private void checkWinDiagonal() {
        int rowStart = 0;
        int colStart = 0;
        int rowMax = 6;
        int colMax = 7;
        for (rowStart = 0; rowStart < rowMax; rowStart++) {
            int redCounter = 0;
            int yellowCounter = 0;
            int row, col;
            for (row = rowStart, col = 0; row < rowMax && col < colMax; row++, col++) {
                if (boardData[row][col] == Token.RED) {
                    redCounter++;
                    if (redCounter >= 4) {
                        System.out.println("Red Player wins!");
                    }
                } else if (boardData[row][col] == Token.YELLOW) {
                    yellowCounter++;
                    if (yellowCounter >= 4) {
                        System.out.println("Yellow Player wins!");
                    }
                } else {
                    redCounter = 0;
                    yellowCounter = 0;
                }

            }
        }


        for (colStart = 1; colStart < colMax; rowStart++) {
            int redCounter = 0;
            int yellowCounter = 0;
            int row, col;
            for (row = 0, col = colStart; row < rowMax && col < colMax; row++, col++) {
                if (boardData[row][col] == Token.RED) {
                    redCounter++;
                    if (redCounter >= 4) {
                        System.out.println("Red Player wins!");
                    }
                } else if (boardData[row][col] == Token.YELLOW) {
                    yellowCounter++;
                    if (yellowCounter >= 4) {
                        System.out.println("Yellow Player wins!");
                    }
                } else {
                    redCounter = 0;
                    yellowCounter = 0;
                }

            }
        }
    }