>我有一个像下面这样的类
class Paginator(object):
@cached_property
def count(self):
some_implementation
class CachingPaginator(Paginator):
def _get_count(self):
if self._count is None:
try:
key = "admin:{0}:count".format(hash(self.object_list.query.__str__()))
self._count = cache.get(key, -1)
if self._count == -1:
self._count = self.count # Here, I want to get count property in the super-class, this is giving me -1 which is wrong
cache.set(key, self._count, 3600)
except:
self._count = len(self.object_list)
count = property(_get_count)
如上面的注释所示,self._count = <expression>
应该在超类中获取 count 属性。如果是方法,我们可以这样称呼它super(CachingPaginator,self).count()
AFAIK。我在SO中提出了许多问题,但没有一个对我有帮助。谁能帮我解决这个问题。
属性只是类属性。要获取父类属性,请使用对父类的直接查找(Paginator.count
)或super()
调用。现在在这种情况下,如果你在父类上使用直接查找,你必须手动调用描述符协议,这有点冗长,所以使用 super()
是最简单的解决方案:
class Paginator(object):
@property
def count(self):
print "in Paginator.count"
return 42
class CachingPaginator(Paginator):
def __init__(self):
self._count = None
def _get_count(self):
if self._count is None:
self._count = super(CachingPaginator, self).count
# Here, I want to get count property in the super-class, this is giving me -1 which is wrong
return self._count
count = property(_get_count)
如果要直接查找父类,请替换:
self._count = super(CachingPaginator, self).count
跟
self._count = Paginator.count.__get__(self, type(self))