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Date: Sun, 21 Sep 2003 15:58:25 +0200
From: Erez Efrati <ereze@netmedia.net.il>
Subject: Wizard pages in Struts design question
To: 'Struts Users Mailing List' <struts-user@jakarta.apache.org>
Message-id: <02ac01c38048$70179460$050aa8c0@Erez>
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I read the HowTo write a wizard on the Struts web-site but I wasn't
really happy with the solution, and I am looking for a better one. I
came up with another way and I would appreciate your comments. 

The design consists of: 
- The 'form' is a session scope form
- WizardAction class (a DispatchAction based) with following methods:
	* init () - starting the wizard and redirect to the first page
	* finish () - (or save()) finish the wizard and save the
information 			  in the form using some business logic
delegate.
	
- Each Page or step in the wizard is a separate Action class, extending
a 	WizrardBaseAction (a DispatchAction based) which contains some
shared 	methods.

	For example: Page1Action extends WizardBaseAction {

			// initializes the page (done only on first
encounter)
			ActionForward init (mapping,...) throws
Exception;
			ActionForward back (mapping,...) throws
Exception;
			ActionForward next (mapping,...) throws
Exception;				ActionForward finish
(mapping,...) throws Exception;
	}		

- Each page/step has a separate action-mapping item in the configuration
with local forwards for : 'back' (if not the first page), 'next',
'finish' (if allowed from that page).

 I apologize for not sketching the whole idea down to the last bit but I
hope you get the picture. 

Only problem is that this design touches the question of chaining
actions verses forward redirection (not just dispatching). 

For example the Page1Action.next() does the following:
	1. validate the page
	2. perform whatever processing required
	3. return the next action to forward to (redirect or chain with
all 	its illness..)

In my opinion (humble one of course :) having such a separation keeping
each step in its own class is better and clearer design than having them
all in the same Action class. 

Isn't there a way to prevent the reset + pre-population of the form done
while chaining actions? Furthermore, is it so bad to redirect between
actions? 

Thanks in advance,
Erez


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