9x9 Connect 4: 2 players, with a special move

// this is a 9x9 connect 4, where you can place the tokens anywhere on the board // there is a single use, choice move "gravity" that shifts all the pieces on the board in a general direction // have fun

import java.util.Scanner;

public class Connect4_MKIII extends Thread { public static Scanner in = new Scanner(System.in); public static String[][] board = new String[9][9]; public static boolean player = true; public static boolean usedGravityPlayer1 = false; public static boolean usedGravityPlayer2 = false; public static boolean justUsedGravity = false; public static String p1 = ""; public static String p2 = "";

public static void main(String[] args) {
	// print rules
	printRules();
    // checks for custom play
    setPlay();
    // sets full board to " "
    for (int row = 0; row < board.length; row++)
        for (int column = 0; column < board[row].length; column++)
            board[row][column] = " ";

    // prints an empty board for reference
    printBoard();
    game: while (true) {
        // 2 players
        for (int n = 0; n < 2; n++) {
            // checks if the user wants to use their gravity move
            if ((player && !usedGravityPlayer1) || (!player && !usedGravityPlayer2)) {
                System.out.print("  Would you like to use gravity? ");
                if (in.next().substring(0, 1).equalsIgnoreCase("y")) {
                    useGravity();
                }
            }
            // makes move if player did not use gravity
            if (!justUsedGravity) {
                System.out.print("  Please input row and column ");
                updateBoard(in.nextInt(), in.nextInt());
            }
            // if gravity was used, it clears it for the next player
            if (justUsedGravity) {
            	justUsedGravity = false;
            	if(player) {
            		usedGravityPlayer1 = true;
            	} else {
            		usedGravityPlayer2 = true;
            	}
            }
            // prints the new board updated with the newest play
            printBoard();
            // checks for a draw
            if (checkDraw()) {
                System.out.println("  You're both bad at this");
                break game;
            }
            // checks if there is a winner
            if (player) {
                if (checkForWinner(p1)) {
                    System.out.println("  Player 1 won!");
                    break;
                }
            } else {
                if (checkForWinner(p2)) {
                    System.out.println("  Player 2 won!");
                    break;
                }
            }
            // switches the players
            player = !player;
        }
    }
}

public static void printRules() {
	System.out.println("\n\n\tHere are the rules for this game\n"
					 + "\tYou need to get 4 in a row to win\n"
					 + "\tYou can use gravity once per game\n"
					 + "\tBEGIN!\n\n");
}

public static void setPlay() {
    if (p1 == "")
        p1 = "O";
    if (p2 == "")
        p2 = "X";
}

public static void printBoard() {
    System.out.println("    -4    -3    -2    -1     0     1     2     3     4");
    System.out.println("  +-----+-----+-----+-----+-----+-----+-----+-----+-----+");
    for (int n = board.length - 1; n >= 0; n--) {
        for (int x = 0; x < board[n].length; x++) {
            System.out.print("  |  " + board[n][x]);
        }
        System.out.println("  |  " + (n - 4));
        System.out.println("  +-----+-----+-----+-----+-----+-----+-----+-----+-----+");
    }
}

public static void useGravity() {
    while (true) {
        justUsedGravity = true;
        System.out.print("  What direction would you like to shift everything? ");
        String choiceOfDirection = in.next();
        if (choiceOfDirection.substring(0, 1).equalsIgnoreCase("U")) {
            gravityUp();
            break;
        } else if (choiceOfDirection.substring(0, 1).equalsIgnoreCase("D")) {
            gravityDown();
            break;
        } else if (choiceOfDirection.substring(0, 1).equalsIgnoreCase("L")) {
            gravityLeft();
            break;
        } else if (choiceOfDirection.substring(0, 1).equalsIgnoreCase("R")) {
            gravityRight();
            break;
        } else {
            System.out.println("  Please try again.");
        }
    }

}

public static void gravityUp() {
	for(int column = 0; column < board[0].length; column++) {
		column:
		while(true) {
			// finds topmost row
			int topmostRow = board.length - 1;
			boolean fullColumn = true;
			for(int row = topmostRow; row >= 0; row--) {
				if(board[row][column] == " ") {
					topmostRow = row;
					fullColumn = false;
					break;
				}
			}
			if(fullColumn)
				break column;
			// shifts everything up
			for(int row = topmostRow; row >= 0; row--) {
				if(board[row][column] != " ") {
					// shifts to topmost row
					board[topmostRow--][column] = board[row][column];
					board[row][column] = " ";
				}
				// if hit wall, then move on to the next column
				if(row == 0) {
					break column;
				}
			}
		}
	}
}

