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 }