python 设计模式-工厂方法模式

python-design-patter-factory-method.py

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

"""
工厂方法模式
"""


class Pizza:

    name = None
    dough = None
    sauce = None
    toppings = []

    def prepare(self):
        print("Preparing %s" % self.name)
        print("Tossing dough...")
        print("Adding sauce...")
        print("Adding toppings: ")
        for topping in self.toppings:
            print("  %s" % topping)

    def bake(self):
        print("Bake for 25 minutes at 350")

    def cut(self):
        print("Cutting the pizza into diagonal slices")

    def box(self):
        print("Place pizza in official PizzaStore box")

    def __str__(self):
        return self.name


class NYStyleCheesePizza(Pizza):

    name = "NY Style Sauce and Cheese Pizza"
    dough = "Thin Crust Dough"
    sauce = "Marinara Sauce"
    toppings = ["Grated", "Reggiano", "Cheese"]


class ChicagoStyleCheesePizza(Pizza):

    name = "Chicago Style Deep Dish Cheese Pizza"
    dough = "Extra Thick Crust Dough"
    sauce = "Plum Tomato Sauce"
    toppings = ["Shredded", "Mozzarella", "Cheese"]

    def cut(self):
        print("Cutting the pizza into square slices")


class PizzaStore:

    def create_pizza(self, pizza_type):
        # 每个需要子类实现的方法都会抛出NotImplementedError
        # 我们也可以把 PizzaStore 的 metaclass 设置成 abc.ABCMeta
        # 这样的话，这个类就是真正的抽象基类
        raise NotImplementedError()

    def order_pizza(self, pizza_type):  # 现在把 pizza 的类型传入 order_pizza()

        pizza = self.create_pizza(pizza_type)

        #  一旦我们有了一个 pizza，需要做一些准备（擀面皮、加佐料），然后烘烤、切片、装盒
        pizza.prepare()
        pizza.bake()
        pizza.cut()
        pizza.box()
        return pizza

    # 下边是其他可能用到的方法


class NYStylePizzStore(PizzaStore):

    def create_pizza(self, pizza_type):
        # 根据 pizza 类型，我们实例化正确的具体类，然后将其赋值给 pizza 实例变量
        if pizza_type == 'cheese':
            pizza = NYStyleCheesePizza()
        return pizza


class ChicagoStylePizzaStore(PizzaStore):

    def create_pizza(self, pizza_type):
        # 根据 pizza 类型，我们实例化正确的具体类，然后将其赋值给 pizza 实例变量
        if pizza_type == 'cheese':
            pizza = ChicagoStyleCheesePizza()
        return pizza


def main():
    nystore = NYStylePizzStore()
    pizza = nystore.order_pizza('cheese')
    print("goodspeed ordered a %s" % pizza)

    print("*" * 100)
    chicago_store = ChicagoStylePizzaStore()
    pizza = chicago_store.order_pizza('cheese')
    print("goodspeed ordered a %s" % pizza)


if __name__ == '__main__':
    main()