jdk自带的观察者模式

jdk自带观察者模式的实现，java.util.Observable，java.util.Observer

代码示例

package com.kevinlsui.observer.jdk;

import java.util.Observable;

/**
* 天气预报，被观察者
*/
public class WeatherData extends Observable{

	private int low;
	private int hight;
	private String weather;
	
	public int getLow() {
		return low;
	}

	public int getHight() {
		return hight;
	}

	public String getWeather() {
		return weather;
	}
	// 天气信息发布，需要推送给观察者
	public void setData(int low,int hight,String weather){
		this.low = low;
		this.hight = hight;
		this.weather = weather;
		
		setChanged();//查看源码，只有更改了该属性，才能进行发布。
		//1.消息推过去
		notifyObservers(new Object[]{getLow(),getHight(),getWeather()});
		//2.对象传过去
		/*notifyObservers();*/
		
	}

	

	
}

package com.kevinlsui.observer.jdk;

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

/**
* 观察类，要及时获取天气信息
*/
public class Ipad implements Observer{
	private Observable sub;
	
	public Ipad(Observable subject){
		this.sub = subject;
		// 添加到被观察者的推送对象列表
		subject.addObserver(this);;
	}
	
	public void cancle(){
	    // 取消关注
		sub.deleteObserver(this);;
	}
	
    // 坐等天气消息
	@Override
	public void update(Observable o, Object arg) {
		if(arg!=null){
			Object[] obj = (Object[]) arg;
			System.out.println("Ipd222....low:"+obj[0]+";hight:"+obj[1]+";weather:"+obj[2]);
		}else{
			WeatherData we = (WeatherData) o;
			System.out.println("Ipd....low:"+we.getLow()+";hight:"+we.getHight()+";weather:"+we.getWeather());
			
		}
		
		
	}

}

package com.kevinlsui.observer.jdk;

/**
 * JDK自带的观察者模式测试
 * @author admin
 *
 */
public class Test {
	public static void main(String[] args) {
		System.out.println("JDK观察者模式.........");
		WeatherData we = new WeatherData();
		
		Ipad ipad = new Ipad(we);
		we.setData(1, 12, "晴天");
		ipad.cancle();
		we.setData(5, 18, "大晴天");
	}
}