Nathan Harmston wrote:
> HI,
>
> I m trying to start an api in a similar way to the djangic way of
> Class.objects.all(). Ie objects is a "Manager" class.
>
> So:
>
> class Foo(object):
> def __init__(self):
> self.test = "NEE"
>
> class Manager(object):
> def __init__(self):
> pass
> def all(self):
> return "COCONUTS"
>
> Because of how some of the code is set up I cant use
> metaclasses........so I try to use a decorator:
>
> def addto(instance):
> def decorator(f):
> import new
> f = new.instancemethod(f, instance, instance.__class__)
> setattr(instance, "objects", f)
> return f
> return decorator
>
> class Manager(object):
> @addto(Foo)
> def __init__(self):
> .............
>
> however this only binds the init method to the Foo.objects, so not
> what I want. If I try using classmethod...then it just says the
> Foo.objects doesnt exist.
>
> Does anyone have any ideas how I can accomplish this using decorators?
> And also preventing more than one Manager instance instantiated at one
> time.
>
> Many Thanks in advance,
>
> Nathan
What you are trying to do is a little obscure to me, but I think you
want want to rebind Foo.objects to a new manager every time you
instantiate a Manager? This will do it:
class Foo(object):
def __init__(self):
self.test = "NEE"
class Manager(object):
def __init__(self):
pass
def all(self):
return "COCONUTS"
def addto(cls):
def decorator(f):
def _f(self, *args, **kwargs):
cls.objects = self
f(self, *args, **kwargs)
return _f
return decorator
class Manager(object):
@addto(Foo)
def __init__(self):
pass
Example:
py> class Foo(object):
... def __init__(self):
... self.test = "NEE"
...
py> class Manager(object):
... def __init__(self):
... pass
... def all(self):
... return "COCONUTS"
...
py> def addto(cls):
... def decorator(f):
... def _f(self, *args, **kwargs):
... cls.objects = self
... f(self, *args, **kwargs)
... return _f
... return decorator
...
py> class Manager(object):
... @addto(Foo)
... def __init__(self):
... pass
...
py> hasattr(Foo, 'objects')
False
py> m = Manager()
py> print m
<__main__.Manager object at 0x121b870>
py> print Foo.objects
<__main__.Manager object at 0x121b870>
py> n = Manager()
py> print n
<__main__.Manager object at 0x121b250>
py> print Foo.objects
<__main__.Manager object at 0x121b250>
If you just want the class Foo to have the class Manager as its objects,
just do this:
Foo.objects = Manager
But I don't think that's what you want.
I'm not familiar with django, so if I haven't hit it, please elaborate.
James
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