fbfserver.java

java3D game engine design of the source [three-dimensionalvirtualrealitynetworkprogram] - "virtual

// FBFServer.java
// Andrew Davison, June 2003, [e-mail]

/* A threaded server specialised to deal with at most two
   concurrent links from the two players involved in the
   FourByFour game.

   This is a thin server -- all the game logic is located
   on the client-side.

   The shared data is an array of references to the handlers
   and the current number of players. Since this is so little,
   a shared object is not used to maintain it. 
*/

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


public class FBFServer
{
  private static final int PORT = 1234;

  private static final int MAX_PLAYERS = 2;   // two-person game
  private final static int PLAYER1    = 1;
  private final static int PLAYER2    = 2;   // use to be MACHINE

  // data structures shared by the handlers
  private PlayerServerHandler[] handlers;     // handlers for players
  private int numPlayers;

  
  public FBFServer()
  // Concurrently process players
  {
    handlers = new PlayerServerHandler[MAX_PLAYERS];
    handlers[0] = null;
    handlers[1] = null;
    numPlayers = 0;

    try {
      ServerSocket serverSock = new ServerSocket(PORT);
      Socket clientSock;
      while (true) {
        System.out.println("Waiting for a client...");
        clientSock = serverSock.accept();
        new PlayerServerHandler(clientSock, this).start();
      }
    }
    catch(Exception e)
    {  System.out.println(e);  }
  }  // end of ChatServer()


  // methods for child threads to access shared data structures

  synchronized public boolean enoughPlayers()
  { return (numPlayers == MAX_PLAYERS); }


  synchronized public int addPlayer(PlayerServerHandler h)
  /* Store a reference to the handler, and return a player ID to
     the handler. The ID is the array index where the handler is 
     stored + 1.
  */
  { for(int i=0; i < MAX_PLAYERS; i++)
      if (handlers[i] == null) {
        handlers[i] = h;
        numPlayers++; 
        return i+1;   // playerID is 1 or 2  (array index + 1)
      }
    return -1;  // means we have enough players already
  }  // end of addPlayer()


  synchronized public void removePlayer(int playerID)
  { handlers[playerID-1] = null;     // no checking done of player value
    numPlayers--; 
  }  // end of removePlayer()


  synchronized public void tellOther(int playerID, String msg)
  // send mesg to the other player
  { int otherID = ((playerID == PLAYER1) ? PLAYER2 : PLAYER1 );
    if (handlers[otherID-1] != null)     // index is ID-1
      handlers[otherID-1].sendMessage(msg);
  }  // end of tellOther()


  // -----------------------------------

  public static void main(String args[]) 
  {  new FBFServer();  }

} // end of FBFServer class