Strategy pattern

• Ducks fly and quack
• Rubber ducks don't fly and quack
• => Different fly and quack behaviour

Encapsulate what varies! => Fly and quackbehaviour.

How

• Create duckbehaviour- and flybehaviour-interfaces (Program to interface)
• Different implementation in the concrete behaviour classes.
• Duck base-class with reference to FlyBehaviour- and QuackBehaviour-interface.
• The concrete Duck-classes will then use the appropriate implementation of the behaviours. (Composition)