java-design mode (structural type)-"appearance mode"

1. Appearance mode (facade)

Know the principle at least: a class should interact with the other classes as little as possible , making the classes relatively independent and the system functional modules relatively independent.

Definition: Reduce the dependency between classes and classes, just like spring, you can configure relationships between classes and classes into a configuration file .

The appearance pattern is to put the relationship between their classes in a facade class , reducing the coupling between classes and classes, which does not involve interfaces.

2. Illustrations

public class Computer {//Individual parts (classes) Private CPU Cpu=new CPU ();p rivate memory M=new memory ();p rivate disk d=new disk ();p u         Blic static void Main (string[] args) {//TODO auto-generated method stub computer cp=new computer ();         Cp.start (); Cp.shutdown ();}      Computer starts public void start () {Cpu.start ();      M.start ();    D.start ();    SYSTEM.OUT.PRINTLN ("Computer is up and ready");      }//Computer off public void shutdown () {cpu.shutdown ();      M.shutdown ();    D.shutdown ();    SYSTEM.OUT.PRINTLN ("Computer complete shutdown");      }}class CPU {public void start () {System.out.println ("CPU boot ...");      } public void Shutdown () {System.out.println ("CPU off ...");    }}class memory{public void Start () {System.out.println ("Memory start ...");    } public void Shutdown () {System.out.println ("Memory closed ...");    }}class disk{public void Start () {System.out.println ("Hard disk boot ..."); } public void Shutdown () {System.out.println ("hard disk closed ..."); }}

Operation Result:

CPU boot ... Memory boot ... Hard Drive Boot ... CPU off after computer starts ... Memory off ... Hard drive off ...

　　

java-design mode (structural type)-"appearance mode"