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.io.SessionOutputBuffer;
34 import org.apache.http.util.Args;
35
36 /**
37 * Output stream that cuts off after a defined number of bytes. This class
38 * is used to send content of HTTP messages where the end of the content entity
39 * is determined by the value of the {@code Content-Length header}.
40 * Entities transferred using this stream can be maximum {@link Long#MAX_VALUE}
41 * long.
42 * <p>
43 * Note that this class NEVER closes the underlying stream, even when close
44 * gets called. Instead, the stream will be marked as closed and no further
45 * output will be permitted.
46 *
47 * @since 4.0
48 */
49 public class ContentLengthOutputStream extends OutputStream {
50
51 /**
52 * Wrapped session output buffer.
53 */
54 private final SessionOutputBuffer out;
55
56 /**
57 * The maximum number of bytes that can be written the stream. Subsequent
58 * write operations will be ignored.
59 */
60 private final long contentLength;
61
62 /** Total bytes written */
63 private long total;
64
65 /** True if the stream is closed. */
66 private boolean closed;
67
68 /**
69 * Wraps a session output buffer and cuts off output after a defined number
70 * of bytes.
71 *
72 * @param out The session output buffer
73 * @param contentLength The maximum number of bytes that can be written to
74 * the stream. Subsequent write operations will be ignored.
75 *
76 * @since 4.0
77 */
78 public ContentLengthOutputStream(final SessionOutputBuffer out, final long contentLength) {
79 super();
80 this.out = Args.notNull(out, "Session output buffer");
81 this.contentLength = Args.notNegative(contentLength, "Content length");
82 }
83
84 /**
85 * <p>Does not close the underlying socket output.</p>
86 *
87 * @throws IOException If an I/O problem occurs.
88 */
89 @Override
90 public void close() throws IOException {
91 if (!this.closed) {
92 this.closed = true;
93 this.out.flush();
94 }
95 }
96
97 @Override
98 public void flush() throws IOException {
99 this.out.flush();
100 }
101
102 @Override
103 public void write(final byte[] b, final int off, final int len) throws IOException {
104 if (this.closed) {
105 throw new IOException("Attempted write to closed stream.");
106 }
107 if (this.total < this.contentLength) {
108 final long max = this.contentLength - this.total;
109 int chunk = len;
110 if (chunk > max) {
111 chunk = (int) max;
112 }
113 this.out.write(b, off, chunk);
114 this.total += chunk;
115 }
116 }
117
118 @Override
119 public void write(final byte[] b) throws IOException {
120 write(b, 0, b.length);
121 }
122
123 @Override
124 public void write(final int b) throws IOException {
125 if (this.closed) {
126 throw new IOException("Attempted write to closed stream.");
127 }
128 if (this.total < this.contentLength) {
129 this.out.write(b);
130 this.total++;
131 }
132 }
133
134 }