Distinguishing between delegation, composition and aggregation (Java OO Design)

Question

I am facing a continuing problem distinguishing delegation, composition and aggregation from each other, and identifying the cases where it\'s the best to use one over the o

Answer 1

1) Delegation: Man-driver-car example. A Man bought a car. But that man does not know to drive the car. So he will appoint a driver who knows driving a car. So the Man class wants to perform a transportation using car. But it does not have the interacting- functionality/compatibility with car. So he uses a class which has compatibility with car that is driver which is compatible with man class. Assuming that driver can understand what man says

2) Composition: Car simulation is a routine example. To make a car move, wheel rotates. Car class using wheel class rotate functinality as part of its move function, where as wheel is part of car.

3) Aggregation: Car and its colour. Car class object ferrari will have a colour class object red. But colour class object red can be there as individual class, when user search happens with a specification of red colour.