/* 
    P/P   *  Method: net.sourceforge.pebble.web.filter.GZIPResponseStream__static_init
          */
     1  /*
     2   * Copyright (c) 2003-2006, Simon Brown
     3   * All rights reserved.
     4   *
     5   * Redistribution and use in source and binary forms, with or without
     6   * modification, are permitted provided that the following conditions are met:
     7   *
     8   *   - Redistributions of source code must retain the above copyright
     9   *     notice, this list of conditions and the following disclaimer.
    10   *
    11   *   - Redistributions in binary form must reproduce the above copyright
    12   *     notice, this list of conditions and the following disclaimer in
    13   *     the documentation and/or other materials provided with the
    14   *     distribution.
    15   *
    16   *   - Neither the name of Pebble nor the names of its contributors may
    17   *     be used to endorse or promote products derived from this software
    18   *     without specific prior written permission.
    19   *
    20   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    21   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    22   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    23   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
    24   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    25   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    26   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    27   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    28   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    29   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    30   * POSSIBILITY OF SUCH DAMAGE.
    31   */
    32  package net.sourceforge.pebble.web.filter;
    33  
    34  import java.io.*;
    35  import java.util.zip.GZIPOutputStream;
    36  import javax.servlet.*;
    37  import javax.servlet.http.*;
    38  
    39  public class GZIPResponseStream extends ServletOutputStream {
    40  
    41    protected ByteArrayOutputStream baos = null;
    42    protected GZIPOutputStream gzipstream = null;
    43    protected boolean closed = false;
    44    protected HttpServletResponse response = null;
    45    protected ServletOutputStream output = null;
    46  
           /* 
    P/P     *  Method: void net.sourceforge.pebble.web.filter.GZIPResponseStream(HttpServletResponse)
            * 
            *  Preconditions:
            *    response != null
            * 
            *  Postconditions:
            *    this.baos == &new ByteArrayOutputStream(GZIPResponseStream#1)
            *    this.closed == 0
            *    this.gzipstream == &new GZIPOutputStream(GZIPResponseStream#2)
            *    init'ed(this.output)
            *    this.response == response
            *    this.response != null
            *    new ByteArrayOutputStream(GZIPResponseStream#1) num objects == 1
            *    new GZIPOutputStream(GZIPResponseStream#2) num objects == 1
            */
    47    public GZIPResponseStream(HttpServletResponse response) throws IOException {
    48      closed = false;
    49      this.response = response;
    50      this.output = response.getOutputStream();
    51      baos = new ByteArrayOutputStream();
    52      gzipstream = new GZIPOutputStream(baos);
    53    }
    54  
    55    public void close() throws IOException {
    56      if (closed) {
    57        throw new IOException("This output stream has already been closed");
    58      }
    59      gzipstream.finish();
    60      gzipstream.flush();
    61      gzipstream.close();
    62  
    63      byte[] bytes = baos.toByteArray();
    64      response.setContentLength(bytes.length);
    65      response.addHeader("Content-Encoding", "gzip");
    66      output.write(bytes);
    67      output.flush();
    68      output.close();
    69      closed = true;
    70    }
    71  
           /* 
    P/P     *  Method: void flush()
            * 
            *  Preconditions:
            *    this.closed == 0
            *    this.gzipstream != null
            */
    72    public void flush() throws IOException {
    73      if (closed) {
    74        throw new IOException("Cannot flush a closed output stream");
    75      }
    76      gzipstream.flush();
    77    }
    78  
           /* 
    P/P     *  Method: void write(int)
            * 
            *  Preconditions:
            *    this.closed == 0
            *    this.gzipstream != null
            */
    79    public void write(int b) throws IOException {
    80      if (closed) {
    81        throw new IOException("Cannot write to a closed output stream");
    82      }
    83      gzipstream.write((byte) b);
    84    }
    85  
           /* 
    P/P     *  Method: void write(byte[])
            * 
            *  Preconditions:
            *    b != null
            *    b.length <= 232-1
            *    this.closed == 0
            *    this.gzipstream != null
            */
    86    public void write(byte b[]) throws IOException {
    87      write(b, 0, b.length);
    88    }
    89  
           /* 
    P/P     *  Method: void write(byte[], int, int)
            * 
            *  Preconditions:
            *    this.closed == 0
            *    this.gzipstream != null
            */
    90    public void write(byte b[], int off, int len) throws IOException {
    91      if (closed) {
    92        throw new IOException("Cannot write to a closed output stream");
    93      }
    94      gzipstream.write(b, off, len);
    95    }
    96  
           /* 
    P/P     *  Method: bool closed()
            * 
            *  Preconditions:
            *    init'ed(this.closed)
            * 
            *  Postconditions:
            *    return_value == this.closed
            *    init'ed(return_value)
            */
    97    public boolean closed() {
    98      return (this.closed);
    99    }
   100  
           /* 
    P/P     *  Method: void reset()
            */
   101    public void reset() {
   102    }
   103  
   104  }