/*
    * 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.beans.BeanInfo;
  import java.beans.IntrospectionException;
  import java.beans.Introspector;
  import java.beans.PropertyDescriptor;
  import java.io.Serializable;
  import java.lang.reflect.Method;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Map;
  import java.util.Set;
  import java.util.WeakHashMap;
  import java.util.concurrent.ConcurrentHashMap;
  
  import javax.el.ValueExpression;
  import javax.faces.FacesException;
  import javax.faces.application.Resource;
  import javax.faces.context.FacesContext;
  
  /**
   * <p>
   * A custom implementation of the Map interface, where get and put calls
   * try to access getter/setter methods of an associated UIComponent before
   * falling back to accessing a real Map object.
   * </p>
   * <p>
   * Some of the behaviours of this class don't really comply with the
   * definitions of the Map class; for example the key parameter to all
   * methods is required to be of type String only, and after clear(),
   * calls to get can return non-null values. However the JSF spec
   * requires that this class behave in the way implemented below. See
   * UIComponent.getAttributes for more details.
   * </p>
   * <p>
   * The term "property" is used here to refer to real javabean properties
   * on the underlying UIComponent, while "attribute" refers to an entry
   * in the associated Map.
   * </p>
   */
  class _ComponentAttributesMap implements Map<String, Object>, Serializable
  {
      private static final long serialVersionUID = -9106832179394257866L;
  
      private static final Object[] EMPTY_ARGS = new Object[0];
      
      private final static String MARK_CREATED = "oam.vf.MARK_ID";
      
      private final static String FACET_NAME_KEY = "facelets.FACET_NAME";
      
      public final static String FACET_CREATED_UIPANEL_MARKER = "oam.vf.createdUIPanel";
      
      private final static String COMPONENT_ADDED_BY_HANDLER_MARKER = "oam.vf.addedByHandler";
      
      public static final String PROPERTY_DESCRIPTOR_MAP_KEY = "oam.cc.beanInfo.PDM";
      
      /**
       * This variable works as a check to indicate the minimun lenght we need to check
       * for the special attributes, and save some time in get(), containsKey() and 
       * put() operations.
       */
      private final static int MIN_LENGHT_CHECK = MARK_CREATED.length();
  
      // The component that is read/written via this map.
      private UIComponentBase _component;
  
      // We delegate instead of derive from HashMap, so that we can later
      // optimize Serialization
      // JSF 2.0 Changed getUnderlyingMap to point to StateHelper attributesMap
      //private Map<String, Object> _attributes = null;
  
      // A cached hashmap of propertyName => PropertyDescriptor object for all
      // the javabean properties of the associated component. This is built by
      // introspection on the associated UIComponent. Don't serialize this as
      // it can always be recreated when needed.
      private transient Map<String, _PropertyDescriptorHolder> _propertyDescriptorMap = null;
  
      // Cache for component property descriptors
      private static Map<Class<?>, Map<String, _PropertyDescriptorHolder>> propertyDescriptorCache =
          new WeakHashMap<Class<?>, Map<String, _PropertyDescriptorHolder>>();
      
     private boolean _isCompositeComponent;
     private boolean _isCompositeComponentSet;
     
     private BeanInfo _ccBeanInfo;
 
     /**
      * Create a map backed by the specified component.
      * <p/>
      * This method is expected to be called when a component is first created.
      */
     _ComponentAttributesMap(UIComponentBase component)
     {
         _component = component;
     }
     
     /**
      * Create a map backed by the specified component. Attributes already
      * associated with the component are provided in the specified Map
      * class. A reference to the provided map is kept; this object's contents
      * are updated during put calls on this instance.
      * <p/>
      * This method is expected to be called during the "restore view" phase.
      */
     //JSF 2.0 removed because _attributes has been replaced with StateHelper attributesMap
     //_ComponentAttributesMap(UIComponent component, Map<String, Object> attributes)
     //{
     //    _component = component;
         //_attributes = new HashMap<String, Object>(attributes);
     //}
     
     /**
      * Return the number of <i>attributes</i> in this map. Properties of the
      * underlying UIComponent are not counted.
      * <p/>
      * Note that because the get method can read properties of the
      * UIComponent and evaluate value-bindings, it is possible to have
      * size return zero while calls to the get method return non-null
      * values.
      */
     @Override
     public int size()
     {
         return getUnderlyingMap().size();
     }
 
