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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