Big talk Design pattern note synthesis/aggregation multiplexing principle

Synthetic/aggregation reuse principle, use composition/aggregation as much as possible, and do not use class inheritance as much as possible.

Aggregation (Aggregation) represents a weak ' owning ' relationship, which shows that a object can contain a B object but a B object is not part of a object.

Synthesis (composition) is a strong ' own ' relationship that embodies a strict part-and-whole relationship, as well as part and whole life cycle.

Prioritizing the composition/aggregation of objects will help you keep each class encapsulated and focused on a single task so that class and class inheritance levels remain small and unlikely to grow into uncontrollable behemoths.

Inheritance is a strongly-coupled structure. Subclasses change as the parent class changes, so be sure to consider using a relationship that is ' is-a '.

Bridging mode (bridge), separating the abstract part from its implementation, so that they can vary independently.

 Package Bridge;  Public Abstract class IMP {    publicabstractvoid  operation ();}

 Package Bridge;  Public class extends Imp {    @Override    publicvoid  operation () {        System.out.println (" Concreteimpa operation ");}    }

 Package Bridge;  Public class extends Imp {    @Override    publicvoid  operation () {        System.out.println (" CONCRETEIMPB operation ");}    }

 Package Bridge;  Public Abstract class IMP {    publicabstractvoid  operation ();}

 Package Bridge;  Public class extends Abstraction {    publicstaticvoid  main (string[] args) {        abstraction Abstraction=new  refinedabstraction ();                Abstraction.setimp (new  Concreteimpa ());        Abstraction.operation ();                Abstraction.setimp (new  CONCRETEIMPB ());        Abstraction.operation ();    }}

To realize that the system may have multiple angles of classification, each of which is likely to change, then the multi-angle is separated to allow them to change independently, reducing the coupling between them.

Big talk Design pattern note synthesis/aggregation multiplexing principle