//StatsServer.java, modified to accept callback requests.  M. Liu, 11-4-99.import java.rmi.*;import java.rmi.server.*;import java.rmi.registry.Registry;import java.rmi.registry.LocateRegistry;import java.net.*;import java.io.*;import java.util.*;public class StatsServer extends UnicastRemoteObject    implements StatsServerInterface {  private Vector callbackObjects;  // vector to store list of callback objects that need to be tended to  public StatsServer() throws RemoteException {    super();    callbackObjects = new Vector();  }  public void setStatistics (    String teamName,    int    passingYards,    int    rushingYards,    int    turnovers  )  {    // invoke each callback object to update the passing yardage    System.out.println("**************************************\n" +                       "Server initiating callbacks ---");    for (int i = 0; i < callbackObjects.size(); i++)    {     System.out.println("doing "+ i +"-th callback\n");          // convert the vector object to a callback object      StatsCallbackInterface callback =         (StatsCallbackInterface) callbackObjects.elementAt (i);      // invoke the callback     try {       callback.statsChanged ( teamName, passingYards, rushingYards,                               turnovers);     }     catch (java.rmi.RemoteException re) {       System.out.println("Exception in StatsServer callback: " + re);    }    }  // end for    System.out.println("**************************************\n" +                       "Server completed callbacks ---");  } // end setStatistics  public void addCallback(     StatsCallbackInterface StatsCallbackObject) {     // store the callback object into the vector     callbackObjects.addElement (StatsCallbackObject);  }    public int getTotalRunningYardage( String teamName)                throws RemoteException  {     if (teamName.equals ( "Packers"))       return 4320;     else        return 128;  }  public int getTotalPassingYardage( String teamName)                throws RemoteException  {     if (teamName.equals ( "Packers"))       return 1320;     else        return 28;  }  public int getTotalTurnovers( String teamName)                throws RemoteException  {     if (teamName.equals ( "Packers"))       return 0;     else        return 12;  }  public static void main(String args[]) {    InputStreamReader is = new InputStreamReader(System.in);    BufferedReader br = new BufferedReader(is);    String s;    int RMIPort;    Registry registry;    try{         System.out.println("Enter the RMIregistry port number:");         s = br.readLine();         RMIPort = Integer.parseInt(s);         System.setSecurityManager(new RMISecurityManager());         StatsServer h = new StatsServer();         try {            registry = LocateRegistry.getRegistry(RMIPort);            registry.list();           }         catch (Exception e) { // here if registry is not found            registry = null;         }         if (registry == null)            registry = LocateRegistry.createRegistry(RMIPort);       // Edit the following line to change the registry ID of the server        registry.rebind("stats99", h);       registry.list();       System.out.println("Stats Server ready.");    }// end try    catch (Exception re) {      System.out.println("Exception in StatsServer.main: " + re);    } // end catch  } // end main} // end class