python - 如何在python中定义一个抽象类并强制实现变量

Question

所以，我试图用几个变量定义一个抽象基类，我想强制要求任何“继承”这个基类的类都必须拥有这些变量。所以，像这样:

class AbstractBaseClass(object):
   foo = NotImplemented
   bar = NotImplemented

现在，

class ConcreteClass(AbstractBaseClass):
    # here I want the developer to force create the class variables foo and bar:
    def __init__(self...):
        self.foo = 'foo'
        self.bar = 'bar'

这应该会抛出错误:

class ConcreteClass(AbstractBaseClass):
    # here I want the developer to force create the class variables foo and bar:
    def __init__(self...):
        self.foo = 'foo'
        #error because bar is missing??

我可能使用了错误的术语..但基本上，我希望每个“实现”上述类的开发人员都强制定义这些变量？？

Answer 1

更新:abc.abstractproperty 已在 Python 3.3 中弃用。将 property 与 abc.abstractmethod 结合使用，如图所示 here .

import abc

class AbstractBaseClass(object):

    __metaclass__ = abc.ABCMeta

    @abc.abstractproperty
    def foo(self):
        pass

    @abc.abstractproperty
    def bar(self):
        pass

class ConcreteClass(AbstractBaseClass):

    def __init__(self, foo, bar):
        self._foo = foo
        self._bar = bar

    @property
    def foo(self):
        return self._foo

    @foo.setter
    def foo(self, value):
        self._foo = value

    @property
    def bar(self):
        return self._bar

    @bar.setter
    def bar(self, value):
        self._bar = value