cached_property.py

   1 # -*- coding: utf-8 -*-
   2
   3 __author__ = 'Daniel Greenfeld'
   4 __email__ = 'pydanny@gmail.com'
   5 __version__ = '0.1.0'
   6
   7
   8 class cached_property(object):
   9     """ A property that is only computed once per instance and then replaces
  10         itself with an ordinary attribute. Deleting the attribute resets the
  11         property. """
  12
  13     def __init__(self, func):
  14         self.__doc__ = getattr(func, '__doc__')
  15         self.func = func
  16
  17     def __get__(self, obj, cls):
  18         if obj is None:
  19             return self
  20         value = obj.__dict__[self.func.__name__] = self.func(obj)
  21         return value