/*
    * 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.behavior;
  
  import java.util.Collections;
  import java.util.Set;
  
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.render.ClientBehaviorRenderer;
  
  /**
   * @since 2.0
   */
  public class ClientBehaviorBase extends BehaviorBase implements ClientBehavior
  {
  
      private transient FacesContext _facesContext;
      
      /**
       * 
       */
      public ClientBehaviorBase()
      {
      }
  
      /**
       * {@inheritDoc}
       */
      public void decode(FacesContext context, UIComponent component)
      {
          if (context == null)
          {
              throw new NullPointerException("context");
          }
          
          if (component == null)
          {
              throw new NullPointerException("component");
          }
          
          // If a BehaviorRenderer is available for the specified behavior renderer type, this method delegates 
          // to the BehaviorRenderer's decode() method. Otherwise, no decoding is performed. 
          ClientBehaviorRenderer renderer = getRenderer(context);
          if (renderer != null)
          {
              renderer.decode(context, component, this);
          }
      }
  
      /**
       * {@inheritDoc}
       */
       public Set<ClientBehaviorHint> getHints()
      {
          return Collections.<ClientBehaviorHint>emptySet();
      }
  
      /**
       * {@inheritDoc}
       */
      public String getRendererType()
      {
          return null;
      }
  
      /**
       * {@inheritDoc}
       */
      public String getScript(ClientBehaviorContext behaviorContext)
      {
          if (behaviorContext == null)
          {
              throw new NullPointerException("behaviorContext");
          }
          
          ClientBehaviorRenderer renderer = getRenderer(behaviorContext.getFacesContext());
          if (renderer != null)
          {
              // If a BehaviorRenderer is available for the specified behavior renderer type, this method delegates 
              // to the BehaviorRenderer.getScript method.
              try
              {
                 setCachedFacesContext(behaviorContext.getFacesContext());
                 return renderer.getScript(behaviorContext, this);
             }
             finally
             {
                 setCachedFacesContext(null);
             }
         }
         
         // Otherwise, this method returns null.
         return null;
     }
     
     protected ClientBehaviorRenderer getRenderer(FacesContext context)
     {
         if (context == null)
         {
             throw new NullPointerException("context");
         }
         
         String rendererType = getRendererType();
         if (rendererType != null)
         {
             return context.getRenderKit().getClientBehaviorRenderer(rendererType);
         }
         
         return null;
     }
     
     FacesContext getFacesContext()
     {
         if (_facesContext == null)
         {
             return FacesContext.getCurrentInstance();
         }
         else
         {
             return _facesContext;
         }
     }
     
     boolean isCachedFacesContext()
     {
         return _facesContext != null;
     }
     
     void setCachedFacesContext(FacesContext facesContext)
     {
         _facesContext = facesContext;
     }
 }