newseater wrote:
>
> Robert Kern wrote:
>
>>newseater wrote:
>>
>>>Hello. I need to be able to control how objects are created. Sometimes
>>>when creating an object, i want to reuse another object instead. I've
>>>searched for factory method implementations and singleton
>>>implementations. They were too much of a hack!
>>>
>>>My first attempt of doing this was to play around with the __new__()
>>>method. But i didn't quite succed. Then i came up with making a static
>>>method which can create my instances or re-use other instances.
>>>However, the below code I cannot get to work :(
>>>
>>>class Creator
>>> def createInstance(cls, *args, **kwargs):
>>> anewinstance = cls.__new__(cls, *args, **kwargs)
>>> anewinstance.__init__(*args, **kwargs)
>>>
>>> return anewinstance
>>> createInstance = staticmethod(createInstance)
>>
>>You want a classmethod, not a staticmethod.
>
> why do i want that? how should the code look like? currently the
> objects fail to get initialized etc...
A staticmethod does not take a cls argument. It is essentially just a
function that is attached to a class.
class Something(object):
def foo(x, y, z):
print x, y, z
foo = staticmethod(foo)
A classmethod does that a cls argument.
class Creator(object):
def createInstance(cls, *args, **kwds):
pass
createInstance = classmethod(createInstance)
As for the desired content of the classmethod, I don't care to
speculate. I usually just use the Borg pattern or a factory or any one
of the Singleton implementations floating around. They are no more hacky
than this, but they have the added benefit of working.
--
Robert Kern
[EMAIL PROTECTED]
"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter
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