Python 设计模式——门面模式-CoLaBug.com

门面（facade）指建筑物的表面，尤其是最有吸引力的那一面。当人们从建筑物旁边经过时，可以欣赏其外部面貌，而不必了解其本身结构的复杂性。门面在隐藏内部复杂性的同时，也为客户端提供了一个可以轻松访问的接口。

比如需要到某个商店买东西，但对于该商店的布局并不清楚。可以直接找店主说明需要哪些东西，由店主将这些商品找到并提供给顾客。即店主作为购物的接口，顾客无需了解具体商品的位置。

门面设计模式的特点：

为子系统的一组接口提供一个统一的高级接口，帮助客户端以更简单的方式使用这些子系统
门面并不是封装子系统，而是对底层子系统进行组合。即用单个接口对象表示复杂的子系统

门面

一个接口，知道某个请求应该交由那个子系统处理
通过组合的方式将客户端的请求委派给相应的子系统对象

系统

实现子系统的功能，由一组负责不同任务的类来表示
处理门面对象分配的工作，但并不知道门面也不引用它

客户端

会实例化门面
会向门面提出请求

class EventManager:
def __init__(self):
print("Event Manager:: Let me talk to the folks\n")
def arrange(self):
self.hotelier = Hotelier()
self.hotelier.bookHotel()
self.florist = Florist()
self.florist.setFlowerRequirements()
self.caterer = Caterer()
self.caterer.setCuisine()
self.musician = Musician()
self.musician.setMusicType()
class Hotelier:
def __init__(self):
print("Arranging the Hotel for Marriage? --")
def __isAvailable(self):
print("Is the Hotel free for the event on given day?")
return True
def bookHotel(self):
if self.__isAvailable():
print("Registered the Booking\n\n")
class Florist:
def __init__(self):
print("Flower Decorations for the Event? --")
def setFlowerRequirements(self):
print("Carnations, Roses and Lilies would be used for Decorations\n\n")
class Caterer:
def __init__(self):
print("Food Arrangements for the Event --")
def setCuisine(self):
print("Chinese & Continental Cuisine to be served\n\n")
class Musician:
def __init__(self):
print("Musical Arrangements for the Marriage --")
def setMusicType(self):
print("Jazz and Classical will be played\n\n")
class You:
def __init__(self):
print("You:: Whoa! Marriage Arrangements??!!!")
def asskEventManager(self):
print("You:: Let's Contact the Event Manager\n\n")
em = EventManager()
em.arrange()
def __del__(self):
print("You:: Thanks to Event Manager, all preparations done!")
you = You()
you.asskEventManager()
# => You:: Whoa! Marriage Arrangements??!!!
# => You:: Let's Contact the Event Manager
# => Event Manager:: Let me talk to the folks
# => Arranging the Hotel for Marriage? --
# => Is the Hotel free for the event on given day?
# => Registered the Booking
# => Flower Decorations for the Event? --
# => Carnations, Roses and Lilies would be used for Decorations
# => Food Arrangements for the Event --
# => Chinese & Continental Cuisine to be served
# => Musical Arrangements for the Marriage --
# => Jazz and Classical will be played
# => You:: Thanks to Event Manager, all preparations done!