     /**
      * Clear all the <i>attributes</i> in this map. Properties of the
      * underlying UIComponent are not modified.
      * <p/>
      * Note that because the get method can read properties of the
      * UIComponent and evaluate value-bindings, it is possible to have
      * calls to the get method return non-null values immediately after
      * a call to clear.
      */
     @Override
     public void clear()
     {
         getUnderlyingMap().clear();
     }
 
     /**
      * Return true if there are no <i>attributes</i> in this map. Properties
      * of the underlying UIComponent are not counted.
      * <p/>
      * Note that because the get method can read properties of the
      * UIComponent and evaluate value-bindings, it is possible to have
      * isEmpty return true, while calls to the get method return non-null
      * values.
      */
     @Override
     public boolean isEmpty()
     {
         return getUnderlyingMap().isEmpty();
     }
 
     /**
      * Return true if there is an <i>attribute</i> with the specified name,
      * but false if there is a javabean <i>property</i> of that name on the
      * associated UIComponent.
      * <p/>
      * Note that it should be impossible for the attributes map to contain
      * an entry with the same name as a javabean property on the associated
      * UIComponent.
      *
      * @param key <i>must</i> be a String. Anything else will cause a
      *            ClassCastException to be thrown.
      */
     @Override
     public boolean containsKey(Object key)
     {
         checkKey(key);
 
         int keyLength = ((String)key).length();
         if (keyLength >= MIN_LENGHT_CHECK)
         {
             if (MARK_CREATED.length() == keyLength &&
                 MARK_CREATED.equals(key))
             {
                 return ((UIComponentBase)_component).getOamVfMarkCreated() != null;
             }
             else if (FACET_NAME_KEY.length() == keyLength &&
                 FACET_NAME_KEY.equals(key))
             {
                 return _component.getOamVfFacetName() != null;
             }
             else if (COMPONENT_ADDED_BY_HANDLER_MARKER.length() == keyLength &&
                 COMPONENT_ADDED_BY_HANDLER_MARKER.equals(key))
             {
                 return _component.isOamVfAddedByHandler();
             }
             else if (FACET_CREATED_UIPANEL_MARKER.length() == keyLength &&
                 FACET_CREATED_UIPANEL_MARKER.equals(key))
             {
                 return _component.isOamVfFacetCreatedUIPanel();
             }
             // The most common call to this method comes from UIComponent.isCompositeComponent()
             // to reduce the impact. This is better than two lookups, once over property descriptor map
             // and the other one from the underlying map.
             if (Resource.COMPONENT_RESOURCE_KEY.length() == keyLength &&
                 Resource.COMPONENT_RESOURCE_KEY.equals(key))
             {
                 if (!_isCompositeComponentSet)
                 {
                     // Note we are not setting _isCompositeComponentSet, because when the component tree is built
                     // using JSF 1.2 state saving, PostAddToViewEvent is propagated and the component is check 
                     // if is a composite component, but the state is not restored, so the check return always
                     // false. A check for processing events was added to prevent that scenario, but anyway that 
                     // makes invalid set _isCompositeComponentSet to true on this location.
                     _isCompositeComponent = getUnderlyingMap().containsKey(Resource.COMPONENT_RESOURCE_KEY);
                 }
                 return _isCompositeComponent;
             }
         }
         return getPropertyDescriptor((String) key) == null ? getUnderlyingMap().containsKey(key) : false;
     }
 
     /**
      * Returns true if there is an <i>attribute</i> with the specified
      * value. Properties of the underlying UIComponent aren't examined,
      * nor value-bindings.
      *
      * @param value null is allowed
      */
     @Override
     public boolean containsValue(Object value)
     {
         return getUnderlyingMap().containsValue(value);
     }
 
     /**
      * Return a collection of the values of all <i>attributes</i>. Property
      * values are not included, nor value-bindings.
      */
     @Override
     public Collection<Object> values()
     {
         return getUnderlyingMap().values();
     }
 
     /**
      * Call put(key, value) for each entry in the provided map.
      */
     @Override
     public void putAll(Map<? extends String, ?> t)
     {
         for (Map.Entry<? extends String, ?> entry : t.entrySet())
         {
             put(entry.getKey(), entry.getValue());
         }
     }
 
     /**
      * Return a set of all <i>attributes</i>. Properties of the underlying
      * UIComponent are not included, nor value-bindings.
      */
     @Override
     public Set<Map.Entry<String, Object>> entrySet()
     {
         return getUnderlyingMap().entrySet();
     }
 
