12:26 p.m.
With Guvnor, you can also use "working set" (see here ) to restrict the
availiable fields to expose to a business user, by selecting class and/or fields of an
existing class, and even more (businnes contraints on values, with rules).
The only problem I see with working sets, is that you must explicitely set the working set
to use when you create your rule (not very natural for a business user).
So, if one create a new rule from Guvnor, he can access the whole object model. The fact
model filtering is not enabled until a working set is associated.
May be one day, for a package or a category (or a user as said in the doc for future
devs), we will be able to set a default working set, so that all rule of this package will
automatically associated with filterered model.
But it could be a good solution for you, avoiding complex proxies, factories and so on ...
----- Mail original -----
De: GPatel(a)tsys.com
À: "Rules Users List" <rules-users(a)lists.jboss.org>
Cc: rules-users-bounces(a)lists.jboss.org
Envoyé: Vendredi 20 Janvier 2012 18:59:02
Objet: Re: [rules-users] Declarative fact model or Java?
If you are starting from scratch, this is possible. However, I find myself having to
expose operations from the *preexisting* technical domain into the business (i.e expose
methods from existing technical domain code that has all kinds of annotations and code
references to 3rd party software). The only way out, in that case, is to have your own
separate business domain classes that wrap around (proxy) the existing technical domain
From: Wolfgang Laun <wolfgang.laun(a)gmail.com>
To: Rules Users List <rules-users(a)lists.jboss.org>
Date: 01/20/2012 06:36 AM
Subject: Re: [rules-users] Declarative fact model or Java?
Sent by: rules-users-bounces(a)lists.jboss.org
Let me mention that I've used Java classes derived from XML Schema
as facts.
If there are technical properties you'd like to hide from the rule programmer,
define a "business" type and extend it with the technical properties. The
rule programmer must make do with the "business" type, which is
possible even if the object (fact) type is the "technical" subclass.
-W
On 20/01/2012, Stephen Masters <stephen.masters(a)me.com> wrote:
Hi Davide,
Thanks for your thoughts. The application is just a service which takes an
XML request, converts that into a fact and inserts that into the working
memory. Based on rule evaluations, it responds to the client with more XML
indicating whether the requested action is permitted.
On of the key aims of the project is to enable management of some rules by
'the business' through Guvnor. The current 1-1 mapping you mention is partly
what put me off using Java models, as it leads to 'technical' attributes
being present in the Guvnor fact model, which are not relevant to the
business. The more I can keep the fact model within Guvnor minimal, the
better.
So following your logic, given that:
There is no legacy model to deal with.
~80% of what is going on will be within Drools, with the Java code just to
insert/update facts and marshal XML.
I would really like to avoid a 1-1 mapping of Java classes to DRL facts.
... I think I'll stick with DRL facts.
Given that I'm not too sure exactly what I want out of it yet, I'm not sure
how much I could contribute to a spec, but I'd be happy to help out with
things. If only by testing out early code and providing feedback. If there's
anything you think I might be able to help out with, feel free to ping me an
email.
Many thanks,
Steve
stephen.masters(a)me.com
On Jan 20, 2012, at 11:44 AM, Davide Sottara <dsotty(a)gmail.com> wrote:
Hi Steve,
let me share my thoughts on this.
You will probably want to use a Java model when it's already available :) Or
when you're using the rule engine to implement the business logic layer of
your application, processing data coming from an external source.
A DRL model, instead, is definitely recommended for "temporary" facts, or
data structures which are used by the rules to do their computations.
The main problem with DRL fact classes is that they're quite cumbersome to
use outside the rule engine. On the other hand, you will be sure that the
declared types will correspond to an implementation fully compatible and
optimized for the rule engine.
Very roughly : if the rule engine is a component in a larger architecture,
use java classes. If you're building a rule-based application - i.e. DRL is
your programming language and Drools is your execution environment, go for
DRL.
As for mapping, we have added this very experimental feature lately:
http://blog.athico.com/2011/12/new-feature-spotlight-traits-part-1.html
http://blog.athico.com/2011/12/dynamic-typing-in-rules-traits-part-2.html
I have plans to use annotations to improve the mapping, avoiding the 1-1
correspondence between fields, so if you want to contribute, if only to the
specifications, let us know :)
Best
Davide
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