/*
    * 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 javax.faces.component;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.MissingResourceException;
  import java.util.PropertyResourceBundle;
  import java.util.ResourceBundle;
  import java.util.Set;
  
  import javax.el.ELException;
  import javax.el.ValueExpression;
  import javax.faces.FacesException;
  import javax.faces.application.Application;
  import javax.faces.application.Resource;
  import javax.faces.component.visit.VisitCallback;
  import javax.faces.component.visit.VisitContext;
  import javax.faces.component.visit.VisitHint;
  import javax.faces.component.visit.VisitResult;
  import javax.faces.context.FacesContext;
  import javax.faces.el.ValueBinding;
  import javax.faces.event.AbortProcessingException;
  import javax.faces.event.ComponentSystemEvent;
  import javax.faces.event.ComponentSystemEventListener;
  import javax.faces.event.FacesEvent;
  import javax.faces.event.FacesListener;
  import javax.faces.event.PostRestoreStateEvent;
  import javax.faces.event.SystemEvent;
  import javax.faces.event.SystemEventListener;
  import javax.faces.event.SystemEventListenerHolder;
  import javax.faces.render.Renderer;
  import javax.faces.view.ViewDeclarationLanguage;
  
  import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFComponent;
  
  /**
   *
   * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">J
   * SF Specification</a>
   *
   * @author Manfred Geiler (latest modification by $Author: lu4242 $)
   * @version $Revision: 1297574 $ $Date: 2012-03-06 11:58:54 -0500 (Tue, 06 Mar 2012) $
   */
  @JSFComponent(type = "javax.faces.Component", family = "javax.faces.Component", desc = "abstract base component", configExcluded = true)
  public abstract class UIComponent implements PartialStateHolder, SystemEventListenerHolder, ComponentSystemEventListener {
      // TODO: Reorder methods, this class is a mess
      /**
       * Constant used in component attribute map to retrieve the BeanInfo of a composite
       * component.
       *
       * @see javax.faces.view.ViewDeclarationLanguage#getComponentMetadata(FacesContext, Resource)
       * @see javax.faces.view.ViewDeclarationLanguage#retargetAttachedObjects(FacesContext, UIComponent, List)
       * @see javax.faces.view.ViewDeclarationLanguage#retargetMethodExpressions(FacesContext, UIComponent)
       * @see javax.faces.application.Application#createComponent(FacesContext, Resource)
       */
      public static final String BEANINFO_KEY = "javax.faces.component.BEANINFO_KEY";
  
      /**
       * Constant used in BeanInfo descriptor as a key for retrieve an alternate component type
       * for create the composite base component. 
       *
       * @see javax.faces.application.Application#createComponent(FacesContext, Resource)
       */
      public static final String COMPOSITE_COMPONENT_TYPE_KEY = "javax.faces.component.COMPOSITE_COMPONENT_TYPE";
  
      /**
       * Constant used to define the facet inside this component that store the component hierarchy
       * generated by a composite component implementation, and then rendered. In other words, 
       * note that direct children of a component are not rendered, instead components inside 
       * this face are rendered.
       */
      public static final String COMPOSITE_FACET_NAME = "javax.faces.component.COMPOSITE_FACET_NAME";
 
     /**
      * Constant used to store the current component that is being processed.
      *
      * @see #pushComponentToEL(FacesContext, UIComponent)
      * @see #popComponentFromEL(FacesContext)
      */
     public static final String CURRENT_COMPONENT = "javax.faces.component.CURRENT_COMPONENT";
 
     /**
      * Constant used to store the current composite component that is being processed. 
      *
      * @see #pushComponentToEL(FacesContext, UIComponent)
      * @see #popComponentFromEL(FacesContext)
      */
     public static final String CURRENT_COMPOSITE_COMPONENT = "javax.faces.component.CURRENT_COMPOSITE_COMPONENT";
 
     /**
      * This constant has two usages. The first one is in component attribute map to identify the 
      * facet name under this component is child of its parent. The second one is on BeanInfo descriptor
      * as a key for a Map&lt;String, PropertyDescriptor&gt; that contains metadata information defined
      * by composite:facet tag and composite:implementation(because this one fills the facet referenced
      * by COMPOSITE_FACET_NAME constant). 
      */
     public static final String FACETS_KEY = "javax.faces.component.FACETS_KEY";
 
     /**
      * Constant used in component attribute map to store the {@link javax.faces.view.Location} object
      * where the definition of this component is.
      */
     public static final String VIEW_LOCATION_KEY = "javax.faces.component.VIEW_LOCATION_KEY";
 
     /**
      * The key under which the component stack is stored in the FacesContext.
      * ATTENTION: this constant is duplicate in CompositeComponentExpressionUtils.
      */
     private static final String _COMPONENT_STACK = "componentStack:" + UIComponent.class.getName();
 
     Map<Class<? extends SystemEvent>, List<SystemEventListener>> _systemEventListenerClassMap;
 
     /**
      * @deprecated
      */
     @Deprecated
     protected Map<String, ValueExpression> bindings;
     /**
      * Used to cache the map created using getResourceBundleMap() method, since this method could be called several
      * times when rendering the composite component. This attribute may not be serialized, so transient is used (There
      * are some very few special cases when UIComponent instances are serializable like t:schedule, so it is better if
      * transient is used).
      */
     private transient Map<String, String> _resourceBundleMap = null;
     private boolean _inView = false;
     private StateHelper _stateHelper = null;
 
