抽象工厂模式:
提供一个接口,用户创建多个相关或依赖对象,而不需要指定具体类。
原则:
依赖抽象,不依赖具体类。
实例:
用不同原材料制作不同口味的披萨,创建不同原材料的工厂,不同实体店做出口味不同的披萨。创建一个产品家族(Dough、Sauce、Cheese和Clam)的抽象类型(PizzaIngredientFactory),这个类型的子类(NYPizzaIngredientFactory和ChicagoPizzaIngredientFactory)定义了产品被产生的方法。
工厂模式和抽象工厂模式的区别:
工厂模式是在派生类中定义一个工厂的抽象接口,然后基类负责创建具体对象;抽象工厂模式是维护一个产品家族,由基类定义产品被生产的方法,客户根据派生类的接口进行开发。
代码:
#!/usr/bin/python # -*- coding:utf-8 -*- import sys reload(sys) sys.setdefaultencoding('utf-8') ''' 披萨 ''' class Pizza: name = "" dough = None sauce = None cheese = None clam = None def prepare(self): pass def bake(self): print "烘烤25分钟在350。".decode('utf-8') def cut(self): print "切割成对角线切片。".decode('utf-8') def box(self): print "放在官方的盒子中。".decode('utf-8') 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 += " 面团: %s\n" % self.dough.to_string() if self.dough else "" string += " 酱汁: %s\n" % self.sauce.to_string() if self.sauce else "" string += " 奶酪: %s\n" % self.cheese.to_string() if self.cheese else "" string += " 文蛤: %s\n" % self.clam.to_string() if self.clam else "" return string ''' 什么类别的披萨 ''' class CheesePizza(Pizza): def __init__(self, ingredient_factory): self.ingredient_factory = ingredient_factory def prepare(self): print "准备: %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 "准备: %s" % self.name self.dough = self.ingredient_factory.create_dough() self.sauce = self.ingredient_factory.create_sauce() self.clam = self.ingredient_factory.create_clam() ''' 披萨店 ''' 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 ''' 纽约披萨实体店1 ''' class NYPizzaStore(PizzaStore): def create_pizza(self, pizza_type): ingredient_factory = NYPizzaIngredientFactory() if pizza_type == "cheese": pizza = CheesePizza(ingredient_factory) pizza.set_name("纽约风格芝士披萨".decode('utf-8')) elif pizza_type == "clam": pizza = ClamPizza(ingredient_factory) pizza.set_name("纽约风格文蛤披萨".decode('utf-8')) else: pizza = None return pizza ''' 芝加哥披萨实体店2 ''' class ChicagoPizzaStore(PizzaStore): def create_pizza(self, pizza_type): ingredient_factory = ChicagoPizzaIngredientFactory() if pizza_type == "cheese": pizza = CheesePizza(ingredient_factory) pizza.set_name("芝加哥风格芝士披萨".decode('utf-8')) elif pizza_type == "clam": pizza = ClamPizza(ingredient_factory) pizza.set_name("芝加哥风格文蛤披萨".decode('utf-8')) else: pizza = None return pizza ''' 生产披萨的工厂 ''' class PizzaIngredientFactory: def create_dough(self): pass def create_sauce(self): pass def create_cheese(self): pass def create_clam(self): pass ''' 生产披萨的实体工厂1 ''' class NYPizzaIngredientFactory(PizzaIngredientFactory): def create_dough(self): return ThinDough() def create_sauce(self): return MarinaraSauce() def create_cheese(self): return FreshCheese() def create_clam(self): return FreshClam() ''' 生产披萨的实体工厂2 ''' class ChicagoPizzaIngredientFactory(PizzaIngredientFactory): def create_dough(self): return ThickDough() def create_sauce(self): return MushroomSauce() def create_cheese(self): return BlueCheese() def create_clam(self): return FrozenClam() class Dough: def to_string(self): pass class ThinDough(Dough): def to_string(self): return "薄的面团" class ThickDough(Dough): def to_string(self): return "厚的生面团" class Sauce: def to_string(self): pass class MarinaraSauce(Sauce): def to_string(self): return "番茄酱" class MushroomSauce(Sauce): def to_string(self): return "蘑菇酱" class Cheese: def to_string(self): pass class FreshCheese(Cheese): def to_string(self): return "新鲜的奶酪" class BlueCheese(Cheese): def to_string(self): return "蓝纹奶酪" class Clam: def to_string(self): pass class FreshClam(Clam): def to_string(self): return "新鲜的文蛤" class FrozenClam(Clam): def to_string(self): return "冷冻的文蛤" if __name__ == "__main__": # 创建了两个披萨实体店 ny_store = NYPizzaStore() chicago_store = ChicagoPizzaStore() # 在第一个披萨对象中订购了一个cheese风味的披萨 pizza = ny_store.order_pizza("cheese") print pizza.to_string() print "迈克订购了一个 %s" % pizza.get_name() print pizza = chicago_store.order_pizza("clam") print pizza.to_string() print "约翰订购了一个%s" % pizza.get_name() print
结果:
准备: 纽约风格芝士披萨 烘烤25分钟在350。 切割成对角线切片。 放在官方的盒子中。 纽约风格芝士披萨: 面团: 薄的面团 酱汁: 番茄酱 奶酪: 新鲜的奶酪 迈克订购了一个 纽约风格芝士披萨 准备: 芝加哥风格文蛤披萨 烘烤25分钟在350。 切割成对角线切片。 放在官方的盒子中。 芝加哥风格文蛤披萨: 面团: 厚的生面团 酱汁: 蘑菇酱 文蛤: 冷冻的文蛤 约翰订购了一个芝加哥风格文蛤披萨