class XrayGogglesModel extends Observable implements Cloneable {

    public void setScreenPosition(ScreenPosition upperLeft, ScreenPosition upperRight, ScreenPosition lowerLeft,
            ScreenPosition lowerRight)
    {
        if (myValidator == null || myValidator.isValid(upperLeft, upperRight, lowerLeft, lowerRight))
        {
            myUpperLeft = upperLeft;
            myUpperRight = upperRight;
            myLowerLeft = lowerLeft;
            myLowerRight = lowerRight;
            setChanged();
            notifyObservers(SCREEN_POSITION);
        }
    }

}