[rules-users] Maintaining DB/Working Memory Synchronization

[Andrew Waterman]

It can depend on how you want to use working memory as well.  If you are
working statelessly, you can load objects through some type of transactional
framework, insert them into memory (or the ones relevant to you at that
moment in time) let Drools evaluate the objects, make changes and then
serialize those changes once rules have stopped firing.  I do something like
this using EJB and JPA.  I've been interested in pushing this into the rules
themselves; which I believe is now possible using the JPA support within
Drools flow.  This might work much better if you were using statefull and
long running working memory process.  Even in the event of catastrophic
failure, your transactionally serialized changes would still remain in the
database.  So you could restart and pick up work from where you were last.

You may wish to take a look at the following blog entries:

http://blog.athico.com/2009/03/drools-50-cr1-new-and-noteworthy.html

And the Drools flow documentation.

I'm hoping to move our work in this direction so please do pass on your
results; unless I'm completely misunderstanding how one can use flow, expert
and JPA together with transactions.

best wishes,

Andrew

On Sat, Nov 7, 2009 at 9:23 AM, ken.p <ken.annihilation at gmail.com> wrote:

>
> I am also looking similar feature. We can currently use AOP to send event
> to
> stream. However, we have events with relevant duration for days and some
> time weeks. If server were to restart for maintenance, how do we restore to
> the same state?
>
>
>
> Daniel Miller-9 wrote:
> >
> > So I hope that someone out here, or many of you, can give me some idea
> > of how you do this.
> >
> > I have about 20+ entities in my database that I want Drools to know
> > about.  Obviously my hope is to apply CEP, rules and processes to
> > these items.  However, I feel like I'm missing some type of connection
> > between how Drools recommends keeping my working memory in sync with
> > my database changes.
> >
> > Ideally, I'd love to be able to just update my entities as I have been
> > doing in the database, but have those changes automatically move their
> > way over into the working memory.  How do any of you recommend I
> > accomplish this?
> >
> > Thanks in advance for any suggestions.
> >
> > Dan Miller
> >
> > _______________________________________________
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> > https://lists.jboss.org/mailman/listinfo/rules-users
> >
> >
>
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>
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