Python - 设计模式 - Adapter Pattern

 

本作品采用知识共享署名-非商业性使用-相同方式共享 3.0 Unported许可协议进行许可。允许非商业转载，但应注明作者及出处。

 

作者：liuyuan_jq

2011-04-27

 

http://ginstrom.com/scribbles/2008/11/06/generic-adapter-class-in-python/

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class Adapter(object): """ Adapts an object by replacing methods. Usage: dog = Dog dog = Adapter(dog, dict(make_noise=dog.bark)) """ def __init__(self, obj, adapted_methods): """We set the adapted methods in the object's dict""" self.obj = obj self.__dict__.update(adapted_methods) def __getattr__(self, attr): """All non-adapted calls are passed to the object""" return getattr(self.obj, attr)

 

完整实例

 

import os class Dog(object): def __init__(self): self.name = "Dog" def bark(self): return "woof!" class Cat(object): def __init__(self): self.name = "Cat" def meow(self): return "meow!" class Human(object): def __init__(self): self.name = "Human" def speak(self): return "'hello'" class Car(object): def __init__(self): self.name = "Car" def make_noise(self, octane_level): return "vroom%s" % ("!" * octane_level) class Adapter(object): """ Adapts an object by replacing methods. Usage: dog = Dog dog = Adapter(dog, dict(make_noise=dog.bark)) """ def __init__(self, obj, adapted_methods): """We set the adapted methods in the object's dict""" self.obj = obj self.__dict__.update(adapted_methods) def __getattr__(self, attr): """All non-adapted calls are passed to the object""" return getattr(self.obj, attr) def main(): objects = [] dog = Dog() objects.append(Adapter(dog, dict(make_noise=dog.bark))) cat = Cat() objects.append(Adapter(cat, dict(make_noise=cat.meow))) human = Human() objects.append(Adapter(human, dict(make_noise=human.speak))) car = Car() car_noise = lambda : car.make_noise(3) objects.append(Adapter(car, dict(make_noise=car_noise))) for obj in objects: print "A", obj.name, "goes", obj.make_noise() if __name__ == "__main__": main() 

 

运行结果

 

A Dog goes woof! A Cat goes meow! A Human goes 'hello' A Car goes vroom!!!