factory.py

# This is ripe for some refactoring, but I think it shows an okay
# implementation of the factory pattern

class Animal(object):
    sound = ""
    description = ""

    def describe(self):
        return self.description

class Dog(Animal):
    sound = "bark"
    description = "A Dog %ss" % sound

class Bird(Animal):
    sound = "tweet"
    description = "A bird %ss" % sound
    
class Programmer(Animal):
    sound = "tap tap"
    description = "A programmer %ss" % sound
    
class AnimalFactory():
    def build(self, typ):
        tc = typ.capitalize()
        # WOO GLOBALS
        return globals()[tc]()

animal_factory = AnimalFactory()
animals = ['dog', 'bird', 'programmer']
for a in animals:
    print animal_factory.build(a).describe()