ContentLengthOutputStream.java revision 069490a5ca2fd1988d29daf45d892f47ad665115 
1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/impl/io/ContentLengthOutputStream.java $
3 * $Revision: 560343 $
4 * $Date: 2007-07-27 11:18:19 -0700 (Fri, 27 Jul 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.impl.io;
33
34import java.io.IOException;
35import java.io.OutputStream;
36
37import org.apache.http.io.SessionOutputBuffer;
38
39/**
40 * A stream wrapper that closes itself after a defined number of bytes.
41 *
42 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
43 *
44 * @version $Revision: 560343 $
45 *
46 * @since 4.0
47 */
48public class ContentLengthOutputStream extends OutputStream {
49
50    /**
51     * Wrapped session outbut buffer.
52     */
53    private final SessionOutputBuffer out;
54
55    /**
56     * The maximum number of bytes that can be written the stream. Subsequent
57     * write operations will be ignored.
58     */
59    private final long contentLength;
60
61    /** Total bytes written */
62    private long total = 0;
63
64    /** True if the stream is closed. */
65    private boolean closed = false;
66
67    /**
68     * Creates a new length limited stream
69     *
70     * @param out The data transmitter to wrap
71     * @param contentLength The maximum number of bytes that can be written to
72     * the stream. Subsequent write operations will be ignored.
73     *
74     * @since 4.0
75     */
76    public ContentLengthOutputStream(final SessionOutputBuffer out, long contentLength) {
77        super();
78        if (out == null) {
79            throw new IllegalArgumentException("Session output buffer may not be null");
80        }
81        if (contentLength < 0) {
82            throw new IllegalArgumentException("Content length may not be negative");
83        }
84        this.out = out;
85        this.contentLength = contentLength;
86    }
87
88    /**
89     * <p>Does not close the underlying socket output.</p>
90     *
91     * @throws IOException If an I/O problem occurs.
92     */
93    public void close() throws IOException {
94        if (!this.closed) {
95            this.closed = true;
96            this.out.flush();
97        }
98    }
99
100    public void flush() throws IOException {
101        this.out.flush();
102    }
103
104    public void write(byte[] b, int off, int len) throws IOException {
105        if (this.closed) {
106            throw new IOException("Attempted write to closed stream.");
107        }
108        if (this.total < this.contentLength) {
109            long max = this.contentLength - this.total;
110            if (len > max) {
111                len = (int) max;
112            }
113            this.out.write(b, off, len);
114            this.total += len;
115        }
116    }
117
118    public void write(byte[] b) throws IOException {
119        write(b, 0, b.length);
120    }
121
122    public void write(int b) throws IOException {
123        if (this.closed) {
124            throw new IOException("Attempted write to closed stream.");
125        }
126        if (this.total < this.contentLength) {
127            this.out.write(b);
128            this.total++;
129        }
130    }
131
132}
133