Java Implementation Observer pattern

Recently, Java has been used to implement the observer pattern in design mode, the source code is as follows:

　　

Package Cn.demo;public class Testobersver {public static void main (string[] args) {people person=new person ();//Declaration by Observer SYS Tem.err.println ("Person:" +person);p Erson.addpersonlistener (new Personlistener () {public void running (personevent pe {System.err.println ("The person being observed:" +pe.getsource ()); System.err.println ("He is running");}); Person.run ();}} Class person{private Personlistener pl;public void Addpersonlistener (Personlistener pl) {this.pl=pl;} public void Run () {if (pl!=null) {pl.running (new personevent (This));} System.err.println ("Running .....");} Interface personlistener{void running (personevent PE);} Class Personevent{private Object Obj;public personevent (Object obj) {this.obj=obj;} Public Object GetSource () {return obj;}}

After the code executes:

　　

In this way, a simple observer pattern is implemented.

Java Implementation Observer pattern