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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.uptime;
17  
18  import io.netty.channel.ChannelHandler.Sharable;
19  import io.netty.channel.ChannelHandlerContext;
20  import io.netty.channel.SimpleChannelInboundHandler;
21  import io.netty.handler.timeout.IdleState;
22  import io.netty.handler.timeout.IdleStateEvent;
23  
24  import java.util.concurrent.TimeUnit;
25  
26  /**
27   * Keep reconnecting to the server while printing out the current uptime and
28   * connection attempt getStatus.
29   */
30  @Sharable
31  public class UptimeClientHandler extends SimpleChannelInboundHandler<Object> {
32  
33      long startTime = -1;
34  
35      @Override
36      public void channelActive(ChannelHandlerContext ctx) {
37          if (startTime < 0) {
38              startTime = System.currentTimeMillis();
39          }
40          println("Connected to: " + ctx.channel().remoteAddress());
41      }
42  
43      @Override
44      public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
45          // Discard received data
46      }
47  
48      @Override
49      public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
50          if (!(evt instanceof IdleStateEvent)) {
51              return;
52          }
53  
54          IdleStateEvent e = (IdleStateEvent) evt;
55          if (e.state() == IdleState.READER_IDLE) {
56              // The connection was OK but there was no traffic for last period.
57              println("Disconnecting due to no inbound traffic");
58              ctx.close();
59          }
60      }
61  
62      @Override
63      public void channelInactive(final ChannelHandlerContext ctx) {
64          println("Disconnected from: " + ctx.channel().remoteAddress());
65      }
66  
67      @Override
68      public void channelUnregistered(final ChannelHandlerContext ctx) throws Exception {
69          println("Sleeping for: " + UptimeClient.RECONNECT_DELAY + 's');
70  
71          ctx.channel().eventLoop().schedule(new Runnable() {
72              @Override
73              public void run() {
74                  println("Reconnecting to: " + UptimeClient.HOST + ':' + UptimeClient.PORT);
75                  UptimeClient.connect();
76              }
77          }, UptimeClient.RECONNECT_DELAY, TimeUnit.SECONDS);
78      }
79  
80      @Override
81      public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
82          cause.printStackTrace();
83          ctx.close();
84      }
85  
86      void println(String msg) {
87          if (startTime < 0) {
88              System.err.format("[SERVER IS DOWN] %s%n", msg);
89          } else {
90              System.err.format("[UPTIME: %5ds] %s%n", (System.currentTimeMillis() - startTime) / 1000, msg);
91          }
92      }
93  }