python实现Decorator形式

python实现Decorator模式
#-*-coding:utf-8-*-


'''
意图：动态地给一个对象添加一些额外的职责。比通过生成子类更为灵活
'''
from abc import ABCMeta

class Component():
    __metaclass__ = ABCMeta
    def __init__(self):
        pass
    def operation(self):
        pass
    
class ConcreteComponent(Component):
    def operation(self):
        print 'ConcreteComponent operation...'

class Decorator(Component):
    def __init__(self, comp):
        self._comp = comp
    def operation(self):
        pass

class ConcreteDecorator(Decorator):
    def operation(self):
        self._comp.operation()
        self.addedBehavior()
    def addedBehavior(self):
        print 'ConcreteDecorator addedBehavior...'  
              
if __name__ == "__main__":
     comp = ConcreteComponent()
     dec = ConcreteDecorator(comp)
     dec.operation()