观察者模式-大话设计模式

 
import java.util.ArrayList;
 
//主题
public class Subject {
    protected String name;
 
    public Subject(String name) {
        this.name = name;
    }
 
    //同事列表
    private ArrayList<Observer> list = new ArrayList<>();
    private String action;
 
    //增加同事
    public void attach(Observer observer) {
        list.add(observer);
    }
 
    //通知
    public void notifyEmployee() {
        for (Observer item : list) {
            item.update();
        }
    }
 
    //获取通知
    public void setAction(String action) {
        this.action = action;
    }
 
    //设置通知
    public String getAction() {
        return this.action;
    }
}
 
//前台秘书类
public class Secretary  extends Subject{
 
    public Secretary(String name) {
        super(name);
    }
 
 
}
//boos
public class Boss extends Subject{
 
    public Boss(String name) {
        super(name);
    }
 
 
}
//观察者
public abstract class Observer {
    protected String name;
    protected  Subject sub;
 
    public Observer(String name, Subject sub) {
        this.name = name;
        this.sub = sub;
    }
    public abstract  void update();
}
public class StockObserver extends Observer {
 
    public StockObserver(String name, Subject sub) {
        super(name, sub);
    }
 
    public void update() {
        System.out.println(this.sub.name + ": " + this.sub.getAction() + this.name + "，股票,请开始工作。");
    }
}
 
public class NBAObserver extends Observer{
 
 
    public NBAObserver(String name, Subject sub) {
        super(name,sub);
    }
 
    public void update() {
        System.out.println(this.sub.name + ": " + this.sub.getAction() + this.name + "，NBA,请开始工作。");
    }
}
  public static void main(String[] args) {
        Subject secretary1=new Secretary("童子喆");
 
        Observer employee1=new StockObserver("zhangsan",secretary1);
        Observer employee2=new NBAObserver("lisi",secretary1);
 
        secretary1.attach(employee1);
        secretary1.attach(employee2);
 
        secretary1.setAction("老板回来了.");
        secretary1.notifyEmployee();
    }