Re: How to return an empty aggregate

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 5 Kwi, 01:58, george.p...@gmail.com wrote:

> To me it seems that simple callback will be much more simple and clear
> way to achieve the same result.

It depends where you start with the design. If you start with
stateless concrete factories (or you just see the whole picture right
from the beginning), then callbacks will seem attractive. But if you
start from the user site without knowing up-front what will kind of
factory will be used then 'Class is the OO way to solve the problem.

What will you do with the callback interface if at some point you
discover that stateful factory will be most appropriate? Will you mess
around with local functions that manipulate state from their enclosing
scope? What about many such factories that have distinct states? And
so on.

> > If it's stateless, then it does not need any protection - there is
> > nothing to protect.
>
> except for reenterance that in most of cases matter for that type of
> objects.

If it's stateless, then reentrance is given for free.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com