[66] | 1 | /* |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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| 3 | * contributor license agreements. See the NOTICE file distributed with |
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| 4 | * this work for additional information regarding copyright ownership. |
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| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 |
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| 6 | * (the "License"); you may not use this file except in compliance with |
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| 7 | * the License. You may obtain a copy of the License at |
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| 8 | * |
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| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 10 | * |
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| 11 | * Unless required by applicable law or agreed to in writing, software |
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| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 14 | * See the License for the specific language governing permissions and |
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| 15 | * limitations under the License. |
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| 16 | */ |
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| 17 | package compressionFilters; |
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| 18 | |
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| 19 | import java.io.IOException; |
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| 20 | import java.io.OutputStream; |
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| 21 | import java.util.zip.GZIPOutputStream; |
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| 22 | import javax.servlet.ServletOutputStream; |
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| 23 | import javax.servlet.http.HttpServletResponse; |
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| 24 | |
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| 25 | |
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| 26 | /** |
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| 27 | * Implementation of <b>ServletOutputStream</b> that works with |
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| 28 | * the CompressionServletResponseWrapper implementation. |
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| 29 | * |
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| 30 | * @author Amy Roh |
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| 31 | * @author Dmitri Valdin |
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| 32 | * @version $Revision: 500668 $, $Date: 2007-01-28 00:07:51 +0100 (Sun, 28 Jan 2007) $ |
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| 33 | */ |
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| 34 | |
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| 35 | public class CompressionResponseStream |
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| 36 | extends ServletOutputStream { |
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| 37 | |
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| 38 | |
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| 39 | // ----------------------------------------------------------- Constructors |
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| 40 | |
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| 41 | |
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| 42 | /** |
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| 43 | * Construct a servlet output stream associated with the specified Response. |
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| 44 | * |
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| 45 | * @param response The associated response |
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| 46 | */ |
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| 47 | public CompressionResponseStream(HttpServletResponse response) throws IOException{ |
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| 48 | |
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| 49 | super(); |
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| 50 | closed = false; |
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| 51 | this.response = response; |
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| 52 | this.output = response.getOutputStream(); |
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| 53 | |
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| 54 | } |
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| 55 | |
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| 56 | |
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| 57 | // ----------------------------------------------------- Instance Variables |
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| 58 | |
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| 59 | |
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| 60 | /** |
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| 61 | * The threshold number which decides to compress or not. |
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| 62 | * Users can configure in web.xml to set it to fit their needs. |
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| 63 | */ |
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| 64 | protected int compressionThreshold = 0; |
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| 65 | |
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| 66 | /** |
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| 67 | * Debug level |
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| 68 | */ |
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| 69 | private int debug = 0; |
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| 70 | |
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| 71 | /** |
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| 72 | * The buffer through which all of our output bytes are passed. |
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| 73 | */ |
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| 74 | protected byte[] buffer = null; |
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| 75 | |
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| 76 | /** |
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| 77 | * The number of data bytes currently in the buffer. |
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| 78 | */ |
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| 79 | protected int bufferCount = 0; |
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| 80 | |
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| 81 | /** |
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| 82 | * The underlying gzip output stream to which we should write data. |
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| 83 | */ |
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| 84 | protected OutputStream gzipstream = null; |
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| 85 | |
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| 86 | /** |
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| 87 | * Has this stream been closed? |
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| 88 | */ |
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| 89 | protected boolean closed = false; |
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| 90 | |
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| 91 | /** |
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| 92 | * The content length past which we will not write, or -1 if there is |
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| 93 | * no defined content length. |
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| 94 | */ |
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| 95 | protected int length = -1; |
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| 96 | |
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| 97 | /** |
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| 98 | * The response with which this servlet output stream is associated. |
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| 99 | */ |
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| 100 | protected HttpServletResponse response = null; |
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| 101 | |
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| 102 | /** |
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| 103 | * The underlying servket output stream to which we should write data. |
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| 104 | */ |
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| 105 | protected ServletOutputStream output = null; |
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| 106 | |
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| 107 | |
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| 108 | // --------------------------------------------------------- Public Methods |
