Java 观察者模式示例

ObserverMe.java

import java.util.Observable;
import java.util.Observer;
/*
 * Java 观察者模式示例
 */
class MyDataObservable extends Observable {
  private String data;

	public String getData() {
		return data;
	}

	public void setData(String data) {
		this.data = data;
		this.setChanged();
		this.notifyObservers();
	}
}

class MyDataObserver implements Observer {

	@Override
	public void update(Observable arg0, Object arg1) {
		MyDataObservable data = (MyDataObservable) arg0;
		System.out.println("data has changed:" + data.getData());
	}
}

public class ObserverMe {

	public static void main(String[] args) {
		MyDataObservable data = new MyDataObservable();
		MyDataObserver observer = new MyDataObserver();
		data.addObserver(observer);
		data.setData("data1");
		data.setData("data2");
	}
}