/* * Java Network Programming, Second Edition * Merlin Hughes, Michael Shoffner, Derek Hamner * Manning Publications Company; ISBN 188477749X * * http://nitric.com/jnp/ * * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner; * all rights reserved; see license.txt for details. */import java.rmi.*;import java.util.*;import java.rmi.server.*;import java.rmi.registry.*;public class RMICallbackServerImpl extends UnicastRemoteObject implements RMICallbackServer {  protected Vector clients;  public RMICallbackServerImpl () throws RemoteException {    clients = new Vector ();  }  public void register (RMICallbackClient client) {    try {      say (getClientHost () + " has joined.");    } catch (ServerNotActiveException ignored) {    }    clients.addElement (client);  }  public void deregister (RMICallbackClient client) {    clients.removeElement (client);    try {      say (getClientHost () + " has left.");    } catch (ServerNotActiveException ignored) {    }  }  public void say (String message) {    Vector clients = (Vector) this.clients.clone ();    for (int i = 0; i < clients.size (); ++ i) {      RMICallbackClient client = (RMICallbackClient) clients.elementAt (i);      try {        client.said (message);      } catch (RemoteException ex) {        this.clients.removeElement (client);      }    }  }  public static void main (String[] args) throws RemoteException {    RMICallbackServerImpl callbackServer = new RMICallbackServerImpl ();    Registry registry = LocateRegistry.getRegistry ();    registry.rebind (REGISTRY_NAME, callbackServer);  }}