     /**
      * In JSF 2.0 bindings map was deprecated, and replaced with a map
      * inside stateHelper. We need this one here because stateHelper needs
      * to be implemented from here and internally it depends from this property.
      */
     private boolean _initialStateMarked = false;
 
     public UIComponent()
     {
     }
 
     public abstract Map<String, Object> getAttributes();
 
     /**
      *
      * {@inheritDoc}
      *
      * @since 2.0
      */
     public boolean initialStateMarked()
     {
         return _initialStateMarked;
     }
 
     /**
      * Invokes the <code>invokeContextCallback</code> method with the component, specified by <code>clientId</code>.
      * 
      * @param context
      *            <code>FacesContext</code> for the current request
      * @param clientId
      *            the id of the desired <code>UIComponent</code> clazz
      * @param callback
      *            Implementation of the <code>ContextCallback</code> to be called
      * @return has component been found ?
      * @throws javax.faces.FacesException
      */
     public boolean invokeOnComponent(FacesContext context, String clientId, ContextCallback callback)
             throws FacesException
     {
         // java.lang.NullPointerException - if any of the arguments are null
         if (context == null || clientId == null || callback == null)
         {
             throw new NullPointerException();
         }
 
         pushComponentToEL(context, this);
         try
         {
             // searching for this component?
             boolean found = clientId.equals(this.getClientId(context));
             if (found)
             {
                 try
                 {
                     callback.invokeContextCallback(context, this);
                 }
                 catch (Exception e)
                 {
                     throw new FacesException(e);
                 }
                 return found;
             }
             // Searching for this component's children/facets
             for (Iterator<UIComponent> it = this.getFacetsAndChildren(); !found && it.hasNext(); )
             {
                 found = it.next().invokeOnComponent(context, clientId, callback);
             }
             return found;
         }
         finally
         {
             //all components must call popComponentFromEl after visiting is finished
             popComponentFromEL(context);
         }
     }
 
     /**
      *
      * @param component
      * @return true if the component is a composite component otherwise false is returned
      *
      *
      * @throws NullPointerException if the component is null
      * @since 2.0
      */
     public static boolean isCompositeComponent(UIComponent component)
     {
 
         //since _isCompositeComponent does it the same way we do it here also although I
         //would prefer following method
 
         //return component.getRendererType().equals("javax.faces.Composite");
 
         return component.getAttributes().containsKey(Resource.COMPONENT_RESOURCE_KEY);
     }
 
     /**
      * Indicate if this component is inside a view,
      * or in other words is contained by an UIViewRoot
      * instance (which represents the view). If this component
      * is a UIViewRoot instance, the components "always"
      * is on the view.
      *
      * By default it is false but for UIViewRoot instances is
      * true. 
      *
      * @return
      *
      * @since 2.0
      */
     public boolean isInView()
     {
         return _inView;
     }
 
     public abstract boolean isRendered();
 
     public void markInitialState()
     {
         _initialStateMarked = true;
     }
 
     /**
      *
      * This method indicates if a component is visitable
      * according to the hints passed by the VisitContext parameter!
      *
      * This method internally is used by visitTree and if it returns false
      * it short circuits the visitTree execution.
      *
      *
      *
      * @param context
      * @return
      *
      * @since 2.0
      */
     protected boolean isVisitable(VisitContext context)
     {
 
         Collection<VisitHint> hints = context.getHints();
 
         if (hints.contains(VisitHint.SKIP_TRANSIENT) && this.isTransient())
         {
             return false;
         }
 
         if (hints.contains(VisitHint.SKIP_UNRENDERED) && !this.isRendered())
         {
             return false;
         }
 
         //executable cannot be handled here because we do not have any method to determine
         //whether a component is executable or not, this seems to be a hole in the spec!
         //but we can resolve it on ppr context level, where it is needed!
         //maybe in the long run we can move it down here, if it makes sense
 
         return true;
     }
 
     /**
      * @deprecated Replaced by setValueExpression
      */
     public abstract void setValueBinding(String name, ValueBinding binding);
 
     public void setValueExpression(String name, ValueExpression expression)
     {
         if (name == null)
         {
             throw new NullPointerException("name");
         }
         if (name.equals("id"))
         {
             throw new IllegalArgumentException("Can't set a ValueExpression for the 'id' property.");
         }
         if (name.equals("parent"))
         {
             throw new IllegalArgumentException("Can't set a ValueExpression for the 'parent' property.");
         }
 
         if (expression == null)
         {
             //if (bindings != null) {
             //    bindings.remove(name);
             //    if (bindings.isEmpty()) {
             //        bindings = null;
             //    }
             //}
             getStateHelper().remove(PropertyKeys.bindings, name);
         }
         else
         {
             if (expression.isLiteralText())
             {
                 try
                 {
                     Object value = expression.getValue(getFacesContext().getELContext());
                     getAttributes().put(name, value);
                     return;
                 }
                 catch (ELException e)
                 {
                     throw new FacesException(e);
                 }
             }
 
             //if (bindings == null) {
             //    bindings = new HashMap<String, ValueExpression>();
             //}
             //
             //bindings.put(name, expression);
             getStateHelper().put(PropertyKeys.bindings, name, expression);
         }
     }
 
     public String getClientId()
     {
         return getClientId(getFacesContext());
     }
 
     public abstract String getClientId(FacesContext context);
 
