/*
* Copyright 2011 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 java.net.InetSocketAddress;
import java.util.concurrent.Executors;
import io.netty.bootstrap.ClientBootstrap;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPipelineFactory;
import io.netty.channel.Channels;
import io.netty.channel.socket.nio.NioClientSocketChannelFactory;
import io.netty.handler.timeout.ReadTimeoutHandler;
import io.netty.util.HashedWheelTimer;
import io.netty.util.Timer;
/**
* 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;
public UptimeClient(String host, int port) {
this.host = host;
this.port = port;
}
public void run() {
// Initialize the timer that schedules subsequent reconnection attempts.
final Timer timer = new HashedWheelTimer();
// Configure the client.
final ClientBootstrap bootstrap = new ClientBootstrap(
new NioClientSocketChannelFactory(
Executors.newCachedThreadPool(),
Executors.newCachedThreadPool()));
// Configure the pipeline factory.
bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
private final ChannelHandler timeoutHandler =
new ReadTimeoutHandler(timer, READ_TIMEOUT);
private final ChannelHandler uptimeHandler =
new UptimeClientHandler(bootstrap, timer);
public ChannelPipeline getPipeline() throws Exception {
return Channels.pipeline(
timeoutHandler, uptimeHandler);
}
});
bootstrap.setOption(
"remoteAddress", new InetSocketAddress(host, port));
// Initiate the first connection attempt - the rest is handled by
// UptimeClientHandler.
bootstrap.connect();
}
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() +
" <host> <port>");
return;
}
// Parse options.
String host = args[0];
int port = Integer.parseInt(args[1]);
new UptimeClient(host, port).run();
}
}