/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.myfaces.orchestra.conversation.jsf;
import java.util.Iterator;
import java.util.Set;
import javax.faces.component.UIViewRoot;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.myfaces.orchestra.conversation.AccessScopeManager;
import org.apache.myfaces.orchestra.conversation.Conversation;
import org.apache.myfaces.orchestra.conversation.ConversationAccessLifetimeAspect;
import org.apache.myfaces.orchestra.conversation.ConversationManager;
/**
* Handle access-scoped conversations.
* <p>
* After a <i>new view</i> has been rendered, delete any access-scope conversations for which no
* bean in that scope has been accessed <i>during the render phase</i> of the request.
* <p>
* This allows a page which handles a postback to store data into beans in an access-scoped
* conversation, then navigate to a new page. That information is available for the new
* page during its rendering. And if that data is referenced, it will remain around
* until the user does a GET request, or a postback that causes navigation again. Then
* following the rendering of that new target page, any access-scoped conversations will be
* discarded except for those that the new target page references.
* <p>
* Any access-scoped conversations that a page was using, but which the new page does NOT use
* are therefore automatically cleaned up at the earliest possibility - after rendering of the
* new page has completed.
* <p>
* Note: When a "master" and "detail" page pair exist, that navigating master->detail->master->detail
* correctly uses a fresh conversation for the second call to the detail page (and not reuse the
* access-scoped data from the first call). By only counting accesses during the render phase, this
* works correctly.
* <p>
* Note: Access-scoped conversations must be preserved when AJAX calls cause only
* part of a page to be processed, and must be preserved when conversion/validation failure
* cause reads of the values of input components to be skipped. By deleting unaccessed
* conversations only after the <i>first</i> render, this happens automatically.
* <p>
* Note: If a view happens to want its postbacks handled by a bean in conversation A,
* but the render phase never references anything in that conversation, then the
* conversation will be effectively request-scoped. This is not expected to be a
* problem in practice as it would be a pretty odd view that has stateful event
* handling but either renders nothing or fetches its data from somewhere other
* than the same conversation. If such a case is necessary, the view can be modified
* to "ping" the conversation in order to keep it active via something like an
* h:outputText with rendered="#{backingBean.class is null}" (which always resolves
* to false, ie not rendered, but does force a method-invocation on the backingBean
* instance). Alternatively, a manual-scoped conversation can be used.
* <p>
* Note: If FacesContext.responseComplete is called during processing of a postback,
* then no phase-listeners for the RENDER_RESPONSE phase are executed. And any navigation
* rule that specifies "redirect" causes responseComplete to be invoked. Therefore
* access-scoped beans are not cleaned up immediately. However the view being
* redirected to always runs its "render" phase only, no postback. The effect,
* therefore, is exactly the same as when an internal forward is performed to
* the same view: in both cases, the access-scoped beans are kept if the next view
* refers to them, and discarded otherwise.
* <p>
* Note: Some AJAX libraries effectively do their own "rendering" pass from within
* a custom PhaseListener, during the beforePhase for RENDER_RESPONSE. This could
* have undesirable effects on Orchestra - except that for all AJAX requests, the
* viewRoot restored during RESTORE_VIEW will be the same viewRoot used during
* render phase - so this PhaseListener will ignore the request anyway.
* <p>
* Backwards-compatibility note: The behaviour of this class has changed between
* releases 1.2 and 1.3. In earlier releases, the access-scope checking ran on every
* request (not just GET or navigation). Suppose a bean is in its own access-scoped
* conversation, and the only reference to that bean is from a component that is
* rendered or not depending upon a checkbox editable by the user. In the old version,
* hiding the component would cause the access-scoped conversation to be discarded
* (not accessed), while the current code will not discard it. The new behaviour does
* fix a couple of bugs: access-scoped conversations discarded during AJAX requests
* and after conversion/validation failure.
*
* @since 1.1
*/
public class AccessScopePhaseListener implements PhaseListener
{
private static final long serialVersionUID = 1L;
private final Log log = LogFactory.getLog(AccessScopePhaseListener.class);
private static final String OLD_VIEW_KEY = AccessScopePhaseListener.class.getName() + ":oldView";
public PhaseId getPhaseId()
{
return PhaseId.ANY_PHASE;
}
public void beforePhase(PhaseEvent event)
{
PhaseId pid = event.getPhaseId();
if (pid == PhaseId.RENDER_RESPONSE)
{
doBeforeRenderResponse(event);
}
}
public void afterPhase(PhaseEvent event)
{
PhaseId pid = event.getPhaseId();
if (pid == PhaseId.RESTORE_VIEW)
{
doAfterRestoreView(event);
}
else if (pid == PhaseId.RENDER_RESPONSE)
{
doAfterRenderResponse(event);
}
}
/**
* Handle "afterPhase" callback for RESTORE_VIEW phase.
