//   6/30/10   M. Brenner


public class Board extends Observable
{
	static public final int		EMPTY = 0,
					CROSS = 1,
					CIRCLE = 2;

	static private final int	COLS = 3,
					ROWS = 3;

	static private Board		instance_;

	private int		board_[][];



	static public Board
	getinstance()
	{
		if (instance_ == null) {
			instance_ = new Board();
		}

		return  instance_;
	}

	private
	Board()
	{
		board_ = new int[ROWS][COLS];
	}


	public void
	clear()
	{
		int		col,
				row;


		for (row = 0; row < ROWS; row++) {
			for (col = 0; col < COLS; col++) {
				board_[row][col] = EMPTY;
			}
		}
		changed();
	}


	private void
	changed()
	{
		setChanged();
		notifyObservers();
	}


	public int
	getelement (int row, int col)
	{
		return  board_[row][col];
	}


	public boolean
	isempty (int row, int col)
	{
		return  board_[row][col] == EMPTY;
	}


	public void
	mark (int row, int col, int symbol)
	{
		if (board_[row][col] == EMPTY) {
			board_[row][col] = symbol;
			changed();
		}
	}


	public void
	replay()
	{
		clear();
	}


 	public String
 	toString()
 	{
		char		chr;

 		int		col,
 				row;

 		StringBuffer	text;


 		text = new StringBuffer ("Board\n  ");
 		for (row = 0; row < ROWS; row++) {
 			for (col = 0; col < COLS; col++) {
				chr = '_';
				switch (board_[row][col]) {
				 case CROSS:
					chr = 'X';
					break;

				 case  CIRCLE:
					chr = 'O';
					break;
				}
 				text.append (" " + chr + " ");
 			}
 			text.append ("\n  ");
 		}

 		return  text.toString();
 	}
}