tic tac toe 1

//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);
        Board board= new Board();
        window.add(board);
    }
}

//Board.java

import javax.swing.*;
import javax.swing.event.MouseInputListener;
import java.awt.*; // wildcard first level only
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.*; // drawing
//import java.awt.event.*;
public class Board extends JComponent implements MouseListener, MouseInputListener{
    // the board contains the 9 cells which need drawn
    public Cell[] cells = new Cell[9];

    // status is the message on the bottom of the window
    public String status= "Player X's move";
    // move determines whose turn it is
    public String move="X";
    public Board()
    {
        int x,y, xlower, xupper, ylower, yupper;
        for (int i=0; i<3; i++)
        {
            for (int j=0; j<3; j++)
            {
                x=276+i*100; // where the marker is to be put
                y=224+j*100;
                xlower= 250+i*100; // top left corner of area
                ylower= 150+j*100;
                xupper= 350+i*100; // bottom right corner of area
                yupper= 250+j*100;
                // Cells need to be created now to allow for screen refreshes
                this.cells[i+j*3]=new Cell(x,y,xlower,ylower,xupper,yupper,"");
            }
        }
        addMouseListener(this); // adds listener to cover the entire board (screen)
    }
    /* 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(this.cells[i].getContent(), (int)this.cells[i].getx(), (int)this.cells[i].gety());
        }
        // change font for bottom text
        Font textstatus= new Font("serif", Font.PLAIN, 16);
        g2.setFont(textstatus);
        g2.drawString(status, 350, 550);
    }
    /*
     * function ValidMove
     * paramters: id (int)
     * determines if the selected move is legal
     * returns boolean
     */
    public boolean ValidMove(int id)
    {
      // check if id is out of range, which would otherwise cause out of bounds error (shouldn't ever be the case)
      if (id>8 || id<0) return false;
      // make sure the selected cell hasn't already been taken
      if (this.cells[id].getContent()!="") return false;
      // if neither of these tests fail, the move is valid
      return true;
    }
    /*
     * function GameState
     * parameters: none
     * determines the current state of the game
     * returns int (0=ongoing, 1=X wins, 2=O wins, 3=drawn)
     */
    public int 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 (this.cells[WinCombos[i][0]].getContent()==this.cells[WinCombos[i][1]].getContent())
            {
                if (this.cells[WinCombos[i][0]].getContent()==this.cells[WinCombos[i][2]].getContent())
                {
                    // if it's got in here, then one of the winning combos has happened, check who won
                    if (this.cells[WinCombos[i][0]].getContent()=="X") return 1; // player X wins
                    if (this.cells[WinCombos[i][0]].getContent()=="O") return 2; // player O wins
                }
            }
        }
        // if no-one has won, is the game still ongoing?
        for (i=0; i<9; i++)
        {
            if (this.cells[i].getContent()=="") return 0; // game still in progress
        }
        return 3; // game drawn
    }
    // required by interface, but not used
    @Override
    public void mouseDragged(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    // required by interface, but not used
    @Override
    public void mouseMoved(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    // this function is where the game does whatever it has to do for each turn.
    @Override
    public void mouseClicked(MouseEvent e) {
        // TODO Auto-generated method stub
        // find where on the screen the click heppened
        double x=e.getX();
        double y=e.getY();
        int state;
        if (this.GameState()==0)
        {
            for (int i=0; i<9; i++)
            {
                // check each region to see if the click happened inside one of the cells
                // using > and < rather than >= and <= to guard against selecting the wrong cell
                if(x>this.cells[i].getxlower() && x<this.cells[i].getxupper())
                {
                    // this if could be combined with the above, but neater this way
                    if (y>this.cells[i].getylower() && y<this.cells[i].getyupper())
                    {
                        // we have found the cell clicked, now see if move is valid
                        if (this.ValidMove(i))
                        {
                            // change the content of the cell
                            this.cells[i].setContent(move);
                            // switch turns
                            if (move=="X") move="O";
                            else move="X";
                            // check the current state of the game
                            state=this.GameState();
                            if (state==1)
                            {
                                // player X has won
                                status="Player X wins";
                            }
                            else if (state==2)
                            {
                                // player O has won
                                status="Player O wins";
                            }
                            else if (state==3)
                            {
                                // all moves have been made, no winner
                                status="Draw";
                            }
                            else
                            {
                                // game still ongoing
                                status="Player "+move+"\'s move.";
                            }
                            // refreshes the screen
                            repaint();
                            // prevent any more iterations to save processing time, they would be false anyway
                            break;
                        }
                    }
                }
            }
        }
    }
    // required by interface, but not used
    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    // required by interface, but not used
    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    // required by interface, but not used
    @Override
    public void mousePressed(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
    // required by interface, but not used
    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub

    }
}

//Cell.java

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

import javax.swing.event.MouseInputListener;

public class Cell{

    private String content;
    private double x;
    private double y;
    private double xlower;
    private double ylower;
    private double xupper;
    private double yupper;

    /* 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, String text)
    {
        this.x=x;
        this.y=y;
        this.xlower=xlower;
        this.ylower=ylower;
        this.xupper=xupper;
        this.yupper=yupper;
        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;
    }
}