Python-Design-Patterns delegation_pattern
delegation_pattern Model
Python-Design-Patterns delegation_pattern
# file: 'delegation_pattern.py'
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Reference: https://en.wikipedia.org/wiki/Delegation_pattern
Author: https://github.com/IuryAlves
*TL;DR80
Allows object composition to achieve the same code reuse as inheritance.
"""
class Delegator(object):
"""
>>> delegator = Delegator(Delegate())
>>> delegator.p1
123
>>> delegator.p2
Traceback (most recent call last):
...
AttributeError: 'Delegate' object has no attribute 'p2'
>>> delegator.do_something("nothing")
'Doing nothing'
>>> delegator.do_anything()
Traceback (most recent call last):
...
AttributeError: 'Delegate' object has no attribute 'do_anything'
"""
def __init__(self, delegate):
self.delegate = delegate
def __getattr__(self, name):
attr = getattr(self.delegate, name)
if not callable(attr):
return attr
def wrapper(*args, **kwargs):
return attr(*args, **kwargs)
return wrapper
class Delegate(object):
def __init__(self):
self.p1 = 123
def do_something(self, something):
return "Doing %s" % something
if __name__ == '__main__':
import doctest
doctest.testmod()
delegation_pattern.py
