我读到了有关装饰器的内容,并且我正在尝试装饰类的所有方法而不使用静态方法。
现在我只使用我为非静态的特定函数编写的装饰器,所以我想知道是否有一种方法可以既装饰很多方法又避免静态方法
我用我的装饰器得到了什么:
TypeError: unbound method test() must be called with ClassTest instance as first argument (got nothing instead)
我的装饰器:
def decorator(func):
def wrapper(self, *args, **kwargs):
print "test"
return func(self, *args, **kwargs)
return wrapper
最佳答案
首先,装饰一个类非常简单:
def class_decorator(cls):
# modify cls
return cls
为了向方法添加/删除/修改功能,您可以使用方法(或变量)的修饰版本调用 setattr
:
setattr(some_class, some_attribute, decorator(some_callable))
为了区分不同类型的方法,您可以使用几个属性 判断一个方法是否是实例/类/静态方法。
完整的工作示例:
def _is_instance_method(var):
if not hasattr(var, '__call__'): # It's not a callable
return False
if not hasattr(var, 'im_self'): # It's a callable, but it's not a bound method
return False
if getattr(var, 'im_self') is not None: # At this point, if it's a class method,
# it will be bound to the class, while
# the instance method is still unbound
# return False if it's bound (i.e. a class method)
return False
return True # All that remains is a callable, that's boundable, but not yet -- an instance method!
def func_decorator(func):
def func_wrapper(self, *args, **kwargs):
print "Inside %s!" % (func.__name__,)
return func(self, *args, **kwargs)
return func_wrapper
def class_decorator(cls):
for attr in cls.__dict__:
var = getattr(cls, attr)
if _is_instance_method(var): # Determine whether the attribute is an instance method
setattr(cls, attr, func_decorator(var)) # Replace the function with a decorated one
return cls # Return the class with its new decorated instance methods
@class_decorator
class B(object):
@staticmethod
def static_method():
return "static method"
@classmethod
def cls_method(cls):
return "cls method"
def instance_method(self):
return "instance method"
print B.static_method()
print B.cls_method()
b = B()
print b.instance_method()
关于python - 装饰类的特定方法,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35526210/