Python 设计模式 抽象工厂设计模式

   抽象工厂同简单工厂模式的最大区别是 ： 简单工厂模式 或者 工厂方法是 通过父类，屏蔽子类，创建单个产品。

   抽象工厂是创建一个产品族。

   UML 类图如下：

 

抽象产品 AbstractPrd 的定义，我们将其定义为Pissza

 class Pizza:  

    name = ""  
    dough = None  
    sauce = None  
    cheese = None  
    clam = None  
  
    def prepare(self):  
        pass  
  
    def bake(self):  
        print "Bake for 25 minutes at 350."  
  
    def cut(self):  
        print "Cutting into diagonal slices."  
  
    def box(self):  
        print "Put into official box."  
  
    def get_name(self):  
        return self.name  
  
    def set_name(self, name):  
        self.name = name  
  
    def to_string(self):  
        string = "%s:\n" % self.name   
        string += "    Dough: %s\n" % self.dough.to_string() if self.dough else ""  
        string += "    Sauce: %s\n" % self.sauce.to_string() if self.sauce else ""  
        string += "    Cheese: %s\n" % self.cheese.to_string() if self.cheese else ""  
        string += "    Clam: %s\n" % self.clam.to_string() if self.clam else ""  
        return string 

定义Pissza 的两个子类 ， CheesePissa ,PalmPissa

class CheesePizza(Pizza):  
   def __init__(self, ingredient_factory):  
        self.ingredient_factory = ingredient_factory  
  
    def prepare(self):  
        print "Preparing: %s" % self.name  
        self.dough = self.ingredient_factory.create_dough()  
        self.sauce = self.ingredient_factory.create_sauce()  
        self.cheese = self.ingredient_factory.create_cheese()  
  
  
class ClamPizza(Pizza):  
    def __init__(self, ingredient_factory):  
        self.ingredient_factory = ingredient_factory  
  
    def prepare(self):  
        print "Preparing: %s" % self.name  
        self.dough = self.ingredient_factory.create_dough()  
        self.sauce = self.ingredient_factory.create_sauce()  
        self.clam = self.ingredient_factory.create_clam() 

创建Pissza的抽象工厂父类

class PizzaStore:  
    def order_pizza(self, pizza_type):  
        self.pizza = self.create_pizza(pizza_type)  
        self.pizza.prepare()  
        self.pizza.bake()  
        self.pizza.cut()  
        self.pizza.box()  
        return self.pizza  
  
    def create_pizza(self, pizza_type):  
        pass  

创建一个产品族的具体工厂

class NYPizzaStore(PizzaStore):  

    def create_pizza(self, pizza_type):  
        ingredient_factory = NYPizzaIngredientFactory()  
  
        if pizza_type == "cheese":  
            pizza = CheesePizza(ingredient_factory)  
            pizza.set_name("New York Style Cheese Pizza")  
        elif pizza_type == "clam":  
            pizza = ClamPizza(ingredient_factory)  
            pizza.set_name("New York Style Clam Pizza")  
        else:  
            pizza = None  
  
        return pizza  
  
  
class ChicagoPizzaStore(PizzaStore):  
     def create_pizza(self, pizza_type):  
        ingredient_factory = ChicagoPizzaIngredientFactory()  
  
        if pizza_type == "cheese":  
            pizza = CheesePizza(ingredient_factory)  
            pizza.set_name("Chicago Style Cheese Pizza")  
        elif pizza_type == "clam":  
            pizza = ClamPizza(ingredient_factory)  
            pizza.set_name("Chicago Style Clam Pizza")  
        else:  
            pizza = None  
  
        return pizza  

简单也就这样，还可以更复杂！不过还是简单就是美吧!