     /**
      * Return a set of the keys for all <i>attributes</i>. Properties of the
      * underlying UIComponent are not included, nor value-bindings.
      */
     @Override
     public Set<String> keySet()
     {
         return getUnderlyingMap().keySet();
     }
 
     /**
      * In order: get the value of a <i>property</i> of the underlying
      * UIComponent, read an <i>attribute</i> from this map, or evaluate
      * the component's value-binding of the specified name.
      *
      * @param key must be a String. Any other type will cause ClassCastException.
      */
     @Override
     public Object get(Object key)
     {
         checkKey(key);
         
         Object value;
 
         int keyLength = ((String)key).length();
         if (keyLength >= MIN_LENGHT_CHECK)
         {
             if (MARK_CREATED.length() == keyLength &&
                 MARK_CREATED.equals(key))
             {
                 return _component.getOamVfMarkCreated();
             }
             else if (FACET_NAME_KEY.length() == keyLength &&
                 FACET_NAME_KEY.equals(key))
             {
                 return _component.getOamVfFacetName();
             }
             else if (COMPONENT_ADDED_BY_HANDLER_MARKER.length() == keyLength &&
                 COMPONENT_ADDED_BY_HANDLER_MARKER.equals(key))
             {
                 return _component.isOamVfAddedByHandler();
             }
             else if (FACET_CREATED_UIPANEL_MARKER.length() == keyLength &&
                 FACET_CREATED_UIPANEL_MARKER.equals(key))
             {
                 return _component.isOamVfFacetCreatedUIPanel();
             }
         }
         // is there a javabean property to read?
         _PropertyDescriptorHolder propertyDescriptor = getPropertyDescriptor((String) key);
         if (propertyDescriptor != null)
         {
             value = getComponentProperty(propertyDescriptor);
         }
         else
         {
             // is there a literal value to read?
             value = getUnderlyingMap().get(key);
             if (value == null)
             {
                 // is there a value-binding to read?
                 ValueExpression ve = _component.getValueExpression((String) key);
                 if (ve != null)
                 {
                     value = ve.getValue(_component.getFacesContext().getELContext());
                 }
                 else
                 {
                     if (!_isCompositeComponentSet)
                     {
                         _isCompositeComponent = getUnderlyingMap().containsKey(Resource.COMPONENT_RESOURCE_KEY);
                         _isCompositeComponentSet = true;
                     }
                     if (_isCompositeComponent)
                     {
                         BeanInfo ccBeanInfo = _ccBeanInfo != null ? _ccBeanInfo :
                             (BeanInfo) getUnderlyingMap().get(UIComponent.BEANINFO_KEY);
                         if (ccBeanInfo != null)
                         {
                             //Fast shortcut to allow fast lookup.
                             Map<String, PropertyDescriptor> attributeMap = (Map<String, PropertyDescriptor>) 
                                 ccBeanInfo.getBeanDescriptor().getValue(
                                     PROPERTY_DESCRIPTOR_MAP_KEY);
                             if (attributeMap != null)
                             {
                                 PropertyDescriptor attribute = attributeMap.get(key);
                                 if (attribute != null)
                                 {
                                     String attributeName = attribute.getName();
                                     boolean isKnownMethod = "action".equals(attributeName)
                                             || "actionListener".equals(attributeName)
                                             || "validator".equals(attributeName)
                                             || "valueChangeListener".equals(attributeName);
 
                                     // <composite:attribute> method-signature attribute is 
                                     // ValueExpression that must evaluate to String
                                     ValueExpression methodSignatureExpression
                                             = (ValueExpression) attribute.getValue("method-signature");
                                     String methodSignature = null;
                                     if (methodSignatureExpression != null)
                                     {
                                         // Check if the value expression holds a method signature
                                         // Note that it could be null, so in that case we don't have to 
                                         // do anything
                                         methodSignature = (String) methodSignatureExpression.getValue(
                                                                     _component.getFacesContext().getELContext());
                                     }
 
                                     // either the attributeName has to be a knownMethod
                                     // or there has to be a method-signature
                                     if (isKnownMethod || methodSignature != null)
                                     {
                                         //In this case it is expecting a ValueExpression
                                         return attribute.getValue("default");
                                     }
                                     else
                                     {
                                         value = attribute.getValue("default");
                                     }
                                 }
                             }
                             else
                             {
                                 // Failsafe if another implementation for composite components is set
                                 for (PropertyDescriptor attribute : ccBeanInfo.getPropertyDescriptors())
                                 {
                                     if (attribute.getName().equals(key))
                                     {
                                         String attributeName = attribute.getName();
                                         boolean isKnownMethod = "action".equals(attributeName)
                                                 || "actionListener".equals(attributeName)
                                                 || "validator".equals(attributeName)
                                                 || "valueChangeListener".equals(attributeName);
 
