Java: Example - Five-in-a-row

// Five.java - main program for Five-In-A-Row Program
import javax.swing.JFrame;

////////////////////////////////////////////////////// class Five
/** Five.java - Winner is able to put 5 pieces in a row.
   The Five program consists of three files:
   Five.java      - this file with main to create window.
   FiveGUI.java   - implements the GUI interface.
   FiveLogic.java - the logical functioning.
   @author Fred Swartz
   @version 2004-05-02
   */
class Five {
    //================================================ method main
    public static void main(String[] args) {
        JFrame window = new JFrame("Five In A Row");
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setContentPane(new FiveGUI());
        window.pack();  // finalize layout
        window.setResizable(false);
        window.show();  // make window visible
    }//end main
}//endclass Five

// FiveGUI.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

/////////////////////////////////////////////////// class FiveGUI
/** A Graphical User Interface for a Five-In-A-Row game.
    This implements the user interface (view and controller),
    but the logic (model) is implemented in a separate class that
    knows nothing about the user interface.
    <p>This subclasses JPanel and puts the some buttons in the north,
    a graphical display of the board in the center, and
    a status field in the south.
    </p>
    <p>Exercise: This game probably originated on a Go board where
       the pieces are placed on the intersections, not in the 
       empty spaces.  Change the program to put all pieces on the
       intersections.
    </p>
    <p>Exercise: The Undo button doesn't do anything.  Fix it here
       in the GUI and in the logic.
    </p>
    <p>Exercise: Create a machine player.</p>
    @author Fred Swartz
    @version 2004-05-02 Rodenbach
    */
class FiveGUI extends JPanel {
    //=============================================== instance variables
    private GraphicsPanel boardDisplay_;
    private JTextField    statusField_ = new JTextField();
    private FiveLogic     gameLogic_ = new FiveLogic(9, 9);
    private boolean       gameOver_ = false;
    
    private static final Color[]  PLAYER_COLOR = {null, Color.BLACK, Color.WHITE};
    private static final String[] PLAYER_NAME  = {null, "BLACK", "WHITE"};

    //====================================================== constructor
    public FiveGUI() {
        //--- Create some buttons
        JButton newGameButton = new JButton("New Game");
        JButton undoButton = new JButton("Undo");

        //--- Create control panel
        JPanel controlPanel = new JPanel();
        controlPanel.setLayout(new FlowLayout());
        controlPanel.add(newGameButton);
        controlPanel.add(undoButton);
        
        //--- Create graphics panel
        boardDisplay_ = new GraphicsPanel();
        
        //--- Set the layout and add the components
        this.setLayout(new BorderLayout());
        this.add(controlPanel , BorderLayout.NORTH);
        this.add(boardDisplay_, BorderLayout.CENTER);
        this.add(statusField_ , BorderLayout.SOUTH);
        
        //-- Add action listeners
        newGameButton.addActionListener(new NewGameAction());
    }//end constructor

    //////////////////////////////////////////////// class GraphicsPanel
    // This is defined inside the outer class so that
    // it can use the game logic variable.
    class GraphicsPanel extends JPanel implements MouseListener {
        private static final int ROWS = 9;
        private static final int COLS = 9;
        private static final int CELL_SIZE = 30; // Pixels
        private static final int WIDTH  = COLS * CELL_SIZE;
        private static final int HEIGHT = ROWS * CELL_SIZE;
        
        //================================================== constructor
        public GraphicsPanel() {
            this.setPreferredSize(new Dimension(WIDTH, HEIGHT));
            this.setBackground(Color.GRAY);
            this.addMouseListener(this);  // Listen own mouse events.
        }//end constructor
        
        //============================================== paintComponent
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            //-- Paint grid (could be done once and saved).
            for (int r=1; r<ROWS; r++) {  // Horizontal lines
                g.drawLine(0, r*CELL_SIZE, WIDTH, r*CELL_SIZE);
            }
            for (int c=1; c<COLS; c++) {
                g.drawLine(c*CELL_SIZE, 0, c*CELL_SIZE, HEIGHT);
            }
            
            //-- Draw players pieces.
            for (int r=0; r<ROWS; r++) {
                for (int c=0; c<COLS; c++) {
                    int x = c * CELL_SIZE;
                    int y = r * CELL_SIZE;
                    int who = gameLogic_.getPlayerAt(r, c);
                    if (who != gameLogic_.EMPTY) {
                        g.setColor(PLAYER_COLOR[who]);
                        g.fillOval(x+2, y+2, CELL_SIZE-4, CELL_SIZE-4);
                    }
                }
            }
        }//end paintComponent
        
        //======================================== listener mousePressed
        public void mousePressed(MouseEvent e) {
            //--- map x,y coordinates into a row and col.
            int col = e.getX()/CELL_SIZE;
            int row = e.getY()/CELL_SIZE;
            
            int currentOccupant = gameLogic_.getPlayerAt(row, col);
            if (!gameOver_ && currentOccupant == gameLogic_.EMPTY) {
                gameLogic_.move(row, col);
                switch (gameLogic_.getGameStatus()) {
                    case 1: // Player one wins.  Game over.
                            gameOver_ = true;
                            statusField_.setText("BLACK WINS");
                            break;
                    case 2: // Player two wins.  Game over.
                            gameOver_ = true;
                            statusField_.setText("WHITE WINS");
                            break;
                            
                    case FiveLogic.TIE:  // Tie game.  Game over.
                            gameOver_ = true;
                            statusField_.setText("TIE GAME");
                            break;
                            
                    default: showNextPlayer();
                }
                            
            } else {  // Not legal
                Toolkit.getDefaultToolkit().beep();
            }
            
            this.repaint();  // Show any updates to game.
        }//end mousePressed
        
        //========================================== ignore these events
        public void mouseClicked (MouseEvent e) {}
        public void mouseReleased(MouseEvent e) {}
        public void mouseEntered (MouseEvent e) {}
        public void mouseExited  (MouseEvent e) {}
    }//end inner class GraphicsPanel
    
    //======================================= untility method showNextPlayer
    private void showNextPlayer() {
       statusField_.setText(PLAYER_NAME[gameLogic_.getNextPlayer()] + " to play");
    }//end showNextPlayer
        
    
    ///////////////////////////////////////// inner class NewGameAction
    private class NewGameAction implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            gameLogic_.reset();
            gameOver_ = false;
            showNextPlayer();
            boardDisplay_.repaint();
        }
    }//end inner class NewGameAction

}//end class FiveGUI