dataobserver1.java

来自「这个是我做j2ee培训时候自己整理和编写的设计模式的学习例子」· Java 代码 · 共 27 行

package org.hyq.observer0;

import java.util.Iterator;

@SuppressWarnings("unchecked")
public class DataObserver1 implements Observer {
	private DataSubject bag;

	public DataObserver1(DataSubject bag) {
		this.bag = bag;
		bag.addObserver(this);
	}

	public void update(Subject o) {
		if (o == bag) {
			System.out.println("The contents of the DataSubject have changed.");
			int counter = 0;
			Iterator i = bag.iterator();
			while (i.hasNext()) {
				i.next();
				counter++;
			}
			System.out.println("The new sum of the car number is: " + counter);
		}
	}
}