     /**
      * search for the nearest parent composite component, if no parent is found
      * it has to return null!
      *
      * if the component itself is null we have to return null as well!
      *
      * @param component the component to start from
      * @return the parent composite component if found otherwise null
      *
      * @since 2.0
      */
     public static UIComponent getCompositeComponentParent(UIComponent component)
     {
 
         if (component == null)
         {
             return null;
         }
         UIComponent parent = component;
 
         do
         {
             parent = parent.getParent();
             if (parent != null && UIComponent.isCompositeComponent(parent))
             {
                 return parent;
             }
         } while (parent != null);
         return null;
     }
 
     /**
      * @since 1.2
      */
     public String getContainerClientId(FacesContext ctx)
     {
         if (ctx == null)
         {
             throw new NullPointerException("FacesContext ctx");
         }
 
         return getClientId(ctx);
     }
 
     /**
      *
      * @param context
      * @return
      *
      * @since 2.0
      */
     public static UIComponent getCurrentComponent(FacesContext context)
     {
         return (UIComponent) context.getAttributes().get(UIComponent.CURRENT_COMPONENT);
     }
 
     /**
      *
      * @param context
      * @return
      *
      * @since 2.0
      */
     public static UIComponent getCurrentCompositeComponent(FacesContext context)
     {
         return (UIComponent) context.getAttributes().get(UIComponent.CURRENT_COMPOSITE_COMPONENT);
     }
 
     public abstract String getFamily();
 
     public abstract String getId();
 
     public List<SystemEventListener> getListenersForEventClass(Class<? extends SystemEvent> eventClass)
     {
         List<SystemEventListener> listeners;
         if (_systemEventListenerClassMap == null)
         {
             listeners = Collections.emptyList();
         }
         else
         {
             listeners = _systemEventListenerClassMap.get(eventClass);
             if (listeners == null)
             {
                 listeners = Collections.emptyList();
             }
             else
             {
                 listeners = Collections.unmodifiableList(listeners);
             }
         }
 
         return listeners;
     }
 
     /**
      *
      * @return
      *
      * @since 2.0
      */
     public UIComponent getNamingContainer()
     {
         // Starting with "this", return the closest component in the ancestry that is a NamingContainer 
         // or null if none can be found.
         UIComponent component = this;
         do
         {
             if (component instanceof NamingContainer)
             {
                 return component;
             }
 
             component = component.getParent();
         } while (component != null);
 
         return null;
     }
 
     public abstract void setId(String id);
 
     /**
      * Define if the component is on the view or not.
      * <p>
      * This value is set in the following conditions:
      * </p>
      * <ul>
      * <li>Component / Facet added: if the parent isInView = true, 
      *     set it to true and all their children or facets,
      *     otherwise take no action</li>
      * <li>Component / Facet removed: if the parent isInView = false,
      *     set it to false and all their children or facets,
      *     otherwise take no action</li>
      * <ul>
      * @param isInView
      *
      * @since 2.0
      */
     public void setInView(boolean isInView)
     {
         _inView = isInView;
     }
 
     /**
      * For JSF-framework internal use only. Don't call this method to add components to the component tree. Use
      * <code>parent.getChildren().add(child)</code> instead.
      */
     public abstract void setParent(UIComponent parent);
 
     /**
      * Returns the parent of the component. Children can be added to or removed from a component even if this method
      * returns null for the child.
      */
     public abstract UIComponent getParent();
 
     public abstract void setRendered(boolean rendered);
 
     public abstract String getRendererType();
 
     public abstract void setRendererType(String rendererType);
 
     public abstract boolean getRendersChildren();
 
     public Map<String, String> getResourceBundleMap()
     {
         if (_resourceBundleMap == null)
         {
             FacesContext context = getFacesContext();
             Locale locale = context.getViewRoot().getLocale();
             ClassLoader loader = _ClassUtils.getContextClassLoader();
 
             try
             {
                 // looks for a ResourceBundle with a base name equal to the fully qualified class
                 // name of the current UIComponent this and Locale equal to the Locale of the current UIViewRoot.
                 _resourceBundleMap = new BundleMap(ResourceBundle.getBundle(getClass().getName(), locale, loader));
             }
             catch (MissingResourceException e)
             {
                 // If no such bundle is found, and the component is a composite component
                 if (this._isCompositeComponent())
                 {
                     // No need to check componentResource (the resource used to build the composite
                     // component instance) to null since it is already done on this._isCompositeComponent()
                     Resource componentResource = (Resource) getAttributes().get(Resource.COMPONENT_RESOURCE_KEY);
                     // Let resourceName be the resourceName of the Resource for this composite component,
                     // replacing the file extension with ".properties"
                     int extensionIndex = componentResource.getResourceName().lastIndexOf('.');
                     String resourceName = (extensionIndex < 0
                             ? componentResource.getResourceName()
                             : componentResource.getResourceName().substring(0, extensionIndex)) + ".properties";
 
