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Jakarta Faces defines an MVC framework for building user interfaces for web applications,
including UI components, state management, event handing, input validation, page navigation, and
support for internationalization and accessibility.
/*
* Copyright (c) 2012, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.faces.context;
import static com.sun.faces.RIConstants.DYNAMIC_CHILD_COUNT;
import static com.sun.faces.RIConstants.DYNAMIC_COMPONENT;
import static com.sun.faces.util.ComponentStruct.ADD;
import static com.sun.faces.util.ComponentStruct.REMOVE;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.logging.Logger;
import com.sun.faces.RIConstants;
import com.sun.faces.application.ApplicationAssociate;
import com.sun.faces.application.ApplicationStateInfo;
import com.sun.faces.facelets.tag.jsf.ComponentSupport;
import com.sun.faces.util.ComponentStruct;
import com.sun.faces.util.FacesLogger;
import com.sun.faces.util.MostlySingletonSet;
import jakarta.faces.FacesException;
import jakarta.faces.component.UIComponent;
import jakarta.faces.component.UIViewRoot;
import jakarta.faces.context.FacesContext;
import jakarta.faces.event.AbortProcessingException;
import jakarta.faces.event.PostAddToViewEvent;
import jakarta.faces.event.PreRemoveFromViewEvent;
import jakarta.faces.event.SystemEvent;
import jakarta.faces.event.SystemEventListener;
/**
* Context for dealing with partial state saving mechanics.
*/
public class StateContext {
private static final String KEY = StateContext.class.getName() + "_KEY";
private boolean partial;
private boolean partialLocked;
private boolean trackMods = true;
private AddRemoveListener modListener;
private ApplicationStateInfo stateInfo;
private WeakReference viewRootRef = new WeakReference<>(null);
private static final Logger LOGGER = FacesLogger.CONTEXT.getLogger();
// ------------------------------------------------------------ Constructors
private StateContext(ApplicationStateInfo stateInfo) {
this.stateInfo = stateInfo;
}
// ---------------------------------------------------------- Public Methods
/**
* Release the state context.
*
* @param facesContext the Faces context.
*/
public static void release(FacesContext facesContext) {
StateContext stateContext = (StateContext) facesContext.getAttributes().get(KEY);
UIViewRoot viewRoot = facesContext.getViewRoot();
if (viewRoot != null && stateContext.modListener != null) {
viewRoot.unsubscribeFromViewEvent(PostAddToViewEvent.class, stateContext.modListener);
viewRoot.unsubscribeFromViewEvent(PreRemoveFromViewEvent.class, stateContext.modListener);
}
facesContext.getAttributes().remove(KEY);
}
/**
* @param ctx the FacesContext for the current request
* @return StateContext for this request
*/
public static StateContext getStateContext(FacesContext ctx) {
StateContext stateCtx = (StateContext) ctx.getAttributes().get(KEY);
if (stateCtx == null) {
ApplicationAssociate associate = ApplicationAssociate.getCurrentInstance();
ApplicationStateInfo info = associate.getApplicationStateInfo();
stateCtx = new StateContext(info);
ctx.getAttributes().put(KEY, stateCtx);
}
return stateCtx;
}
/**
* @param ctx FacesContext.
* @param viewId the view ID to check or null if viewId is unknown.
* @return true if partial state saving should be used for the specified view ID, otherwise
* false
*/
public boolean isPartialStateSaving(FacesContext ctx, String viewId) {
// track UIViewRoot changes
UIViewRoot root = ctx.getViewRoot();
UIViewRoot refRoot = viewRootRef.get();
if (root != refRoot) {
// set weak reference to current viewRoot
viewRootRef = new WeakReference<>(root);
// On first call in restore phase, viewRoot is null, so we treat the first
// change to not null not as a changing viewRoot.
if (refRoot != null) {
// view root changed in request processing - force usage of a
// new AddRemoveListener instance for the new viewId ...
modListener = null;
// ... and also force check for partial state saving for the new viewId
partialLocked = false;
}
}
if (!partialLocked) {
if (viewId == null) {
if (root != null) {
viewId = root.getViewId();
} else {
// View root has not yet been initialized. Check to see whether
// the target view id has been stashed away for us.
viewId = (String) ctx.getAttributes().get(RIConstants.VIEWID_KEY_NAME);
}
}
partial = stateInfo.usePartialStateSaving(viewId);
partialLocked = true;
}
return partial;
}
/**
* @return true if view modifications outside of the initial construction of the view are being tracked.