                                         // <composite:attribute> method-signature attribute is 
                                         // ValueExpression that must evaluate to String
                                         ValueExpression methodSignatureExpression
                                                 = (ValueExpression) attribute.getValue("method-signature");
                                         String methodSignature = null;
                                         if (methodSignatureExpression != null)
                                         {
                                             // Check if the value expression holds a method signature
                                             // Note that it could be null, so in that case we don't have to 
                                             // do anything
                                             methodSignature = (String) methodSignatureExpression.getValue(
                                                                         _component.getFacesContext().getELContext());
                                         }
 
                                         // either the attributeName has to be a knownMethod
                                         // or there has to be a method-signature
                                         if (isKnownMethod || methodSignature != null)
                                         {
                                             //In this case it is expecting a ValueExpression
                                             return attribute.getValue("default");
                                         }
                                         else
                                         {
                                             value = attribute.getValue("default");
                                             break;
                                         }
                                     }
                                 }
                             }
                             // We have to check for a ValueExpression and also evaluate it
                             // here, because in the PropertyDescriptor the default values are
                             // always stored as (Tag-)ValueExpressions.
                             if (value != null && value instanceof ValueExpression)
                             {
                                 return ((ValueExpression) value).getValue(_component.getFacesContext().getELContext());
                             }
                         }
                     }
                     // no value found
                     //return null;
                 }
             }
         }
         
         // Otherwise, return the actual value from the get() method. 
         return value;
     }
 
     /**
      * Remove the attribute with the specified name. An attempt to
      * remove an entry whose name is that of a <i>property</i> on
      * the underlying UIComponent will cause an IllegalArgumentException.
      * Value-bindings for the underlying component are ignored.
      *
      * @param key must be a String. Any other type will cause ClassCastException.
      */
     @Override
     public Object remove(Object key)
     {
         checkKey(key);
         int keyLength = ((String)key).length();
         if (keyLength >= MIN_LENGHT_CHECK)
         {
             if (MARK_CREATED.length() == keyLength &&
                 MARK_CREATED.equals(key))
             {
                 Object oldValue = _component.getOamVfMarkCreated();
                 _component.setOamVfMarkCreated(null);
                 return oldValue;
             }
             else if (FACET_NAME_KEY.length() == keyLength &&
                 FACET_NAME_KEY.equals(key))
             {
                 Object oldValue = _component.getOamVfFacetName();
                 _component.setOamVfFacetName(null);
                 return oldValue;
             }
             else if (COMPONENT_ADDED_BY_HANDLER_MARKER.length() == keyLength &&
                 COMPONENT_ADDED_BY_HANDLER_MARKER.equals(key))
             {
                 Object oldValue = _component.isOamVfAddedByHandler();
                 _component.setOamVfAddedByHandler(false);
                 return oldValue;
             }
             else if (FACET_CREATED_UIPANEL_MARKER.length() == keyLength &&
                 FACET_CREATED_UIPANEL_MARKER.equals(key))
             {
                 Object oldValue = _component.isOamVfFacetCreatedUIPanel();
                 _component.setOamVfFacetCreatedUIPanel(false);
                 return oldValue;
             }
             else if (UIComponent.BEANINFO_KEY.length() == keyLength 
                 && UIComponent.BEANINFO_KEY.equals(key))
             {
                 _ccBeanInfo = null;
             }
         }
         _PropertyDescriptorHolder propertyDescriptor = getPropertyDescriptor((String) key);
         if (propertyDescriptor != null)
         {
             throw new IllegalArgumentException("Cannot remove component property attribute");
         }
         return _component.getStateHelper().remove(
                 UIComponentBase.PropertyKeys.attributesMap, key);
     }
 