                     // Let libraryName be the libraryName of the the Resource for this composite component.
                     // Call ResourceHandler.createResource(java.lang.String,java.lang.String), passing the derived
                     // resourceName and
                     // libraryName.
                     Resource bundleResource = context.getApplication().getResourceHandler()
                             .createResource(resourceName, componentResource.getLibraryName());
 
                     if (bundleResource != null)
                     {
                         // If the resultant Resource exists and can be found, the InputStream for the resource
                         // is used to create a ResourceBundle. If either of the two previous steps for obtaining the
                         // ResourceBundle
                         // for this component is successful, the ResourceBundle is wrapped in a Map<String, String> and
                         // returned.
                         try
                         {
                             _resourceBundleMap
                                     = new BundleMap(new PropertyResourceBundle(bundleResource.getInputStream()));
                         }
                         catch (IOException e1)
                         {
                             // Nothing happens, then resourceBundleMap is set as empty map
                         }
                     }
                 }
                 // Otherwise Collections.EMPTY_MAP is returned.
                 if (_resourceBundleMap == null)
                 {
                     _resourceBundleMap = Collections.emptyMap();
                 }
             }
         }
 
         return _resourceBundleMap;
     }
 
     /**
      * @deprecated Replaced by getValueExpression
      */
     public abstract ValueBinding getValueBinding(String name);
 
     public ValueExpression getValueExpression(String name)
     {
         if (name == null)
         {
             throw new NullPointerException("name can not be null");
         }
 
         Map<String, Object> bindings = (Map<String, Object>) getStateHelper().
                 get(PropertyKeys.bindings);
 
         if (bindings == null)
         {
             if (!(this instanceof UIComponentBase))
             {
                 // if the component does not inherit from UIComponentBase and don't implements JSF 1.2 or later
                 ValueBinding vb = getValueBinding(name);
                 if (vb != null)
                 {
                     //bindings = new HashMap<String, ValueExpression>();
                     ValueExpression ve = new _ValueBindingToValueExpression(vb);
                     getStateHelper().put(PropertyKeys.bindings, name, ve);
                     return ve;
                 }
             }
         }
         else
         {
             //return bindings.get(name);
             return (ValueExpression) bindings.get(name);
         }
         return null;
     }
 
     public abstract List<UIComponent> getChildren();
 
     public abstract int getChildCount();
 
     public abstract UIComponent findComponent(String expr);
 
     public abstract Map<String, UIComponent> getFacets();
 
     public abstract UIComponent getFacet(String name);
 
     public abstract Iterator<UIComponent> getFacetsAndChildren();
 
     public abstract void broadcast(FacesEvent event) throws AbortProcessingException;
 
     /**
      * {@inheritDoc}
      *
      * @since 2.0
      */
     public void clearInitialState()
     {
         _initialStateMarked = false;
     }
 
     public abstract void decode(FacesContext context);
 
     public abstract void encodeBegin(FacesContext context) throws IOException;
 
     public abstract void encodeChildren(FacesContext context) throws IOException;
 
     public abstract void encodeEnd(FacesContext context) throws IOException;
 
     public void encodeAll(FacesContext context) throws IOException
     {
         if (context == null)
         {
             throw new NullPointerException();
         }
 
         pushComponentToEL(context, this);
         try
         {
             if (!isRendered())
             {
                 return;
             }
         }
         finally
         {
             popComponentFromEL(context);
         }
 
         //if (isRendered()) {
         this.encodeBegin(context);
 
         // rendering children
         if (this.getRendersChildren())
         {
             this.encodeChildren(context);
         } // let children render itself
         else
         {
             if (this.getChildCount() > 0)
             {
                 for (int i = 0; i < this.getChildCount(); i++)
                 {
                     UIComponent comp = this.getChildren().get(i);
                     comp.encodeAll(context);
                 }
             }
         }
         this.encodeEnd(context);
         //}
     }
 
     protected abstract void addFacesListener(FacesListener listener);
 
     protected abstract FacesListener[] getFacesListeners(Class clazz);
 
     protected abstract void removeFacesListener(FacesListener listener);
 
     public abstract void queueEvent(FacesEvent event);
 
     public abstract void processRestoreState(FacesContext context, Object state);
 
     public abstract void processDecodes(FacesContext context);
 
     public void processEvent(ComponentSystemEvent event) throws AbortProcessingException
     {
         // The default implementation performs the following action. If the argument event is an instance of
         // AfterRestoreStateEvent,
         if (event instanceof PostRestoreStateEvent)
         {
 
             // call this.getValueExpression(java.lang.String) passing the literal string "binding"
             ValueExpression expression = getValueExpression("binding");
 
             // If the result is non-null, set the value of the ValueExpression to be this.
             if (expression != null)
             {
                 expression.setValue(getFacesContext().getELContext(), this);
             }
 
             //we issue a PostRestoreStateEvent
             //we issue it here because the spec clearly states what UIComponent is allowed to do
             //the main issue is that the spec does not say anything about a global dispatch on this level
             //but a quick blackbox test against the ri revealed that the event clearly is dispatched
             //at restore level for every component so we either issue it here or in UIViewRoot and/or the facelet
             // and jsp restore state triggers, a central point is preferrble so we do it here
             //TODO ask the EG the spec clearly contradicts blackbox RI behavior here 
 
             //getFacesContext().getApplication().publishEvent(getFacesContext(),
             // PostRestoreStateEvent.class, UIComponent.class, this);
         }
 
