<br> Interesting analogy, but careful here:<br><br>"Statefull is just series of
stateless session where you transfer state from one session to
another."<br><br> Not sure what lead you to think that way, but it is actually the opposite, and trying to explain that will make things REALLY confusing for some. So, I would recommend anyone not interested in knowing internal details to **stop reading here**! <br>
<br> Ok, if you are still reading, then I will try to explain in the simplest way I can: "there is no such thing as stateless session in Drools internals". Deep in drools internals, there is only stateful working memory, that is exposed to the user in 2 different ways: a properly stateful session, that allows users to manage the state, and a helper object that we call "staless session". This helper staless session object, among other things, simply holds a reference to the kbase and when the execute(...) method is called, internally it creates a stateful session, inserts the facts, fire the rules and disposes the session automatically. There are a bunch of other helper mechanisms there, but the essence is just that: simplify the use of stateful sessions for stateless scenarios.<br>
<br> Edson<br><br><div class="gmail_quote">2010/3/8 Pavel Tavoda <span dir="ltr"><<a href="mailto:pavel.tavoda@gmail.com">pavel.tavoda@gmail.com</a>></span><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
It's like synchronous vs. asynchronous communication. In reality it's<br>
always asynchronous but from top view it appear synchronous.<br>
Similar to stateless vs. statefull. Statefull is just series of<br>
stateless session where you transfer state from one session to<br>
another. Look for Drools statefull persistency. In reality it is<br>
series of stateless sessions where you store status from one session<br>
result and use it as start for another session plus some new changes.<br>
This is my point of view of difference between stateless/statefull<br>
session specially how Drools make it.<br>
<br>
Regards<br>
<font color="#888888"><br>
Pavel<br>
</font><div><div></div><div class="h5"><br>
On Mon, Mar 8, 2010 at 4:23 PM, Tim de Jager <<a href="mailto:tim.dejager@student.hu.nl">tim.dejager@student.hu.nl</a>> wrote:<br>
><br>
> Hi everybody,<br>
><br>
> I'm currently doing my bachelor thesis on Rule engines. This includes<br>
> comapring different Rule engine products. I have set up a small Java program<br>
> (Conway's game of life) and I'm writing the 'engine' in different Rule<br>
> engines, while keeping the same GUI,CellGrid etc. I have already made a<br>
> Drools based engine.<br>
><br>
> I have been studying the Rule engine subject for somewhat more then a month<br>
> now. And I'm currently seeing two different developments namely the use of<br>
> an inference engine and the generation of embedded code instead (Take,<br>
> Visual Rules etc.) I can see some of the pro's and cons with both<br>
> paradigms. But I'm wondering what opinion some of you guys have on the<br>
> subject.<br>
><br>
> I can see that without inferencing it is very hard (or even impossible) to<br>
> keep a statefull session inside the rule engine, haven't seen a<br>
> non-inferencing rule engine which does offer this possibility. And also lose<br>
> features like TMS. But what would be a concrete example where a statefull<br>
> session is absolutely necessary? Instead of letting the engine reason over<br>
> all the facts in stateless way. And managing conflicts with a ruleflow (see<br>
> Visual Rules for a nice example).<br>
><br>
> I'm looking forward to hearing your thoughts.<br>
><br>
> Thanks,<br>
><br>
> Tim<br>
><br>
> P.S I already read two of Mark Proctors blogs on inferencing, but while<br>
> enlightening, they didn't supply me with a definitive awnser<br>
> --<br>
> View this message in context: <a href="http://n3.nabble.com/Inferencing-tp435411p435411.html" target="_blank">http://n3.nabble.com/Inferencing-tp435411p435411.html</a><br>
> Sent from the Drools - User mailing list archive at Nabble.com.<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br> Edson Tirelli<br> JBoss Drools Core Development<br> JBoss by Red Hat @ <a href="http://www.jboss.com">www.jboss.com</a><br>