/*
    * 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.renderkit.html;
  
  import java.io.IOException;
  import java.io.Writer;
  import javax.faces.FacesException;
  import javax.faces.component.UIComponent;
  import javax.faces.context.FacesContext;
  import javax.faces.context.ResponseWriter;
  import org.apache.myfaces.shared.renderkit.html.HTML;
  import org.apache.myfaces.shared.renderkit.html.HtmlResponseWriterImpl;
  
  /**
   * This implementation is just the default html response writer with the early flush logic. The
   * idea is detect when the end "head" element is rendered and in that moment, when the flush call
   * is done, force the flush of the current underlying writer.
   *
   * @author Leonardo Uribe
   */
  public class EarlyFlushHtmlResponseWriterImpl extends HtmlResponseWriterImpl
  {
      /**
       * Check if a end head tag was recently done. The idea is 
       */
      private boolean _endHeadTag;
  
      public EarlyFlushHtmlResponseWriterImpl(Writer writer, String contentType, String characterEncoding)
      {
          super(writer, contentType, characterEncoding);
      }
  
      public EarlyFlushHtmlResponseWriterImpl(Writer writer, String contentType, String characterEncoding, 
              boolean wrapScriptContentWithXmlCommentTag)
      {
          super(writer, contentType, characterEncoding, wrapScriptContentWithXmlCommentTag);
      }
  
      public EarlyFlushHtmlResponseWriterImpl(Writer writer, String contentType, String characterEncoding,
              boolean wrapScriptContentWithXmlCommentTag, String writerContentTypeMode) throws FacesException
      {
          super(writer, contentType, characterEncoding, wrapScriptContentWithXmlCommentTag, writerContentTypeMode);
      }
  
      @Override
      public ResponseWriter cloneWithWriter(Writer writer)
      {
          EarlyFlushHtmlResponseWriterImpl newWriter
                  = new EarlyFlushHtmlResponseWriterImpl(writer, getContentType(), getCharacterEncoding(), 
                          getWrapScriptContentWithXmlCommentTag(), getWriterContentTypeMode());
          return newWriter;        
      }
  
      @Override
      public void startElement(String name, UIComponent uiComponent) throws IOException
      {
          _endHeadTag = false;
          super.startElement(name, uiComponent);
      }
  
      @Override
      public void endElement(String name) throws IOException
      {
          super.endElement(name);
          if (HTML.HEAD_ELEM.equalsIgnoreCase(name))
          {
              _endHeadTag = true;
          }
      }
      
      @Override
      public void flush() throws IOException
      {
          super.flush();
          
          if (_endHeadTag)
          {
              FacesContext facesContext = getFacesContext();
              if (!facesContext.getPartialViewContext().isAjaxRequest() &&
                  !facesContext.getPartialViewContext().isPartialRequest())
              {
                  forceFlush();
              }
         }
     }
 }