轻松理解设计模式——观察者模式

观察者模式，学习代码。

package com.kevinlsui.observer.example;

/**
* 被观察类接口
*/
public interface Subject {
	// 观察者注册
	public void add(Observer o);
	//观察者注销
	public void remove(Observer o);
	// 消息发布
	public void update();
}

package com.kevinlsui.observer.example;

import java.util.ArrayList;
import java.util.List;

/**
* 被观察类
*/
public class WeatherData implements Subject{

	private int low;
	private int hight;
	private String weather;
	private List<Observer> list = new ArrayList<Observer>();
	
	public int getLow() {
		return low;
	}

	public int getHight() {
		return hight;
	}

	public String getWeather() {
		return weather;
	}
	
	public void setData(int low,int hight,String weather){
		this.low = low;
		this.hight = hight;
		this.weather = weather;
		update();
	}

	@Override
	public void add(Observer o) {
		if(!list.contains(o)){
			list.add(o);
		}
		
	}

	@Override
	public void remove(Observer o) {
		if(list.contains(o)){
			list.remove(o);
		}
	}

	@Override
	public void update() {
		for(Observer o :list){
			o.update(getLow(),getHight(),getWeather());
		}
		
	}
}

package com.kevinlsui.observer.example;

/**
* 观察类接口
*/
public interface Observer {
    //坐等信息发布过来
	public void update(int low,int hight,String weather);
}

package com.kevinlsui.observer.example;

/**
* 观察类1
*/
public class Ipad implements Observer{
	private Subject sub;
	
	public Ipad(Subject subject){
		this.sub = subject;
		subject.add(this);
	}
	
	public void cancle(){
		sub.remove(this);
	}
	@Override
	public void update(int low, int hight, String weather) {
		System.out.println("Ipd....low:"+low+";hight:"+hight+";weather:"+weather);
		
	}

}

package com.kevinlsui.observer.example;

/**
* 观察类2
*/
public class Phone implements Observer{

	private Subject sub;
	
	public Phone(Subject subject){
		this.sub = subject;
		subject.add(this);
	}
	
	public void cancle(){
		sub.remove(this);
	}
	
	@Override
	public void update(int low, int hight, String weather) {
		System.out.println("Phone..........low:"+low+";hight:"+hight+";weather:"+weather);
		
	}

}

package com.kevinlsui.observer.example;

/**
*测试类
*/
public class Test {
	
	public static void main(String[] args) {
		System.out.println("观察者模式.........");
		WeatherData we = new WeatherData();
		
		Phone p = new Phone(we);
		Ipad ipad = new Ipad(we);
		we.setData(1, 12, "晴天");
		p.cancle();
		we.setData(5, 18, "大晴天");
		
	}
}