Question about ajax design

[parki]

Hello -

Getting into rich faces - kudos all - this is really great. I have a design question - hoping someone can chime in on the "best way".

I have a tree model object which is serving up an o.r.m.TreeNode object and the tree is displaying loverly. The actual tree data can change by a back end process at any time, so I'd like to be able rerender the tree component when this happens.

My idea was to use a4j:poll to force an ajax call to the server, and then block in the method until there is a change to the underlying model, at which point the blocked thread continues, and allows the rerender from the client. Something like:

<rich:tree id="thermostat" .... />

<a4j:region>
<h:form>
<a4j:poll id="poll" interval="500"
actionListener="#{thermostatModel.processAjax}"
reRender="poll,thermostat"/>
</h:form>
</a4j:region>

but I so far haven't been able to make this work - the processAjax method doesn't get called.

Then I started to think that this is perhaps not the right way to do this - is it time to delve deeper into the event model in JSF?

Any help on the preferred design would be great - suspect using a4j:poll is not the best thing here.

Thanks, and happy holidays.

parki...

[parki]

Aha - can I use <a4j:push> ?

Here's part of the xhtml page:

<rich:tree id="thermostat" style="width:300px" nodeSelectListener="#{thermostatAdaptor.processSelection}"
 reRender="province" ajaxSubmitSelection="true" switchType="client"
 value="#{thermostatAdaptor.treeNode}" var="item">
</rich:tree>

<a4j:push reRender="thermostat" eventProducer="#{thermostatAdaptor.addListener}" interval="1000"/>

and part of the model code:

public void notifyModified()
{
 loadThermostat();

 if(listener_ != null)
 {
 listener_.onEvent(new EventObject(this));
 }
}

public void addListener(EventListener listener)
{
 synchronized (listener)
 {
 if(listener_ != listener) listener_ = (PushEventsCounter) listener;
 }
}

When I try this, addListener gets called (with a PushEventsCounter). When the tree data is updated (by another process), the notifyModified method is called, but the thermostat is not rerendered.

Methinks something is missing?

Any why is there a polling interval on push - is this the time delay between calls to the server?

Any help is appreciated - the demo doesn't have example code I can steal.

Thanks.

parki...

[parki]

Doesn't work in FireFox - see:

http://jira.jboss.org/jira/browse/RF-1753

I was using FireFox. In the bug report, alexsmirnox reports "this exception does not occur if the FireBug extension is enabled" which I can confirm - when running FireFox with Firebug, the <a4j:push> element works fine.

Off to check on IE on Windows.

parki...