享元设计模式 - 黑马程序员技术交流社区

package com.source;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
abstract class Order {
// 执行卖出动作
public abstract void sell();
}
class FlavorOrder extends Order {
public String flavor;
// 获取咖啡口味
public FlavorOrder(String flavor) {
this.flavor = flavor;
}
@Override
public void sell() {
// TODO Auto-generated method stub
System.out.println("卖出一份" + flavor + "的咖啡。");
}
}
class FlavorFactory {
private Map<String, Order> flavorPool = new HashMap<String, Order>();
// 静态工厂,负责生成订单对象
private static FlavorFactory flavorFactory = new FlavorFactory();
private FlavorFactory() {
}
public static FlavorFactory getInstance() {
return flavorFactory;
}
public Order getOrder(String flavor) {
Order order = null;
if (flavorPool.containsKey(flavor)) {// 如果此映射包含指定键的映射关系，则返回 true
order = flavorPool.get(flavor);
} else {
order = new FlavorOrder(flavor);
flavorPool.put(flavor, order);
}
return order;
}
public int getTotalFlavorsMade() {
return flavorPool.size();
}
}
public class Client {
// 客户下的订单
private static List<Order> orders = new ArrayList<Order>();
// 订单对象生成工厂
private static FlavorFactory flavorFactory;
// 增加订单
private static void takeOrders(String flavor) {
orders.add(flavorFactory.getOrder(flavor));
}
public static void main(String[] args) {
// 订单生成工厂
flavorFactory = FlavorFactory.getInstance();
// 增加订单
takeOrders("摩卡");
takeOrders("卡布奇诺");
takeOrders("香草星冰乐");
takeOrders("香草星冰乐");
takeOrders("拿铁");
takeOrders("卡布奇诺");
takeOrders("拿铁");
takeOrders("卡布奇诺");
takeOrders("摩卡");
takeOrders("香草星冰乐");
takeOrders("卡布奇诺");
takeOrders("摩卡");
takeOrders("香草星冰乐");
takeOrders("拿铁");
takeOrders("拿铁");
// 卖咖啡
for (Order order : orders) {
order.sell();
}
// 打印生成的订单java对象数量
System.out.println("\n客户一共买了 " + orders.size() + " 杯咖啡! ");
// 打印生成的订单java对象数量
System.out.println("共生成了 " + flavorFactory.getTotalFlavorsMade()
+ " 个 FlavorOrder java对象! ");
}
}

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