Forms: building data-driven form definition files, is it possible?

[Enrico Migliore <en...@fatti.com>]

Hi guys,
 
 I'm developing a web application where the user retrieves data from a DB,
 for update. I would like to use Cocoon Forms for submitting the data.
 The problem I got is that each query is different from the other, and I
 can't build a universal form definition file. The problem here is that
 I don't know in advance the size of the recordset coming out from the DB.

 I would like to build the form definition file based upon the retrieved 
data,
 and not load a static file.
 The major problem seems to be the following:

               FormInstance form = new FormInstance("forms/form1.xml");

 That dictates that the form definition file must be static and can't
 be an XML stream.

 Has someone solved this problem?

 thanks
 Enrico
 

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Re: Forms: building data-driven form definition files, is it possible?

[Bruno Dumon <br...@outerthought.org>]

On Tue, 2004-06-29 at 17:07, Enrico Migliore wrote:
> Hi guys,
>  
>  I'm developing a web application where the user retrieves data from a DB,
>  for update. I would like to use Cocoon Forms for submitting the data.
>  The problem I got is that each query is different from the other, and I
>  can't build a universal form definition file. The problem here is that
>  I don't know in advance the size of the recordset coming out from the DB.

"size of the recordset": I assume then that each resulting record would
describe another field? Otherwise a repeater is what you need.

Only dynamically generate your forms if it's really necessary.

> 
>  I would like to build the form definition file based upon the retrieved 
> data,
>  and not load a static file.
>  The major problem seems to be the following:
> 
>                FormInstance form = new FormInstance("forms/form1.xml");
> 
>  That dictates that the form definition file must be static and can't
>  be an XML stream.
> 
>  Has someone solved this problem?

Here's a snippet of code that should do it (in Java):

        PipelineUtil pipelineUtil = new PipelineUtil();
        FormManager formManager = null;
        try {
            LifecycleHelper.setupComponent(pipelineUtil, null, context, serviceManager, null, null, false);

            Map viewData = new HashMap();
            // optional: put anything in viewData that you might need in the view

            org.w3c.dom.Document formDocument = pipelineUtil.processToDOM("MyPipe", viewData);

            formManager = (FormManager)serviceManager.lookup(FormManager.ROLE);
            Form form = formManager.createForm(formDocument.getDocumentElement());

            return form;
        } finally {
            LifecycleHelper.dispose(pipelineUtil);
            if (formManager != null)
                serviceManager.release(formManager);
        }

An alternative approach is to simply use a "cocoon:/..." URL as argument
to the FormInstance class, but that will be somewhat slower since it
will need an additional parse in between, and I think the FormManager
will also cache the FormDefinition even if it's uncacheable.

-- 
Bruno Dumon                             http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
bruno@outerthought.org                          bruno@apache.org


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