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| 109 | |
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| 110 | /** |
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| 111 | * Set debug level |
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| 112 | */ |
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| 113 | public void setDebugLevel(int debug) { |
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| 114 | this.debug = debug; |
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| 115 | } |
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| 116 | |
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| 117 | |
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| 118 | /** |
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| 119 | * Set the compressionThreshold number and create buffer for this size |
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| 120 | */ |
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| 121 | protected void setBuffer(int threshold) { |
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| 122 | compressionThreshold = threshold; |
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| 123 | buffer = new byte[compressionThreshold]; |
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| 124 | if (debug > 1) { |
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| 125 | System.out.println("buffer is set to "+compressionThreshold); |
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| 126 | } |
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| 127 | } |
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| 128 | |
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| 129 | /** |
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| 130 | * Close this output stream, causing any buffered data to be flushed and |
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| 131 | * any further output data to throw an IOException. |
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| 132 | */ |
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| 133 | public void close() throws IOException { |
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| 134 | |
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| 135 | if (debug > 1) { |
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| 136 | System.out.println("close() @ CompressionResponseStream"); |
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| 137 | } |
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| 138 | if (closed) |
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| 139 | throw new IOException("This output stream has already been closed"); |
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| 140 | |
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| 141 | if (gzipstream != null) { |
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| 142 | flushToGZip(); |
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| 143 | gzipstream.close(); |
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| 144 | gzipstream = null; |
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| 145 | } else { |
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| 146 | if (bufferCount > 0) { |
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| 147 | if (debug > 2) { |
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| 148 | System.out.print("output.write("); |
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| 149 | System.out.write(buffer, 0, bufferCount); |
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| 150 | System.out.println(")"); |
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| 151 | } |
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| 152 | output.write(buffer, 0, bufferCount); |
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| 153 | bufferCount = 0; |
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| 154 | } |
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| 155 | } |
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| 156 | |
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| 157 | output.close(); |
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| 158 | closed = true; |
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| 159 | |
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| 160 | } |
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| 161 | |
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| 162 | |
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| 163 | /** |
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| 164 | * Flush any buffered data for this output stream, which also causes the |
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| 165 | * response to be committed. |
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| 166 | */ |
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| 167 | public void flush() throws IOException { |
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| 168 | |
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| 169 | if (debug > 1) { |
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| 170 | System.out.println("flush() @ CompressionResponseStream"); |
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| 171 | } |
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| 172 | if (closed) { |
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| 173 | throw new IOException("Cannot flush a closed output stream"); |
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| 174 | } |
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| 175 | |
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| 176 | if (gzipstream != null) { |
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| 177 | gzipstream.flush(); |
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| 178 | } |
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| 179 | |
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| 180 | } |
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| 181 | |
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| 182 | public void flushToGZip() throws IOException { |
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| 183 | |
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| 184 | if (debug > 1) { |
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| 185 | System.out.println("flushToGZip() @ CompressionResponseStream"); |
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| 186 | } |
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| 187 | if (bufferCount > 0) { |
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| 188 | if (debug > 1) { |
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| 189 | System.out.println("flushing out to GZipStream, bufferCount = " + bufferCount); |
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| 190 | } |
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| 191 | writeToGZip(buffer, 0, bufferCount); |
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| 192 | bufferCount = 0; |
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| 193 | } |
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| 194 | |
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| 195 | } |
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| 196 | |
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| 197 | /** |
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| 198 | * Write the specified byte to our output stream. |
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| 199 | * |
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| 200 | * @param b The byte to be written |
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| 201 | * |
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| 202 | * @exception IOException if an input/output error occurs |
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| 203 | */ |
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| 204 | public void write(int b) throws IOException { |
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| 205 | |
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| 206 | if (debug > 1) { |
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| 207 | System.out.println("write "+b+" in CompressionResponseStream "); |
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| 208 | } |
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| 209 | if (closed) |
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| 210 | throw new IOException("Cannot write to a closed output stream"); |
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| 211 | |
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| 212 | if (bufferCount >= buffer.length) { |
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| 213 | flushToGZip(); |
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| 214 | } |
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| 215 | |
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| 216 | buffer[bufferCount++] = (byte) b; |
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| 217 | |
