lazy.py
28 lines
| 760 B
| text/x-python
|
PythonLexer
| r2007 | class LazyProperty(object): | |||
| """ | ||||
| Decorator for easier creation of ``property`` from potentially expensive to | ||||
| calculate attribute of the class. | ||||
| Usage:: | ||||
| class Foo(object): | ||||
| @LazyProperty | ||||
| def bar(self): | ||||
| print 'Calculating self._bar' | ||||
| return 42 | ||||
| Taken from http://blog.pythonisito.com/2008/08/lazy-descriptors.html and | ||||
| used widely. | ||||
| """ | ||||
| def __init__(self, func): | ||||
| self._func = func | ||||
| r2494 | self.__module__ = func.__module__ | |||
| r2007 | self.__name__ = func.__name__ | |||
| self.__doc__ = func.__doc__ | ||||
| def __get__(self, obj, klass=None): | ||||
| if obj is None: | ||||
| r2494 | return self | |||
| r2007 | result = obj.__dict__[self.__name__] = self._func(obj) | |||
| return result | ||||
