io.netty.example.uptime.UptimeClient Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.example.uptime;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;
/**
* Connects to a server periodically to measure and print the uptime of the
* server. This example demonstrates how to implement reliable reconnection
* mechanism in Netty.
*/
public class UptimeClient {
// Sleep 5 seconds before a reconnection attempt.
static final int RECONNECT_DELAY = 5;
// Reconnect when the server sends nothing for 10 seconds.
private static final int READ_TIMEOUT = 10;
private final String host;
private final int port;
// A single handler will be reused across multiple connection attempts to keep when the last
// successful connection attempt was.
private final UptimeClientHandler handler = new UptimeClientHandler(this);
public UptimeClient(String host, int port) {
this.host = host;
this.port = port;
}
public void run() {
configureBootstrap(new Bootstrap()).connect();
}
private Bootstrap configureBootstrap(Bootstrap b) {
return configureBootstrap(b, new NioEventLoopGroup());
}
Bootstrap configureBootstrap(Bootstrap b, EventLoopGroup g) {
b.group(g)
.channel(NioSocketChannel.class)
.remoteAddress(host, port)
.handler(new ChannelInitializer() {
@Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new IdleStateHandler(READ_TIMEOUT, 0, 0), handler);
}
});
return b;
}
public static void main(String[] args) throws Exception {
// Print usage if no argument is specified.
if (args.length != 2) {
System.err.println(
"Usage: " + UptimeClient.class.getSimpleName() +
" ");
return;
}
// Parse options.
String host = args[0];
int port = Integer.parseInt(args[1]);
new UptimeClient(host, port).run();
}
}