActionForm1, and then do the setup to display 
JSP2, right?  So, just create the ActionForm2 manually 
       

inside Action1:
   

// Create AF2 as an input/output form
ActionForm2 af2 = new ActionForm2();  
session.setAttribute("actionForm2", af2);

// ... and pre-populate it with the data the user has 
       

already input
   

ActionForm1 af1 =
         (ActionForm1) getActionForm(mapping, form,
request, session);
af2.loadDataFromAF1(af1);
// forward control to JSP2
return (mapping.findForward("jsp2"));
  

       

My current solution simply accesses both action forms, AF1 and AF2 
(getting the one not available as the "form"-parameter by 
         

MyForm mf =
   

(MyForm)session.getAttribute("AFi");
but my feeling is that this is not really good style.
    

         

I guess it depends on whether you consider the two forms to 
       

represent
   

one logical command or two logical commands.
The other thing to consider, though, is whether or not you
want to store 
the ActionForms at session scope.   Session scope is 
problematic because 
you might end up accessing old data (if the user previously 
quit in the 
middle of a wizard).  Also, I imagine things would fail in a 
distributed 
application where the user's requests are randomly routed 
       

to multiple 
   

servers.    The alternative is to use request level scope, 
but in this 
case the information entered in Form#1 has to be embedded in 
the output 
of JSP2 as hidden HTML variables.

Bill
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