Added the uptime client example

src/main/java/org/jboss/netty/example/uptime/UptimeClient.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.example.uptime;
+
+import java.net.InetSocketAddress;
+import java.util.concurrent.Executors;
+
+import org.jboss.netty.bootstrap.ClientBootstrap;
+import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
+import org.jboss.netty.handler.timeout.ReadTimeoutHandler;
+import org.jboss.netty.util.HashedWheelTimer;
+import org.jboss.netty.util.Timer;
+
+
+/**
+ * Connects to a server periodically to measure the uptime of the server.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ *
+ * @version $Rev: 1685 $, $Date: 2009-08-28 16:15:49 +0900 (Fri, 28 Aug 2009) $
+ */
+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;
+
+    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]);
+
+        // Initialize the timer that schedules subsequent reconnection attempts.
+        Timer timer = new HashedWheelTimer();
+
+        // Configure the client.
+        ClientBootstrap bootstrap = new ClientBootstrap(
+                new NioClientSocketChannelFactory(
+                        Executors.newCachedThreadPool(),
+                        Executors.newCachedThreadPool()));
+
+        bootstrap.getPipeline().addLast(
+                "timeout", new ReadTimeoutHandler(timer, READ_TIMEOUT));
+        bootstrap.getPipeline().addLast(
+                "handler", new UptimeClientHandler(bootstrap, timer));
+
+        bootstrap.setOption(
+                "remoteAddress", new InetSocketAddress(host, port));
+
+        // Initiate the first connection attempt - the rest is handled by
+        // UptimeClientHandler.
+        bootstrap.connect();
+    }
+}

src/main/java/org/jboss/netty/example/uptime/UptimeClientHandler.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2009 Red Hat, Inc.
+ *
+ * Red Hat 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 org.jboss.netty.example.uptime;
+
+import java.net.ConnectException;
+import java.net.InetSocketAddress;
+import java.util.concurrent.TimeUnit;
+
+import org.jboss.netty.bootstrap.ClientBootstrap;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.channel.ChannelPipelineCoverage;
+import org.jboss.netty.channel.ChannelStateEvent;
+import org.jboss.netty.channel.ExceptionEvent;
+import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
+import org.jboss.netty.util.Timeout;
+import org.jboss.netty.util.Timer;
+import org.jboss.netty.util.TimerTask;
+
+/**
+ * Keep reconnecting to the server while printing out the current uptime and
+ * connection attempt status.
+ *
+ * @author The Netty Project (netty-dev@lists.jboss.org)
+ * @author Trustin Lee (tlee@redhat.com)
+ *
+ * @version $Rev: 1685 $, $Date: 2009-08-28 16:15:49 +0900 (Fri, 28 Aug 2009) $
+ */
+@ChannelPipelineCoverage("one")
+public class UptimeClientHandler extends SimpleChannelUpstreamHandler {
+
+    final ClientBootstrap bootstrap;
+    private final Timer timer;
+    private volatile long startTime = -1;
+
+    public UptimeClientHandler(ClientBootstrap bootstrap, Timer timer) {
+        this.bootstrap = bootstrap;
+        this.timer = timer;
+    }
+
+    InetSocketAddress getRemoteAddress() {
+        return (InetSocketAddress) bootstrap.getOption("remoteAddress");
+    }
+
+    @Override
+    public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
+        println("Disconnected from: " + getRemoteAddress());
+    }
+
+    @Override
+    public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) {
+        println("Sleeping for: " + UptimeClient.RECONNECT_DELAY + "s");
+        timer.newTimeout(new TimerTask() {
+            public void run(Timeout timeout) throws Exception {
+                println("Reconnecting to: " + getRemoteAddress());
+                bootstrap.connect();
+            }
+        }, UptimeClient.RECONNECT_DELAY, TimeUnit.SECONDS);
+    }
+
+    @Override
+    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
+        if (startTime < 0) {
+            startTime = System.currentTimeMillis();
+        }
+
+        println("Connected to: " + getRemoteAddress());
+    }
+
+    @Override
+    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) {
+        Throwable cause = e.getCause();
+        if (cause instanceof ConnectException) {
+            startTime = -1;
+            println("Failed to connect: " + cause.getMessage());
+        }
+        ctx.getChannel().close();
+    }
+
+    void println(String msg) {
+        if (startTime < 0) {
+            System.err.format("[SERVER IS DOWN] %s%n", msg);
+        } else {
+            System.err.format("[UPTIME: %5ds] %s%n", (System.currentTimeMillis() - startTime) / 1000, msg);
+        }
+    }
+}