设计模式01观察者模式(java)

先发代码，有空来写内容。

observer1

 import java.util.Observer;
 import java.util.Observable;

 //学生类(Student)继承Observable后变得可以被观察
 class Student extends Observable{
     //属性
     private String name;
     private boolean isSleep = false;
     private boolean isLate = false;
     //构造函数
     public Student(){}
     public Student(String name){
         this.name = name;
     }
     //睡觉行为
     public void sleep(){
         System.out.println(name + " is sleeping");
         isSleep = true;
         setChanged();
         notifyObservers();

     }
     public String toString(){
         return name;
     }
 }
 //教师类(Teacher)实现Observer接口成为观察者
 class Teacher implements Observer{
     @Override
     public void update(Observable o,Object arg){
             System.out.println("teacher: "+o+",wakeup!wakeup!");
     }
 }
 //班主任类(ClassHead)实现Observer接口成为观察者
 class ClassHead implements Observer{
     @Override
     public void update(Observable o,Object arg){
             System.out.println("classHead: "+o+",cleanTheRoomAfterSchool");
     }
 }
 public class ObserverDemo{
     public static void main(String[] arguments){
         Student tom = new Student("Tom");
         tom.addObserver(new ClassHead());
         tom.addObserver(new Teacher());

         System.out.println("有 "+tom.countObservers()+" 个观察者在观察Tom");
         tom.sleep();

     }
 }

observer2

import java.util.Map;
import java.util.HashMap;
import java.util.Observer;
import java.util.Observable;

//学生类(Student)继承Observable后变得可以被观察
class Student extends Observable{
    //属性
    private String name;
    private boolean isSleep = false;
    private boolean isLate = false;
    //构造函数
    public Student(){}
    public Student(String name){
        this.name = name;
    }
    //睡觉行为
    public void sleep(){
        System.out.println(name + " is sleeping");
        isSleep = true;
        setChanged();
        notifyObservers("sleep");

    }
    //迟到行为
    public void late(){
        System.out.println(name + " was lated");
        isLate = true;
        setChanged();
        notifyObservers("late");
    }
    public String toString(){
        return name;
    }
}
//教师类(Teacher)实现Observer接口成为观察者
class Teacher implements Observer{
    //参数arg作为key，该参数触发的回应作为value存储在Map中
    private Map<String,String> info = new HashMap<String,String>();
    public Teacher(){
        info.put("sleep",",wakeup!wakeup!");
        info.put("late",",come in.");
    }
    //添加键值对
    public boolean addSay(String k,String v){
        return info.put(k,v)==null?false:true;
    }
    @Override
    public void update(Observable o,Object arg){
            String say = info.get(arg);
            if(say == null){
                return;
            }
            System.out.println("teacher: "+o+say);
    }
}
//班主任类(ClassHead)实现Observer接口成为观察者
class ClassHead implements Observer{
    private Map<String,String> info = new HashMap<String,String>();
    public ClassHead(){
        info.put("sleep",",goOutWashBaFace");
        info.put("late",",cleanTheRoom!");
    }
    public boolean addSay(String k,String v){
        return info.put(k,v)==null?false:true;
    }
    @Override
    public void update(Observable o,Object arg){
            String say = info.get(arg);
            if(say == null){
                return;
            }
            System.out.println("classHead: "+o+say);
    }
}
public class ObserverDemo{
    public static void main(String[] arguments){
        Student tom = new Student("Tom");
        tom.addObserver(new ClassHead());
        tom.addObserver(new Teacher());

        System.out.println("有 "+tom.countObservers()+" 个观察者在观察Tom");
        tom.sleep();
        tom.late();
    }
}

Observer与Obvsevable实现

 import java.util.List;
 import java.util.ArrayList;
 import java.util.Iterator;
 //定义observer接口
 interface observer{
     public void update(observable o,Object arg);
 }
 //定义observable类
 class observable{
     //isChanged记录实例是否改变
     private boolean isChanged;
     //obsers存储观察者集合
     private List<observer> obsers;
     //构造函数初始化实例
     public observable(){
         isChanged = false;
         obsers = new ArrayList<observer>();
     }
     //设置是否发生变化为false
     protected void clearChanged(){
         isChanged = false;
     }
     //设置是否发生变化为true
     public void setChanged(){
         isChanged = true;
     }
     //返回对象是否发生改变
     public boolean hasChanged(){
         return isChanged;
     }
     //添加观察者
     public void addObserver(observer o){
         obsers.add(o);
     }
     //删除指定观察者
     public void deleteObserver(observer o){
         obsers.remove(o);
     }
     //清空所有观察者
     public void deleteObservers(){
         obsers.clear();
     }
     //返回观察者数量
     public int countObservers(){
         return obsers.size();
     }

     //如果对象发生改变就通知所有观察者，然后将变化状态设置为false
     public void notifyObservers(){
         notifyObservers(new Object());
     }
     public void notifyObservers(Object arg){
         if(!hasChanged())
             return;
         Iterator it = obsers.iterator();
         while(it.hasNext()){
             ((observer)(it.next())).update(this,arg);
         }
         clearChanged();
     }
 }