priceobserver.java

23种GOF模式的java代码实现

package org.gof.action.observer;

import java.util.Observer;
import java.util.Observable;

//观察者PriceObserver主要用来对产品价格(price)进行观察的
public class PriceObserver
    implements Observer {

  private float price = 0;

  public void update(Observable obj, Object arg) {

    if (arg instanceof Float) {

      price = ( (Float) arg).floatValue();

      System.out.println("PriceObserver :price changet to " + price);
    }
  }

}