import java.io.*;import java.util.Enumeration;import java.util.Vector;import net.jxta.peergroup.PeerGroup;import net.jxta.peergroup.PeerGroupFactory;import net.jxta.exception.PeerGroupException;import net.jxta.document.AdvertisementFactory;import net.jxta.document.Advertisement;import net.jxta.discovery.DiscoveryService;import net.jxta.pipe.PipeService;import net.jxta.protocol.PeerGroupAdvertisement;// HungryPeer tries to find a restaurant to// get a good meal. It finds all RestoPeers in// the RestoNet peergroup and (in later examples)// requests bids from them.public class HungryPeer {    private PeerGroup netpg = null;     // NetPeergroup    private PeerGroup restoNet = null;  // Resto Peergroup    private int timeout = 3000;         // Timeout; can be adjusted    // Services within the RestoNet Peergroup    private DiscoveryService disco;     // Discovery Service    private PipeService pipes;          // Pipe Service    // Vector of discovered RestoPeers    private Vector restaurantAdvs = new Vector();    public static void main(String args[]) {        HungryPeer myapp = new HungryPeer();        myapp.startJxta();        System.exit(0);    }    // Start the JXTA application    private void startJxta() {        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);        }    }    // This method is used to discover the RestoNet Peergroup.    // If found the peer will join the peergroup    private boolean joinRestoNet() {        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;    }}