weatherdata.java

设计模式中的Observer模式。有一气象台例子说明。

package DP.Chapter2;

import java.util.ArrayList;


public class WeatherData implements Subject {
	
	private ArrayList observers;
	private float temperature;
	private float humidity;
	private float pressure;
	
	public WeatherData(){
		observers = new ArrayList();
	}

	public void notifyObservers() {
		for(int i = 0; i < observers.size(); i++){
			Observer observer = (Observer)observers.get(i);
			observer.update(temperature, humidity, pressure);
		}

	}

	public void registerObserver(Observer o) {
		observers.add(o);

	}

	public void removeObserver(Observer o) {
		int i = observers.indexOf(o);
		if(i >=0){
			observers.remove(i);
		}

	}
	
	public void measurementsChanged(){
		notifyObservers();
	}
	
	public void setMeasurements(float temperature, float humidity, float pressure){
		this.temperature = temperature;
		this.humidity = humidity;
		this.pressure = pressure;
		measurementsChanged();
	}

}