*/
public boolean trackViewModifications() {
return trackMods;
}
/**
* Installs a SystemEventListener on the UIViewRoot to track components added to or removed
* from the view.
*/
public void startTrackViewModifications(FacesContext ctx, UIViewRoot root) {
if (modListener == null) {
if (root != null) {
modListener = createAddRemoveListener(ctx, root);
root.subscribeToViewEvent(PostAddToViewEvent.class, modListener);
root.subscribeToViewEvent(PreRemoveFromViewEvent.class, modListener);
} else {
LOGGER.warning("Unable to attach AddRemoveListener to UIViewRoot because it is null");
}
}
setTrackViewModifications(true);
}
/**
* Toggles the current modification tracking status.
*
* @param trackMods if true and the listener installed by
* {@link #startTrackViewModifications(jakarta.faces.context.FacesContext, jakarta.faces.component.UIViewRoot) is
* present, then view modifications will be tracked. If false, then modification events will be ignored.
*/
public void setTrackViewModifications(boolean trackMods) {
this.trackMods = trackMods;
}
/**
* @param c the UIComponent to check
* @return true if the component was added after the initial view construction
*/
public boolean componentAddedDynamically(UIComponent c) {
return c.getAttributes().containsKey(DYNAMIC_COMPONENT);
}
public int getIndexOfDynamicallyAddedChildInParent(UIComponent c) {
int result = -1;
Map attrs = c.getAttributes();
if (attrs.containsKey(DYNAMIC_COMPONENT)) {
result = (Integer) attrs.get(DYNAMIC_COMPONENT);
}
return result;
}
public boolean hasOneOrMoreDynamicChild(UIComponent parent) {
return parent.getAttributes().containsKey(DYNAMIC_CHILD_COUNT);
}
private int incrementDynamicChildCount(FacesContext context, UIComponent parent) {
int result;
Map attrs = parent.getAttributes();
Integer cur = (Integer) attrs.get(DYNAMIC_CHILD_COUNT);
if (null != cur) {
result = cur++;
} else {
result = 1;
}
attrs.put(DYNAMIC_CHILD_COUNT, result);
context.getViewRoot().getAttributes().put(RIConstants.TREE_HAS_DYNAMIC_COMPONENTS, Boolean.TRUE);
return result;
}
private int decrementDynamicChildCount(FacesContext context, UIComponent parent) {
int result = 0;
Map attrs = parent.getAttributes();
Integer cur = (Integer) attrs.get(DYNAMIC_CHILD_COUNT);
if (null != cur) {
result = 0 < cur ? cur-- : 0;
}
if (0 == result && null != cur) {
attrs.remove(DYNAMIC_CHILD_COUNT);
}
context.getViewRoot().getAttributes().put(RIConstants.TREE_HAS_DYNAMIC_COMPONENTS, Boolean.TRUE);
return result;
}
/**
* Get the dynamic list (of adds and removes).
*/
public List getDynamicActions() {
return modListener != null ? modListener.getDynamicActions() : null;
}
/**
* Get the hash map of dynamic components.
*
* @return the hash map of dynamic components.
*/
public HashMap getDynamicComponents() {
return modListener != null ? modListener.getDynamicComponents() : null;
}
// ---------------------------------------------------------- Nested Classes
private AddRemoveListener createAddRemoveListener(FacesContext context, UIViewRoot root) {
return isPartialStateSaving(context, root.getViewId()) ? new DynamicAddRemoveListener(context) : new StatelessAddRemoveListener(context);
}
abstract private class AddRemoveListener implements SystemEventListener {
/**
* Stores the state context we work for,
*/
private StateContext stateCtx;
/**
* Constructor.
*
* @param context the Faces context.
*/
protected AddRemoveListener(FacesContext context) {
stateCtx = StateContext.getStateContext(context);
}
/**
* Get the list of adds/removes.
*
* @return the list of adds/removes.
*/
abstract public List getDynamicActions();
/**
* Get the hash map of dynamic components.
*
* @return the hash map of dynamic components.
