# -*- coding: utf-8 -*-

from abc import ABCMeta, abstractmethod


# 提供接口Command
class Order(metaclass=ABCMeta):
    @abstractmethod
    def execute(self):
        pass


# 具体命令 ConcreteCommand
class BuyStockOrder(Order):
    def __init__(self, stock):
        self.stock = stock

    def execute(self):
        self.stock.buy()


class SellStockOrder(Order):
    def __init__(self, stock):
        self.stock = stock

    def execute(self):
        self.stock.sell()


# Receiver对象
class StockTrade(object):
    def buy(self):
        print("buy stock")

    def sell(self):
        print("sell stock")


# 调用者Agent，中介
class Broker(object):
    def __init__(self):
        self.__order_list = []  # 订单队列

    def add_order(self, order):
        self.__order_list.append(order)

    def place_order(self):
        for order in self.__order_list:
            order.execute()

        self.__order_list.clear()


if __name__ == '__main__':
    # client
    stock = StockTrade()
    buy_stock = BuyStockOrder(stock)
    sell_stock = SellStockOrder(stock)

    # invoker
    broker = Broker()
    broker.add_order(buy_stock)
    broker.add_order(sell_stock)

    broker.place_order()
"""
buy stock
sell stock
"""