简单工厂、工厂模式、抽象工厂模式

简单工厂其实不是一个设计模式，反而比较像是一种编程习惯

产品基类Pizza， 子类 CheesePizza、 PepperoniPizza、ClamPizza、VeggiePizza

顾客通过商店PizzaStore的order_pizza函数预订pizza。

而pizza的生产依赖SimpleFactory， 通过SimpleFactory的create_pizza获取实际的pizza 。

调用过程如下

pizza_store = PizzaStore(SimplePizzaFactory())
pizza_store.order_pizza('cheese')
pizza_store.order_pizza('clam')

完整代码如下：

# coding:utf-8
import inspect

# pizza接口 实际pizza子类
class Pizza(object):
def __init__(self):
print 'create a %s' % self

def prepare(self):
print '%s-->prepare' % self

def bake(self):
print '%s-->Bake' % self

def cut(self):
print '%s-->cut' % self

def box(self):
print '%s-->box' % self

def __str__(self):
return self.__class__.__name__

class CheesePizza(Pizza): pass

class ClamPizza(Pizza): pass

class SimplePizzaFactory:
def create_pizza(self, type):
if type == 'cheese':
pizza = CheesePizza()
elif type == 'clam':
pizza = ClamPizza()
else:
pizza = None
return pizza

class PizzaStore:
def __init__(self, factory):
self.factory = factory

def order_pizza(self, type):
pizza = self.factory.create_pizza(type)
pizza.prepare()
pizza.bake()
pizza.cut()
pizza.box()
pizza.box()
return pizza

pizza_store = PizzaStore(SimplePizzaFactory())
pizza_store.order_pizza('cheese')
pizza_store.order_pizza('clam')

工厂模式 通过让子类决定该创建的对象是什么， 达到将对象创建的过程封装的目的。

pizza的生产不再通过SimpleFactory ， 而是把create_pizza放到PizzaStore中，并设置成抽象方法， 让继承PizzaStore的子类在根据实际需要实现create_pizza

NYPizzaStore、ChicagoPizzaStore继承PizzaStore，并实现对应的create_pizza

# coding:utf-8
import inspect

# pizza接口 实际pizza子类
class Pizza(object):
def __init__(self):
print 'create a %s' % self

def prepare(self):
print '%s-->prepare' % self

def bake(self):
print '%s-->Bake' % self

def cut(self):
print '%s-->cut' % self

def box(self):
print '%s-->box' % self

def __str__(self):
return self.__class__.__name__

class NYCheesePizza(Pizza):pass

class NYClamPizza(Pizza):pass

class ChicagoCheesePizza(Pizza):pass

class ChicagoClamPizza(Pizza):pass

# pizza商店 和实际子类商店
class PizzaStore(object):
def order_pizza(self, type):
pizza = self.create_pizza(type)
pizza.prepare()
pizza.bake()
pizza.cut()
pizza.box()
return pizza

def create_pizza(self, type):
raise NotImplemented()

class NYPizzaStore(PizzaStore):
def create_pizza(self, type):
if type == 'cheese':
pizza = NYCheesePizza()
elif type == 'clam':
pizza = NYClamPizza()
else:
pizza = None
return pizza

class ChicagoPizzaStore(PizzaStore):
def create_pizza(self, type):
if type == 'cheese':
pizza = ChicagoCheesePizza()
elif type == 'clam':
pizza = ChicagoClamPizza()
else:
pizza = None
return pizza

pizza_store = NYPizzaStore()
pizza_store.order_pizza('cheese')
pizza_store = ChicagoPizzaStore()
pizza_store.order_pizza('cheese')

抽象工厂方法

提供一个接口， 用于创建相关或依赖对象的家族，而不需要指明具体类

在上个例子的基础上，增加了原料工厂

# coding:utf-8
import inspect

# 原料接口 和实际原料子类
class Dough(object):
def get_name(self): raise NotImplemented

class ThickCrustDough(Dough):
def get_name(self):
return 'Thick Crust Dough'

class ThinCrustDough(Dough):
def get_name(self):
return 'Thin Crust Dough'

class Sauce(object):
def get_name(self): raise NotImplemented

class PlumTomatoSauce(object):
def get_name(self):
return 'Plum Tomato Sauce'

class MainaraSauce(object):
def get_name(self):
return 'Mainara Sauce'