*/
abstract public HashMap getDynamicComponents();
/**
* Process the add/remove event.
*
* @param event the add/remove event.
* @throws AbortProcessingException when processing should be aborted.
*/
@Override
public void processEvent(SystemEvent event) throws AbortProcessingException {
FacesContext ctx = FacesContext.getCurrentInstance();
if (event instanceof PreRemoveFromViewEvent) {
if (stateCtx.trackViewModifications()) {
handleRemove(ctx, ((PreRemoveFromViewEvent) event).getComponent());
ctx.getViewRoot().getAttributes().put(RIConstants.TREE_HAS_DYNAMIC_COMPONENTS, Boolean.TRUE);
}
} else {
if (stateCtx.trackViewModifications()) {
handleAdd(ctx, ((PostAddToViewEvent) event).getComponent());
ctx.getViewRoot().getAttributes().put(RIConstants.TREE_HAS_DYNAMIC_COMPONENTS, Boolean.TRUE);
}
}
}
/**
* Are we listening for these particular changes.
*
*
* Note we are only interested in UIComponent adds/removes that are not the UIViewRoot itself.
*
*
* @param source the source object we might be listening for.
* @return true if the source is OK, false otherwise.
*/
@Override
public boolean isListenerForSource(Object source) {
return source instanceof UIComponent && !(source instanceof UIViewRoot);
}
/**
* Handle the remove.
*
* @param context the Faces context.
* @param component the UI component to add to the list as a REMOVE.
*/
abstract protected void handleRemove(FacesContext context, UIComponent component);
/**
* Handle the add.
*
* @param context the Faces context.
* @param component the UI component to add to the list as an ADD.
*/
abstract protected void handleAdd(FacesContext context, UIComponent component);
}
public class NoopAddRemoveListener extends AddRemoveListener {
// This is silly. We should be able to use Colletions.emptyMap(),
// but cannot as StateContext.getDynamicComponents() API returns a
// HashMap instead of a Map.
private HashMap emptyComponentsMap = new HashMap();
public NoopAddRemoveListener(FacesContext context) {
super(context);
}
@Override
public List getDynamicActions() {
return Collections.emptyList();
}
@Override
public HashMap getDynamicComponents() {
return emptyComponentsMap;
}
@Override
protected void handleRemove(FacesContext context, UIComponent component) {
}
@Override
protected void handleAdd(FacesContext context, UIComponent component) {
}
}
/**
* An AddRemoveListener that implements the new dynamic component strategy where no state is managed by the listener
* itself. Instead, we use expando attributes on the dynamic components (and their parents) to track/preserve the
* dynamic nature of these components.
*/
public class StatelessAddRemoveListener extends NoopAddRemoveListener {
public StatelessAddRemoveListener(FacesContext context) {
super(context);
}
private boolean thisEventCorrespondsToSubtreeRootRemove(FacesContext context, UIComponent c) {
boolean result = false;
if (null != c) {
c = c.getParent();
if (null != c) {
result = c.isInView();
}
}
return result;
}
private boolean thisEventCorrespondsToSubtreeRootAdd(FacesContext context, UIComponent c) {
boolean result = false;
Map contextMap = context.getAttributes();
UIViewRoot root = context.getViewRoot();
UIComponent originalComponent = c;
if (null != c) {
Collection dynamics = getDynamicComponentCollection(contextMap);
if (dynamics.contains(c)) {
result = true;
} else {
c = c.getParent();
while (null != c && !dynamics.contains(c)) {
c = c.getParent();
}
if (null == c || root.equals(c)) {
dynamics.add(originalComponent);
result = true;
}
}
}
return result;
}
private static final String DYNAMIC_COMPONENT_ADD_COLLECTION = RIConstants.FACES_PREFIX + "DynamicComponentSubtreeRoots";
private Collection getDynamicComponentCollection(Map contextMap) {
Collection result = (Collection) contextMap.get(DYNAMIC_COMPONENT_ADD_COLLECTION);
if (null == result) {
result = new HashSet<>();
contextMap.put(DYNAMIC_COMPONENT_ADD_COLLECTION, result);
}
return result;
}
@Override
protected void handleRemove(FacesContext context, UIComponent component) {
if (!thisEventCorrespondsToSubtreeRootRemove(context, component)) {
return;
}
Map attrs = component.getAttributes();
// If the component is a tag-created child, we remove its
// MARK_CREATED expando so that it will now be treated as
// a dynamic/non-tag created component.
