python-patterns/adapter.py at master · aglenis/python-patterns · GitHub

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#!/usr/bin/env python

# -*- 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 = Dog

dog = Adapter(dog, dict(make_noise=dog.bark))

>>> 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 {} 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, 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__":

import doctest

doctest.testmod()

### OUTPUT ###

python-patterns/adapter.py at master · aglenis/python-patterns · GitHub

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