FileDocCategorySizeDatePackage
HungryPeer.javaAPI DocExample4892Wed May 08 22:23:20 BST 2002None

HungryPeer

public class HungryPeer extends Object

Fields Summary
private net.jxta.peergroup.PeerGroup
netpg
private net.jxta.peergroup.PeerGroup
restoNet
private int
timeout
private net.jxta.discovery.DiscoveryService
disco
private net.jxta.pipe.PipeService
pipes
private Vector
restaurantAdvs
Constructors Summary
Methods Summary
private booleanjoinRestoNet()


        int count = 3; // maximum number of attempts to discover

        System.out.println("Attempting to discover the RestoNet Peergroup");

        // Get the Discovery service handle from the NetPeerGroup
        DiscoveryService hdisco = netpg.getDiscoveryService();

        // All discovered RestoNet Peers
        Enumeration ae = null;

        // Loop until we find the "RestoNet" Peergroup advertisement
        // or we've exhausted the desired number of attempts
        while (count-- > 0) {
            try {
                // Check if we have the advertisement in the local
                // peer cache
                ae = hdisco.getLocalAdvertisements(DiscoveryService.GROUP,
                                            "Name", "RestoNet");

                // If we found the RestoNet advertisement, we are done
                if ((ae != null) && ae.hasMoreElements())
                    break;

                // The RestoNet advertisement is not in the local
                // cache . Send a discovery request to search for it.
                hdisco.getRemoteAdvertisements(null,
                       DiscoveryService.GROUP, "Name", "RestoNet", 1, null);

                // Wait to give peers a chance to respond
                try {
                    Thread.sleep(timeout);
                } catch (InterruptedException ie) {}
            } catch (IOException e) {
                // Found nothing! Move on.
            }
        }

        // Check if we found the RestoNet advertisement
        if (ae == null || !ae.hasMoreElements()) {
            return false;
        }

        System.out.println("Found the RestoNet PeerGroup Advertisement");
        // Get the advertisement
        PeerGroupAdvertisement adv =
            (PeerGroupAdvertisement) ae.nextElement();

        try {
            // Call the PeerGroup Factory to instantiate a new
            // peergroup instance
            restoNet = netpg.newGroup(adv);
        } catch (Exception e) {
          System.out.println("Could not create RestoPeerGroup");
          return false;
        }

        try {
            // Call the PeerGroup Factory to instantiate a new
            // peergroup instance
            restoNet = netpg.newGroup(adv);

            // Get the Discovery and Pipe services to
            // be used within the RestoNet Peergroup
            disco = restoNet.getDiscoveryService();
            pipes = restoNet.getPipeService();
        } catch (Exception e) {
          System.out.println("Could not create RestoPeerGroup");
          return false;
        }

        System.out.println("The HungryPeer joined the restoNet PeerGroup");
        return true;
public static voidmain(java.lang.String[] args)


         
        HungryPeer myapp = new HungryPeer();
        myapp.startJxta();
        System.exit(0);
private voidstartJxta()

        try {
            // Discover (or create) and join the default jxta NetPeerGroup
            netpg = PeerGroupFactory.newNetPeerGroup();
        } catch (PeerGroupException e) {
            // Couldn't initialize; can't continue
            System.out.println("Fatal error : creating the net PeerGroup");
            System.exit(1);
        }

        // Discover and join the RestoNet Peergroup
        // HungryPeers never create the RestoNet peergroup
        try {
            if (!joinRestoNet()) {
                System.out.println("Sorry could not find the RestoNet Peergroup");
                System.exit(2);
            }
        } catch (Exception e) {
            System.out.println("Can't join RestoNet group");
            System.exit(1);
        }