#!/usr/bin/env python # -*- coding: utf-8 -*- """http://ginstrom.com/scribbles/2008/11/06/generic-adapter-class-in-python/""" 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{0}".format("!" * octane_level) class Adapter(object): """ Adapts an object by replacing methods. Usage: dog = Dog dog = Adapter(dog, dict(make_noise=dog.bark)) >>> objects = [] >>> dog = Dog() >>> objects.append(Adapter(dog, make_noise=dog.bark)) >>> cat = Cat() >>> objects.append(Adapter(cat, make_noise=cat.meow)) >>> human = Human() >>> objects.append(Adapter(human, make_noise=human.speak)) >>> car = Car() >>> car_noise = lambda: car.make_noise(3) >>> objects.append(Adapter(car, make_noise=car_noise)) >>> for obj in objects: ... print('A {} goes {}'.format(obj.name, obj.make_noise())) A Dog goes woof! A Cat goes meow! A Human goes 'hello' A Car goes vroom!!! """ 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, make_noise=dog.bark)) cat = Cat() objects.append(Adapter(cat, make_noise=cat.meow)) human = Human() objects.append(Adapter(human, make_noise=human.speak)) car = Car() objects.append(Adapter(car, make_noise=lambda: car.make_noise(3))) for obj in objects: print("A {0} goes {1}".format(obj.name, obj.make_noise())) if __name__ == "__main__": main() ### OUTPUT ### # A Dog goes woof! # A Cat goes meow! # A Human goes 'hello' # A Car goes vroom!!!