I haven't really researched this but while each can do vice versa,
neither is as fast as if it was native - with backward chaining
emulating forwarding chaining being slower than the other way around.
Mark
Hamu, Dave wrote:
I think that you can easily do forward chaining and backward chaining
with Drools. For that matter, you can achieve forward chaining with a
backward chaining engine and vice-versa...
-----Original Message-----
From: Adrian Bigland [mailto:[EMAIL PROTECTED]
Sent: Thursday, November 10, 2005 5:17 AM
To: [email protected]
Subject: Re: [drools-user] input validation in rules used by JSR-94
clients
It just occurred to me that validation may be more of a
backward-chaining concept. You have a goal, i.e. a valid input set for
the rules, and want to prove that the current set is actually valid.
Is it right that a pure forward chaining rule engine will have
difficulty handling the absence of things?
I've been using JRules in the recent past, which has rules that match
working memory itself if it contains a certain number of instances of a
class - or if there are none. This sort of thing made validation rules
easier to write. It also had initial and final actions which provided
some mode support for free. However, I got the feeling that the
implementation was becoming complicated and less 'pure' whatever that
means.
Maybe the answer is to write rules that match working memory, then - and
perhaps supply a working memory implementation that can count instances
for you.
**********************************************************************
This e-mail and any attachment is intended for the named addressee(s)
only, or person authorised to receive it on their behalf. The content
should be treated as confidential and the recipient may not disclose
this message or any attachment to anyone else without authorisation.
Unauthorised use, copying or disclosure may be unlawful. If this
transmission is received in error please notify the sender immediately
and delete this message from your e-mail system. Any view expressed by
the sender of this message or any attachment may be personal and may not
represent the view held by First Choice Holidays PLC and its
subsidiaries. All electronic transmissions to and from First Choice are
recorded, may be monitored and are scanned for viruses and content.
E-mails containing viruses will be deleted without notification. Whilst
we maintain virus checks on inbound e-mails we accept no liability for
viruses or other material introduced with this message.
All companies form part of the First Choice Holidays PLC group of
companies.
First Choice Holidays PLC Company Registration No: 48967 (England)
Registered Office: First Choice House, London Road, Crawley, WestSussex
RH10 9GX
**********************************************************************
