tic tac toe 2

//Main.java
import javax.swing.JFrame; // for creating windows
public class Main {

    public static void main(String[] args) {
        JFrame window= new JFrame();
        window.setSize(800, 600);
        window.setTitle("Tic-tac-toe");
        window.setVisible(true);
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Game game=new Game();
        //Board board= new Board();
        window.add(game);
    }
}

//Board.java (basically a trimmed down version from before separating the game from the graph
import javax.swing.*;
import java.awt.*; // wildcard first level only
import java.awt.geom.*; // drawing
//import java.awt.event.*;
public class Board extends JComponent{
    /* method paintConponent
     * inherited from JComponent
     * non-Javadoc)
     * @see javax.swing.JComponent#paintComponent(java.awt.Graphics)
     */
    public void paintComponent(Graphics g)
    {
        Graphics2D g2= (Graphics2D) g;
        // create background
        g2.setColor(Color.BLUE);
        g2.fillRect(0, 0, this.getWidth(), this.getHeight());
        g2.setColor(Color.WHITE);
        // first vertical line of board
        Line2D.Double v1=new Line2D.Double(350, 150, 350, 450);
        g2.draw(v1);

        // second vertical line of board
        Line2D.Double v2=new Line2D.Double(450, 150, 450, 450);
        g2.draw(v2);

        // first horizontal line of board
        Line2D.Double h1=new Line2D.Double(250, 250, 550, 250);
        g2.draw(h1);

        // second horizontal line of board
        Line2D.Double h2=new Line2D.Double(250, 350, 550, 350);
        g2.draw(h2);

        // creating the content for the 9 cells;
        Font text= new Font("serif", Font.BOLD, 72);
        g2.setFont(text);
        for (int i=0; i<9; i++)
        {
            // type-casting required as drawstring required ints while x and y in cells are doubles
            g2.drawString(Game.cells[i].getContent(), (int)Game.cells[i].getx(), (int)Game.cells[i].gety());
        }
        // change font for bottom text
        Font textstatus= new Font("serif", Font.PLAIN, 16);
        g2.setFont(textstatus);
        g2.drawString(Game.status, 350, 550);
    }
}

//Game.java (contains all the game info from the old Board.java)

// displays key information about game
public class Game extends Board{
    public static String move="X";
    public static String status="Player X's move";
    // the board contains the 9 cells which need drawn
    public static Cell[] cells = new Cell[9];
    public static int state=0;
    public Game()
    {
        // create the cells here
        int x,y,xlower,ylower,xupper,yupper,id;
        for (int i=0; i<3; i++)
        {
            for (int j=0; j<3; j++)
            {
                x=274+100*i;
                y=174+100*j;
                xlower=250+100*i;
                ylower=150+100*j;
                xupper=350+100*i;
                yupper=250+100*j;
                id=3*i+j;
                Game.cells[id]=new Cell(x,y,xlower,ylower,xupper,yupper,id,"");
                addMouseListener(Game.cells[id]);
            }
        }
    }
    public void GameState()
    {
        // standard iterator
        int i=0;
        // WinCombos is a 2D array showing the 8 possible ways of winning
        int[][] WinCombos= {{0,1,2},{3,4,5},{6,7,8},{0,3,6},{1,4,7},{2,3,8},{0,4,8},{2,4,6}};
        // iterate through the above array
        for (i=0; i<8; i++)
        {
            // these 2 if statements should be combined, but this way leads to shorter lines
            if (Game.cells[WinCombos[i][0]].getContent()==Game.cells[WinCombos[i][1]].getContent())
            {
                if (Game.cells[WinCombos[i][0]].getContent()==Game.cells[WinCombos[i][2]].getContent())
                {
                    // if it's got in here, then one of the winning combos has happened, check who won
                    if (Game.cells[WinCombos[i][0]].getContent()=="X")
                    {
                        Game.status="Player X wins";
                        Game.state=1;
                        this.repaint();
                        return;
                    }
                    if (Game.cells[WinCombos[i][0]].getContent()=="O")
                    {
                        Game.status="Player O wins";
                        Game.state=2;
                        this.repaint();
                        return;
                    }
                }
            }
        }
        // if no-one has won, is the game still ongoing?
        for (i=0; i<9; i++)
        {
            if (Game.cells[i].getContent()=="")
            {
                Game.status="Player "+Game.move+"'s turn";
                Game.state=0; // game still in progress
                this.repaint();
                return;
            }
        }
        Game.status="Draw";
        Game.state=3;
        this.repaint();
        return; // game drawn
    }
}

//Cell.java
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.event.MouseInputListener;

public class Cell implements MouseListener, MouseInputListener{

    private String content;
    private double x;
    private double y;
    private double xlower;
    private double ylower;
    private double xupper;
    private double yupper;
    public int id;
    /* constructor Cell:
     * parameters:-
     * x: x co-ordinate for the text
     * y: y-co-ordinate for the text
     * xlower: the lower x bound for the cell
     * ylower: the lower y bound for the cell
     * xupper: the upper x bound for the cell
     * yupper: the upper y bound for the cell
     * text: what the cell should display
     *
     */
    public Cell(double x, double y, double xlower, double ylower, double xupper, double yupper, int id, String text)
    {
        this.x=x;
        this.y=y;
        this.xlower=xlower;
        this.ylower=ylower;
        this.xupper=xupper;
        this.yupper=yupper;
        this.id=id;
        this.content=text;
    }
    public void setx(double x)
    {
        this.x=x;
    }
    public double getx()
    {
        return this.x;
    }
    public void sety(double y)
    {
        this.y=y;
    }
    public double gety()
    {
        return this.y;
    }
    public void setContent(String text)
    {
        this.content=text;
    }
    public String getContent()
    {
        return this.content;
    }
    // upper and lower bounds are never changed hence no setter function
    public double getxlower()
    {
        return this.xlower;
    }
    public double getylower()
    {
        return this.ylower;
    }
    public double getxupper()
    {
        return this.xupper;
    }
    public double getyupper()
    {
        return this.yupper;
    }
    @Override
    public void mouseDragged(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mouseMoved(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mouseClicked(MouseEvent e) {
        // TODO Auto-generated method stub
        System.out.println("Cell "+this.id+" clicked");
        if (this.getContent()!="")
        {
            this.setContent(Game.move);
            if (Game.move=="X")
            {
                Game.move="O";
            }
            else
            {
                Game.move="X";
            }
            Game.cells[this.id].setContent(Game.move);
        }
    }
    @Override
    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mousePressed(MouseEvent e) {
        // TODO Auto-generated method stub

    }
    @Override
    public void mouseReleased(MouseEvent e) {
        // TODO Auto-generated method stub

    }
}