*
* @since 1.3
*/
private void doAfterRestoreView(PhaseEvent event)
{
javax.faces.context.FacesContext fc = event.getFacesContext();
UIViewRoot oldViewRoot = fc.getViewRoot();
if ((oldViewRoot != null) && fc.getRenderResponse())
{
// No view was restored; instead the viewRoot that FacesContext just returned
// is a *newly created* view that should be rendered, not a postback to be processed.
// In this case, save null as the "old" view to indicate that no view was restored,
// which will trigger the access-scope checking after rendering is complete.
oldViewRoot = null;
}
fc.getExternalContext().getRequestMap().put(OLD_VIEW_KEY, oldViewRoot);
}
/**
* Handle "beforePhase" callback for RENDER_RESPONSE phase.
*
* @since 1.3
*/
private void doBeforeRenderResponse(PhaseEvent event)
{
AccessScopeManager accessManager = AccessScopeManager.getInstance();
accessManager.beginRecording();
}
/**
* Handle "afterPhase" callback for RENDER_RESPONSE phase.
*
* @since 1.3
*/
private void doAfterRenderResponse(PhaseEvent event)
{
javax.faces.context.FacesContext fc = event.getFacesContext();
UIViewRoot viewRoot = fc.getViewRoot();
UIViewRoot oldViewRoot = (UIViewRoot) fc.getExternalContext().getRequestMap().get(OLD_VIEW_KEY);
if (viewRoot != oldViewRoot)
{
// Either this is a GET request (oldViewRoot is null) or this is a postback which
// triggered a navigation (oldViewRoot is not null, but is a different instance).
// In these cases (and only in these cases) we want to discard unaccessed conversations at
// the end of the render phase.
//
// There are reasons why it is not a good idea to run the invalidation check
// on every request:
// (a) it doesn't work well with AJAX requests; an ajax request that only accesses
// part of the page should not cause access-scoped conversations to be discarded.
// (b) on conversion or validation failure, conversations that are only referenced
// via the "value" attribute of an input component will not be accessed because
// the "submittedValue" for the component is used rather than fetching the value
// from the backing bean.
// (c) running each time is somewhat inefficient
//
// Note that this means that an access-scoped conversation will continue to live
// even when the components that reference it are not rendered, ie it was not
// technically "accessed" during a request.
invalidateAccessScopedConversations(event.getFacesContext().getViewRoot().getViewId());
}
}
/**
* Invalidates any conversation with aspect {@link ConversationAccessLifetimeAspect}
* which has not been accessed during a http request
*/
protected void invalidateAccessScopedConversations(String viewId)
{
AccessScopeManager accessManager = AccessScopeManager.getInstance();
if (accessManager.isIgnoreRequest())
{
return;
}
if (accessManager.getAccessScopeManagerConfiguration() != null)
{
Set ignoredViewIds = accessManager.getAccessScopeManagerConfiguration().getIgnoreViewIds();
if (ignoredViewIds != null && ignoredViewIds.contains(viewId))
{
// The scope configuration has explicitly stated that no conversations should be
// terminated when processing this specific view, so just return.
//
// Special "ignored views" are useful when dealing with things like nested
// frames within a page that periodically refresh themselves while the "main"
// part of the page remains unsubmitted.
return;
}
}
ConversationManager conversationManager = ConversationManager.getInstance(false);
if (conversationManager == null)
{
return;
}
boolean isDebug = log.isDebugEnabled();
Iterator iterConversations = conversationManager.iterateConversations();
while (iterConversations.hasNext())
{
Conversation conversation = (Conversation) iterConversations.next();
// This conversation has "access" scope if it has an attached Aspect
// of type ConversationAccessLifetimeAspect. All other conversations
// are not access-scoped and should be ignored here.
ConversationAccessLifetimeAspect aspect =
(ConversationAccessLifetimeAspect)
conversation.getAspect(ConversationAccessLifetimeAspect.class);
if (aspect != null)
{
if (aspect.isAccessed())
{
if (isDebug)
{
log.debug(
"Not clearing accessed conversation " + conversation.getName()
+ " after rendering view " + viewId);
}
}
else
{
if (isDebug)
{
log.debug(
"Clearing access-scoped conversation " + conversation.getName()
+ " after rendering view " + viewId);
}
conversation.invalidate();
}
}
}
}
}