感觉这个观察者模式也没什么了不得的,和还不如普通的处理,将观察者放一张表上,每次数据变化就去加载表内观察者的数据,再去推送 就ok
public interface Subject {
public void registerObserver(Observer o);
public void removeObserver(Observer o);
public void notifyObservers();
}
/**
* 1. 包含最新的天气情况信息
* 2. 含有 观察者集合,使用ArrayList管理
* 3. 当数据有更新时,就主动的调用 ArrayList, 通知所有的(接入方)就看到最新的信息
* @author Administrator
*/
public class WeatherData implements Subject {
private float temperatrue;
private float pressure;
private float humidity;
//观察者集合
private ArrayList<Observer> observers;
//加入新的第三方
public WeatherData() {
observers = new ArrayList<Observer>();
}
public float getTemperature() {
return temperatrue;
}
public float getPressure() {
return pressure;
}
public float getHumidity() {
return humidity;
}
public void dataChange() {
//调用 接入方的 update
notifyObservers();
}
//当数据有更新时,就调用 setData
public void setData(float temperature, float pressure, float humidity) {
this.temperatrue = temperature;
this.pressure = pressure;
this.humidity = humidity;
//调用dataChange, 将最新的信息 推送给 接入方 currentConditions
dataChange();
}
//注册一个观察者
@Override
public void registerObserver(Observer o) {
observers.add(o);
}
//移除一个观察者
@Override
public void removeObserver(Observer o) {
if(observers.contains(o)) {
observers.remove(o);
}
}
//遍历所有的观察者,并通知
@Override
public void notifyObservers() {
for(int i = 0; i < observers.size(); i++) {
observers.get(i).update(this.temperatrue, this.pressure, this.humidity);
}
}
}
//观察者接口,有观察者来实现
public interface Observer {
public void update(float temperature, float pressure, float humidity);
}
public class BaiduSite implements Observer {
// 温度,气压,湿度
private float temperature;
private float pressure;
private float humidity;
// 更新 天气情况,是由 WeatherData 来调用,我使用推送模式
public void update(float temperature, float pressure, float humidity) {
this.temperature = temperature;
this.pressure = pressure;
this.humidity = humidity;
display();
}
// 显示
public void display() {
System.out.println("===百度网站====");
System.out.println("***百度网站 气温 : " + temperature + "***");
System.out.println("***百度网站 气压: " + pressure + "***");
System.out.println("***百度网站 湿度: " + humidity + "***");
}
}
public class CurrentConditions implements Observer {
// 温度,气压,湿度
private float temperature;
private float pressure;
private float humidity;
// 更新 天气情况,是由 WeatherData 来调用,我使用推送模式
public void update(float temperature, float pressure, float humidity) {
this.temperature = temperature;
this.pressure = pressure;
this.humidity = humidity;
display();
}
// 显示
public void display() {
System.out.println("***Today mTemperature: " + temperature + "***");
System.out.println("***Today mPressure: " + pressure + "***");
System.out.println("***Today mHumidity: " + humidity + "***");
}
}
public class Client {
public static void main(String[] args) {
//创建一个WeatherData
WeatherData weatherData = new WeatherData();
//创建观察者
CurrentConditions currentConditions = new CurrentConditions();
BaiduSite baiduSite = new BaiduSite();
//注册到weatherData
weatherData.registerObserver(currentConditions);
weatherData.registerObserver(baiduSite);
//测试
System.out.println("通知各个注册的观察者, 看看信息");
weatherData.setData(10f, 100f, 30.3f);
weatherData.removeObserver(currentConditions);
//测试
System.out.println();
System.out.println("通知各个注册的观察者, 看看信息");
weatherData.setData(10f, 100f, 30.3f);
}
}
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