Work Notes--5 most commonly used design patterns

Work Notes – 5 Most Commonly Used Design Modes

1 Factory method Focus on object creation.
2 Policy mode Focus on object behavior. When business changes, the addition and modification of the data module will not be affected, and the principle of openness and closure is not affected.
3 Appearance mode BS/CS
4 Adapter model: Self-development of reports or purchase of third parties
5Observer modeThe main interface menu (Enable and Vieable status of the menu) is event-driven

Spring (ICO control inversion/DI dependency injection)

Single Responsibilities: Interface andalgorithmSeparate, mobile phones and DV (Digital Video cameras) are all made. Although mobile phones can shoot, they are definitely not as professional as DV.
Principle of openness and closure:softwareExtensible and maintainable, new additions are open, while modifications are closed. Inc, Dec, Mul, Div classes, such as adding a Squear class will not affect the original class, and modifying any of the classes will not affect the other classes.
The principle of dependency inversion (or dependency inversion) can also be called the Lisch substitution principle. Subclasses can replace parent classes, aiming at abstraction and interface programming, rather than facial image implementation and detailed programming.
Dimit principle: Assume that Class A and Class B are unique to each other, if they need to call each other, it can be implemented through a third party.

Simple factory: Define Calculate class (the base class of Inc class) object in the Factory class, implement it through switch statement, put Inc, Dec, Mul, and Div into it, and create (new ()) the object at the same time

Abstract Base Class + Factory Method Class => Strategy

Abstract Factory Abstract (database may change) => Simple Factory + Reflection

Proxy mode:
Complex situation: A call B =>C call B. For example, Class A needs to call B to class. Class B has a reference to Class B in Class A. At this time, a class C (Proxy) is added to reference Class A in Class C. At the same time, an object of Class A is created, and an interface Intf class, A:Int, C:Int. In this way, when the client calls, we are Intf:i=new C(b instance);();
Or simply: call A => call C. We now need to call Class A. We could have directly A a = new A();(); on the client, but now it becomes Intf i= new C();();;

Appearance mode Facade: is a very commonly used design mode, classic three-layer architecture BLL and DAL,WebUIWhat is used between the BLL is the appearance pattern, which depends on the perfect embodiment of the inversion and the Dimit principle.

Mediator mode Mediator: You can refer to the Dimitese principle.
Enjoy the Yuan mode Flyweight: Multiple people register blogs or Go games, only black and white. If you don’t use this mode to create a game of chess, there may be hundreds of objects, and the memory will be exhausted.

The status mode is somewhat similar to the responsibility chain mode

Visitor Mode Vistor: It is the most difficult of the 23 modes of GOF.