public class BallBallCollisionEvent extends HeronObject { // attributes public Ball ball1; public Ball ball2; // operations public BallBallCollisionEvent(final double timeElapsed, final Ball ball1, final Ball ball2){ { this .timeElapsed = timeElapsed ; this .ball1 = ball1 ; this .ball2 = ball2 ; } } // state entry procedures // dispatch function public void onSignal(HeronSignal signal) { if (false) { } } }