Rules Bases System and OO design
guanyu
quoted from one of your messages earilier :
"BTW, one of my favorite things to do is try something new just to see
whether it "shakes" up the way I have of seeing the world. A year ago
I took a foray into rule based systems and how they could be
integrated into oo applications...that was interesting...any time
someone wants to talk about rules engines meets oo design, well, give
me a holler........ "
yes i am interested in the topic of integerating rules based system
into OO design, i have tried building a small rule based system of
about 15 to 20 rules as a class project using a CLIPS bridge to .NET
(i.e the CLIPS bridge allow .NET to assert facts, rules etc), whereby
the rules are done in the CLIPS programming language and the user
interface/error checking are done in C#. i was wondering if you have
any insights on designing,testing,implementing of such systems.
-guanyu
Rebecca Wirfs-Brock
One thing I did learn is that in order to really exploit the power of
a rules engine, it is a good idea to write a very few rules and to
carefully design the data to feed the rules in a way that allows you
to write general rules that can work across a wide variety of cases.
This design of metadata to effectively support a rules engine is one
thing that isn't very often talked about in in the published
literature- but I think it is vital.
In my consulting project I had the privilege of working with an old
pro who had been working with designing information and writing
genric rules since the early 80s. He was truly a master at what he did.
We ended up implementing a generic way of representing object
attributes, named relationships and expected values for those
attributes so we could use pattern matching to cause rules to fire.
I suspect (and I've talked to several architects at large IT shops)
that many people tend to use rules engines in a way that doesn't
exploit their strengths. For example, a rules engine that loads in
thousands of rules to fire that are very explicit in their conditions
is going to run much, much slower than plain old code in Java or C#.
I'd be interested in hearing more about the kinds of rules you are
writing and how you designed the context you load into the rules
engine you use.
Regards,
Rebecca
Rebecca Wirfs-Brock President, Wirfs-Brock Associates
website: www.wirfs-brock.com blog:
http://www.wirfs-brock.com/rebeccasblog.html
cell: 503-313-4978 phone: 503-625-9529
reb...@wirfs-brock.com fax: 503-625-1969
"A man should learn to detect and watch that gleam of light which
flashes across his mind from within, more than the lustre of the
firmament of bards and sages. Yet he dismisses without notice his
thought, because it is his." --Ralph Waldo Emerson
Don't you want to take responsibility for your design?