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1 /* 2 * $Header: /home/cvs/jakarta-commons/httpclient/src/java/org/apache/commons/httpclient/AutoCloseInputStream.java,v 1.7 2003/01/28 04:40:20 jsdever Exp $ 3 * $Revision: 1.7 $ 4 * $Date: 2003/01/28 04:40:20 $ 5 * 6 * ==================================================================== 7 * 8 * The Apache Software License, Version 1.1 9 * 10 * Copyright (c) 2002-2003 The Apache Software Foundation. All rights 11 * reserved. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in 22 * the documentation and/or other materials provided with the 23 * distribution. 24 * 25 * 3. The end-user documentation included with the redistribution, if 26 * any, must include the following acknowlegement: 27 * "This product includes software developed by the 28 * Apache Software Foundation (http://www.apache.org/)." 29 * Alternately, this acknowlegement may appear in the software itself, 30 * if and wherever such third-party acknowlegements normally appear. 31 * 32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software 33 * Foundation" must not be used to endorse or promote products derived 34 * from this software without prior written permission. For written 35 * permission, please contact apache@apache.org. 36 * 37 * 5. Products derived from this software may not be called "Apache" 38 * nor may "Apache" appear in their names without prior written 39 * permission of the Apache Group. 40 * 41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 52 * SUCH DAMAGE. 53 * ==================================================================== 54 * 55 * This software consists of voluntary contributions made by many 56 * individuals on behalf of the Apache Software Foundation. For more 57 * information on the Apache Software Foundation, please see 58 * <http://www.apache.org/>;. 59 * 60 * [Additional notices, if required by prior licensing conditions] 61 * 62 */ 63 64 package org.apache.commons.httpclient; 65 66 import java.io.FilterInputStream; 67 import java.io.IOException; 68 import java.io.InputStream; 69 70 /*** 71 * Closes an underlying stream as soon as the end of the stream is reached, and 72 * notifies a client when it has done so. 73 * 74 * @author Ortwin Gl�ck 75 * @author Eric Johnson 76 * @author <a href="mailto:mbowler@GargoyleSoftware.com">Mike Bowler</a> 77 * 78 * @since 2.0 79 */ 80 81 class AutoCloseInputStream extends FilterInputStream { 82 83 /*** 84 * True if this stream is open. Assume that the underlying stream 85 * is open until we get an EOF indication. 86 */ 87 private boolean streamOpen = true; 88 89 /*** True if the stream closed itself. */ 90 private boolean selfClosed = false; 91 92 /*** 93 * The watcher is notified when the contents of the stream have 94 * been exhausted 95 */ 96 private ResponseConsumedWatcher watcher = null; 97 98 /*** 99 * Create a new auto closing stream for the provided connection 100 * 101 * @param in the input stream to read from 102 * @param watcher To be notified when the contents of the stream have been 103 * consumed. 104 */ 105 public AutoCloseInputStream( 106 final InputStream in, final ResponseConsumedWatcher watcher) { 107 super(in); 108 this.watcher = watcher; 109 } 110 111 /*** 112 * Reads the next byte of data from the input stream. 113 * 114 * @throws IOException when there is an error reading 115 * @return the character read, or -1 for EOF 116 */ 117 public int read() throws IOException { 118 int l = -1; 119 120 if (isReadAllowed()) { 121 // underlying stream not closed, go ahead and read. 122 l = super.read(); 123 checkClose(l); 124 } 125 126 return l; 127 } 128 129 /*** 130 * Reads up to <code>len</code> bytes of data from the stream. 131 * 132 * @param b a <code>byte</code> array to read data into 133 * @param off an offset within the array to store data 134 * @param len the maximum number of bytes to read 135 * @return the number of bytes read or -1 for EOF 136 * @throws IOException if there are errors reading 137 */ 138 public int read(byte[] b, int off, int len) throws IOException { 139 int l = -1; 140 141 if (isReadAllowed()) { 142 l = super.read(b, off, len); 143 checkClose(l); 144 } 145 146 return l; 147 } 148 149 /*** 150 * Reads some number of bytes from the input stream and stores them into the 151 * buffer array b. 152 * 153 * @param b a <code>byte</code> array to read data into 154 * @return the number of bytes read or -1 for EOF 155 * @throws IOException if there are errors reading 156 */ 157 public int read(byte[] b) throws IOException { 158 int l = -1; 159 160 if (isReadAllowed()) { 161 l = super.read(b); 162 checkClose(l); 163 } 164 return l; 165 } 166 167 /*** 168 * Close the stream, and also close the underlying stream if it is not 169 * already closed. 170 * @throws IOException If an IO problem occurs. 171 */ 172 public void close() throws IOException { 173 if (!selfClosed) { 174 selfClosed = true; 175 notifyWatcher(); 176 } 177 } 178 179 /*** 180 * Close the underlying stream should the end of the stream arrive. 181 * 182 * @param readResult The result of the read operation to check. 183 * @throws IOException If an IO problem occurs. 184 */ 185 private void checkClose(int readResult) throws IOException { 186 if (readResult == -1) { 187 notifyWatcher(); 188 } 189 } 190 191 /*** 192 * See whether a read of the underlying stream should be allowed, and if 193 * not, check to see whether our stream has already been closed! 194 * 195 * @return <code>true</code> if it is still OK to read from the stream. 196 * @throws IOException If an IO problem occurs. 197 */ 198 private boolean isReadAllowed() throws IOException { 199 if (!streamOpen && selfClosed) { 200 throw new IOException("Attempted read on closed stream."); 201 } 202 return streamOpen; 203 } 204 205 /*** 206 * Notify the watcher that the contents have been consumed. 207 * @throws IOException If an IO problem occurs. 208 */ 209 private void notifyWatcher() throws IOException { 210 if (streamOpen) { 211 super.close(); 212 streamOpen = false; 213 214 if (watcher != null) { 215 watcher.responseConsumed(); 216 } 217 } 218 } 219 } 220

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