package myoven.button;import java.util.*;public class BaseButton {  Vector Observers; //預(yù)定者集合  public BaseButton() {    Observers=new Vector();  }  public void pressed(){//通知所有預(yù)定者    for(int i=0;i<Observers.size();i++){      ((ButtonObserver)Observers.elementAt(i)).recieveButtonNotification();    }  }  public void subscribe(Object obt){//預(yù)定    Observers.add(obt);  }  public void unsubscribe(Object obt){//撤消預(yù)定    Observers.remove(obt);  }}