Question

I defined this simple method:

public static boolean isBorder(int x, int y) throws CollisionDetectionException {
        try {
            if ( (levelItems[x][y] instanceof StaticGameObject && levelItems[x][y].isVisible()) ||
                (levelItems[x-1][y] instanceof StaticGameObject && levelItems[x-1][y].isVisible()) ||
                (levelItems[x][y+1] instanceof StaticGameObject && levelItems[x][y+1].isVisible()) ||
                (levelItems[x][y-1] instanceof StaticGameObject && levelItems[x][y-1].isVisible()) ||
                (levelItems[x-1][y-1] instanceof StaticGameObject && levelItems[x-1][y-1].isVisible()) ||
                (levelItems[x-1][y+1] instanceof StaticGameObject &&levelItems[x-1][y+1].isVisible()) ||
                (levelItems[x+1][y] instanceof StaticGameObject && levelItems[x+1][y].isVisible()) ||
                (levelItems[x+1][y+1] instanceof StaticGameObject && levelItems[x+1][y+1].isVisible()) ||
                (levelItems[x+1][y-1] instanceof StaticGameObject && levelItems[x+1][y-1].isVisible()) ) {
                return true;
            } else {
                return false;
            } 
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new CollisionDetectionException("Collision couldn't be checked because checking position " + x + "/" + y + " caluclated values below (0/0)");
        }
    }

As you can see i have a 2dimensional array. Now i want to check a specific position ((x/y) -> the method arguments), if there are any visible StaticGameObject in the neighbouring fields of the 2dimensional array.

The levelItems array consists of so called GameObject. StaticGameObject is a a direct subclass of GameObject.

Any hints how to improve this method?

Answer 1

Add a method to GameObject

bool isBorderObject() { return false; }

Then override in StaticGameObject

bool isBorderObject() { return true; }

change the test to

(levelItems[x][y].isBorderObject() && levelItems[x][y].isVisible())

Also, the if could be this nested for

for (int i = x-1; i <= x+1; ++i) {
   for (int j = y-1; j <= y+1; ++j) {
       GameObject item = levelItems[i][j];
       if (item.isBorderObject() && item.isVisible()) 
           return true;
   }
}
return false;