求分析缓存装饰器的执行思路及流程是什么，思路流程,2017/2/6描述比如

求分析缓存装饰器的执行思路及流程是什么，思路流程,2017/2/6描述比如

2017/2/6

描述

比如, 考虑这样一段代码, 它的执行流程是怎样的呢 ?

class Foo(object):    @cached_property    def foo(self):        # calculate something important here        return 42        f = Foo()f.foof.foo   

相关代码

以class为基础的缓存装饰器

class cached_property(property):    """A decorator that converts a function into a lazy property.  The    function wrapped is called the first time to retrieve the result    and then that calculated result is used the next time you access    the value::        class Foo(object):            @cached_property            def foo(self):                # calculate something important here                return 42    The class has to have a `__dict__` in order for this property to    work.    """    # implementation detail: A subclass of python's builtin property    # decorator, we override __get__ to check for a cached value. If one    # choses to invoke __get__ by hand the property will still work as    # expected because the lookup logic is replicated in __get__ for    # manual invocation.    def __init__(self, func, name=None, doc=None):        self.__name__ = name or func.__name__        self.__module__ = func.__module__        self.__doc__ = doc or func.__doc__        self.func = func    def __set__(self, obj, value):        obj.__dict__[self.__name__] = value    def __get__(self, obj, type=None):        if obj is None:            return self        value = obj.__dict__.get(self.__name__, _missing)        if value is _missing:            value = self.func(obj)            obj.__dict__[self.__name__] = value        return value

上下文环境

产品版本: Python2

操作系统: Linux

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相似的问题: http://stackoverflow.com/ques...

def cached_property(func):    def _deco(*args, **kwargs):        print(22222222222222)        ret = func(*args, **kwargs) #这是调用foo方法        print(44444444444444)        return ret    return _decoclass Foo(object):    def __init__(self):        print (111111111111111111)    @cached_property    def foo(self):        print(3333333333333)        return 42f = Foo()f.foo()

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