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.ReadableByteChannel;
33
34 import org.apache.http.annotation.NotThreadSafe;
35 import org.apache.http.impl.io.HttpTransportMetricsImpl;
36 import org.apache.http.nio.ContentDecoder;
37 import org.apache.http.nio.reactor.SessionInputBuffer;
38 import org.apache.http.util.Args;
39
40 /**
41 * Abstract {@link ContentDecoder} that serves as a base for all content
42 * decoder implementations.
43 *
44 * @since 4.0
45 */
46 @NotThreadSafe
47 public abstract class AbstractContentDecoder implements ContentDecoder {
48
49 protected final ReadableByteChannel channel;
50 protected final SessionInputBuffer buffer;
51 protected final HttpTransportMetricsImpl metrics;
52
53 protected boolean completed;
54
55 /**
56 * Creates an instance of this class.
57 *
58 * @param channel the source channel.
59 * @param buffer the session input buffer that can be used to store
60 * session data for intermediate processing.
61 * @param metrics Transport metrics of the underlying HTTP transport.
62 */
63 public AbstractContentDecoder(
64 final ReadableByteChannel channel,
65 final SessionInputBuffer buffer,
66 final HttpTransportMetricsImpl metrics) {
67 super();
68 Args.notNull(channel, "Channel");
69 Args.notNull(buffer, "Session input buffer");
70 Args.notNull(metrics, "Transport metrics");
71 this.buffer = buffer;
72 this.channel = channel;
73 this.metrics = metrics;
74 }
75
76 public boolean isCompleted() {
77 return this.completed;
78 }
79
80 /**
81 * Reads from the channel to the destination.
82 *
83 * @param dst destination.
84 * @return number of bytes transferred.
85 *
86 * @since 4.3
87 */
88 protected int readFromChannel(final ByteBuffer dst) throws IOException {
89 final int bytesRead = this.channel.read(dst);
90 if (bytesRead > 0) {
91 this.metrics.incrementBytesTransferred(bytesRead);
92 }
93 return bytesRead;
94 }
95
96 /**
97 * Reads from the channel to the session buffer.
98 * @return number of bytes transferred.
99 *
100 * @since 4.3
101 */
102 protected int fillBufferFromChannel() throws IOException {
103 final int bytesRead = this.buffer.fill(this.channel);
104 if (bytesRead > 0) {
105 this.metrics.incrementBytesTransferred(bytesRead);
106 }
107 return bytesRead;
108 }
109
110 /**
111 * Reads from the channel to the destination.
112 *
113 * @param dst destination.
114 * @param limit max number of bytes to transfer.
115 * @return number of bytes transferred.
116 *
117 * @since 4.3
118 */
119 protected int readFromChannel(final ByteBuffer dst, final int limit) throws IOException {
120 final int bytesRead;
121 if (dst.remaining() > limit) {
122 final int oldLimit = dst.limit();
123 final int newLimit = oldLimit - (dst.remaining() - limit);
124 dst.limit(newLimit);
125 bytesRead = this.channel.read(dst);
126 dst.limit(oldLimit);
127 } else {
128 bytesRead = this.channel.read(dst);
129 }
130 if (bytesRead > 0) {
131 this.metrics.incrementBytesTransferred(bytesRead);
132 }
133 return bytesRead;
134 }
135
136 }