/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.remoting.samples.detection;
import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.Notification;
import javax.management.NotificationListener;
import javax.management.ObjectName;
import org.jboss.remoting.Client;
import org.jboss.remoting.InvokerLocator;
import org.jboss.remoting.detection.multicast.MulticastDetector;
import org.jboss.remoting.network.NetworkNotification;
import org.jboss.remoting.network.NetworkRegistry;
/**
* Simple remoting client that uses detection to discover the remoting server to make invocation on. Note that this
* class is a standard JMX NotificationListener so it can listen for discovery JMX notifications coming from the
* NetworkRegistry. This is how the NetworkRegistry tells us when new servers have come online and when dead
* servers go offline.
*
* @author <a href="mailto:telrod@e2technologies.net">Tom Elrod</a>
* @author <a href="mailto:mazz@jboss.com">John Mazzitelli</a>
*/
public class SimpleDetectorClient
implements NotificationListener
{
/**
* Sets up NetworkRegistry and MulticastDetector so we can listen for any additions or removals of remoting
* servers on the network.
*
* @throws Exception
*/
public void setupDetector()
throws Exception
{
// we need an MBeanServer to store our network registry and multicast detector services
MBeanServer server = MBeanServerFactory.createMBeanServer();
// the registry will house all remoting servers discovered
NetworkRegistry registry = NetworkRegistry.getInstance();
server.registerMBean(registry, new ObjectName("remoting:type=NetworkRegistry"));
println("NetworkRegistry has been created");
// register class as listener, so know when new server found
registry.addNotificationListener(this, null, null);
println("NetworkRegistry has added the client as a listener");
// multicast detector will detect new network registries that come online
MulticastDetector detector = new MulticastDetector();
server.registerMBean(detector, new ObjectName("remoting:type=MulticastDetector"));
detector.start();
println("MulticastDetector has been created and is listening for new NetworkRegistries to come online");
return;
}
/**
* Callback method from the broadcaster MBean this listener implementation is registered to. When a new server
* is detected, a welcome message will immediately be sent to the newly discovered server.
*
* @param notification the notification object
* @param handback the handback object given to the broadcaster upon listener registration
*/
public void handleNotification(Notification notification,
Object handback)
{
// check to see if network notification
if(notification instanceof NetworkNotification)
{
println("GOT A NETWORK-REGISTRY NOTIFICATION: " + notification.getType());
NetworkNotification networkNotification = (NetworkNotification) notification;
if(NetworkNotification.SERVER_ADDED.equals(networkNotification.getType()))
{ // notification is for new servers being added
println("New server(s) have been detected - getting locators and sending welcome messages");
InvokerLocator[] locators = networkNotification.getLocator();
for(int x = 0; x < locators.length; x++)
{
try
{
// get the new found server's locator and invoke a call
InvokerLocator newServerLocator = locators[x];
makeInvocation(newServerLocator.getLocatorURI());
}
catch(Throwable throwable)
{
throwable.printStackTrace();
}
}
}
else if(NetworkNotification.SERVER_REMOVED.equals(networkNotification.getType()))
{ // notification is for old servers that have gone down
InvokerLocator[] locators = networkNotification.getLocator();
for(int x = 0; x < locators.length; x++)
{
println("It has been detected that a server has gone down with a locator of: " + locators[x]);
}
}
}
return;
}
/**
* Make call on remoting server based on locator uri provided.
*
* @param locatorURI the URI of the remote server we want to send the message to
* @throws Throwable
*/
public void makeInvocation(String locatorURI)
throws Throwable
{
InvokerLocator locator = new InvokerLocator(locatorURI);
println("Sending welcome message to remoting server with locator uri of: " + locatorURI);
Client remotingClient = new Client(locator);
Object response = remotingClient.invoke("Welcome Aboard!", null);
println("The newly discovered server sent this response to our welcome message: " + response);
return;
}
/**
* Starts the JBoss/Remoting client.
*
* @param args unused
*/
public static void main(String[] args)
{
println("Starting JBoss/Remoting client... to stop this client, kill it manually via Control-C");
SimpleDetectorClient client = new SimpleDetectorClient();
try
{
client.setupDetector();
// let this client run forever - welcoming new servers when then come online
while(true)
{
Thread.sleep(1000);
}
}
catch(Throwable e)
{
e.printStackTrace();
}
println("Stopping JBoss/Remoting client");
}
/**
* Outputs a message to stdout.
*
* @param msg the message to output
*/
public static void println(String msg)
{
System.out.println(new java.util.Date() + ": [CLIENT]: " + msg);
}
}