2nd try: Using to change scope

[Steve Bang <SB...@alphablox.com>]

Can anyone help me on this?  

Thanks,
Steve

> -----Original Message-----
> From: Steve Bang [mailto:SBang@alphablox.com]
> Sent: Friday, March 08, 2002 11:03 AM
> To: 'Tag Libraries Users List'
> Subject: Using <set> to change scope
> 
> 
> We have a custom tag library that treats all of our tags with 
> a session scope (by design).  Is it possible to use JSTL's 
> <c:set> tag to change the scope on one of the attributes on 
> our tags?  Users are requesting the ability to dynamically 
> change an attribute value on our tags when a page is refreshed, 
> but so far this is not possible within the tags themselves --
> they are only interpreted the first time a page loads.  If 
> so, do we have to modify our tag library to support this?
> 
> Steve

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Re: 2nd try: Using to change scope

[Shawn Bayern <ba...@essentially.net>]

Ah, I meant to try to answer this, but it slipped through...

I wasn't sure exactly what you meant by "change the scope on one of the
attributes on our tags."  You can use <c:set> to override an existing
attribute, and thus to change the scope of a scoped variable:

 <c:set var="foo" scope="session" value="${page.foo}"/>

but I'm not sure if that's what you mean.

You can't make the 'scope' attribute dynamic, which might be another thing
you mean.  That is, you can't say scope="${myscope}".  This restriction is
designed primarily to aid tool support and translation-time error
checking.  If you need to decide on the fly what scope to use, you'll need
to use a <c:if> or <c:choose> block.  We didn't consider this case very
common, so the somewhat circuitous solution didn't seem to be a major
issue.  (Hmm, that's the first I've used the word "circuitous" to actually
refer to circuit-like logic.  I wonder if that counts as a pun or not...)

--
Shawn Bayern
Author, "JSP Standard Tag Library"  http://www.jstlbook.com
(coming this spring from Manning Publications)

On Mon, 11 Mar 2002, Steve Bang wrote:

> Can anyone help me on this?  
> 
> Thanks,
> Steve
> 
> > -----Original Message-----
> > From: Steve Bang [mailto:SBang@alphablox.com]
> > Sent: Friday, March 08, 2002 11:03 AM
> > To: 'Tag Libraries Users List'
> > Subject: Using <set> to change scope
> > 
> > 
> > We have a custom tag library that treats all of our tags with 
> > a session scope (by design).  Is it possible to use JSTL's 
> > <c:set> tag to change the scope on one of the attributes on 
> > our tags?  Users are requesting the ability to dynamically 
> > change an attribute value on our tags when a page is refreshed, 
> > but so far this is not possible within the tags themselves --
> > they are only interpreted the first time a page loads.  If 
> > so, do we have to modify our tag library to support this?
> > 
> > Steve
> 
> --
> To unsubscribe, e-mail:   <ma...@jakarta.apache.org>
> For additional commands, e-mail: <ma...@jakarta.apache.org>
> 


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