我现在
learning
python中的模板方法模式。
我想知道是否有任何方法可以保护基类中的某些函数,以便子类不能覆盖?如下所示
_primitive_operation_3
从子类重写基类中的相同函数。
import abc
class AbstractClass(metaclass=abc.ABCMeta):
"""
Define abstract primitive operations that concrete subclasses define
to implement steps of an algorithm.
Implement a template method defining the skeleton of an algorithm.
The template method calls primitive operations as well as operations
defined in AbstractClass or those of other objects.
"""
def template_method(self):
self._primitive_operation_1()
self._primitive_operation_2()
self._primitive_operation_3()
# Functions must be specified by subclass (i.e., subclass variant)
@abc.abstractmethod
def _primitive_operation_1(self):
pass
# Functions must be specified by subclass (i.e., subclass variant)
@abc.abstractmethod
def _primitive_operation_2(self):
pass
# Functions inherited and not modified by subclass (i.e., subclass invariant)
def _primitive_operation_3(self):
print ('Execute operation #3 from main class')
class ConcreteClass(AbstractClass):
"""
Implement the primitive operations to carry out
subclass-specificsteps of the algorithm.
"""
def _primitive_operation_1(self):
pass
def _primitive_operation_2(self):
pass
# You can still overwrite it if you want
def _primitive_operation_3(self):
print ('Execute operation #3 from subclass')
def main():
concrete_class = ConcreteClass()
concrete_class.template_method()
if __name__ == "__main__":
main()
如果无法防止基类中的方法被重写,我如何放置一些东西来发出自动警报/警告,指示基类中的特定方法已被重写?