001    //$HeadURL: svn+ssh://jwilden@svn.wald.intevation.org/deegree/base/branches/2.5_testing/src/org/deegree/enterprise/servlet/GZIPResponseStream.java $
002    /*----------------------------------------------------------------------------
003     This file originated as work from Jayson Falkner.
004    
005     Copyright 2003 Jayson Falkner (jayson@jspinsider.com)
006     This code is from "Servlets and JavaServer pages; the J2EE Web Tier",
007     http://www.jspbook.com. You may freely use the code both commercially
008     and non-commercially. If you like the code, please pick up a copy of
009     the book and help support the authors, development of more free code,
010     and the JSP/Servlet/J2EE community.
011     ----------------------------------------------------------------------------*/
012    package org.deegree.enterprise.servlet;
013    
014    import java.io.ByteArrayOutputStream;
015    import java.io.IOException;
016    import java.util.zip.GZIPOutputStream;
017    
018    import javax.servlet.ServletOutputStream;
019    import javax.servlet.http.HttpServletResponse;
020    
021    /**
022     *
023     *
024     * @author <a href="mailto:jayson@jspinsider.com">Jayson Falkner</a>
025     * @author last edited by: $Author: mschneider $
026     *
027     * @version $Revision: 20326 $, $Date: 2009-10-22 18:41:56 +0200 (Do, 22 Okt 2009) $
028     */
029    public class GZIPResponseStream extends ServletOutputStream {
030        /**
031         * the output as a byte array
032         */
033        protected ByteArrayOutputStream baos = null;
034    
035        /**
036         * the output as a gzipped stream
037         */
038        protected GZIPOutputStream gzipstream = null;
039    
040        /**
041         * true if the stream is closed
042         */
043        protected boolean closed = false;
044    
045        /**
046         * the response wrapper
047         */
048        protected HttpServletResponse response = null;
049    
050        /**
051         * the output as a stream
052         */
053        protected ServletOutputStream output = null;
054    
055        /**
056         *
057         * @param response
058         * @throws IOException
059         */
060        public GZIPResponseStream( HttpServletResponse response ) throws IOException {
061            super();
062            closed = false;
063            this.response = response;
064            this.output = response.getOutputStream();
065            baos = new ByteArrayOutputStream();
066            gzipstream = new GZIPOutputStream( baos );
067        }
068    
069        /**
070         * @throws IOException
071         */
072        @Override
073        public void close()
074                                throws IOException {
075            if ( closed ) {
076                throw new IOException( "This output stream has already been closed" );
077            }
078            gzipstream.finish();
079    
080            byte[] bytes = baos.toByteArray();
081    
082            response.addHeader( "Content-Length", Integer.toString( bytes.length ) );
083            response.addHeader( "Content-Encoding", "gzip" );
084            output.write( bytes );
085            output.flush();
086            output.close();
087            closed = true;
088        }
089    
090        /**
091         * @throws IOException
092         */
093        @Override
094        public void flush()
095                                throws IOException {
096            if ( closed ) {
097                throw new IOException( "Cannot flush a closed output stream" );
098            }
099            gzipstream.flush();
100        }
101    
102        /**
103         * @param b
104         *            data to write
105         * @throws IOException
106         */
107        @Override
108        public void write( int b )
109                                throws IOException {
110            if ( closed ) {
111                throw new IOException( "Cannot write to a closed output stream" );
112            }
113            gzipstream.write( (byte) b );
114        }
115    
116        /**
117         * @param b
118         *            data array to write
119         * @throws IOException
120         */
121        @Override
122        public void write( byte b[] )
123                                throws IOException {
124            write( b, 0, b.length );
125        }
126    
127        /**
128         * @param b
129         *            data array to write
130         * @param off
131         *            index of the for byte
132         * @param len
133         *            number of bytes to write
134         * @throws IOException
135         */
136        @Override
137        public void write( byte b[], int off, int len )
138                                throws IOException {
139            System.out.println( "writing..." );
140            if ( closed ) {
141                throw new IOException( "Cannot write to a closed output stream" );
142            }
143            gzipstream.write( b, off, len );
144        }
145    
146        /**
147         *
148         * @return true if already has been closed
149         */
150        public boolean closed() {
151            return ( this.closed );
152        }
153    
154        /**
155         *
156         *
157         */
158        public void reset() {
159            // noop
160        }
161    }