I suspect that there are many cases where parent components are looking
at rendered on their children before deciding to traverse into these
children. If EL-binding rendered to the component is supported, then
the parent is either going to need to stop performing this optimization,
or it is going to have to ensure that the context is setup and torn down
around each call to isRendered.
-- Blake Sullivan
On 5/25/11 11:27 AM, Martin Koci wrote:
Hi,
for spec I've created bug few days ago:
http://java.net/jira/browse/JAVASERVERFACES_SPEC_PUBLIC-1002
but I didn't realize how deep impact this bug have: I did a training
about JSF implicit objects in our company and now practically every
coder uses #{component.something} :)
For myfaces:
https://issues.apache.org/jira/browse/MYFACES-3157
Leonardo Uribe píše v St 25. 05. 2011 v 12:36 -0500:
Hi
I have seen that. The problem is in spec javadoc, the behavior for
UIComponent.process*
and encode* is clear about the ordering.
In theory, pushComponentToEL should be called before any call to
isRendered, but after
isTransient. Look on MyFaces UIComponentBase.processRestoreState. It has this
public void processRestoreState(FacesContext context, Object state)
{
if (context == null)
{
throw new NullPointerException("context");
}
Object[] stateValues = (Object[]) state;
try
{
// Call
UIComponent.pushComponentToEL(javax.faces.context.FacesContext,
javax.faces.component.UIComponent)
pushComponentToEL(context, this);
// Call the restoreState() method of this component.
restoreState(context, stateValues[0]);
The spec javadoc says the opposite, restoreState should be called "before"
pushComponentToEL but in practice that breaks UIComponent.EventListenerWrapper.
I reported the bug long time ago, but it wasn't fixed (I don't know why).
This case is similar. This should be fixed on the spec, but I don't
see a reason why we shouldn't commit that into myfaces code, because
after all, nobody relies on the buggy behavior.
I think we should open a new issue on the spec issue tracker:
http://java.net/jira/browse/JAVASERVERFACES_SPEC_PUBLIC
but fix it on myfaces code.
regards,
Leonardo Uribe
2011/5/25 Martin Koci<martin.kocicak.k...@gmail.com>:
Hi,
<h:form>
<h:panelGroup>
<h:inputText id="testId"
rendered="#{component.id eq 'testId'}"
value="#{bean.value}" />
</h:panelGroup>
</h:form>
please notice the expression:
rendered="#{component.id eq 'testId'}"
that is clearly true.
But that does not work as expected: inputText is rendered, but never
updates model value.
Problem 1.
from specification, methods UIComponent.process* and encode*
1) If the rendered property of this {@link UIComponent}
false, skip further processing
2) Call {@link #pushComponentToEL}
-> #{component} resolves in rendered="#{}" to parent!
Problem 2.
MyFaces implement that (pointless) requirement inconsistently: from
UIComponentBase.process*:
(!isRendered())
return;
pushComponentToEL(context, this)
and from UIComponentBase.encodeBegin*
pushComponentToEL(context, this);
if (isRendered())
causes that example above renderes inputText, but never updates model.
Problem 3.
RendererUtils.renderChild(FacesContext, UIComponent):
in this method it is unappropriate to use following code:
if (!child.isRendered()) {
return;
}
child.encodeBegin(facesContext);
because:
1) it does not take into account pushComponentToEL ( #{component}
resolves to parent)
2) behaviour is incosistent with UIComponent.encodeBegin : you'll get
"random" rendering - depends if parent of component renders it's
children or not! For this case I've created MYFACES-3126, but I'll
reopen it now, because simple remove of 'if (!child.isRendered())' does
not solve that problem and causes another problem if component
getRendersChildren = false;
What do yout think about this problem?
Regards,
Kočičák
