/*
   * Copyright 2004 The Apache Software Foundation
   *
   * Licensed 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 compressionFilters;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.util.Locale;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.ServletException;
  import javax.servlet.ServletOutputStream;
  import javax.servlet.ServletResponse;
  import javax.servlet.ServletResponseWrapper;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpServletResponseWrapper;
  
  /**
   * Implementation of <b>HttpServletResponseWrapper</b> that works with
   * the CompressionServletResponseStream implementation..
   *
   * @author Amy Roh
   * @author Dmitri Valdin
   * @version $Revision: 267129 $, $Date: 2004-03-18 08:40:35 -0800 (Thu, 18 Mar 2004) $
   */
  
  public class CompressionServletResponseWrapper extends HttpServletResponseWrapper {
  
      // ----------------------------------------------------- Constructor
  
      /**
       * Calls the parent constructor which creates a ServletResponse adaptor
       * wrapping the given response object.
       */
  
      public CompressionServletResponseWrapper(HttpServletResponse response) {
          super(response);
          origResponse = response;
          if (debug > 1) {
              System.out.println("CompressionServletResponseWrapper constructor gets called");
          }
      }
  
  
      // ----------------------------------------------------- Instance Variables
  
      /**
       * Original response
       */
  
      protected HttpServletResponse origResponse = null;
  
      /**
       * Descriptive information about this Response implementation.
       */
  
      protected static final String info = "CompressionServletResponseWrapper";
  
      /**
       * The ServletOutputStream that has been returned by
       * <code>getOutputStream()</code>, if any.
       */
  
      protected ServletOutputStream stream = null;
  
  
      /**
       * The PrintWriter that has been returned by
       * <code>getWriter()</code>, if any.
       */
  
      protected PrintWriter writer = null;
  
      /**
       * The threshold number to compress
       */
      protected int threshold = 0;
  
      /**
       * Debug level
       */
      private int debug = 0;
  
      /**
      * Content type
      */
     protected String contentType = null;
 
     // --------------------------------------------------------- Public Methods
 
 
     /**
      * Set content type
      */
     public void setContentType(String contentType) {
         if (debug > 1) {
             System.out.println("setContentType to "+contentType);
         }
         this.contentType = contentType;
         origResponse.setContentType(contentType);
     }
 
 
     /**
      * Set threshold number
      */
     public void setCompressionThreshold(int threshold) {
         if (debug > 1) {
             System.out.println("setCompressionThreshold to " + threshold);
         }
         this.threshold = threshold;
     }
 
 
     /**
      * Set debug level
      */
     public void setDebugLevel(int debug) {
         this.debug = debug;
     }
 
 
     /**
      * Create and return a ServletOutputStream to write the content
      * associated with this Response.
      *
      * @exception IOException if an input/output error occurs
      */
     public ServletOutputStream createOutputStream() throws IOException {
         if (debug > 1) {
             System.out.println("createOutputStream gets called");
         }
 
         CompressionResponseStream stream = new CompressionResponseStream(origResponse);
         stream.setDebugLevel(debug);
         stream.setBuffer(threshold);
 
         return stream;
 
     }
 
 
     /**
      * Finish a response.
      */
     public void finishResponse() {
         try {
             if (writer != null) {
                 writer.close();
             } else {
                 if (stream != null)
                     stream.close();
             }
         } catch (IOException e) {
         }
     }
 
 
     // ------------------------------------------------ ServletResponse Methods
 
 
     /**
      * Flush the buffer and commit this response.
      *
      * @exception IOException if an input/output error occurs
      */
     public void flushBuffer() throws IOException {
         if (debug > 1) {
             System.out.println("flush buffer @ CompressionServletResponseWrapper");
         }
         ((CompressionResponseStream)stream).flush();
 
     }
 
     /**
      * Return the servlet output stream associated with this Response.
      *
      * @exception IllegalStateException if <code>getWriter</code> has
      *  already been called for this response
      * @exception IOException if an input/output error occurs
      */
     public ServletOutputStream getOutputStream() throws IOException {
 
         if (writer != null)
             throw new IllegalStateException("getWriter() has already been called for this response");
 
         if (stream == null)
             stream = createOutputStream();
         if (debug > 1) {
             System.out.println("stream is set to "+stream+" in getOutputStream");
         }
 
         return (stream);
 
     }
 
     /**
      * Return the writer associated with this Response.
      *
      * @exception IllegalStateException if <code>getOutputStream</code> has
      *  already been called for this response
      * @exception IOException if an input/output error occurs
      */
     public PrintWriter getWriter() throws IOException {
 
         if (writer != null)
             return (writer);
 
         if (stream != null)
             throw new IllegalStateException("getOutputStream() has already been called for this response");
 
         stream = createOutputStream();
         if (debug > 1) {
             System.out.println("stream is set to "+stream+" in getWriter");
         }
         //String charset = getCharsetFromContentType(contentType);
         String charEnc = origResponse.getCharacterEncoding();
         if (debug > 1) {
             System.out.println("character encoding is " + charEnc);
         }
         // HttpServletResponse.getCharacterEncoding() shouldn't return null
         // according the spec, so feel free to remove that "if"
         if (charEnc != null) {
             writer = new PrintWriter(new OutputStreamWriter(stream, charEnc));
         } else {
             writer = new PrintWriter(stream);
         }
         
         return (writer);
 
     }
 
 
     public void setContentLength(int length) {
     }
 
 
     /**
      * Returns character from content type. This method was taken from tomcat.
      * @author rajo
      */
     private static String getCharsetFromContentType(String type) {
 
         if (type == null) {
             return null;
         }
         int semi = type.indexOf(";");
         if (semi == -1) {
             return null;
         }
         String afterSemi = type.substring(semi + 1);
         int charsetLocation = afterSemi.indexOf("charset=");
         if(charsetLocation == -1) {
             return null;
         } else {
             String afterCharset = afterSemi.substring(charsetLocation + 8);
             String encoding = afterCharset.trim();
             return encoding;
         }
     }
 
 }