Python 为类和静态方法提供装饰器

import time
from functools import wraps

# A simple decorator
def timethis(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        start = time.time()
        r = func(*args, **kwargs)
        end = time.time()
        print(end-start)
        return r
    return wrapper

# Class illustrating application of the decorator to different kinds of methods
class Spam:
    @timethis
    def instance_method(self, n):
        print(self, n)
        while n > 0:
            n -= 1

    @classmethod
    @timethis
    def class_method(cls, n):
        print(cls, n)
        while n > 0:
            n -= 1

    @staticmethod
    @timethis
    def static_method(n):
        print(n)
        while n > 0:
            n -= 1

>>> s = Spam()
>>> s.instance_method(1000000)
<__main__.Spam object at 0x1006a6050> 1000000
0.11817407608032227
>>> Spam.class_method(1000000)
<class '__main__.Spam'> 1000000
0.11334395408630371
>>> Spam.static_method(1000000)
1000000
0.11740279197692871
>>>

class Spam:
    @timethis
    @staticmethod
    def static_method(n):
        print(n)
        while n > 0:
            n -= 1

>>> Spam.static_method(1000000)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "timethis.py", line 6, in wrapper
start = time.time()
TypeError: 'staticmethod' object is not callable
>>>

from abc import ABCMeta, abstractmethod
class A(metaclass=ABCMeta):
    @classmethod
    @abstractmethod
    def method(cls):
        pass