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| 218 | } |
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| 219 | |
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| 220 | |
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| 221 | /** |
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| 222 | * Write <code>b.length</code> bytes from the specified byte array |
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| 223 | * to our output stream. |
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| 224 | * |
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| 225 | * @param b The byte array to be written |
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| 226 | * |
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| 227 | * @exception IOException if an input/output error occurs |
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| 228 | */ |
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| 229 | public void write(byte b[]) throws IOException { |
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| 230 | |
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| 231 | write(b, 0, b.length); |
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| 232 | |
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| 233 | } |
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| 234 | |
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| 235 | |
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| 236 | /** |
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| 237 | * Write <code>len</code> bytes from the specified byte array, starting |
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| 238 | * at the specified offset, to our output stream. |
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| 239 | * |
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| 240 | * @param b The byte array containing the bytes to be written |
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| 241 | * @param off Zero-relative starting offset of the bytes to be written |
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| 242 | * @param len The number of bytes to be written |
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| 243 | * |
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| 244 | * @exception IOException if an input/output error occurs |
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| 245 | */ |
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| 246 | public void write(byte b[], int off, int len) throws IOException { |
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| 247 | |
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| 248 | if (debug > 1) { |
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| 249 | System.out.println("write, bufferCount = " + bufferCount + " len = " + len + " off = " + off); |
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| 250 | } |
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| 251 | if (debug > 2) { |
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| 252 | System.out.print("write("); |
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| 253 | System.out.write(b, off, len); |
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| 254 | System.out.println(")"); |
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| 255 | } |
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| 256 | |
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| 257 | if (closed) |
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| 258 | throw new IOException("Cannot write to a closed output stream"); |
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| 259 | |
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| 260 | if (len == 0) |
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| 261 | return; |
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| 262 | |
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| 263 | // Can we write into buffer ? |
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| 264 | if (len <= (buffer.length - bufferCount)) { |
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| 265 | System.arraycopy(b, off, buffer, bufferCount, len); |
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| 266 | bufferCount += len; |
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| 267 | return; |
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| 268 | } |
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| 269 | |
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| 270 | // There is not enough space in buffer. Flush it ... |
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| 271 | flushToGZip(); |
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| 272 | |
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| 273 | // ... and try again. Note, that bufferCount = 0 here ! |
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| 274 | if (len <= (buffer.length - bufferCount)) { |
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| 275 | System.arraycopy(b, off, buffer, bufferCount, len); |
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| 276 | bufferCount += len; |
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| 277 | return; |
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| 278 | } |
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| 279 | |
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| 280 | // write direct to gzip |
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| 281 | writeToGZip(b, off, len); |
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| 282 | } |
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| 283 | |
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| 284 | public void writeToGZip(byte b[], int off, int len) throws IOException { |
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| 285 | |
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| 286 | if (debug > 1) { |
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| 287 | System.out.println("writeToGZip, len = " + len); |
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| 288 | } |
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| 289 | if (debug > 2) { |
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| 290 | System.out.print("writeToGZip("); |
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| 291 | System.out.write(b, off, len); |
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| 292 | System.out.println(")"); |
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| 293 | } |
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| 294 | if (gzipstream == null) { |
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| 295 | if (debug > 1) { |
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| 296 | System.out.println("new GZIPOutputStream"); |
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| 297 | } |
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| 298 | if (response.isCommitted()) { |
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| 299 | if (debug > 1) |
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| 300 | System.out.print("Response already committed. Using original output stream"); |
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| 301 | gzipstream = output; |
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| 302 | } else { |
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| 303 | response.addHeader("Content-Encoding", "gzip"); |
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| 304 | gzipstream = new GZIPOutputStream(output); |
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| 305 | } |
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| 306 | } |
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| 307 | gzipstream.write(b, off, len); |
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| 308 | |
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| 309 | } |
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| 310 | |
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| 311 | |
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| 312 | // -------------------------------------------------------- Package Methods |
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| 313 | |
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| 314 | |
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| 315 | /** |
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| 316 | * Has this response stream been closed? |
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| 317 | */ |
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| 318 | public boolean closed() { |
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| 319 | |
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| 320 | return (this.closed); |
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| 321 | |
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| 322 | } |
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| 323 | |
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| 324 | } |
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