001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.impl.nio.codecs; 029 030import java.io.IOException; 031import java.nio.ByteBuffer; 032import java.nio.channels.FileChannel; 033import java.nio.channels.ReadableByteChannel; 034 035import org.apache.http.impl.io.HttpTransportMetricsImpl; 036import org.apache.http.nio.FileContentDecoder; 037import org.apache.http.nio.reactor.SessionInputBuffer; 038import org.apache.http.util.Args; 039 040/** 041 * Content decoder that reads data without any transformation. The end of the 042 * content entity is delineated by closing the underlying connection 043 * (EOF condition). Entities transferred using this input stream can be of 044 * unlimited length. 045 * <p> 046 * This decoder is optimized to transfer data directly from the underlying 047 * I/O session's channel to a {@link FileChannel}, whenever 048 * possible avoiding intermediate buffering in the session buffer. 049 * 050 * @since 4.0 051 */ 052public class IdentityDecoder extends AbstractContentDecoder 053 implements FileContentDecoder { 054 055 public IdentityDecoder( 056 final ReadableByteChannel channel, 057 final SessionInputBuffer buffer, 058 final HttpTransportMetricsImpl metrics) { 059 super(channel, buffer, metrics); 060 } 061 062 /** 063 * Sets the completed status of this decoder. Normally this is not necessary 064 * (the decoder will automatically complete when the underlying channel 065 * returns EOF). It is useful to mark the decoder as completed if you have 066 * some other means to know all the necessary data has been read and want to 067 * reuse the underlying connection for more messages. 068 */ 069 public void setCompleted(final boolean completed) { 070 this.completed = completed; 071 } 072 073 @Override 074 public int read(final ByteBuffer dst) throws IOException { 075 Args.notNull(dst, "Byte buffer"); 076 if (this.completed) { 077 return -1; 078 } 079 080 final int bytesRead; 081 if (this.buffer.hasData()) { 082 bytesRead = this.buffer.read(dst); 083 } else { 084 bytesRead = readFromChannel(dst); 085 } 086 if (bytesRead == -1) { 087 this.completed = true; 088 } 089 return bytesRead; 090 } 091 092 @Override 093 public long transfer( 094 final FileChannel dst, 095 final long position, 096 final long count) throws IOException { 097 098 if (dst == null) { 099 return 0; 100 } 101 if (this.completed) { 102 return 0; 103 } 104 105 long bytesRead; 106 if (this.buffer.hasData()) { 107 dst.position(position); 108 bytesRead = this.buffer.read(dst); 109 } else { 110 if (this.channel.isOpen()) { 111 if (position > dst.size()) { 112 throw new IOException("Position past end of file [" + position + 113 " > " + dst.size() + "]"); 114 } 115 bytesRead = dst.transferFrom(this.channel, position, count); 116 if (count > 0 && bytesRead == 0) { 117 bytesRead = this.buffer.fill(this.channel); 118 } 119 } else { 120 bytesRead = -1; 121 } 122 if (bytesRead > 0) { 123 this.metrics.incrementBytesTransferred(bytesRead); 124 } 125 } 126 if (bytesRead == -1) { 127 this.completed = true; 128 } 129 return bytesRead; 130 } 131 132 @Override 133 public String toString() { 134 final StringBuilder sb = new StringBuilder(); 135 sb.append("[identity; completed: "); 136 sb.append(this.completed); 137 sb.append("]"); 138 return sb.toString(); 139 } 140 141}