     /**
      * Store the provided value as a <i>property</i> on the underlying
      * UIComponent, or as an <i>attribute</i> in a Map if no such property
      * exists. Value-bindings associated with the component are ignored; to
      * write to a value-binding, the value-binding must be explicitly
      * retrieved from the component and evaluated.
      * <p/>
      * Note that this method is different from the get method, which
      * does read from a value-binding if one exists. When a value-binding
      * exists for a non-property, putting a value here essentially "masks"
      * the value-binding until that attribute is removed.
      * <p/>
      * The put method is expected to return the previous value of the
      * property/attribute (if any). Because UIComponent property getter
      * methods typically try to evaluate any value-binding expression of
      * the same name this can cause an EL expression to be evaluated,
      * thus invoking a getter method on the user's model. This is fine
      * when the returned value will be used; Unfortunately this is quite
      * pointless when initialising a freshly created component with whatever
      * attributes were specified in the view definition (eg JSP tag
      * attributes). Because the UIComponent.getAttributes method
      * only returns a Map class and this class must be package-private,
      * there is no way of exposing a "putNoReturn" type method.
      *
      * @param key   String, null is not allowed
      * @param value null is allowed
      */
     @Override
     public Object put(String key, Object value)
     {
         if (key == null)
         {
             throw new NullPointerException("key");
         }
         int keyLength = ((String)key).length();
         if (keyLength >= MIN_LENGHT_CHECK)
         {
             if (MARK_CREATED.length() == keyLength &&
                 MARK_CREATED.equals(key))
             {
                 String oldValue = _component.getOamVfMarkCreated();
                 _component.setOamVfMarkCreated((String)value);
                 return oldValue;
             }
             else if (FACET_NAME_KEY.length() == keyLength &&
                 FACET_NAME_KEY.equals(key))
             {
                 Object oldValue = _component.getOamVfFacetName();
                 _component.setOamVfFacetName((String)value);
                 return oldValue;
             }
             else if (COMPONENT_ADDED_BY_HANDLER_MARKER.length() == keyLength &&
                 COMPONENT_ADDED_BY_HANDLER_MARKER.equals(key))
             {
                 Object oldValue = _component.isOamVfAddedByHandler();
                 _component.setOamVfAddedByHandler((Boolean)value);
                 return oldValue;
             }
             else if (FACET_CREATED_UIPANEL_MARKER.length() == keyLength &&
                 FACET_CREATED_UIPANEL_MARKER.equals(key))
             {
                 Object oldValue = _component.isOamVfFacetCreatedUIPanel();
                 _component.setOamVfFacetCreatedUIPanel((Boolean)value);
                 return oldValue;
             }
         }
         _PropertyDescriptorHolder propertyDescriptor = getPropertyDescriptor(key);
         if (propertyDescriptor == null)
         {
             if (value == null)
             {
                 throw new NullPointerException("value is null for a not available property: " + key);
             }
         }
         else
         {
             if (propertyDescriptor.getReadMethod() != null)
             {
                 Object oldValue = getComponentProperty(propertyDescriptor);
                 setComponentProperty(propertyDescriptor, value);
                 return oldValue;
             }
             setComponentProperty(propertyDescriptor, value);
             return null;
         }
         // To keep this code in good shape, The fastest way to compare is look if the length first here
         // because we avoid an unnecessary cast later on equals().
         if ( Resource.COMPONENT_RESOURCE_KEY.length() == keyLength 
              && Resource.COMPONENT_RESOURCE_KEY.equals(key))
         {
             _isCompositeComponent = true;
             _isCompositeComponentSet = true;
         }
         if (UIComponent.BEANINFO_KEY.length() == keyLength 
             && UIComponent.BEANINFO_KEY.equals(key))
         {
             _ccBeanInfo = (BeanInfo) value;
         }
         return _component.getStateHelper().put(UIComponentBase.PropertyKeys.attributesMap, key, value);
     }
 