     }
 
     public abstract void processValidators(FacesContext context);
 
     public abstract void processUpdates(FacesContext context);
 
     public abstract java.lang.Object processSaveState(FacesContext context);
 
     public void subscribeToEvent(Class<? extends SystemEvent> eventClass,
                                  ComponentSystemEventListener componentListener)
     {
         // The default implementation creates an inner SystemEventListener instance that wraps argument
         // componentListener as the listener argument.
         if (eventClass == null)
         {
             throw new NullPointerException("eventClass required");
         }
         if (componentListener == null)
         {
             throw new NullPointerException("componentListener required");
         }
 
         SystemEventListener listener = new EventListenerWrapper(this, componentListener);
 
         // Make sure the map exists
         if (_systemEventListenerClassMap == null)
         {
             _systemEventListenerClassMap = new HashMap<Class<? extends SystemEvent>, List<SystemEventListener>>();
         }
 
         List<SystemEventListener> listeners = _systemEventListenerClassMap.get(eventClass);
         // Make sure the list for class exists
         if (listeners == null)
         {
             // how many listeners per event type can single component have? 
             // We use 3 here as expected number, but it is a question 
             listeners = new _DeltaList<SystemEventListener>(new ArrayList<SystemEventListener>(3));
             _systemEventListenerClassMap.put(eventClass, listeners);
         }
 
         // Deal with contains? Spec is silent
         listeners.add(listener);
     }
 
     public void unsubscribeFromEvent(Class<? extends SystemEvent> eventClass,
                                      ComponentSystemEventListener componentListener)
     {
         /*
          * When doing the comparison to determine if an existing listener is equal to the argument componentListener
          * (and thus must be removed), the equals() method on the existing listener must be invoked, passing the
          * argument componentListener, rather than the other way around.
          * 
          * -=Simon Lessard=- What is that supposed to mean? Are we supposed to keep
          * an internal map of created listener wrappers?
          * -= Leonardo Uribe=- Yes, it is supposed a wrapper should be used to hold listener references, to prevent
          * serialize component instances on the state.
          */
         if (eventClass == null)
         {
             throw new NullPointerException("eventClass required");
         }
         if (componentListener == null)
         {
             throw new NullPointerException("componentListener required");
         }
 
         if (_systemEventListenerClassMap != null)
         {
             List<SystemEventListener> listeners = _systemEventListenerClassMap.get(eventClass);
 
             if (listeners != null && !listeners.isEmpty())
             {
                 for (Iterator<SystemEventListener> it = listeners.iterator(); it.hasNext(); )
                 {
                     ComponentSystemEventListener listener
                             = ((EventListenerWrapper) it.next()).getComponentSystemEventListener();
                     if (listener != null && listener.equals(componentListener))
                     {
                         it.remove();
                         break;
                     }
                 }
             }
         }
     }
 
     /**
      * The visit tree method, visit tree walks over a subtree and processes
      * the callback object to perform some operation on the subtree
      * <p>
      * there are some details in the implementation which according to the spec have
      * to be in place:
      * a) before calling the callback and traversing into the subtree  pushComponentToEL
      * has to be called
      * b) after the processing popComponentFromEL has to be performed to remove the component
      * from the el
      * </p>
      * <p>
      * The tree traversal optimizations are located in the visit context and can be replaced
      * via the VisitContextFactory in the faces-config factory section
      * </p>
      *
      * @param context the visit context which handles the processing details
      * @param callback the callback to be performed
      * @return false if the processing is not done true if we can shortcut
      * the visiting because we are done with everything
      *
      * @since 2.0
      */
     public boolean visitTree(VisitContext context, VisitCallback callback)
     {
         try
         {
             pushComponentToEL(context.getFacesContext(), this);
 
             if (!isVisitable(context))
             {
                 return false;
             }
 
             VisitResult res = context.invokeVisitCallback(this, callback);
             switch (res)
             {
                 //we are done nothing has to be processed anymore
                 case COMPLETE:
                     return true;
 
                 case REJECT:
                     return false;
 
                 //accept
                 default:
                     if (getFacetCount() > 0)
                     {
                         for (UIComponent facet : getFacets().values())
                         {
                             if (facet.visitTree(context, callback))
                             {
                                 return true;
                             }
                         }
                     }
                     int childCount = getChildCount();
                     if (childCount > 0)
                     {
                         for (int i = 0; i < childCount; i++)
                         {
                             UIComponent child = getChildren().get(i);
                             if (child.visitTree(context, callback))
                             {
                                 return true;
                             }
                         }
                     }
                     return false;
             }
         }
         finally
         {
             //all components must call popComponentFromEl after visiting is finished
             popComponentFromEL(context.getFacesContext());
         }
     }
 
     protected abstract FacesContext getFacesContext();
 
     protected abstract Renderer getRenderer(FacesContext context);
 
     /**
      * Note that id, clientId properties
      * never change its value after the component is populated,
      * so we don't need to store it on StateHelper or restore it when
      * initialStateMarked == true
      * (Note that rendererType is suspicious, in theory this field is
      * initialized on constructor, but on 1.1 and 1.2 is saved and restored,
      * so to keep backward behavior we put it on StateHelper )
      *
      * Also, facesListeners can't be wrapped on StateHelper because it
      * needs to handle PartialStateHolder instances when it is saved and
      * restored and this interface does not implement PartialStateHolder,
      * so we can't propagate calls to markInitialState and clearInitialState,
      * in other words, the List wrapped by StateHelper does not handle
      * PartialStateHolder items.
      *
      * "bindings" map does not need to deal with PartialStateHolder instances,
      *  so we can use StateHelper feature (handle delta for this map or in
      *  other words track add/removal from bindings map as delta).
      */
     enum PropertyKeys
     {
         rendered,
         rendererType,
         attributesMap,
         bindings,
         facesListeners
     }
 
     protected StateHelper getStateHelper()
     {
         return getStateHelper(true);
     }
 
