Mailing-List: contact dev-help@cocoon.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@cocoon.apache.org
Message-ID: <408ED30F.9090001@apache.org>
Date: Tue, 27 Apr 2004 23:39:27 +0200
From: Sylvain Wallez <sylvain@apache.org>
Organization: Anyware Technologies
User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US;
 rv:1.6) Gecko/20040113
MIME-Version: 1.0
To: dev@cocoon.apache.org
Subject: Re: cforms: events on widget instances
References: <1083057893.28238.122.camel@23.13 	yum.ot 	yum
In-Reply-To: <1083057893.28238.122.camel@23.13 	yum.ot 	yum
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Bruno Dumon wrote:

>I've just added the instance based event listeners. You can both add and
>remove them.
>
>Following table summarizes the current event situation, see below for
>more info.
>
>                    valuechanged   action
>field                   Y           N/A
>multivaluefield         (*)         N/A
>booleanfield            Y           N/A
>repeater                N/A         N/A
>output                  N/A         N/A
>submit                  N/A         Y
>action                  N/A         Y
>repeater-action         N/A         Y
>row-action              N/A         Y
>aggregatefield          (**)        N/A
>upload                  N/A         N/A
>messages                N/A         N/A
>
>N/A means not applicable
>
>For those events where Y (yes) is mentioned, they are supported both in
>the definition and the instance.
>  
>

I'd like to add "action" on every widget where a @submit-on-change makes 
sense (field, booleanfield, multivaluefield, upload). This would allow 
to have some specific event-handling related to the fact that the widget 
was activated, regardless if its value changed or not.

>And then the special cases:
>
>(*) multivaluefield: the builder happily builds the listeners, but
>multivaluefield seems to nowhere create events. So I haven't added
>instance-based event listeners on that widget either. -> solution I see
>is to add full support for value changed events to this widget.
>
>(**) aggregatefield: the definition and definition builder don't support
>value changed events, and events are hence also nowhere created, but
>since the instance class extends from Field it automatically has the
>possibility to add instance-level event listeners (but they won't ever
>be called) -> solution: unsure. Is it possible/meaningful to support
>value changed listeners on this widget? Volunteers?
>
>                           - o -
>
>And now the practical side: example usage in flowscript:
>
>form.getWidget("test").addActionListener(newActionListener(function(event) {
>        print("hi there");
>}));
>
>where the newActionListener function is as follows:
>
>function newActionListener(listenerFunction) {
>    var listener = {actionPerformed: listenerFunction };
>    var adapter = new
>JavaAdapter(Packages.org.apache.cocoon.forms.event.ActionListener,
>listener);
>    return adapter;
>}
>
>Question: do we add these newActionListener and newValueChangedListener
>functions to the (javascript) form object, or as separate functions next
>to it?
>  
>

It could also be an additional method of ScriptableWidget, which would 
take care of the adaptation.

Sylvain

-- 
Sylvain Wallez                                  Anyware Technologies
http://www.apache.org/~sylvain           http://www.anyware-tech.com
{ XML, Java, Cocoon, OpenSource }*{ Training, Consulting, Projects }