Re: Use cases for multiple models

Hi Eric,

I believe that using XForms in a portal environment is the use case main 
use case.

Logically, I think we want the notion of one form, one model.  We also 
want one portlet, one form.

But for client-side web browser implementations, this means there could be 
one model and set of UI controls per portlet, so the XForms processor 
reading the XHTML for the whole portal has to be able to deal with 
multiple models.

Unfortunately, an XForm does not get off scott-free of modifications to be 
used in a portal environment. 

The IDs of the models have to be made unique, and each portlet's set of 
XForms controls need to be qualified with the proper model identity.  This 
could be as simple as wrapping the controls of the portlet in a group with 
the single-node binding of model='x' and ref=".".  Not hard, but still 
something that needs to be done.

However, a lot of the mixed model tip-toeing that we have been doing for 
context resolution and for action sequences that can *theoretically* touch 
multiple models is really not to address this main use case but rather to 
deal with the nuclear fallout that results from allowing more than one 
model in a host document.

Cheers,
John M. Boyer, Ph.D.
Senior Product Architect/Research Scientist
Co-Chair, W3C XForms Working Group
Workplace, Portal and Collaboration Software
IBM Victoria Software Lab
E-Mail: boyerj@ca.ibm.com  http://www.ibm.com/software/

Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer





Erik Bruchez <ebruchez@orbeon.com> 
Sent by: www-forms-request@w3.org
07/12/2006 06:12 AM

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"'www-forms'" <www-forms@w3.org>
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Subject
Use cases for multiple models







All,

I am wondering what use cases for multiple models XForms users have
encountered.

I personally have very rarely had the need for multiple models, and
encountered issues when trying to use multiple models related to the
XPath evaluation context in controls (for example once you are in the
context of a model, the instance() function can only access instances
from that model).

But I still want to believe there must be good use cases out there, so
don't be shy and please share :-)

-Erik

-- 
Orbeon - XForms Everywhere:
http://www.orbeon.com/blog/