     /**
      * returns a delta state saving enabled state helper
      * for the current component
      * @param create if true a state helper is created if not already existing
      * @return an implementation of the StateHelper interface or null if none exists and create is set to false
      */
     protected StateHelper getStateHelper(boolean create)
     {
         if (_stateHelper != null)
         {
             return _stateHelper;
         }
         if (create)
         {
             _stateHelper = new _DeltaStateHelper(this);
         }
         return _stateHelper;
     }
 
     @SuppressWarnings("unchecked")
     public final void popComponentFromEL(FacesContext context)
     {
         Map<Object, Object> contextAttributes = context.getAttributes();
 
         // Pop the current UIComponent from the FacesContext attributes map so that the previous 
         // UIComponent, if any, becomes the current component.
         List<UIComponent> componentStack
                 = (List<UIComponent>) contextAttributes.get(UIComponent._COMPONENT_STACK);
 
         UIComponent oldCurrent = (UIComponent) contextAttributes.get(UIComponent.CURRENT_COMPONENT);
 
         UIComponent newCurrent = null;
         if (componentStack != null && !componentStack.isEmpty())
         {
             if (!this.equals(oldCurrent))
             {
                 //Check on the componentStack if it can be found
                 int componentIndex = componentStack.lastIndexOf(this);
                 if (componentIndex >= 0)
                 {
                     //for (int i = 0; i < (componentIndex + 1); i++)
                     for (int i = componentStack.size()-1; i >= componentIndex ; i--)
                     {
                         newCurrent = componentStack.remove(componentStack.size()-1);
                     }
                 }
                 else
                 {
                     //Component not found on the stack. Do not pop.
                     return;
                 }
             }
             else
             {
                 newCurrent = componentStack.remove(componentStack.size()-1);
             }
         }
         else
         {
             //Reset the current composite component
             contextAttributes.put(UIComponent.CURRENT_COMPOSITE_COMPONENT, null);
         }
         oldCurrent = (UIComponent) contextAttributes.put(UIComponent.CURRENT_COMPONENT, newCurrent);
 
         if (oldCurrent != null && oldCurrent._isCompositeComponent())
         {
             // Recalculate the current composite component
             if (newCurrent != null)
             {
                 if (newCurrent._isCompositeComponent())
                 {
                     contextAttributes.put(UIComponent.CURRENT_COMPOSITE_COMPONENT, newCurrent);
                 }
                 else
                 {
                     UIComponent previousCompositeComponent = null;
                     for (int i = componentStack.size()-1; i >= 0; i--)
                     {
                         UIComponent component = componentStack.get(i);
                         if (component._isCompositeComponent())
                         {
                             previousCompositeComponent = component;
                             break;
                         }
                     }
                     contextAttributes.put(UIComponent.CURRENT_COMPOSITE_COMPONENT, previousCompositeComponent);
                 }
             }
         }
     }
 
     @SuppressWarnings("unchecked")
     public final void pushComponentToEL(FacesContext context, UIComponent component)
     {
         if (component == null)
         {
             component = this;
         }
         Map<Object, Object> contextAttributes = context.getAttributes();
         UIComponent currentComponent = (UIComponent) contextAttributes.get(UIComponent.CURRENT_COMPONENT);
 
         if (currentComponent != null)
         {
             List<UIComponent> componentStack
                     = (List<UIComponent>) contextAttributes.get(UIComponent._COMPONENT_STACK);
             if (componentStack == null)
             {
                 componentStack = new ArrayList<UIComponent>();
                 contextAttributes.put(UIComponent._COMPONENT_STACK, componentStack);
             }
 
             componentStack.add(currentComponent);
         }
 
         // Push the current UIComponent this to the FacesContext  attribute map using the key CURRENT_COMPONENT 
         // saving the previous UIComponent associated with CURRENT_COMPONENT for a subsequent call to 
         // popComponentFromEL(javax.faces.context.FacesContext).
         contextAttributes.put(UIComponent.CURRENT_COMPONENT, component);
 
         if (component._isCompositeComponent())
         {
             contextAttributes.put(UIComponent.CURRENT_COMPOSITE_COMPONENT, component);
         }
     }
 
     /**
      * @since 1.2
      */
     public int getFacetCount()
     {
         // not sure why the RI has this method in both
         // UIComponent and UIComponentBase
         Map<String, UIComponent> facets = getFacets();
         return facets == null ? 0 : facets.size();
     }
 
     private boolean _isCompositeComponent()
     {
         //moved to the static method
         return UIComponent.isCompositeComponent(this);
     }
 
     private static class BundleMap implements Map<String, String>
     {
 
         private ResourceBundle _bundle;
         private List<String> _values;
 
         public BundleMap(ResourceBundle bundle)
         {
             _bundle = bundle;
         }
 
