import java.util.* ;
class House extends Observable{
private float price ;
public House(float price){
this.price = price ;
}
public float getPrice(){
return this.price ;
}
public void setPrice(float price){
super.setChanged() ;
super.notifyObservers(price) ;
this.price = price ;
}
public String toString(){
return "房子價(jià)格為：" + this.price ;
}
};
class HousePriceObserver implements Observer{
private String name ;
public HousePriceObserver(String name){
this.name = name ;
}
public void update(Observable o,Object arg){
if(arg instanceof Float){
System.out.print(this.name + "觀察到價(jià)格更改為：") ;
System.out.println(((Float)arg).floatValue()) ;
}
}
};
public class ObserDemo01{
public static void main(String args[]){
House h = new House(1000000) ;
HousePriceObserver hpo1 = new HousePriceObserver("購(gòu)房者A") ;
HousePriceObserver hpo2 = new HousePriceObserver("購(gòu)房者B") ;
HousePriceObserver hpo3 = new HousePriceObserver("購(gòu)房者C") ;
h.addObserver(hpo1) ;
h.addObserver(hpo2) ;
h.addObserver(hpo3) ;
System.out.println(h) ;
h.setPrice(666666) ;
System.out.println(h) ;
}
};
