Re: Designing for a reusable Access-Level Constraint library

From: Jeff Grigg (jgrigg_at_mo.net)
Date: 10/31/03 

Date: 31 Oct 2003 06:14:58 -0800

Ryan Kinderman <ryan@kinderman.net> wrote...
> I've been working on a design project for quite some time,
> to come up with a reusable library which provides a general-
> purpose, reusable set of components by which client applica-
> tions may define their own access-level constraints (ALCs)
> [...]. The library will force a consistent design for
> implementing ALCs, [...]
>
> Having relatively little experience in software engineering,
> [...], I'm having trouble deciding whether this library will
> have to be too generalized to be useful. [...]
>
> So, what I was wondering is if any of you seasoned veterans
> out there can spot flaws in this idea right from the start,
> or if you can think of a direction in which I can go with
> this as far as how I may wish to organize or design the
> classes/layers.

I'll try to be nice: The flaw is that you don't know what you need,
so you're trying to make a super-generalized system that will meet all
possible needs. The good news is that you realize that this library
is likely "to be too generalized to be useful."

I'll suggest the standard Extreme Programming answer: Implement the
simplest authentication model you can, for the requirements of your
organization's current application. Refactor the code to reduce
duplication -- bringing the authentication code into a centralized
"place." After doing two or three of these, you'll have some relevant
experience as to what is needed, and how to provide it. Now you can
extract the most useful code from the last few projects and make a
common reusable library.