該代碼實現(xiàn)了一個可以注冊監(jiān)聽類的類，如果注冊了監(jiān)聽類，那么在類的一個方法執(zhí)行前會執(zhí)行監(jiān)聽類的方法。并且該監(jiān)聽類方法的參數(shù)就是被監(jiān)聽對象。

監(jiān)聽類就是事件監(jiān)聽器，被監(jiān)聽對象就是事件源，事件監(jiān)聽器的參數(shù)就是事件對象。

//設(shè)計一個事件源，被監(jiān)聽器監(jiān)聽? Observer（觀察者設(shè)計模式）

public class Demo2 {

?

?????? public static void main(String[] args) {

?????????????

????????????? Person p = new Person();

????????????? p.registerListener(new PersonListener(){

?

???????????????????? public void doeat(Event e) {

??????????????????????????? Person p = e.getSource();

??????????????????????????? System.out.println(p + "吃個死");

???????????????????? }

?

???????????????????? public void dorun(Event e) {

??????????????????????????? // TODO Auto-generated method stub

???????????????????? }

????????????????????

?

????????????? });

????????????? p.eat();

?????? }

?

}

?

class Person{

??????

?????? private PersonListener listener;

??????

?????? public void eat(){

????????????? if(listener!=null){

???????????????????? listener.doeat(new Event(this));

????????????? }

?????? }

??????

?????? public void run(){

????????????? if(listener!=null){

???????????????????? listener.dorun(new Event(this));

????????????? }

?????? }

??????

?????? public void registerListener(PersonListener listener){

????????????? this.listener = listener;

?????? }

}

?

interface PersonListener{

??????

?????? public void doeat(Event e);

??????

?????? public void dorun(Event e);

??????

}

?

class Event{

??????

?????? private Person source;

?????? public Event() {

????????????? super();

????????????? // TODO Auto-generated constructor stub

?????? }

?

?????? public Event(Person source) {

????????????? super();

????????????? this.source = source;

?????? }

?

?????? public Person getSource() {

????????????? return source;

?????? }

?

?????? public void setSource(Person source) {

????????????? this.source = source;

?????? }

??????

}

轉(zhuǎn)載于:https://www.cnblogs.com/flying607/p/3469133.html

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