Tic Tac Toe(Board Class with artificial intelligence)

package tictactoefull;

public class Board {

    private static char [][] board = new char[3][3];
    private int row;
    private int column;

    public Board(){
    board[0][0] = '1';board[0][1] = '2';board[0][2] = '3';
    board[1][0] = '4';board[1][1] = '5';board[1][2] = '6';
    board[2][0] = '7';board[2][1] = '8';board[2][2] = '9';
    }

    public void printBoard(){
        System.out.println();
        for(int i=0; i<3; i++){
            for(int j=0; j<3; j++){
               System.out.printf("[%c]  ", board[i][j]);
            }
            System.out.println();
        }
    }
    public void setIndex(int index, char playerSign){
        this.row = setRow(index);
        this.column = setColumn(index);
        board[row][column] = playerSign;
    }
    private int setRow(int index){
        this.row=0;
        switch(index)
        {
            case 1:
            case 2:
            case 3: return row;
            case 4:
            case 5:
            case 6: return row+1;
            case 7:
            case 8:
            case 9: return row+2;
        }

        return row;
    }
    private int setColumn(int index){
        this.column=0;
        switch(index){
            case 1:
            case 4:
            case 7: return column;
            case 2:
            case 5:
            case 8: column = 1; return column;
            case 3:
            case 6:
            case 9: column = 2; return column;
        }
        return column;
    }

    public boolean testValidity(int index){
        if(index<1 || index>9){
            return false;
        }
        this.row = setRow(index);
        this.column = setColumn(index);
        int initialplayerSign = board[row][column];
        if(initialplayerSign >= '1' && initialplayerSign <= '9')
        {
            return true;
        }
        return false;
    }
    public boolean cheakWin(){

        if((board[0][0]==board[1][1] && board[0][0]==board[2][2]) ||
           (board[0][2]==board[1][1] && board[0][2]==board[2][0]))
        {
            return true;
        }
        else if ((board[0][0]==board[0][1] && board[0][0]==board[0][2]) ||
                (board[0][0]==board[1][0] && board[0][0]==board[2][0]))
        {
            return true;
        }
        else if ((board[2][2]==board[1][2] && board[2][2]==board[0][2]) ||
                (board[2][2]==board[2][1] && board[2][2]==board[2][0]))
        {
            return true;
        }
        else if ((board[0][1]==board[1][1] && board[0][1]==board[2][1]) ||
                (board[1][0]==board[1][1] && board[1][0]==board[1][2]))
        {
            return true;
        }

        return false;
    }
     public int setTarget(char playerSign, char computerSign){

        if((board[0][1]== computerSign && board[0][2]== computerSign) ||
           (board[1][1]== computerSign && board[2][2]== computerSign) ||
           (board[1][0]== computerSign && board[2][0]== computerSign))
        {
            return 1;
        }
        else if((board[0][0]== computerSign && board[0][2]== computerSign) ||
                (board[1][1]== computerSign && board[2][1]== computerSign))
        {
            return 2;
        }
        else if((board[0][0]== computerSign && board[0][1]== computerSign) ||
                (board[1][1]== computerSign && board[2][0]== computerSign) ||
                (board[1][2]== computerSign && board[2][2]== computerSign))
        {
            return 3;
        }
        else if((board[0][0]== computerSign && board[2][0]== computerSign) ||
                (board[1][1]== computerSign && board[1][2]== computerSign))
        {
            return 4;
        }
        else if((board[0][1]== computerSign && board[2][1]== computerSign) ||
                (board[1][0]== computerSign && board[1][2]== computerSign) ||
                (board[0][0]== computerSign && board[2][2]== computerSign) ||
                (board[0][2]== computerSign && board[2][0]== computerSign))
        {
            return 5;
        }
        else if((board[0][2]== computerSign && board[2][2]== computerSign) ||
                (board[1][0]== computerSign && board[1][1]== computerSign))
        {
            return 6;
        }
        else if((board[0][0]== computerSign && board[1][0]== computerSign) ||
                (board[0][2]== computerSign && board[1][1]== computerSign) ||
                (board[2][1]== computerSign && board[2][2]== computerSign))
        {
            return 7;
        }
        else if((board[0][1]== computerSign && board[1][1]== computerSign) ||
                (board[2][0]== computerSign && board[2][2]== computerSign))
        {
            return 8;
        }
        else if((board[0][0]== computerSign && board[1][1]== computerSign) ||
                (board[0][2]== computerSign && board[1][2]== computerSign) ||
                (board[2][0]== computerSign && board[2][1]== computerSign))
        {
            return 9;
        }

        else if((board[0][1]== playerSign && board[0][2]== playerSign) ||
           (board[1][1]== playerSign && board[2][2]== playerSign) ||
           (board[1][0]== playerSign && board[2][0]== playerSign))
        {
            return 1;
        }
        else if((board[0][0]== playerSign && board[0][2]== playerSign) ||
                (board[1][1]== playerSign && board[2][1]== playerSign))
        {
            return 2;
        }
        else if((board[0][0]== playerSign && board[0][1]== playerSign) ||
                (board[1][1]== playerSign && board[2][0]== playerSign) ||
                (board[1][2]== playerSign && board[2][2]== playerSign))
        {
            return 3;
        }
        else if((board[0][0]== playerSign && board[2][0]== playerSign) ||
                (board[1][1]== playerSign && board[1][2]== playerSign))
        {
            return 4;
        }
        else if((board[0][1]== playerSign && board[2][1]== playerSign) ||
                (board[1][0]== playerSign && board[1][2]== playerSign) ||
                (board[0][0]== playerSign && board[2][2]== playerSign) ||
                (board[0][2]== playerSign && board[2][0]== playerSign))
        {
            return 5;
        }
        else if((board[0][2]== playerSign && board[2][2]== playerSign) ||
                (board[1][0]== playerSign && board[1][1]== playerSign))
        {
            return 6;
        }
        else if((board[0][0]== playerSign && board[1][0]== playerSign) ||
                (board[0][2]== playerSign && board[1][1]== playerSign) ||
                (board[2][1]== playerSign && board[2][2]== playerSign))
        {
            return 7;
        }
        else if((board[0][1]== playerSign && board[1][1]== playerSign) ||
                (board[2][0]== playerSign && board[2][2]== playerSign))
        {
            return 8;
        }
        else if((board[0][0]== playerSign && board[1][1]== playerSign) ||
                (board[0][2]== playerSign && board[1][2]== playerSign) ||
                (board[2][0]== playerSign && board[2][1]== playerSign))
        {
            return 9;
        }

        return 0;

    }


}