享元模式--避免创建多对象、对象共享

WebSite.java

package com.godv.flyweight;

public abstract class WebSite {
	//外部状态方法
	public abstract void use(User user);
}

ConcreteWebSite.java

package com.godv.flyweight;

public class ConcreteWebSite extends WebSite {

	// 共享的部分，内部状态map的key
	private String type = "";

	// 构造器
	public ConcreteWebSite(String type) {

		this.type = type;
	}

	@Override
	public void use(User user) {
		// TODO Auto-generated method stub
		System.out.println("type :" + type + "User:" + user.getName());
	}
}

User.java

package com.godv.flyweight;

public 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;
	}

}

WebSiteFactory.java

package com.godv.flyweight;

import java.util.HashMap;

public class WebSiteFactory {
	// 集合， 充当池的作用
	private HashMap<String, ConcreteWebSite> pool = new HashMap<>();

	public WebSite getWebSiteCategory(String type) {
		if (!pool.containsKey(type)) {
			// 池中不包含则创建新的对象，并放入到池中
			pool.put(type, new ConcreteWebSite(type));
		}
		//包含直接返回
		return pool.get(type);
	}
	
	//获取池中的连接数
	public int getWebSiteCount() {
		return pool.size();
	}
}

Client.java

package com.godv.flyweight;

public class Client {
	public static void main(String[] args) {
		WebSiteFactory factory = new WebSiteFactory();

		WebSite webSite1 = factory.getWebSiteCategory("IDLE");

		webSite1.use(new User("tom"));
		
		WebSite webSite2 = factory.getWebSiteCategory("PLAY");

		webSite2.use(new User("jack"));

		WebSite webSite3 = factory.getWebSiteCategory("PLAY");

		webSite3.use(new User("smith"));

		WebSite webSite4 = factory.getWebSiteCategory("PLAY");

		webSite4.use(new User("king"));
		
		System.out.println("分类共=" + factory.getWebSiteCount());
	}
}