     /**
      * Retrieve info about getter/setter methods for the javabean property
      * of the specified name on the underlying UIComponent object.
      * <p/>
      * This method optimises access to javabean properties of the underlying
      * UIComponent by maintaining a cache of ProperyDescriptor objects for
      * that class.
      * <p/>
      * TODO: Consider making the cache shared between component instances;
      * currently 100 UIInputText components means performing introspection
      * on the UIInputText component 100 times.
      */
     private _PropertyDescriptorHolder getPropertyDescriptor(String key)
     {
         if (_propertyDescriptorMap == null)
         {
             // Try to get descriptor map from cache
             _propertyDescriptorMap = propertyDescriptorCache.get(_component.getClass());
             // Cache miss: create descriptor map and put it in cache
             if (_propertyDescriptorMap == null)
             {
                 // Create descriptor map...
                 BeanInfo beanInfo;
                 try
                 {
                     beanInfo = Introspector.getBeanInfo(_component.getClass());
                 }
                 catch (IntrospectionException e)
                 {
                     throw new FacesException(e);
                 }
                 PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
                 _propertyDescriptorMap = new ConcurrentHashMap<String, _PropertyDescriptorHolder>();
                 for (int i = 0; i < propertyDescriptors.length; i++)
                 {
                     PropertyDescriptor propertyDescriptor = propertyDescriptors[i];
                     Method readMethod = propertyDescriptor.getReadMethod();
                     if (readMethod != null)
                     {
                         _propertyDescriptorMap.put(propertyDescriptor.getName(),
                                 new _PropertyDescriptorHolder(propertyDescriptor, readMethod));
                     }
                 }
                 // ... and put it in cache
                 synchronized(propertyDescriptorCache)
                 {
                     // Use a synchronized block to ensure proper operation on concurrent use cases.
                     // This is a racy single check, because initialization over the same class could happen
                     // multiple times, but the same result is always calculated. The synchronized block 
                     // just ensure thread-safety, because only one thread will modify the cache map
                     // at the same time.
                     propertyDescriptorCache.put(_component.getClass(), _propertyDescriptorMap);
                 }
             }
         }
         return _propertyDescriptorMap.get(key);
     }
 
 
     /**
      * Execute the getter method of the specified property on the underlying
      * component.
      *
      * @param propertyDescriptor specifies which property to read.
      * @return the value returned by the getter method.
      * @throws IllegalArgumentException if the property is not readable.
      * @throws FacesException           if any other problem occurs while invoking
      *                                  the getter method.
      */
     private Object getComponentProperty(_PropertyDescriptorHolder propertyDescriptor)
     {
         Method readMethod = propertyDescriptor.getReadMethod();
         if (readMethod == null)
         {
             throw new IllegalArgumentException("Component property " + propertyDescriptor.getName()
                                                + " is not readable");
         }
         try
         {
             return readMethod.invoke(_component, EMPTY_ARGS);
         }
         catch (Exception e)
         {
             FacesContext facesContext = _component.getFacesContext();
             throw new FacesException("Could not get property " + propertyDescriptor.getName() + " of component "
                                      + _component.getClientId(facesContext), e);
         }
     }
 
     /**
      * Execute the setter method of the specified property on the underlying
      * component.
      *
      * @param propertyDescriptor specifies which property to write.
      * @throws IllegalArgumentException if the property is not writable.
      * @throws FacesException           if any other problem occurs while invoking
      *                                  the getter method.
      */
     private void setComponentProperty(_PropertyDescriptorHolder propertyDescriptor, Object value)
     {
         Method writeMethod = propertyDescriptor.getWriteMethod();
         if (writeMethod == null)
         {
             throw new IllegalArgumentException("Component property " + propertyDescriptor.getName()
                                                + " is not writable");
         }
         try
         {
             writeMethod.invoke(_component, new Object[]{value});
         }
         catch (Exception e)
         {
             FacesContext facesContext = _component.getFacesContext();
             throw new FacesException("Could not set property " + propertyDescriptor.getName() +
                     " of component " + _component.getClientId(facesContext) + " to value : " + value + " with type : " +
                     (value == null ? "null" : value.getClass().getName()), e);
         }
     }
 
     private void checkKey(Object key)
     {
         if (key == null)
         {
             throw new NullPointerException("key");
         }
         if (!(key instanceof String))
         {
             throw new ClassCastException("key is not a String");
         }
     }
 
     /**
      * Return the map containing the attributes.
      * <p/>
      * This method is package-scope so that the UIComponentBase class can access it
      * directly when serializing the component.
      */
     Map<String, Object> getUnderlyingMap()
     {
         StateHelper stateHelper = _component.getStateHelper(false);
         Map<String, Object> attributes = null;
         if (stateHelper != null)
         {
             attributes = (Map<String, Object>) stateHelper.get(UIComponentBase.PropertyKeys.attributesMap);
         }
         return attributes == null ? Collections.EMPTY_MAP : attributes;
     }
     
     /**
      * TODO: Document why this method is necessary, and why it doesn't try to
      * compare the _component field.
      */
     @Override
     public boolean equals(Object obj)
     {
         return getUnderlyingMap().equals(obj);
     }
 
     @Override
     public int hashCode()
     {
         return getUnderlyingMap().hashCode();
     }
 }