大话设计模式_享元模式

以建造不同的网站为例子。

package com.wzs.design;

import java.util.Hashtable;

/**
 * 大话设计模式--page274 享元模式
 * 
 * @author Administrator
 * 
 */
public class FlyweightPattern {
	public static void main(String[] args) {
		WebSiteFactory f = new WebSiteFactory();

		WebSite fx = f.getWebSiteCategory("产品展示");
		fx.use(new User("小菜"));

		WebSite fy = f.getWebSiteCategory("产品展示");
		fy.use(new User("大鸟"));

		WebSite fz = f.getWebSiteCategory("产品展示");
		fz.use(new User("娇娇"));

		WebSite fl = f.getWebSiteCategory("博客");
		fl.use(new User("老顽童"));

		WebSite fm = f.getWebSiteCategory("博客");
		fm.use(new User("桃谷六仙"));

		WebSite fn = f.getWebSiteCategory("博客");
		fn.use(new User("南海鳄神"));

		System.out.println("网站分类总数:" + f.getWebSiteCount());
	}
}

/*
 * 用户
 */
class User {
	private String name;

	public User(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

/*
 * 网站抽象类
 */
abstract class WebSite {
	public abstract void use(User user);
}

/*
 * 具体网站类
 */
class ConcreteWebSite extends WebSite {
	private String name;

	public ConcreteWebSite(String name) {
		this.name = name;
	}

	@Override
	public void use(User user) {
		System.out.println("网站分类:" + this.name + "\t用户:" + user.getName());
	}
}

/*
 * 网站工厂
 */
class WebSiteFactory {
	private Hashtable<String, ConcreteWebSite> flyweights = new Hashtable<String, ConcreteWebSite>();

	/*
	 * 获得网站分类
	 */
	public WebSite getWebSiteCategory(String key) {
		if (!flyweights.containsKey(key)) {
			flyweights.put(key, new ConcreteWebSite(key));
		}
		return flyweights.get(key);
	}

	/*
	 * 获得网站分类总数
	 */
	public int getWebSiteCount() {
		return flyweights.size();
	}
}