Design Patterns III - Strategy pattern
Strategy pattern principle is create a interface strategy with methods definitions. The concrete strategies will implement the interface. And context will use interface strategy. With different strategy contexts, different strategies will be called.
There is an interface who is the strategy, it defines a method signature.
Two concrete class implement it and its method.
In a context class, it uses interface strategy as its parameter in its constrcutor. Its execute strategy method will call the interface strategy method.
Usage of strategy: