/*
    * 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.render;
  
  import javax.faces.application.StateManager;
  import javax.faces.application.StateManager.SerializedView;
  import javax.faces.context.FacesContext;
  import java.io.IOException;
  
  /**
   * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>
   *
   * @author Manfred Geiler (latest modification by $Author: skitching $)
   * @author Stan Silvert
   * @version $Revision: 676298 $ $Date: 2008-07-13 05:31:48 -0500 (Sun, 13 Jul 2008) $
   */
  public abstract class ResponseStateManager
  {
      public static final String RENDER_KIT_ID_PARAM = "javax.faces.RenderKitId";
      public static final String VIEW_STATE_PARAM = "javax.faces.ViewState";
      
      public void writeState(FacesContext context, Object state) throws IOException{
          SerializedView view;
          if (state instanceof SerializedView)
          {
              view = (SerializedView) state;
          }
          else
              if (state instanceof Object[])
              {
                  Object[] structureAndState = (Object[]) state;
  
                  if (structureAndState.length == 2)
                  {
                      Object structureObj = structureAndState[0];
                      Object stateObj = structureAndState[1];
  
                      StateManager stateManager = context.getApplication().getStateManager();
                      view = stateManager.new SerializedView(structureObj, stateObj);
                  }
                  else
                  {
                      throw new IOException("The state should be an array of Object[] of lenght 2");
                  }
              }
          else
              {
                  throw new IOException("The state should be an array of Object[] of lenght 2, or a SerializedView instance");
              }
  
          writeState(context, view);
      }
      
      /**
       * @deprecated
       */
      public void writeState(FacesContext context,
                             StateManager.SerializedView state)
              throws IOException {
          // does nothing as per JSF 1.2 javadoc
      }
  
      /**
       * @since 1.2
       */
      public Object getState(FacesContext context, String viewId) {
          Object[] structureAndState = new Object[2];
          structureAndState[0] = getTreeStructureToRestore(context, viewId);
          structureAndState[1] = getComponentStateToRestore(context);
          return structureAndState;
      }
      
      
      /**
       * @deprecated
       */
      public Object getTreeStructureToRestore(FacesContext context,
                                               String viewId) {
          return null;
      }
      
  
      /**
      * @deprecated
      */
     public Object getComponentStateToRestore(FacesContext context) {
         return null;
     }
     
     /**
      * Checks if the current request is a postback
      * @since 1.2
      */
     public boolean isPostback(FacesContext context) {
       return context.getExternalContext().
         getRequestParameterMap().containsKey(
               ResponseStateManager.VIEW_STATE_PARAM);
     }
 
 }