View Javadoc
1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.handler.codec.bytes;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.channel.ChannelHandlerContext;
20  import io.netty.channel.ChannelPipeline;
21  import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
22  import io.netty.handler.codec.LengthFieldPrepender;
23  import io.netty.handler.codec.MessageToMessageDecoder;
24  
25  import java.util.List;
26  
27  /**
28   * Decodes a received {@link ByteBuf} into an array of bytes.
29   * A typical setup for TCP/IP would be:
30   * <pre>
31   * {@link ChannelPipeline} pipeline = ...;
32   *
33   * // Decoders
34   * pipeline.addLast("frameDecoder",
35   *                  new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4));
36   * pipeline.addLast("bytesDecoder",
37   *                  new {@link ByteArrayDecoder}());
38   *
39   * // Encoder
40   * pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4));
41   * pipeline.addLast("bytesEncoder", new {@link ByteArrayEncoder}());
42   * </pre>
43   * and then you can use an array of bytes instead of a {@link ByteBuf}
44   * as a message:
45   * <pre>
46   * void channelRead({@link ChannelHandlerContext} ctx, byte[] bytes) {
47   *     ...
48   * }
49   * </pre>
50   */
51  public class ByteArrayDecoder extends MessageToMessageDecoder<ByteBuf> {
52      @Override
53      protected void decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception {
54           // copy the ByteBuf content to a byte array
55          byte[] array = new byte[msg.readableBytes()];
56          msg.getBytes(0, array);
57  
58          out.add(array);
59      }
60  }