Trying to write Connect Four

Question

I'm fairly new to java. Actually, I'm not that new but I forgot everything I ever learned about applets. I'm trying to write Connect Four but I'm having trouble figuring out what parts of my code are supposed to do. From what I understand, start(), starts the execution of my applet. I'm not sure what code I should put in there. I basically want it to say IF the game is not over, keep playing. I'm not entirely sure what playing is. I think I need a thread somewhere thats constantly checking if the game is over but I'm not sure how to code that. Thanks for any help.
Here's what I have so far:
import java.applet.*;
import java.awt.*;
import java.util.*;
public class GameDisplay extends Applet implements MouseListener
                 ArrayList pieces;
     Image board;
     Toolkit tool;
     Player red,blue;
     Game connect;
     String turn;
     boolean gameOver;
     public void init()
          pieces = new ArrayList();
          tool = Toolkit.getDefaultToolkit();
          board = tool.getImage(fileName);
          red = new Player("red");
          blue = new Player("blue");
          gameOver = false;
          turn = "red";
          connect = new Game();
          addMouseListener(this);
     public void start()
          while(!gameOver)
               //Do something
                stop()
     public void stop()
     public void destroy()
     public void mouseClicked (MouseEvent me)
          Location loc = new Location(me.getX(),me.getY());
          if(loc.isValid())
               if(turn.equals("red"))
                    Piece p = new Piece("red",me.getX(),me.getY());
                    pieces.add(p);
               else if(turn.equals("blue"))
                    Piece p = new Piece("blue",me.getX(),me.getY());
                    pieces.add(p);
                 public void mouseEntered (MouseEvent me) {}
                 public void mousePressed (MouseEvent me) {}
                 public void mouseReleased (MouseEvent me) {}
                 public void mouseExited (MouseEvent me) {}
     public void update()
          paint(g);
     public void paint(Graphics g)
          for(int i=0;i<pieces.size();i++)
               Piece p = pieces.get(i)
               g.drawImage(p.getName(), p.getX(), p.getY(),null);
               g.drawImage(board, 0, 0, null);
}

Answer 1

Ok, I added a couple more things. I'm planning on having a board object which will be a matrix of Piece objects. I think the reason that this was confusing me, was a couple of years ago I tried to right a Monopoly game and I don't remember how I did it, I know I used applets but I also had a thread going and I don't remember why I needed it.
import java.applet.*;
import java.awt.*;
import java.util.*;
public class GameDisplay extends Applet implements MouseListener
                 ArrayList pieces;
     Image board;
     Toolkit tool;
     Player red,blue;
     Game connect;
     String turn,message;
     public void init()
          pieces = new ArrayList();
          tool = Toolkit.getDefaultToolkit();
          board = tool.getImage(fileName);
          red = new Player("red");
          blue = new Player("blue");
          turn = "red";
          message = "";
          connect = new Game();
          addMouseListener(this);
     public void mouseClicked (MouseEvent me)
          Location loc = new Location(me.getX(),me.getY());
          if(loc.isValid())
               if(turn.equals("red"))
                    Piece p = new Piece("red",me.getX(),me.getY());
                    pieces.add(p);
                    update();
               else if(turn.equals("blue"))
                    Piece p = new Piece("blue",me.getX(),me.getY());
                    pieces.add(p);
                    update();
          if(connect.gameOver())//Some recursive check or something to see if game is over.
               message = "Game Over!";
               update();
                 public void mouseEntered (MouseEvent me) {}
                 public void mousePressed (MouseEvent me) {}
                 public void mouseReleased (MouseEvent me) {}
                 public void mouseExited (MouseEvent me) {}
     public void update()
          paint(g);
     public void paint(Graphics g)
          for(int i=0;i<pieces.size();i++)
               Piece p = pieces.get(i)
               g.drawImage(p.getName(), p.getX(), p.getY(),null);
               g.drawImage(board, 0, 0, null);
          if(connect.gameOver())
               g.drawString(message,0,0);
               //Wait a certain amount of time
               init(); //Reset game
}