ADF triggering dynamic number of components

Question

I have a three-level View object dependency Category -> Class -> Subclass and want to create a dynamic form with the following logic:
When user chooses a Category from drop down, page is updated with a number of Class drop-down lists presenting all the Subclasses - i.e. I have a dynamic number of selectOneChoice components depending on Category selection. Category to Class dependency is implemented with Category valueChangeListener querying Classes with category Id, Class to Subclass is simple View Link / tree value binding. Subclass value binding to backing bean is done with a HashMap.
Does ADF faces framework let me re-create actual page components with partial page rendering (or some other mechanism)?
I should fully re-generate all selectOneChoice components inside forEach every time user changes Category.
My page components:
<af:selectOneChoice value="#{bbean.category}"
label="Category"
autoSubmit="true" immediate="true"
id="category" valuePassThru="true"
valueChangeListener="#{bbean.categoryChanged}">
<f:selectItems value="#{bindings.Categories.items}"/>
</af:selectOneChoice>
<af:forEach var="class" items="#{bindings.Classes.children}">
<af:selectOneChoice value="#{bbean.subclass[class.id]}"
label="#{class.name}"
partialTriggers="category"
id="class" valuePassThru="true">
<af:forEach var="subclass" items="#{class.children}">
<af:selectItem label="#{subclass.name}" value="#{subclass.id}"/>
</af:forEach>
</af:selectOneChoice>
</af:forEach>
The above code is a development from earlier less-complex UI. For all I've tried I cannot come up with the desired effect. When I change Category it doesn't affect sub- drop downs in any way. If I activate the Category valueChangeListener, Category change will cause validation phase null property exceptions:
2.9.2008 14:05:40 com.sun.faces.lifecycle.ProcessValidationsPhase execute
SEVERE: Error testing property 'null' in bean of type my.project.view.managed.Search$1
javax.faces.el.PropertyNotFoundException: Error testing property 'null' in bean of type my.project.view.managed.Search$1
...

Answer 1

John & Frank,
Unfortunately enclosing layout component with partialTriggers="category" doesn't help - I've tried that already (panelgroup & panelpage, that is). Thanks for impressive response time though ;)
Edit: Sorry, yes it helps! Thanks. The problem happens to be the HashMap value binding, it breaks up things after valueChangeListener refreshes the Class VO. After removing that the surrounding panelGroup does component refresh correctly. Back to drawing board..
Erik
Edited by: Erik Westerinen on Sep 2, 2008 5:26 AM