python 中的mixin特性
python支持多继承后，但能否支持动态继承性质?在程序运行过程中，重定义类的继承，python是支持这种动态继承性质的。这也就是python中 的mixin，在定义类过程中改变类的继承顺序，继承类。当某个模块不能修改时，通过mixin方式可以动态添加该类的方法，动态改变类的原有继承体系。弄懂了多继承，mixin特性就简单多了。 但需要注意mixin后的具体继承体系的改变。[*]#!/usr/bin/envpython
[*]
[*]import types
[*]
[*]def MixIn(pyClass,mixInClass,makeAncestor=0):
[*]
[*] if makeAncestor:
[*] pyClass.__bases__ = (mixInClass,) + pyClass.__bases__
[*] elif mixInClass not in pyClass.__bases__:
[*] pyClass.__bases__ = pyClass.__bases__ + (mixInClass,)
[*] else:
[*] pass
[*]
[*]class C1(object):
[*] def test(self):
[*] print 'test in C1'
[*]
[*]class C0MixIn(object):
[*] def test(self):
[*] print 'test in C0MixIn'
[*]
[*]class C2(C1,C0MixIn):
[*] def test(self):
[*] print 'test in C2'
[*]
[*]class C0(C1):
[*] pass
[*]
[*]if __name__ == "__main__":
[*]
[*] print C0.__mro__
[*] c1 = C0()
[*] c1.test()
[*] MixIn(C0,C0MixIn,1)
[*] c0 = C0()
[*] c0.test()
[*] print C0.__mro__
[*]
[*] print C2.__mro__
[*] MixIn(C2,C0MixIn)
[*] print C2.__mro__
运行结果如下: python mixin2.py点击(此处)折叠或打开
[*](<class '__main__.C0'>, <class '__main__.C1'>, <type 'object'>)
[*]test in C1
[*]test in C0MixIn
[*](<class '__main__.C0'>, <class '__main__.C0MixIn'>, <class '__main__.C1'>, <type 'object'>)
[*](<class '__main__.C2'>, <class '__main__.C1'>, <class '__main__.C0MixIn'>, <type 'object'>)
[*](<class '__main__.C2'>, <class '__main__.C1'>, <class '__main__.C0MixIn'>, <type 'object'>)
参考资料很详细的MixIn介绍:http://www.linuxjournal.com/node/4540/print
页:
[1]