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.nio.codecs;
29
30 import java.io.IOException;
31 import java.nio.ByteBuffer;
32 import java.nio.channels.FileChannel;
33 import java.nio.channels.ReadableByteChannel;
34
35 import org.apache.http.annotation.NotThreadSafe;
36 import org.apache.http.impl.io.HttpTransportMetricsImpl;
37 import org.apache.http.nio.FileContentDecoder;
38 import org.apache.http.nio.reactor.SessionInputBuffer;
39 import org.apache.http.util.Args;
40
41 /**
42 * Content decoder that reads data without any transformation. The end of the
43 * content entity is delineated by closing the underlying connection
44 * (EOF condition). Entities transferred using this input stream can be of
45 * unlimited length.
46 * <p>
47 * This decoder is optimized to transfer data directly from the underlying
48 * I/O session's channel to a {@link FileChannel}, whenever
49 * possible avoiding intermediate buffering in the session buffer.
50 *
51 * @since 4.0
52 */
53 @NotThreadSafe
54 public class IdentityDecoder extends AbstractContentDecoder
55 implements FileContentDecoder {
56
57 public IdentityDecoder(
58 final ReadableByteChannel channel,
59 final SessionInputBuffer buffer,
60 final HttpTransportMetricsImpl metrics) {
61 super(channel, buffer, metrics);
62 }
63
64 /**
65 * Sets the completed status of this decoder. Normally this is not necessary
66 * (the decoder will automatically complete when the underlying channel
67 * returns EOF). It is useful to mark the decoder as completed if you have
68 * some other means to know all the necessary data has been read and want to
69 * reuse the underlying connection for more messages.
70 */
71 public void setCompleted(final boolean completed) {
72 this.completed = completed;
73 }
74
75 public int read(final ByteBuffer dst) throws IOException {
76 Args.notNull(dst, "Byte buffer");
77 if (this.completed) {
78 return -1;
79 }
80
81 int bytesRead;
82 if (this.buffer.hasData()) {
83 bytesRead = this.buffer.read(dst);
84 } else {
85 bytesRead = readFromChannel(dst);
86 }
87 if (bytesRead == -1) {
88 this.completed = true;
89 }
90 return bytesRead;
91 }
92
93 public long transfer(
94 final FileChannel dst,
95 final long position,
96 final long count) throws IOException {
97
98 if (dst == null) {
99 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 buffer = new StringBuilder();
135 buffer.append("[identity; completed: ");
136 buffer.append(this.completed);
137 buffer.append("]");
138 return buffer.toString();
139 }
140
141 }