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1   /*
2    * Copyright 2020 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    *   https://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  
17  package io.netty.example.haproxy;
18  
19  import io.netty.channel.ChannelFuture;
20  import io.netty.channel.ChannelFutureListener;
21  import io.netty.channel.ChannelHandlerContext;
22  import io.netty.channel.ChannelOutboundHandlerAdapter;
23  import io.netty.channel.ChannelPromise;
24  import io.netty.handler.codec.haproxy.HAProxyMessage;
25  import io.netty.handler.codec.haproxy.HAProxyMessageEncoder;
26  
27  public class HAProxyHandler extends ChannelOutboundHandlerAdapter {
28  
29      @Override
30      public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
31          ctx.pipeline().addBefore(ctx.name(), null, HAProxyMessageEncoder.INSTANCE);
32          super.handlerAdded(ctx);
33      }
34  
35      @Override
36      public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
37          ChannelFuture future = ctx.write(msg, promise);
38          if (msg instanceof HAProxyMessage) {
39              future.addListener(new ChannelFutureListener() {
40                  @Override
41                  public void operationComplete(ChannelFuture future) throws Exception {
42                      if (future.isSuccess()) {
43                          ctx.pipeline().remove(HAProxyMessageEncoder.INSTANCE);
44                          ctx.pipeline().remove(HAProxyHandler.this);
45                      } else {
46                          ctx.close();
47                      }
48                  }
49              });
50          }
51      }
52  }