         // Optimized methods
         public String get(Object key)
         {
             try
             {
                 return (String) _bundle.getObject(key.toString());
             }
             catch (Exception e)
             {
                 return "???" + key + "???";
             }
         }
 
         public boolean isEmpty()
         {
             return !_bundle.getKeys().hasMoreElements();
         }
 
         public boolean containsKey(Object key)
         {
             try
             {
                 return _bundle.getObject(key.toString()) != null;
             }
             catch (MissingResourceException e)
             {
                 return false;
             }
         }
 
         // Unoptimized methods
         public Collection<String> values()
         {
             if (_values == null)
             {
                 _values = new ArrayList<String>();
                 for (Enumeration<String> enumer = _bundle.getKeys(); enumer.hasMoreElements(); )
                 {
                     String v = _bundle.getString(enumer.nextElement());
                     _values.add(v);
                 }
             }
             return _values;
         }
 
         public int size()
         {
             return values().size();
         }
 
         public boolean containsValue(Object value)
         {
             return values().contains(value);
         }
 
         public Set<Map.Entry<String, String>> entrySet()
         {
             Set<Entry<String, String>> set = new HashSet<Entry<String, String>>();
             for (Enumeration<String> enumer = _bundle.getKeys(); enumer.hasMoreElements(); )
             {
                 final String k = enumer.nextElement();
                 set.add(new Map.Entry<String, String>()
                 {
 
                     public String getKey()
                     {
                         return k;
                     }
 
                     public String getValue()
                     {
                         return (String) _bundle.getObject(k);
                     }
 
                     public String setValue(String value)
                     {
                         throw new UnsupportedOperationException();
                     }
                 });
             }
 
             return set;
         }
 
         public Set<String> keySet()
         {
             Set<String> set = new HashSet<String>();
             for (Enumeration<String> enumer = _bundle.getKeys(); enumer.hasMoreElements(); )
             {
                 set.add(enumer.nextElement());
             }
             return set;
         }
 
         // Unsupported methods
         public String remove(Object key)
         {
             throw new UnsupportedOperationException();
         }
 
         public void putAll(Map<? extends String, ? extends String> t)
         {
             throw new UnsupportedOperationException();
         }
 
         public String put(String key, String value)
         {
             throw new UnsupportedOperationException();
         }
 
         public void clear()
         {
             throw new UnsupportedOperationException();
         }
     }
 
     static class EventListenerWrapper implements SystemEventListener, PartialStateHolder
     {
 
         private Class<?> componentClass;
         private ComponentSystemEventListener listener;
 
         private boolean _initialStateMarked;
 
         private int listenerCapability;
 
         private static final int LISTENER_SAVE_STATE_HOLDER = 1;
         private static final int LISTENER_SAVE_PARTIAL_STATE_HOLDER = 2;
         private static final int LISTENER_TYPE_COMPONENT = 4;
         private static final int LISTENER_TYPE_RENDERER = 8;
         private static final int LISTENER_TYPE_OTHER = 16;
 
         public EventListenerWrapper()
         {
             //need a no-arg constructor for state saving purposes
             super();
         }
 
         /**
          * Note we have two cases:
          *
          * 1. listener is an instance of UIComponent. In this case we cannot save and restore
          *    it because we need to point to the real component, but we can assume the instance
          *    is the same because UIComponent.subscribeToEvent says so. Also take into account
          *    this case is the reason why we need a wrapper for UIComponent.subscribeToEvent
          * 2. listener is an instance of Renderer. In this case we can assume the same renderer
          *    used by the source component is the one used by the listener (ListenerFor). 
          * 3. listener is an instance of ComponentSystemEventListener but not from UIComponent.
          *    In this case, the instance could implement StateHolder, PartialStateHolder or do
          *    implement anything, so we have to deal with that case as usual.
          *
          * @param component
          * @param listener
          */
         public EventListenerWrapper(UIComponent component, ComponentSystemEventListener listener)
         {
             assert component != null;
             assert listener != null;
 
             this.componentClass = component.getClass();
             this.listener = listener;
 
             initListenerCapability();
         }
 
         private void initListenerCapability()
         {
             this.listenerCapability = 0;
             if (this.listener instanceof UIComponent)
             {
                 this.listenerCapability = LISTENER_TYPE_COMPONENT;
             }
             else if (this.listener instanceof Renderer)
             {
                 this.listenerCapability = LISTENER_TYPE_RENDERER;
             }
             else
             {
                 if (this.listener instanceof PartialStateHolder)
                 {
                     this.listenerCapability = LISTENER_TYPE_OTHER | LISTENER_SAVE_PARTIAL_STATE_HOLDER;
                 }
                 else if (this.listener instanceof StateHolder)
                 {
                     this.listenerCapability = LISTENER_TYPE_OTHER | LISTENER_SAVE_STATE_HOLDER;
                 }
                 else
                 {
                     this.listenerCapability = LISTENER_TYPE_OTHER;
                 }
             }
         }
 
         @Override
         public boolean equals(Object o)
         {
             if (o == this)
             {
                 return true;
             }
             else if (o instanceof EventListenerWrapper)
             {
                 EventListenerWrapper other = (EventListenerWrapper) o;
                 return componentClass.equals(other.componentClass) && listener.equals(other.listener);
             }
             else
             {
                 return false;
             }
         }
 
         @Override
         public int hashCode()
         {
             return componentClass.hashCode() + listener.hashCode();
         }
 
         public boolean isListenerForSource(Object source)
         {
             // and its implementation of SystemEventListener.isListenerForSource(java.lang.Object) must return true
             // if the instance class of this UIComponent is assignable from the argument to isListenerForSource.
 
