struts-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Raghuram Kanadam" <Suryaprakash_Kana...@infosys.com>
Subject RE: mapping.setInput()
Date Wed, 28 Jul 2004 05:08:17 GMT
	Very true. We agree Craig, but why should the moduleConfig be frozen, there could have been
a provision made for adding an action mapping dynamically, that could determine its config
at runtime. A situation follows:

	Maybe what I'm talking is really bad design but please enlighten me, we had (have!) a situation
wherein, a user has a multistep procedure and can navigate to any previous step through links,
however the form in the current JSP needs to retain its values and needs to be validated,
therefore he is allowed to goto a previous step only after his current input is validated
which would happen only after his values are saved in the form by Struts. 

	However this needs to be done only if the form has changed as validating every field wud
be unnecessary otherwise. 
So we have a saveAndForward Action which is always the target of a link/form submit. In addition
to the form parameters it receives a dirty flag (which says if the user updated the form),
a param saying where to go and a param saying to which form I ought to submit this. Depending
on the value of the forward I either forward it to an action mapping or to the JSP requested.

	Now all that action class does is a forward to the JSP and has no business logic. So we just
needed a dispatch action which could take its "parameter" at runtime, and be associated with
an action form and input at runtime. How would you solve this situation? We are still thinking
about adding an unfrozen action mapping to the existing modules by overloading the initModules.


:)

-----Original Message-----
From: Craig McClanahan [mailto:craigmcc@gmail.com]
Sent: Tuesday, July 27, 2004 10:54 PM
To: Struts Users Mailing List
Subject: Re: mapping.setInput()


On Tue, 27 Jul 2004 11:34:48 +0530, Raghuram Kanadam
<suryaprakash_kanadam@infosys.com> wrote:
> Sory Satish! Configurations freeze upon loading! Check the ActionServlet's code. However
We did find a way through, If you dont specify the input parameter then the ActionConfig.getInput
() returns a new ForwardConfig (Unfrozen)!! Use this. But I would not beleive this is good
design, for that was not the intent. You could override the initModuleConfigMethods () to
create a new Actionmapping of you own for the purpose but...!
> 
> :)

Note that there is a very good reason the configuration objects are
frozen ... they are shared by all users.  If you were allowed to
change, say, a ForwardConfig (as is being proposed here) on the fly,
you would be affecting *all* users of your application that are using
that particuar forward at the same time, not just one user.

Creating a new ForwardConfig object is the way to go for this
particular need ... just be aware that, the more you do this sort of
thing, the more knowledge about the overall organization of your
application is being spread around your Actions, instead of being
centraized in the struts-config.xml file.  You might want to at least
add some comments to struts-config.xml to point your future developers
back at the actions that are affected if you ever decide to change the
organization of forwards in the future -- Murphy's Law guarantees, of
course, that you'll pick ones like this and cause bugs :-).

Craig

---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
For additional commands, e-mail: user-help@struts.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: user-unsubscribe@struts.apache.org
For additional commands, e-mail: user-help@struts.apache.org


Mime
View raw message