python实现Decorator模式实例代码

# -*- coding: utf-8 -*-
def log_cost_time(func):
  def wrapped(*args, **kwargs):
    import time
    begin = time.time()
    try:
      return func(*args, **kwargs)
    finally:
      print 'func %s cost %s' % (func.__name__, time.time() - begin)
  return wrapped
 
@log_cost_time
def complex_func(num):
  ret = 0
  for i in xrange(num):
    ret += i * i
  return ret
#complex_func = log_cost_time(complex_func)
 
if __name__ == '__main__':
  print complex_func(100000)
 
code snippet 0

@dec

def func():pass

#-*-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()