registerhashmap.java

高质量Java程序设计 源代码

package net.betterjava.design.collection.shadowcopy;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

public class RegisterHashMap {

	private HashMap visitors;

	public RegisterHashMap() {
		visitors = new HashMap();
	}

	public RegisterHashMap(HashMap para) {
		visitors = para;
	}

	public void add(Visitor husband, Visitor wife) {
		visitors.put(husband, wife);
	}

	public Object clone() {
		return new RegisterHashMap((HashMap) visitors.clone());
	}

	public String toString() {
		StringBuffer temp = new StringBuffer();
		Set set = visitors.keySet();
		Iterator it = set.iterator();
		while (it.hasNext()) {
			Visitor v = (Visitor) it.next();
			temp.append(v.getName()).append(":").append(v.getAddress()).append("\n");
			v = (Visitor) visitors.get(v);
			temp.append(v.getName()).append(":").append(v.getAddress()).append("\n");
		}
		return temp.toString();
	}

	public static void main(String[] args) {
		RegisterHashMap r = new RegisterHashMap();
		Visitor husband = new Visitor("Charles", "It's secret");
		Visitor wife = new Visitor("Diana", "It's secret");
		r.add(husband, wife);
		System.out.println(r);

		RegisterHashMap copy = (RegisterHashMap) r.clone();
		husband.setAddress("I'm not sure");
		System.out.println(r);
	}
}