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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.example.echo;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.Unpooled;
20  import io.netty.channel.ChannelHandlerContext;
21  import io.netty.channel.ChannelInboundHandlerAdapter;
22  
23  /**
24   * Handler implementation for the echo client.  It initiates the ping-pong
25   * traffic between the echo client and server by sending the first message to
26   * the server.
27   */
28  public class EchoClientHandler extends ChannelInboundHandlerAdapter {
29  
30      private final ByteBuf firstMessage;
31  
32      /**
33       * Creates a client-side handler.
34       */
35      public EchoClientHandler() {
36          firstMessage = Unpooled.buffer(EchoClient.SIZE);
37          for (int i = 0; i < firstMessage.capacity(); i ++) {
38              firstMessage.writeByte((byte) i);
39          }
40      }
41  
42      @Override
43      public void channelActive(ChannelHandlerContext ctx) {
44          ctx.writeAndFlush(firstMessage);
45      }
46  
47      @Override
48      public void channelRead(ChannelHandlerContext ctx, Object msg) {
49          ctx.write(msg);
50      }
51  
52      @Override
53      public void channelReadComplete(ChannelHandlerContext ctx) {
54         ctx.flush();
55      }
56  
57      @Override
58      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
59          // Close the connection when an exception is raised.
60          cause.printStackTrace();
61          ctx.close();
62      }
63  }