private boolean isDiagonalWin(int player) throws Exception {
		boolean win = false;
		if ((player < 0) || (player > TicTacToeBoard.PLAYER_O)) {
			throw new Exception("Invalid player index -- must be 0 or 1");
		}
		String playerSymbol;
		if( player == PLAYER_X) {
			playerSymbol = X;
		} else {
			playerSymbol = O;
		}
		if ((square[0][0] == square[1][1]) && (square[1][1] == square[2][2])
				&& (square[2][2] == playerSymbol)) {
			win = true;
		}

		if ((square[0][2] == square[1][1]) && (square[1][1] == square[2][0])
				&& (square[2][0] == playerSymbol)) {
			win = true;
		}

		return win;
	}