components inside f:metadata are recreated when the whole view is processed
---------------------------------------------------------------------------
Key: MYFACES-3502
URL: https://issues.apache.org/jira/browse/MYFACES-3502
Project: MyFaces Core
Issue Type: Bug
Components: JSR-314
Affects Versions: 2.1.6, 2.0.12
Reporter: Leonardo Uribe
Assignee: Leonardo Uribe
There is a subtle but important when f:metadata sections are processed. Between
the view metadata is created and the whole view is built, facelets algorithm
discard and recreate all components. In typical situations this effect is not
visible, because there is a description spec code that hide this effect. See
UIViewParameter.setSubmittedValue() javadoc:
"... PENDING (docs) Interesting that submitted value isn't saved by the parent
..."
The discussion comes from issue:
MYFACES-2645 The view state is saved before encodeAll() is called on every
UIViewParameter in an AJAX request
In that time, I commented the following:
LU>> The javadocs of UIViewParameter.encodeAll says this:
LU>> ".......Called specially by
UIViewRoot.encodeEnd(javax.faces.context.FacesContext), this method simply sets
the submitted value to be the return from
LU>> getStringValue(javax.faces.context.FacesContext)......"
LU>> My question is why? isn't that bad?
In that time, the discussion was related to how to preserve the view params in
ajax request. The argument was submittedValue is set to null on process
validations, and it is necessary a way to preserve that value into the state.
The solution in that issue is valid, but what happen when validation fails?
submittedValue should not change, so why its value is lost before encodeAll()
is processed?.
By performance reasons, two different facelets are used for a view: one for
create metadata that just process stuff inside <f:metadata> and the other for
build the whole view (including metadata too). Since there are two different
facelets, generated in different way, the associated tagId is different and
then the generated ComponentSupport.MARK_CREATED identifier is different too.
Then, when the whole view is processed, facelets cannot identify the component
as the same, so it is removed and created again, and in the process
submittedValue and localValue are discarded, looking as if they are set to
null.
The solution is ensure facelets generate the same unique ids in
ComponentSupport.MARK_CREATED when f:metadata is processed, no matter if the
metadata facelet or the normal facelet process the view.
CompilationManager.nextTagId() uses the alias and a counter to derive an unique
tag id, so it will obviously generate different tags, so the idea is ignore
that part of the unique id when f:metadata section is processed, and fix
DefaultFaceletContext.generateUniqueId(), so it generate the same id.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
