Py設計模式-命令模式

命令模式：將一個請求封裝成一個對象，從而讓你使用不同的請求把客戶端參數化，對請求排隊或者記錄請求日誌，可以提供命令的撤銷和恢復功能。

最大的特點就是：將具體的命令與對應的接受者相關聯，使得調用方不用關心具體的行動執行者及如何執行，只要發送正確的命令，就能準確無誤的完成相應的任務。

from abc import ABCMeta,abstractmethod

class Chef():
    def steamFood(self,originalMaterial):
        print("%s 清蒸中..."% originalMaterial)
        return "清蒸"+originalMaterial

    def stirFriedFood(self,originalMaterial):
        print("%s 爆炒中..." % originalMaterial)
        return "爆炒" + originalMaterial

class Order(metaclass=ABCMeta):

    def __init__(self,name,originalMaterial):
        self._chef = Chef()
        self._name = name
        self._originalMaterial = originalMaterial

    def getDisplayName(self):
        return self._name + self._originalMaterial

    @abstractmethod
    def processOrder(self):
        pass

class SteamedOrder(Order):

    def __init__(self,originalMaterial):
        super().__init__("清蒸", originalMaterial)

    def processOrder(self):
        if(self._chef is not None):
            return self._chef.steamFood(self._originalMaterial)
        return ""

class SpicyOrder(Order):

    def __init__(self,originalMaterial):
        super().__init__("辣炒", originalMaterial)

    def processOrder(self):
        if (self._chef is not None):
            return self._chef.stirFriedFood(self._originalMaterial)
        return ""

class Waiter:

    def __init__(self,name):
        self.__name = name
        self.__order = None

    def receiveOrder(self,order):
        self.__order = order
        print("%s,您的%s已收到，請耐心等待"%(self.__name,order.getDisplayName()))

    def placeOrder(self):
        food = self.__order.processOrder()
        print("服務員%s:您的餐%s已經準備好，請您慢用"%(self.__name,food))

def test():
    waiter = Waiter("Tom")
    steamOrdern = SteamedOrder("螃蟹")

    waiter.receiveOrder(steamOrdern)
    waiter.placeOrder()

test();

運行結果：

Tom,您的清蒸螃蟹已收到，請耐心等待
螃蟹 清蒸中...
服務員Tom:您的餐清蒸螃蟹已經準備好，請您慢用

aaa