Inheritance method calling - Java

Question

I have a method in a class that sets "Position X" and "Position Y".

public class Player {

    int positionX, postinionY;

    public void setPosition (int position_X, int position_Y)
    {
         positionX = position_X;
         postinionY = position_Y;
    }

}

I have another class "World" that has an array in it called grid. I have to use the values of position x and y from Player to get location from the grid.

public class World extends Player {
    int [] [] grid = new int [16] [16];

    public int getLocationID (int x, int y)
    {
        return grid [x][y];
    }
}

I need help to take Position x,y(Player) and use them instead x,y (World)

Answer 1

You could add another method to World get the own (the players) location id:

public int getPlayerLocationID() {
    return grid[positionX][positionY];
}

But - honestly - in what kind of universum we have a relation "a world is-a player"? In all universums that I know (Ok, only one, actually), we usually have "a world has-many players".

Answer 2

This method should do what you want.

public class World extends Player {
    int [] [] grid = new int [16] [16];
    public int getPlayerID (int locationX, int locationY)
    {
        if((locationX>15)||(locationX>16))
            throw new InvalidArgumentException("Player locations should be less than 16!");
        return grid [locationX][locationY];
    }
}

Note that it will throw an exception in case the arguments provided are not valid.