GoF design pattern with Python. - Adapter

adapter.py

# -*- coding: utf-8 -*-

""""http://ginstrom.com/scribbles/2008/11/06/generic-adapter-class-in-python/"""
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{0}".format("!" * octane_level)


class Adapter(object):
	"""
	Adapts an object by replacing methods.
	Usage:
	dog = Dogdog = Adapter(dog, dict(make_noise=dog.bark))
	"""

	def __init__(self, obj, adapted_methods):
		"""We set the adapted methods in the objects'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()
	objects.append(Adapter(car, dict(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()