// ejecting a ball will eject the ball from the machine add it to the rack.
public Ball ejectBall() {
// we check not to get null reference balls while we are ejecting from machine.
if (machine.getNoOfBalls() > 0 && rack.getNoOfBalls() < rack.getSize()) {
Ball ejectedBall = machine.ejectBall();
rack.addBall(ejectedBall);
return ejectedBall;
} // if
else return null;
} // ejectBall
public int getRackNoOfBalls() {
return rack.getNoOfBalls();
} // getRackNoOfBalls
