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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.WritableByteChannel;
34  
35  import org.apache.http.annotation.NotThreadSafe;
36  import org.apache.http.impl.io.HttpTransportMetricsImpl;
37  import org.apache.http.nio.FileContentEncoder;
38  import org.apache.http.nio.reactor.SessionOutputBuffer;
39  
40  /**
41   * Content encoder that writes data without any transformation. The end of
42   * the content entity is demarcated by closing the underlying connection
43   * (EOF condition). Entities transferred using this input stream can be of
44   * unlimited length.
45   * <p>
46   * This decoder is optimized to transfer data directly from
47   * a {@link FileChannel} to the underlying I/O session's channel whenever
48   * possible avoiding intermediate buffering in the session buffer.
49   *
50   * @since 4.0
51   */
52  @NotThreadSafe
53  public class IdentityEncoder extends AbstractContentEncoder
54          implements FileContentEncoder {
55  
56      public IdentityEncoder(
57              final WritableByteChannel channel,
58              final SessionOutputBuffer buffer,
59              final HttpTransportMetricsImpl metrics) {
60          super(channel, buffer, metrics);
61      }
62  
63      public int write(final ByteBuffer src) throws IOException {
64          if (src == null) {
65              return 0;
66          }
67          assertNotCompleted();
68          int bytesWritten = this.channel.write(src);
69          if (bytesWritten > 0) {
70              this.metrics.incrementBytesTransferred(bytesWritten);
71          }
72          return bytesWritten;
73      }
74  
75      public long transfer(
76              final FileChannel src,
77              long position,
78              long count) throws IOException {
79  
80          if (src == null) {
81              return 0;
82          }
83          assertNotCompleted();
84          long bytesWritten = src.transferTo(position, count, this.channel);
85          if (bytesWritten > 0) {
86              this.metrics.incrementBytesTransferred(bytesWritten);
87          }
88          return bytesWritten;
89      }
90  
91      @Override
92      public String toString() {
93          StringBuilder buffer = new StringBuilder();
94          buffer.append("[identity; completed: ");
95          buffer.append(this.completed);
96          buffer.append("]");
97          return buffer.toString();
98      }
99  
100 }