import java.net.*;
import java.io.*;
import java.util.*;

public class Server extends Thread {

   private ServerSocket ss;
   private Vector clientVector = new Vector();
   private static int port = 4848;

   public static void main(String args[]) {
      if(args.length != 0) {
         port = Integer.parseInt(args[0]);
      }
      new Server();
   }

   public Server() {
      try {
         ss = new ServerSocket(port);
      } catch (IOException e) {
         System.exit(1);
      }
      start();
   }

   public void run() {
      while(true) {
         Socket s = null;
         try {
	    s = ss.accept();
         } catch(IOException e) {}
         addClient(s);
      }
   }

   private synchronized void addClient(Socket s) {
      clientVector.addElement(s);
      new ClientHandler(s, this);
   }
        
   public synchronized void removeClient(Socket s) {
      clientVector.removeElement(s);
   }
        
   public synchronized void broadcast(Socket sFrom, Object o) {
      for(int i = 0; i < clientVector.size(); i++) {
         Socket s = (Socket)clientVector.elementAt(i);
         sendToOne(s, o);
      }
   }

   private synchronized void sendToOne(Socket s, Object o) {
      try {
         ObjectOutputStream out = new ObjectOutputStream(s.getOutputStream());
         out.writeObject(o);
      } catch (IOException e) {}
   }
}

class ClientHandler extends Thread {

   private Server server;
   private Socket s;

   public ClientHandler(Socket s, Server server) {
      this.s = s;
      this.server = server;
      start();
   }
        
   public void run() {
      ObjectInputStream in = null;
      try{
         in = new ObjectInputStream(s.getInputStream());
      } catch(IOException e) {
         System.out.println("FAILED: GET INPUTSTREAM FROM CLIENT SOCKET");
         server.removeClient(s);
         return;
      }
      Object o;
      try {
         while ((o = in.readObject()) != null) {
            server.broadcast(s, o);   
         }
         in.close();
         s.close();
      } catch (Exception e) {
      }
      server.removeClient(s);
   }
}