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From Pat Young <patyoung...@yahoo.com>
Subject RE: Need to pass data to JSP in ActionForm
Date Wed, 04 Feb 2004 05:09:58 GMT
I like the adapter idea.  Does the adapter contain all
data that is required by the jsp page?  so fomr a
modelling perspective, do you have adapter that match
the pages?

Thanks,
Pat Young

--- Andrew Hill <andrew.david.hill@gridnode.com>
wrote:
> If the list doesnt change during the course of a
> users session then the best
> thing to do is to create it on first demand and
> store it in the session.
> This saves you from looking it up from the db
> repeatedly when unnecessary
> and is thus more efficient. If the list is the same
> for all users and doesnt
> change at all then you could store it in the servlet
> (application) context.
> 
> If it does change (for example when new records are
> added) then you will
> still need to look it up each time. In this case
> your best bet might be to
> extend Rick's suggestion about having a seperate
> helper class that assembles
> the list (always a good idea). This
> helper/manager/thing is part of your
> business process layer. Above that you could have an
> aditional (very simple)
> adaptor class that is passed a request, calls this
> helper to obtain the
> list, and stores said list under the appropriate
> request attribute.
> 
> Your validate method could thus call this adapter to
> setup the list when it
> is validating the entered data. Your setup action,
> likewise would call the
> adaptor class rather than directly calling the
> business layer and storing
> the result.
> 
> One thing to beware of when you do such non-trivial
> things in the
> actionform, is that if memory serves me correctly
> (someone please correct me
> if Im wrong on this!), exceptions thrown here wont
> be handled by the
> exception handler you configured in struts config as
> the try/catch that
> invokes that handler is merely around the invocation
> of the actual action
> execute and not the form reset / validate stuff.
> 
> These are some of the reasons I personally prefer to
> do my validation in the
> action itself and dont make use of the forms
> validate method. (Of course if
> your using struts validator that becomes problematic
> too)
> 
> hth
> Andrew
> 
> 
> -----Original Message-----
> From: Rick Reumann [mailto:struttin@reumann.net]
> Sent: Wednesday, 4 February 2004 12:26
> To: Struts Users Mailing List
> Subject: Re: Need to pass data to JSP in ActionForm
> 
> 
> Pat Young wrote:
> 
> > 6.  The problem I am having is that if the
> ActionForm
> > failes validation, then the sales.jsp page gets an
> > error becaue it can not find the bean in the
> Request
> > for the products list.  Should I build this bean
> in my
> > validate and place it in the request at the
> beginning
> > of validate?  If validate fails, there is no other
> > opportunity to build the products list and get it
> into
> > the Request.
> 
> Personally I often opt for the easy solution and put
> the List in Session
> scope, but there are other alternatives that have
> been discussed on this
> list before.
> 
> > 7.  I typically uses Actions to retrieves and
> build
> > beans and then add them to the request for the jsp
> to
> > access.  Is this an acceptable practice also?
> 
> Depends what you mean by "build beans." Nothing
> wrong wtih setting stuff
> into Request scope from your Actions, but make sure
> you are calling some
> business process that does the actual "building."
> For example...
> 
> //in your Action:
> List someList = someBusinessClass.getMyList();
> request.setAttribute("listWhatever", someList);
> 
> --
> Rick
> 
>
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