2016-08-24 33 views
1

什么是最简单/最pythonic的方式来覆盖只有Python 3中的抽象属性的setter?变体3似乎意味着派生类实现者的最小努力。这是对的吗?它有缺点吗?忽略Python 3中属性的抽象setter

import abc 


class A1(metaclass=abc.ABCMeta): 
    def __init__(self, x, **kwargs): 
     super().__init__(**kwargs) 
     self._x = x 

    @property 
    def x(self): 
     return self._x 

    @x.setter 
    @abc.abstractmethod 
    def x(self, value): 
     self._x = value 


class B1(A1): 
    @property 
    def x(self): 
     return super().x 

    @x.setter 
    def x(self, value): 
     print("B1 setter") 
     super(B1, self.__class__).x.fset(self, value) 

b1 = B1(x=1) 
b1.x = 3 
print(b1.x) 


class A2(metaclass=abc.ABCMeta): 
    def __init__(self, x, **kwargs): 
     super().__init__(**kwargs) 
     self._x = x 

    @abc.abstractmethod 
    def _get_x(self): 
     return self._x 

    @abc.abstractmethod 
    def _set_x(self, value): 
     self._x = value 

    x = property(_get_x, _set_x) 


class B2(A2): 

    def _get_x(self): 
     return super()._get_x() 

    def _set_x(self, value): 
     print("B2 setter") 
     super()._set_x(value) 

    x = property(_get_x, _set_x) 

b2 = B2(x=1) 
b2.x = 3 
print(b2.x) 


class A3(metaclass=abc.ABCMeta): 
    def __init__(self, x, **kwargs): 
     super().__init__(**kwargs) 
     self._x = x 

    def _get_x(self): 
     return self._x 

    @abc.abstractmethod 
    def _set_x(self, value): 
     self._x = value 

    x = property(
     lambda self: self._get_x(), 
     lambda self, value: self._set_x(value)) 


class B3(A3): 

    def _set_x(self, value): 
     print("B3 setter") 
     super()._set_x(value) 


b3 = B3(x=1) 
b3.x = 3 
print(b3.x) 

回答

0

所以,是的,你列举了很多的有办法 - 尽管这需要更多的代码的人是你的变体3,最straighforard,最令人惊讶的方式来做到这一点是你变体1 -

它只是起作用,而且是完全可读的,并不意外 - 并且似乎没有比明确调用fget更简单的方法。