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# _*_ coding: utf-8 _*_

"""

python_decorator.py by xianhu

"""

import functools

# 构建不带参数的装饰器

def logging(func):

@functools.wraps(func)

def decorator(*args, **kwargs):

print("%s called" % func.__name__)

result = func(*args, **kwargs)

print("%s end" % func.__name__)

return result

return decorator

# 使用装饰器

@logging

def test01(a, b):

print("in function test01, a=%s, b=%s" % (a, b))

return 1

# 使用装饰器

@logging

def test02(a, b, c=1):

print("in function test02, a=%s, b=%s, c=%s" % (a, b, c))

return 1

# 构建带参数的装饰器

def params_chack(*types, **kwtypes):

def _outer(func):

@functools.wraps(func)

def _inner(*args, **kwargs):

result = [isinstance(_param, _type) for _param, _type in zip(args, types)]

assert all(result), "params_chack: invalid parameters"

result = [isinstance(kwargs[_param], kwtypes[_param]) for _param in kwargs if _param in kwtypes]

assert all(result), "params_chack: invalid parameters"

return func(*args, **kwargs)

return _inner

return _outer

# 使用装饰器

@params_chack(int, (list, tuple))

def test03(a, b):

print("in function test03, a=%s, b=%s" % (a, b))

return 1

# 使用装饰器

@params_chack(int, str, c=(int, str))

def test04(a, b, c):

print("in function test04, a=%s, b=%s, c=%s" % (a, b, c))

return 1

# 在类的成员方法中使用装饰器

class ATest(object):

@params_chack(object, int, str)

def test(self, a, b):

print("in function test of ATest, a=%s, b=%s" % (a, b))

return 1

# 同时使用多个装饰器

@logging

@params_chack(int, str, (list, tuple))

def test05(a, b, c):

print("in function test05, a=%s, b=%s, c=%s" % (a, b, c))

return 1

# 构建不带参数的装饰器类

class Decorator(object):

def __init__(self, func):

self.func = func

return

def __call__(self, *args, **kwargs):

print("%s called" % self.func.__name__)

result = self.func(*args, **kwargs)

print("%s end" % self.func.__name__)

return result

# 使用装饰器

@Decorator

def test06(a, b, c):

print("in function test06, a=%s, b=%s, c=%s" % (a, b, c))

return 1

# 构建带参数的装饰器类

class ParamCheck(object):

def __init__(self, *types, **kwtypes):

self.types = types

self.kwtypes = kwtypes

return

def __call__(self, func):

@functools.wraps(func)

def _inner(*args, **kwargs):

result = [isinstance(_param, _type) for _param, _type in zip(args, self.types)]

assert all(result), "params_chack: invalid parameters"

result = [isinstance(kwargs[_param], self.kwtypes[_param]) for _param in kwargs if _param in self.kwtypes]

assert all(result), "params_chack: invalid parameters"

return func(*args, **kwargs)

return _inner

# 使用装饰器

@ParamCheck(int, str, (list, tuple))

def test07(a, b, c):

print("in function test06, a=%s, b=%s, c=%s" % (a, b, c))

return 1

# 装饰器实例: 函数缓存

def funccache(func):

cache = {}

@functools.wraps(func)

def _inner(*args):

if args not in cache:

cache[args] = func(*args)

return cache[args]

return _inner

# 使用装饰器

@funccache

def test08(a, b, c):

# 其他复杂或耗时计算

return a + b + c

# 使用Python自带的装饰器 @property

class Person(object):

def __init__(self):

self._name = None

return

def get_name(self):

print("get_name")

return self._name

def set_name(self, name):

print("set_name")

self._name = name

return

name = property(fget=get_name, fset=set_name, doc="person name")

# 使用Python自带的装饰器 @property

class People(object):

def __init__(self):

self._name = None

self._age = None

return

@property

def name(self):

return self._name

@name.setter

def name(self, name):

self._name = name

return

@property

def age(self):

return self._age

@age.setter

def age(self, age):

assert 0 < age < 120

self._age = age

return

# 类静态方法和类方法

class A(object):

var = 1

def func(self):

print(self.var)

return

@staticmethod

def static_func():

print(A.var)

return

@classmethod

def class_func(cls):

print(cls.var)

cls().func()

return