代码设计操作

1.多继承

class A:

def get_a(self):

print 'a'

class B:

def get_b(self):

print 'b'

class C(A, B):

pass

c = C()

c.get_a()

c.get_b()

2.python的元编程特性

A.__bases__ += (B,)

a.get_b()

实际上等同于： class C:

pass

C.__bases__ += (A, B, )

3.方式三：可以使用插件的方式，只是修改对象的行为而不是类的行为的。这样的话，可以更加好的便于扩展操作的

class PlugIn(object):

def __init__(self):

self._exported_methods = []

def plugin(self, owner):

for f in self._exported_methods:

owner.__dict__[f.__name__] = f

def plugout(self, owner):

for f in self._exported_methods:

del owner.__dict__[f.__name__]

class AFeature(PlugIn):

def __init__(self):

super(AFeature, self).__init__()

self._exported_methods.append(self.get_a_value)

def get_a_value(self):

print 'a feature.'

class BFeature(PlugIn):

def __init__(self):

super(BFeature, self).__init__()

self._exported_methods.append(self.get_b_value)

def get_b_value(self):

print 'b feature.'

class Combine:pass

c = Combine()

AFeature().plugin(c)

BFeature().plugin(c)

c.get_a_value()

c.get_b_value()