#原料工厂 和实际原料工厂子类
class PizzaIngredientFactory(object):
def createDough(self):  raise NotImplemented()

def createSauce(self): raise NotImplemented()

class NYPizzaIngredientFactory(PizzaIngredientFactory):
def createDough(self):
return ThickCrustDough()

def createSauce(self):
return PlumTomatoSauce()

class ChicagoPizzaIngredientFactory(PizzaIngredientFactory):
def createDough(self):
return ThinCrustDough()

def createSauce(self):
return MainaraSauce()

# pizza接口 实际pizza子类
class Pizza(object):
def __init__(self):
print 'create a %s' % self
self.dough = None
self.sauce = None

def prepare(self):
raise NotImplemented()

def show_ingredient(self):
print 'has ingredient:', self.sauce.get_name(), ';', self.dough.get_name()

def bake(self):
print '%s-->Bake' % self

def cut(self):
print '%s-->cut' % self

def box(self):
print '%s-->box' % self

def __str__(self):
return self.__class__.__name__

class NYCheesePizza(Pizza):
def __init__(self, ingredientFactory):
self.ingredientFactory = ingredientFactory
super(NYCheesePizza, self).__init__()

def prepare(self):
print 'NYCheesePizza Pareparing ...'
self.dough = self.ingredientFactory.createDough()
self.sauce = self.ingredientFactory.createSauce()

class NYClamPizza(Pizza):
def __init__(self, ingredientFactory):
self.ingredientFactory = ingredientFactory
super(NYClamPizza, self).__init__()

def prepare(self):
print 'NYClamPizza Pareparing ...'
self.dough = self.ingredientFactory.createDough()
self.sauce = self.ingredientFactory.createSauce()

class ChicagoCheesePizza(Pizza):
def __init__(self, ingredientFactory):
self.ingredientFactory = ingredientFactory
super(ChicagoCheesePizza, self).__init__()

def prepare(self):
print 'ChicagoCheesePizza Pareparing ...'
self.dough = self.ingredientFactory.createDough()
self.sauce = self.ingredientFactory.createSauce()

class ChicagoClamPizza(Pizza):
def __init__(self, ingredientFactory):
self.ingredientFactory = ingredientFactory
super(ChicagoClamPizza, self).__init__()

def prepare(self):
print 'ChicagoClamPizza Pareparing ...'
self.dough = self.ingredientFactory.createDough()
self.sauce = self.ingredientFactory.createSauce()

# pizza商店 和实际子类商店
class PizzaStore(object):
def order_pizza(self, type):
pizza = self.create_pizza(type)
pizza.prepare()
pizza.show_ingredient()
pizza.bake()
pizza.cut()
pizza.box()
return pizza

def create_pizza(self, type):
raise NotImplemented()

class NYPizzaStore(PizzaStore):
def create_pizza(self, type):
ingreientfactory = NYPizzaIngredientFactory()

if type == 'cheese':
pizza = NYCheesePizza(ingreientfactory)
elif type == 'clam':
pizza = NYClamPizza(ingreientfactory)
else:
pizza = None
return pizza

class ChicagoPizzaStore(PizzaStore):
def create_pizza(self, type):
ingreientfactory = ChicagoPizzaIngredientFactory()
if type == 'cheese':
pizza = ChicagoCheesePizza(ingreientfactory)
elif type == 'clam':
pizza = ChicagoClamPizza(ingreientfactory)
else:
pizza = None
return pizza

pizza_store = NYPizzaStore()
pizza_store.order_pizza('cheese')
pizza_store = ChicagoPizzaStore()
pizza_store.order_pizza('cheese')