stockdata.java

基于股票价格变化的观察者模式的java源代码。初学者可看

import java.util.ArrayList;

public class StockData implements Stock{
	private ArrayList observers;
	private float price;
	public StockData(){ //构造方法
		observers = new ArrayList();
	}
	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 notifyObservers(){
		for(int i = 0; i < observers.size(); i++){
			Observer observer = (Observer)observers.get(i);
			observer.update(price);
		}
	}
	public void priceChanged(){
		notifyObservers();
	}
	public void setPrices(float price){
		this.price = price;
		priceChanged();
	}
}