/*
    * 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 org.apache.myfaces.shared.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  
  import javax.servlet.ServletOutputStream;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpServletResponseWrapper;
  
  /**
   * Implementation of a switching response wrapper to turn 
   * output on and off according to the JSF spec 2.0.
   * <p>
   * Implemented as HttpServletResponseWrapper,
   * so that the switching does not interfere with methods that
   * expect a HttpServletResponse when invoking ExternalContext.getResponse().</p>
   */
  public class HttpServletResponseSwitch extends HttpServletResponseWrapper implements ResponseSwitch
  {
      private PrintWriter _switchableWriter;
      private SwitchableOutputStream _switchableOutputStream;
      private boolean _enabled = true;
  
      public HttpServletResponseSwitch(HttpServletResponse response)
      {
          super(response);
      }
  
      /**
       * Enables or disables the Response's Writer and OutputStream.
       * @param enabled
       */
      public void setEnabled(boolean enabled)
      {
          _enabled = enabled;
      }
  
      /**
       * Are the Response's Writer and OutputStream currently enabled?
       * @return
       */
      public boolean isEnabled()
      {
          return _enabled;
      }
  
  
      @Override
      public int getBufferSize()
      {
          if (isEnabled())
          {
              return super.getBufferSize();
          }
          return 0;
      }
  
      @Override
      public boolean isCommitted()
      {
          if (isEnabled())
          {
              return super.isCommitted();
          }
          return false;
      }
  
      @Override
      public void reset()
      {
          if (isEnabled())
          {
              super.reset();
          }
      }
  
      @Override
      public void resetBuffer()
      {
          if (isEnabled())
         {
             super.resetBuffer();
         }
     }
     
     @Override
     public void flushBuffer() throws IOException
     {
         if (isEnabled())
         {
             super.flushBuffer();
         }
     }
 
     @Override
     public void setResponse(ServletResponse response)
     {
         // only change the response if it is not the same object
         if (response instanceof HttpServletResponse && response != getResponse())
         {
             // our OutputStream and our Writer are not valid for the new response
             _switchableOutputStream = null;
             _switchableWriter = null;
             
             // set the new response
             super.setResponse(response);
         }
     }
 
     @Override
     public ServletOutputStream getOutputStream() throws IOException
     {
         if (_switchableOutputStream == null)
         {
             _switchableOutputStream = new SwitchableOutputStream(super.getOutputStream(), this);
         }
         return _switchableOutputStream;
     }
 
     @Override
     public PrintWriter getWriter() throws IOException
     {
         if (_switchableWriter == null)
         {
             _switchableWriter = new PrintWriter(new SwitchableWriter(super.getWriter(), this));
         }
         return _switchableWriter;
     }
     
 }