18.6

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.*;
import javax.swing.border.LineBorder;

public class Test_18_6 extends JApplet{    
    static char whoseTurn = 'X';
    private static Cell[][] cells = new Cell[3][3];
    static JLabel jlblStatus = new JLabel("X's turn to play");
    JButton newGame = new JButton("NEW GAME");
    
    public Test_18_6(){
        JPanel p = new JPanel(new GridLayout(3,3,0,0));
        for(int i = 0; i < 3; i++)
            for(int j = 0; j < 3; j++)
                p.add(cells[i][j] = new Cell());
        
        p.setBorder(new LineBorder(Color.red,1));
        jlblStatus.setBorder(new LineBorder(Color.yellow,1));
        
        add(newGame,BorderLayout.NORTH);
        add(p,BorderLayout.CENTER);
        add(jlblStatus,BorderLayout.SOUTH);
        newGame.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent arg0) {
                // TODO Auto-generated method stub
                for(int i = 0; i < 3; i++)
                    for(int j = 0; j < 3; j++)
                        cells[i][j].setToken(' ');
                whoseTurn = 'X';
                jlblStatus = new JLabel("X's turn to play");
            }
            
        });
    }
    
    public static boolean isFull(){
        for(int i = 0; i < 3; i++)
            for(int j = 0; j < 3; j++)
                if(cells[i][j].getToken() == ' ')
                    return false;
        
        return true;
    }
    
    public static boolean isWon(char token){
        for(int i = 0; i < 3; i++)
            if((cells[i][0].getToken() == token) && (cells[i][1].getToken() == token) && (cells[i][2].getToken() == token)){
                return true;
            }
        
        for(int j = 0; j < 3; j++)
            if((cells[0][j].getToken() == token) && (cells[1][j].getToken() == token) && (cells[2][j].getToken() == token)){
                return true;
            }
        
        if((cells[0][0].getToken() == token) && (cells[1][1].getToken() == token) && (cells[2][2].getToken() == token)){
            return true;
        }
        
        if((cells[0][2].getToken() == token) && (cells[1][1].getToken() == token) && (cells[2][0].getToken() == token)){
            return true;
        }
        return false;
    }
}

class  Cell extends JPanel{
    private char token = ' ';
    
    public Cell(){
        setBorder(new LineBorder(Color.black,1));
        addMouseListener(new MyMouseListener());
    }
    
    public char getToken(){
        return token;
    }
    
    public void setToken(char c){
        token = c;
        repaint();
    }
    
    protected void paintComponent(Graphics g){
        super.paintComponent(g);
        
        if(token == 'X'){
            g.drawLine(10, 10, getWidth() - 10, getHeight() - 10);
            g.drawLine(getWidth() - 10, 10, 10, getHeight() - 10);
        }
        else if(token == 'O'){
            g.drawOval(10, 10, getWidth() - 20, getHeight() - 20);
        }
    }
    private class MyMouseListener extends MouseAdapter{
        public void mouseClicked(MouseEvent e){
            if(token == ' ' && Test_18_6.whoseTurn != ' '){
                setToken(Test_18_6.whoseTurn);
                
                if(Test_18_6.isWon(Test_18_6.whoseTurn)){
                    Test_18_6.jlblStatus.setText(Test_18_6.whoseTurn + "won! the game is over");
                    Test_18_6.whoseTurn = ' ';
                }
                else if(Test_18_6.isFull()){
                    Test_18_6.jlblStatus.setText("Draw! The game is over");
                    Test_18_6.whoseTurn = ' ';
                }
                else {
                    Test_18_6.whoseTurn = (Test_18_6.whoseTurn == 'X')?'O':'X';
                    Test_18_6.jlblStatus.setText(Test_18_6.whoseTurn + "'s turn");
                }
            }
        }
    }
}