pre-populated ActionForms / suggestion [patch] for beta1.1b2

[Thomas Heller <th...@mx4k.com>]

Hi there,

I'm trying to create a form with some pre-filled which either come from a
cookie or a database. i browsed the archive and found a comment from Craig
where he says the best way to do this is by routing the specified request
into a action and populate the form there. IMHO this way would complicate
the Actions execute method unnecessary complicat cause it must have a
"action-case" for "prepopulate".

IMHO the best way to handle what i would want to do would be done like this.

1. introduce a "prepare(HttpServletRequest request)" method info
"ActionForm"
2. invoke this method in "RequestUtils.createActionForm(...)" right after
"instance.setServlet(servlet)" in line 638

inside the Forms "prepare" (populate or some other name) Method i could
prepare all fields like i want including setting values from session,
request, cookies, context, db, etc since i get the current request as a
method param.

dunno how to submit patches to struts but it would look something like this:

class: org.apache.struts.action.ActionForm
[snip]

    /**
     * Prepare the form before it gets displayed first.
     * <p>
     * The default implementation does nothing.  Subclasses can
    * override this method to insert values from a DB/Cookie into
    * the form
     *
     * @param request The servlet request we are processing
     */
    public void prepare(HttpServletRequest request) {

        ;       // Default implementation does nothing

    }
[/snip]

All forms written before this method would still work and it eases the work
of setting form values by cookies alot.

Comments welcome ...

thanks,
Thomas Heller

> Date: Tue, 25 Jun 2002 20:17:35 -0400 (EDT)
> From: Matt Barnicle <br...@barnicle.org>
> Reply-To: Struts Users Mailing List <st...@jakarta.apache.org>
> To: Struts Users Mailing List <st...@jakarta.apache.org>
> Cc: struts@barnicle.org
> Subject: Re: Playing with cookies - How?
>
> Thanks again, Chris.  This helps me out a bit, but I'm still clueless on
> how to take the cookie value to pre-populate the form.  I know I could
> come up with some way to rig it, like:
>
> <html:radio name="foo" value="1"
>   <logic:equal name="mycookie" property="value"
value="1">checked="checked">
>
> But that seems to defeat the usefulness of Struts, and I'm sure there's a
> more appropriate way to do it.  How?
>

This kind of syntax actually won't work anyway -- you cannot nest an XML
tag inside an attribute value.

IMHO, the best way to deal with situations like this is the same as any
other situation where you need to pre-populate a form -- route the
incoming request through an Action that pulls out whatever you need from
your cookies and uses it to populate beans that are later used by the JSP
page that you forward to.

The struts-example application uses this design pattern (although with a
database lookup instead of cookies) when you select the "edit your
profile" option.  This is routed through the /editRegistration action,
which looks in the pseudo-database and prepopulates the form bean for the
registration form.

Craig


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