How to overload effectively and systematically Python class methods

问题

Assume that you have a Python (>=2.6) class with plenty (hundreds!) of methods. Now someone wants to subclass that but realized that most of the base class methods needs only some simple 'tuning'. Also there are only handful of different ways to tune those methods. Some involving input transformations, some output transformations, some both.

To be more specific I'm looking for a (simple) solution for the inheritance where I just could provide the base class and a list (of lists) of methods to apply the specific transformations, without adding this boilerplate code to each overloaded method.

Thanks, eat

Follow up.
Based on gabo10yf answer, I came up a solution as:

class B(object):
    def f1(self, val):
        print '1: ', val
    def f2(self, val):
        print '2: ', val
def decorator(f):
    def g(self, *args, **kwargs):
        print 'entering'
        result= f(self, *args, **kwargs)
    return g

class A(B):
    pass

_overridden= ['f1', 'f2']
def override(cls):
    for name in _overridden:
        setattr(cls, name, decorator(getattr(cls, name).im_func))
override(A)

if __name__== '__main__':
    b= B()
    b.f1(1)
    b.f2(2)
    a= A()
    a.f1(1)
    a.f2(2)

It really seems to work. However it feels almost too simple, it surely must still contain some murky issues? Anyway thanks to you all letting me figure out this!

回答1:

I hope this helps:


 # the base class
class B(object):
    def f1(self, val):
        pass
    def f2(self, val):
        pass

def decorator(cls, f):
    def g(self, *args, **kwargs):
        # do stuff
        result = f(self, *args, **kwargs)
        # do more stuff
    return g

class A(B):
    _overridden = ['f1', 'f2']
    @classmethod
    def load(cls):
        for name in cls._overridden:
            setattr(name, decorator(getattr(name).im_func))

A.load()

One may have to do some changes in order to handle class and static methods.