String tagId = (String) attrs.remove(ComponentSupport.MARK_CREATED);
if (tagId != null) {
// Actually, we don't just remove the MARK_CREATED - we need
// to stash it away so that we can restore it later if the
// component happens to be re-added to its original parent.
attrs.put(ComponentSupport.MARK_CREATED_REMOVED, tagId);
childRemovedFromParent(component.getParent(), tagId);
}
}
private void childRemovedFromParent(UIComponent parent, String childTagId) {
if (parent != null) {
Collection removedChildrenIds = getPreviouslyRemovedChildren(parent);
removedChildrenIds.add(childTagId);
markChildrenModified(parent);
}
}
private Collection getPreviouslyRemovedChildren(UIComponent parent) {
Map attrs = parent.getAttributes();
Collection removedChildrenIds = (Collection) attrs.get(ComponentSupport.REMOVED_CHILDREN);
if (removedChildrenIds == null) {
removedChildrenIds = new MostlySingletonSet<>();
attrs.put(ComponentSupport.REMOVED_CHILDREN, removedChildrenIds);
}
return removedChildrenIds;
}
private void markChildrenModified(UIComponent parent) {
parent.getAttributes().put(ComponentSupport.MARK_CHILDREN_MODIFIED, true);
}
@Override
protected void handleAdd(FacesContext context, UIComponent component) {
if (!thisEventCorrespondsToSubtreeRootAdd(context, component)) {
return;
}
Map attrs = component.getAttributes();
String tagId = (String) attrs.get(ComponentSupport.MARK_CREATED_REMOVED);
if (childAddedToSameParentAsBefore(component.getParent(), tagId)) {
// Restore MARK_CREATED if the added component was originally
// created as a tag-based child of this parent.
attrs.remove(ComponentSupport.MARK_CREATED_REMOVED);
attrs.put(ComponentSupport.MARK_CREATED, tagId);
}
markChildrenModified(component.getParent());
}
// Handles the addition of a new child to the parent. Returns true
// if the child was previously removed from this parent.
private boolean childAddedToSameParentAsBefore(UIComponent parent, String childTagId) {
if (parent != null) {
Map attrs = parent.getAttributes();
Collection removedChildrenIds = (Collection) attrs.get(ComponentSupport.REMOVED_CHILDREN);
if (removedChildrenIds != null && removedChildrenIds.remove(childTagId)) {
if (removedChildrenIds.isEmpty()) {
attrs.remove(ComponentSupport.REMOVED_CHILDREN);
}
return true;
}
}
return false;
}
}
/**
* A system event listener which is used to listen for changes on the component tree after restore view and before
* rendering out the view.
*/
public class DynamicAddRemoveListener extends AddRemoveListener {
/**
* Stores the list of adds/removes.
*/
private List dynamicActions;
/**
* Stores the hash map of dynamic components.
*/
private transient HashMap dynamicComponents;
/**
* Constructor.
*
* @param context the Faces context.
*/
public DynamicAddRemoveListener(FacesContext context) {
super(context);
}
/**
* Get the list of adds/removes.
*
* @return the list of adds/removes.
*/
@Override
public List getDynamicActions() {
synchronized (this) {
if (dynamicActions == null) {
dynamicActions = new ArrayList<>();
}
}
return dynamicActions;
}
/**
* Get the hash map of dynamic components.
*
* @return the hash map of dynamic components.
*/
@Override
public HashMap getDynamicComponents() {
synchronized (this) {
if (dynamicComponents == null) {
dynamicComponents = new HashMap<>();
}
}
return dynamicComponents;
}
/**
* Handle the remove.
*
* @param context the Faces context.
* @param component the UI component to add to the list as a REMOVE.
*/
@Override
protected void handleRemove(FacesContext context, UIComponent component) {
if (component.isInView()) {
decrementDynamicChildCount(context, component.getParent());
handleAddRemoveWithAutoPrune(component, new ComponentStruct(REMOVE, component.getClientId(context), component.getId()));
}
}
/**
* Handle the add.
*
* @param context the Faces context.
