# -*- coding:gbk -*-
'''示例1: 最簡單的函數(shù),表示調(diào)用了兩次'''
def myfunc():
  print("myfunc() called.")
myfunc()
myfunc()

# -*- coding:gbk -*-
'''示例2: 替換函數(shù)(裝飾)
裝飾函數(shù)的參數(shù)是被裝飾的函數(shù)對象，返回原函數(shù)對象
裝飾的實質(zhì)語句: myfunc = deco(myfunc)'''
 
def deco(func):
  print("before myfunc() called.")
  func()
  print(" after myfunc() called.")
  return func
def myfunc():
  print(" myfunc() called.")
myfunc = deco(myfunc)
myfunc()
myfunc()

# -*- coding:gbk -*-
'''示例3: 使用語法糖@來裝飾函數(shù)，相當(dāng)于“myfunc = deco(myfunc)”
但發(fā)現(xiàn)新函數(shù)只在第一次被調(diào)用，且原函數(shù)多調(diào)用了一次'''
 
def deco(func):
  print("before myfunc() called.")
  func()
  print(" after myfunc() called.")
  return func
@deco
def myfunc():
  print(" myfunc() called.")
myfunc()
myfunc()

# -*- coding:gbk -*-
'''示例4: 使用內(nèi)嵌包裝函數(shù)來確保每次新函數(shù)都被調(diào)用，
內(nèi)嵌包裝函數(shù)的形參和返回值與原函數(shù)相同，
裝飾函數(shù)返回內(nèi)嵌包裝函數(shù)對象'''
 
def deco(func):
  def _deco():
    print("before myfunc() called.")
    func()
    print(" after myfunc() called.")
    # 不需要返回func，實際上應(yīng)返回原函數(shù)的返回值
  return _deco
@deco
def myfunc():
  print(" myfunc() called.")
  return 'ok'
myfunc()
myfunc()

# -*- coding:gbk -*-
'''示例5: 對帶參數(shù)的函數(shù)進(jìn)行裝飾，
內(nèi)嵌包裝函數(shù)的形參和返回值與原函數(shù)相同，
裝飾函數(shù)返回內(nèi)嵌包裝函數(shù)對象'''
def deco(func):
  def _deco(a, b):
    print("before myfunc() called.")
    ret = func(a, b)
    print(" after myfunc() called. result: %s" % ret)
    return ret
  return _deco
@deco
def myfunc(a, b):
  print(" myfunc(%s,%s) called." % (a, b))
  return a + b
myfunc(1, 2)
myfunc(3, 4)

# -*- coding:gbk -*-
'''示例6: 對參數(shù)數(shù)量不確定的函數(shù)進(jìn)行裝飾，
參數(shù)用(*args, **kwargs)，自動適應(yīng)變參和命名參數(shù)'''
def deco(func):
  def _deco(*args, **kwargs):
    print("before %s called." % func.__name__)
    ret = func(*args, **kwargs)
    print(" after %s called. result: %s" % (func.__name__, ret))
    return ret
  return _deco
@deco
def myfunc(a, b):
  print(" myfunc(%s,%s) called." % (a, b))
  return a+b
@deco
def myfunc2(a, b, c):
  print(" myfunc2(%s,%s,%s) called." % (a, b, c))
  return a+b+c
myfunc(1, 2)
myfunc(3, 4)
myfunc2(1, 2, 3)
myfunc2(3, 4, 5)

# -*- coding:gbk -*-
'''示例7: 在示例4的基礎(chǔ)上，讓裝飾器帶參數(shù)，
和上一示例相比在外層多了一層包裝。
裝飾函數(shù)名實際上應(yīng)更有意義些'''
def deco(arg):
  def _deco(func):
    def __deco():
      print("before %s called [%s]." % (func.__name__, arg))
      func()
      print(" after %s called [%s]." % (func.__name__, arg))
    return __deco
  return _deco
@deco("mymodule")
def myfunc():
  print(" myfunc() called.")
@deco("module2")
def myfunc2():
  print(" myfunc2() called.")
myfunc()
myfunc2()

# -*- coding:gbk -*-
'''示例8: 裝飾器帶類參數(shù)'''
class locker:
  def __init__(self):
    print("locker.__init__() should be not called.")
  @staticmethod
  def acquire():
    print("locker.acquire() called.（這是靜態(tài)方法）")
  @staticmethod
  def release():
    print(" locker.release() called.（不需要對象實例）")
def deco(cls):
  '''cls 必須實現(xiàn)acquire和release靜態(tài)方法'''
  def _deco(func):
    def __deco():
      print("before %s called [%s]." % (func.__name__, cls))
      cls.acquire()
      try:
        return func()
      finally:
        cls.release()
    return __deco
  return _deco
@deco(locker)
def myfunc():
  print(" myfunc() called.")
myfunc()
myfunc()

# -*- coding:gbk -*-
'''mylocker.py: 公共類 for 示例9.py'''
class mylocker:
  def __init__(self):
    print("mylocker.__init__() called.")
  @staticmethod
  def acquire():
    print("mylocker.acquire() called.")
  @staticmethod
  def unlock():
    print(" mylocker.unlock() called.")
class lockerex(mylocker):
  @staticmethod
  def acquire():
    print("lockerex.acquire() called.")
  @staticmethod
  def unlock():
    print(" lockerex.unlock() called.")
def lockhelper(cls):
  '''cls 必須實現(xiàn)acquire和release靜態(tài)方法'''
  def _deco(func):
    def __deco(*args, **kwargs):
      print("before %s called." % func.__name__)
      cls.acquire()
      try:
        return func(*args, **kwargs)
      finally:
        cls.unlock()
    return __deco
  return _deco

# -*- coding:gbk -*-
'''示例9: 裝飾器帶類參數(shù)，并分拆公共類到其他py文件中
同時演示了對一個函數(shù)應(yīng)用多個裝飾器'''
from mylocker import *
class example:
  @lockhelper(mylocker)
  def myfunc(self):
    print(" myfunc() called.")
 
  @lockhelper(mylocker)
  @lockhelper(lockerex)
  def myfunc2(self, a, b):
    print(" myfunc2() called.")
    return a + b
if __name__=="__main__":
  a = example()
  a.myfunc()
  print(a.myfunc())
  print(a.myfunc2(1, 2))
  print(a.myfunc2(3, 4))