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# http://ginstrom.com/scribbles/2007/10/08/design-patterns-python-style/
"""Implementation of the abstract factory pattern"""
import random
class PetShop:
"""A pet shop"""
def __init__(self, animal_factory=None):
"""pet_factory is our abstract factory.
We can set it at will."""
self.pet_factory = animal_factory
def show_pet(self):
"""Creates and shows a pet using the
abstract factory"""
pet = self.pet_factory.get_pet()
print("This is a lovely", pet)
print("It says", pet.speak())
print("It eats", self.pet_factory.get_food())
# Stuff that our factory makes
class Dog:
def speak(self):
return "woof"
def __str__(self):
return "Dog"
class Cat:
def speak(self):
return "meow"
def __str__(self):
return "Cat"
# Factory classes
class DogFactory:
def get_pet(self):
return Dog()
def get_food(self):
return "dog food"
class CatFactory:
def get_pet(self):
return Cat()
def get_food(self):
return "cat food"
# Create the proper family
def get_factory():
"""Let's be dynamic!"""
return random.choice([DogFactory, CatFactory])()
# Show pets with various factories
if __name__== "__main__":
shop = PetShop()
for i in range(3):
shop.pet_factory = get_factory()
shop.show_pet()
print("=" * 20)