[jsr-314-open] PostRestoreStateEvent called more that once for components inside UIData instances (h:dataTable)

[Dan Allen]

>From the jsr-314-comments inbox.

---------- Forwarded message ----------
From: Leonardo Uribe <lu4242 at gmail.com>
Date: Tue, Sep 15, 2009 at 1:27 AM
Subject: [jsr-314-open] [jsf 2.0] PostRestoreStateEvent called more that once for
components inside UIData instances (h:dataTable)
To: jsr-314-comments at jcp.org
Cc: MyFaces Development <dev at myfaces.apache.org>

Hi

Checking UIViewRoot class I have noted some side effect on
UIViewRoot.processRestoreState() method.

The javadoc says this:

".....The default implementation must call
UIComponentBase.processRestoreState(javax.faces.context.FacesContext,
java.lang.Object) from within a try block. The try block must have a finally
block that ensures that no FacesEvents remain in the event queue, and that
the this.UIComponent.visitTree(javax.faces.component.visit.VisitContext,
javax.faces.component.visit.VisitCallback) is called, passing a
ContextCallback that takes the following action: call the
UIComponent.processEvent(javax.faces.event.ComponentSystemEvent) method of
the current component. The argument event must be an instance of
PostRestoreStateEvent whose component property is the current component in
the traversal......"

Now just imagine a component inside h:dataTable and read the documentation
of UIData.visitTree(). That algorithm visit child components per row. But
UIData use the same component per each row and only save the values related
to EditableValueHolder interface. The result is that we call
PostRestoreStateEvent as many times as rows are available. This behavior of
UIData.visitTree() has prevented me from using it for partial state saving,
because we only need to call restoreState or saveState only once per
component instance.

In any case, It could be good to know if this behavior is expected or not. I
tried to fix the behavior on myfaces of h:outputScript target="head" and
partial state saving at postback with a listener to this event, but after
reading the javadoc I notice it will not work as I expected.

regards,

Leonardo Uribe
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