1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.http.impl.io;
29
30 import java.io.IOException;
31 import java.io.OutputStream;
32
33 import org.apache.http.annotation.NotThreadSafe;
34 import org.apache.http.io.SessionOutputBuffer;
35 import org.apache.http.util.Args;
36
37 /**
38 * Output stream that cuts off after a defined number of bytes. This class
39 * is used to send content of HTTP messages where the end of the content entity
40 * is determined by the value of the <code>Content-Length header</code>.
41 * Entities transferred using this stream can be maximum {@link Long#MAX_VALUE}
42 * long.
43 * <p>
44 * Note that this class NEVER closes the underlying stream, even when close
45 * gets called. Instead, the stream will be marked as closed and no further
46 * output will be permitted.
47 *
48 * @since 4.0
49 */
50 @NotThreadSafe
51 public class ContentLengthOutputStream extends OutputStream {
52
53 /**
54 * Wrapped session output buffer.
55 */
56 private final SessionOutputBuffer out;
57
58 /**
59 * The maximum number of bytes that can be written the stream. Subsequent
60 * write operations will be ignored.
61 */
62 private final long contentLength;
63
64 /** Total bytes written */
65 private long total = 0;
66
67 /** True if the stream is closed. */
68 private boolean closed = false;
69
70 /**
71 * Wraps a session output buffer and cuts off output after a defined number
72 * of bytes.
73 *
74 * @param out The session output buffer
75 * @param contentLength The maximum number of bytes that can be written to
76 * the stream. Subsequent write operations will be ignored.
77 *
78 * @since 4.0
79 */
80 public ContentLengthOutputStream(final SessionOutputBuffer out, final long contentLength) {
81 super();
82 this.out = Args.notNull(out, "Session output buffer");
83 this.contentLength = Args.notNegative(contentLength, "Content length");
84 }
85
86 /**
87 * <p>Does not close the underlying socket output.</p>
88 *
89 * @throws IOException If an I/O problem occurs.
90 */
91 @Override
92 public void close() throws IOException {
93 if (!this.closed) {
94 this.closed = true;
95 this.out.flush();
96 }
97 }
98
99 @Override
100 public void flush() throws IOException {
101 this.out.flush();
102 }
103
104 @Override
105 public void write(final byte[] b, final int off, int len) throws IOException {
106 if (this.closed) {
107 throw new IOException("Attempted write to closed stream.");
108 }
109 if (this.total < this.contentLength) {
110 final long max = this.contentLength - this.total;
111 if (len > max) {
112 len = (int) max;
113 }
114 this.out.write(b, off, len);
115 this.total += len;
116 }
117 }
118
119 @Override
120 public void write(final byte[] b) throws IOException {
121 write(b, 0, b.length);
122 }
123
124 @Override
125 public void write(final int b) throws IOException {
126 if (this.closed) {
127 throw new IOException("Attempted write to closed stream.");
128 }
129 if (this.total < this.contentLength) {
130 this.out.write(b);
131 this.total++;
132 }
133 }
134
135 }