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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
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package com.sun.faces.context;

import com.sun.faces.RIConstants;
import com.sun.faces.application.ApplicationAssociate;
import com.sun.faces.application.ApplicationStateInfo;
import com.sun.faces.util.ComponentStruct;
import javax.faces.component.UIComponent;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.PostAddToViewEvent;
import javax.faces.event.PreRemoveFromViewEvent;
import javax.faces.event.SystemEvent;
import javax.faces.event.SystemEventListener;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.HashMap;
import java.util.Map.Entry;
import java.util.Set;
import static com.sun.faces.RIConstants.DYNAMIC_CHILD_COUNT;
import static com.sun.faces.RIConstants.DYNAMIC_COMPONENT;
import com.sun.faces.facelets.tag.jsf.ComponentSupport;
import com.sun.faces.util.FacesLogger;
import com.sun.faces.util.MostlySingletonSet;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.logging.Logger;
import javax.faces.FacesException;

/**
 * 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
          this.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(javax.faces.context.FacesContext, javax.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, (Integer) 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.
         */
        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. */ 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()); ComponentStruct struct = new ComponentStruct(); struct.action = ComponentStruct.REMOVE; struct.clientId = component.getClientId(context); struct.id = component.getId(); handleAddRemoveWithAutoPrune(component, struct); } } /** * 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(); struct.action = ComponentStruct.ADD; struct.facetName = facetName; struct.parentClientId = component.getParent().getClientId(context); struct.clientId = component.getClientId(context); struct.id = 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(); struct.action = ComponentStruct.ADD; struct.parentClientId = component.getParent().getClientId(context); struct.clientId = component.getClientId(context); struct.id = 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.clientId, component); } else { int lastIndex = actionList.lastIndexOf(struct); if (lastIndex == firstIndex) { ComponentStruct previousStruct = actionList.get(firstIndex); if (ComponentStruct.ADD.equals(previousStruct.action)) { if (ComponentStruct.ADD.equals(struct.action)) { throw new FacesException("Cannot add the same component twice: " + struct.clientId); } if (ComponentStruct.REMOVE.equals(struct.action)) { actionList.remove(firstIndex); componentMap.remove(struct.clientId); } } if (ComponentStruct.REMOVE.equals(previousStruct.action)) { if (ComponentStruct.ADD.equals(struct.action)) { actionList.add(struct); componentMap.put(struct.clientId, component); } if (ComponentStruct.REMOVE.equals(struct.action)) { throw new FacesException("Cannot remove the same component twice: " + struct.clientId); } } } else { if (ComponentStruct.ADD.equals(struct.action)) { throw new FacesException("Cannot add the same component twice: " + struct.clientId); } if (ComponentStruct.REMOVE.equals(struct.action)) { actionList.remove(lastIndex); } } } } } // END AddRemoveListener } // END StateContext




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