public static void gravityDown() {
	for(int column = 0; column < board[0].length; column++) {
		column:
		while(true) {
			// finds bottommost row
			int bottommostRow = 0;
			boolean fullColumn = true;
			for(int row = bottommostRow; row < board.length; row++) {
				if(board[row][column] == " ") {
					bottommostRow = row;
					fullColumn = false;
					break;
				}
			}
			if(fullColumn)
				break column;
			// shifts everything down
			for(int row = bottommostRow; row < board.length; row++) {
				if(board[row][column] != " ") {
					// shifts to topmost row
					board[bottommostRow++][column] = board[row][column];
					board[row][column] = " ";
					bottommostRow %= 8;
				}
				// if hit wall, then move on to the next column
				if(row == board.length - 1) {
					break column;
				}
			}
		}
	}
}

public static void gravityLeft() {
    for(int row = board.length - 1; row >= 0; row--) {
        row: 
        while(true) {
            // finds the leftmost index
            int leftmostIndex = 0;
            boolean fullRow = true;
            for(int index = leftmostIndex; index < board[row].length; index++) {
                if(board[row][index] == " ") {
                    leftmostIndex = index;
                    fullRow = false;
                    break;
                }
            }
            if(fullRow)
                break row;
            // shifts everything left
            for (int index = leftmostIndex; index < board[row].length; index++) {
                if(board[row][index] != " ") {
                    // shifts to leftmost possible index
                    board[row][leftmostIndex++] = board[row][index];
                    board[row][index] = " ";
                    leftmostIndex %= 8;
                }
                // if hit wall, then move on to the next row;
                if(index == board[row].length - 1) {
                    break row;
                }
            }
        }
    }
}

public static void gravityRight() {
	for(int row = board.length - 1; row >= 0; row--) {
        row: 
        while(true) {
            // finds the rightmost index
            int rightmostIndex = board[row].length - 1;
            boolean fullRow = true;
            for(int index = board[row].length - 1; index >= 0; index--) {
                if(board[row][index] == " ") {
                    rightmostIndex = index;
                    fullRow = false;
                    break;
                }
            }
            if(fullRow)
                break row;
            // shifts everything right
            for(int index = board[row].length - 1; index >= 0; index--) {
                if(board[row][index] != " ") {
                    // shifts to leftmost possible index
                    board[row][rightmostIndex--] = board[row][index];
                    board[row][index] = " ";
                }
                // if hit wall, then move on to the next row;
                if(index == 0) {
                    break row;
                }
            }
        }
    }
}

public static void updateBoard(int row, int column) {
    row += 4; column += 4;
    boolean notFinished = true;
    if (board[row][column] == " ") {
        if (player) {
            board[row][column] = p1;
        } else {
            board[row][column] = p2;
        }
        notFinished = false;
    }
    if (notFinished) {
        System.out.println("  INVALID! Please try again.");
        System.out.print("  Please input row and column");
        updateBoard(in.nextInt(), in.nextInt());
    }
}

public static boolean checkForWinner(String play) {
    boolean isWin = false;
    outerHorizontal: for (int a = 0; a < board.length; a++) {
        for (int b = 0; b < board[a].length - 3; b++) {
            if (board[a][b] == play && board[a][b + 1] == play && board[a][b + 2] == play
                    && board[a][b + 3] == play) {
                isWin = true;
                break outerHorizontal;
            }

        }
    }

    outerVertical: for (int x = 0; x < board.length - 3; x++) {
        for (int y = 0; y < board[x].length; y++) {
            if (board[x][y] == play && board[x + 1][y] == play && board[x + 2][y] == play
                    && board[x + 3][y] == play) {
                isWin = true;
                break outerVertical;
            }
        }
    }

    outerLeftDiagonal: for (int p = 0; p < board.length - 3; p++) {
        for (int o = 0; o < board[p].length - 3; o++) {
            if (board[p][o] == play && board[p + 1][o + 1] == play && board[p + 2][o + 2] == play
                    && board[p + 3][o + 3] == play) {
                isWin = true;
                break outerLeftDiagonal;
            }
        }
    }

    outerRightDiagonal: for (int u = 0; u < board.length - 3; u++) {
        for (int i = 3; i < board[u].length; i++) {
            if (board[u][i] == play && board[u + 1][i - 1] == play && board[u + 2][i - 2] == play
                    && board[u + 3][i - 3] == play) {
                isWin = true;
                break outerRightDiagonal;
            }
        }
    }

    return isWin;
}

public static boolean checkDraw() {
    if (checkForWinner(p1) && checkForWinner(p2)) {
        return true;
    }
    for (int n = 0; n < board.length; n++) {
        for (int a = 0; a < board[n].length; a++) {
            if (board[n][a] == " ")
                return false;
        }
    }
    return true;
}

}