* @param component the UI component to add to the list as an ADD.
*/
@Override
protected void handleAdd(FacesContext context, UIComponent component) {
if (component.getParent() != null && component.getParent().isInView()) {
String id = component.getId();
/*
* Since adding a component, can mean you are really reparenting it, we need to make sure the OLD clientId is not
* cached, we do that by setting the id.
*/
if (id != null) {
component.setId(id);
}
String facetName = findFacetNameForComponent(component);
if (facetName != null) {
incrementDynamicChildCount(context, component.getParent());
component.clearInitialState();
component.getAttributes().put(DYNAMIC_COMPONENT, component.getParent().getChildren().indexOf(component));
ComponentStruct struct = new ComponentStruct(ADD, facetName, component.getParent().getClientId(context), component.getClientId(context),
component.getId());
handleAddRemoveWithAutoPrune(component, struct);
} else {
incrementDynamicChildCount(context, component.getParent());
component.clearInitialState();
component.getAttributes().put(DYNAMIC_COMPONENT, component.getParent().getChildren().indexOf(component));
ComponentStruct struct = new ComponentStruct(ADD, null, component.getParent().getClientId(context), component.getClientId(context),
component.getId());
handleAddRemoveWithAutoPrune(component, struct);
}
}
}
/**
* Return the facet name for the given component or null if the component is not the value of a facets map entry.
*
* @param component the component to look for in the facets map entry value.
* @return the facet name or null if the component is not the value of a facets map entry.
*/
private String findFacetNameForComponent(UIComponent component) {
Set> entrySet = component.getParent().getFacets().entrySet();
Iterator> entries = entrySet.iterator();
while (entries.hasNext()) {
Entry candidate = entries.next();
if (component == candidate.getValue()) {
return candidate.getKey();
}
}
return null;
}
/**
* Methods that takes care of pruning and adding an action to the dynamic action list.
*
*
* If you add a component and the dynamic action list does not contain
* the component yet then add it to the dynamic action list, regardless
* whether or not if was an ADD or REMOVE.
*
*
*
* Else if you add a component and it is already in the dynamic action
* list and it is the only action for that client id in the dynamic
* action list then:
* 1) If the previous action was an ADD then
* a) If the current action is a REMOVE then remove the component
* out of the dynamic action list.
* b) If the current action is an ADD then throw a FacesException.
* 2) If the previous action was a REMOVE then
* a) If the current action is an ADD then add it to the dynamic
* action list.
* b) If the current action is a REMOVE then throw a FacesException.
*
*
*
* Else if a REMOVE and ADD where captured before then:
* 1) If the current action is REMOVE then remove the last dynamic
* action out of the dynamic action list.
* 2) If the current action is ADD then throw a FacesException.
*
*
* @param component the UI component.
* @param struct the dynamic action.
*/
private void handleAddRemoveWithAutoPrune(UIComponent component, ComponentStruct struct) {
List actionList = getDynamicActions();
HashMap componentMap = getDynamicComponents();
int firstIndex = actionList.indexOf(struct);
if (firstIndex == -1) {
actionList.add(struct);
componentMap.put(struct.getClientId(), component);
} else {
int lastIndex = actionList.lastIndexOf(struct);
if (lastIndex == firstIndex) {
ComponentStruct previousStruct = actionList.get(firstIndex);
if (ADD.equals(previousStruct.getAction())) {
if (ADD.equals(struct.getAction())) {
throw new FacesException("Cannot add the same component twice: " + struct.getClientId());
}
if (REMOVE.equals(struct.getAction())) {
actionList.remove(firstIndex);
componentMap.remove(struct.getClientId());
}
}
if (REMOVE.equals(previousStruct.getAction())) {
if (ADD.equals(struct.getAction())) {
actionList.add(struct);
componentMap.put(struct.getClientId(), component);
}
if (REMOVE.equals(struct.getAction())) {
throw new FacesException("Cannot remove the same component twice: " + struct.getClientId());
}
}
} else {
if (ADD.equals(struct.getAction())) {
throw new FacesException("Cannot add the same component twice: " + struct.getClientId());
}
if (REMOVE.equals(struct.getAction())) {
actionList.remove(lastIndex);
}
}
}
}
} // END AddRemoveListener
}