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.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
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 final class UptimeClient {
static final String HOST = System.getProperty("host", "127.0.0.1");
static final int PORT = Integer.parseInt(System.getProperty("port", "8080"));
// Sleep 5 seconds before a reconnection attempt.
static final int RECONNECT_DELAY = Integer.parseInt(System.getProperty("reconnectDelay", "5"));
// Reconnect when the server sends nothing for 10 seconds.
static final int READ_TIMEOUT = Integer.parseInt(System.getProperty("readTimeout", "10"));
private static final UptimeClientHandler handler = new UptimeClientHandler();
public static void main(String[] args) throws Exception {
configureBootstrap(new Bootstrap()).connect();
}
private static Bootstrap configureBootstrap(Bootstrap b) {
return configureBootstrap(b, new NioEventLoopGroup());
}
static 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;
}
static void connect(Bootstrap b) {
b.connect().addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
if (future.cause() != null) {
handler.startTime = -1;
handler.println("Failed to connect: " + future.cause());
}
}
});
}
}