Question

In superclass in Python, how can I call the function that’s overridden in its subclass?

class A:
    @staticmethod
    def interfaceBasedMethod():
        print "Want to delegate to overriding method in subclass"

    @staticmethod
    def a():
        interfaceBasedMethod() # <-- I know this causes error. But here 
                               # I want to call the overridden method in subclass.

class B(A):
    @staticmethod
    def interfaceBasedMethod():
        print "Class B processes."

if __name__ == "__main__":
    b=B
    b.a()

Ideal output:

Class B processes.

Google search doesn’t really return pages about Interface-Based Programming in Python, although it should be common in Java etc. Thanks!

Answer 1

Putting aside questions of style, use classmethod not staticmethod. It passes in the class which is being used.

class A:
    @classmethod
    def interfaceBasedMethod(cls):
        print "Want to delegate to overriding method in subclass"

    @classmethod
    def a(cls):
        cls.interfaceBasedMethod()

class B(A):
    @classmethod
    def interfaceBasedMethod(cls):
        print "Class B processes."

if __name__ == "__main__":
    b=B
    b.a()