             return source.getClass().isAssignableFrom(componentClass);
         }
 
         public ComponentSystemEventListener getComponentSystemEventListener()
         {
             return listener;
         }
 
         public void processEvent(SystemEvent event)
         {
             // This inner class must call through to the argument componentListener in its implementation of
             // SystemEventListener.processEvent(javax.faces.event.SystemEvent)
 
             assert event instanceof ComponentSystemEvent;
 
             listener.processEvent((ComponentSystemEvent) event);
         }
 
         public void clearInitialState()
         {
             //if (!(listener instanceof UIComponent) && listener instanceof PartialStateHolder)
             if ((listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0)
             {
                 ((PartialStateHolder) listener).clearInitialState();
             }
             _initialStateMarked = false;
         }
 
         public boolean initialStateMarked()
         {
             //if (!(listener instanceof UIComponent) && listener instanceof PartialStateHolder)
             if ((listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0)
             {
                 return ((PartialStateHolder) listener).initialStateMarked();
             }
             //return false;
             return _initialStateMarked;
         }
 
         public void markInitialState()
         {
             //if (!(listener instanceof UIComponent) && listener instanceof PartialStateHolder)
             if ((listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0)
             {
                 ((PartialStateHolder) listener).markInitialState();
             }
             _initialStateMarked = true;
         }
 
         public boolean isTransient()
         {
             //if ( listener instanceof StateHolder)
             if ((listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0 ||
                     (listenerCapability & LISTENER_SAVE_STATE_HOLDER) != 0)
             {
                 return ((StateHolder) listener).isTransient();
             }
             return false;
         }
 
         public void restoreState(FacesContext context, Object state)
         {
             if (state == null)
             {
                 return;
             }
             Object[] values = (Object[]) state;
             componentClass = (Class) values[0];
             if (values[1] instanceof _AttachedDeltaWrapper)
             {
                 ((StateHolder) listener).restoreState(context,
                         ((_AttachedDeltaWrapper) values[1]).getWrappedStateObject());
             }
             else
             {
                 //Full restore
                 listenerCapability = (Integer) values[2];
 
                 if ((listenerCapability & LISTENER_TYPE_COMPONENT) != 0)
                 {
                     listener = UIComponent.getCurrentComponent(context);
                 }
                 else if ((listenerCapability & LISTENER_TYPE_RENDERER) != 0)
                 {
                     listener = (ComponentSystemEventListener)
                             UIComponent.getCurrentComponent(context).getRenderer(context);
                 }
                 else
                 {
                     listener = (ComponentSystemEventListener)
                             UIComponentBase.restoreAttachedState(context, values[1]);
                 }
                 /*
                 listener = values[1] == null ? 
                         UIComponent.getCurrentComponent(context) : 
                             (ComponentSystemEventListener) UIComponentBase.restoreAttachedState(context, values[1]);
                             */
             }
         }
 
         public Object saveState(FacesContext context)
         {
             if (!initialStateMarked())
             {
                 /*
                 Object[] state = new Object[2];
                 state[0] = componentClass;
                 if (!(listener instanceof UIComponent))
                 {
                     state[1] = UIComponentBase.saveAttachedState(context, listener);
                 }
                 return state;
                 */
                 Object[] state = new Object[3];
                 state[0] = componentClass;
                 //If this is not a component or a renderer, save it calling UIComponent.saveAttachedState
                 if (!((listenerCapability & LISTENER_TYPE_COMPONENT) != 0 ||
                         (listenerCapability & LISTENER_TYPE_RENDERER) != 0))
                 {
                     state[1] = UIComponentBase.saveAttachedState(context, listener);
                 }
                 else
                 {
                     state[1] = null;
                 }
                 state[2] = (Integer) listenerCapability;
                 return state;
             }
             else
             {
                 // If initialStateMarked() == true means two things:
                 // 1. PSS is being used
                 if ((listenerCapability & LISTENER_TYPE_COMPONENT) != 0)
                 {
                     return null;
                 }
                 else if ((listenerCapability & LISTENER_TYPE_RENDERER) != 0)
                 {
                     return null;
                 }
                 else
                 {
                     if ((listenerCapability & LISTENER_SAVE_STATE_HOLDER) != 0 ||
                             (listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0)
                     {
                         Object listenerSaved = ((StateHolder) listener).saveState(context);
                         if (listenerSaved == null)
                         {
                             return null;
                         }
                         return new Object[]{componentClass,
                                             new _AttachedDeltaWrapper(listener.getClass(), listenerSaved)};
                     }
                     else
                     {
                         //This is not necessary, because the instance is considered serializable!
                         return null;
                     }
                 }
                 /*
                 Object listenerSaved = ((StateHolder) listener).saveState(context);
                 if (listenerSaved == null)
                 {
                     return null;
                 }
                 return new Object[]{componentClass, new _AttachedDeltaWrapper(listener.getClass(), listenerSaved)};
                 */
             }
         }
 
         public void setTransient(boolean newTransientValue)
         {
             if ((listenerCapability & LISTENER_SAVE_PARTIAL_STATE_HOLDER) != 0 ||
                     (listenerCapability & LISTENER_SAVE_STATE_HOLDER) != 0)
             {
                 ((StateHolder) listener).setTransient(newTransientValue);
             }
         }
     }
 }