2007/3/28, Jones, Alan R <alan.r.jones@boeing.com>:

This is actually very close to the approach I am going to try:

The caching is replaced by an object representing/encapsulating a given rulebase created as a new/separate thread. A reference to said object is registered (cached?). When a Fact comes along, the appropriate rulebase/object is looked up and the fact is fed to it (the object has a method that takes the fact and asserts it into a new working memory), then the object fires the rule. Does this approach make sense?

Thanks,

aj

From: Edson Tirelli [mailto:tirelli@post.com]
Sent: Wednesday, March 28, 2007 11:03 AM
To: Rules Users List
Subject: Re: [rules-users] Rules Engine always running

   Alan,

   If you have different sets of rules that you want to apply in different circunstances, you can compile and cache each of this sets as a rulebase (note that the set may contain a single rule).
   Then, for each fact that arrives, you decide which is the rulebase that applies to it, create a working memory for that rulebase, assert the fact, run the rule and throw the working memory away (as, you mentioned you don't want this working memory anymore).

   You can, of course, work with a single rulebase and keep adding and removing rules from it, but it will be more expensive to handle that for the use case you described.

   If you are able to detail your use case, we may be able to help you more.

   Regards,
     Edson

2007/3/28, Jones, Alan R <alan.r.jones@boeing.com>:

Yes, some of these things are being considered. Thanks for your input , it has been helpful!

aj

From: Anstis, Michael (M.) [mailto:manstis1@ford.com]
Sent: Wednesday, March 28, 2007 9:12 AM

To: Rules Users List
Subject: RE: [rules-users] Rules Engine always running

I assume rules are dynamically added to the Rulebase and that there is not a static set of rules associated with each application release?

I believe new rules can be dynamically added to the existing Rulebase - whether existing WM's inherit the new rules I don't know. Agenda Groups could provide the control of which groups of rules fire.

Also, if you retain FactHandles to all asserted Facts depending upon the decision made by the component the legacy Facts can be retracted before the new rule is activated.

I assume you'll also have some "Rule life-cycle" control in place? Either removing rules from a Rulebase (I believe to be possible) or destroying redundant WM's (as per your proposal).

Sorry, this doesn't add much more value - although input from more experienced users is welcomed.

Cheers,

Mike

From: rules-users-bounces@lists.jboss.org [mailto: rules-users-bounces@lists.jboss.org] On Behalf Of Jones, Alan R
Sent: 28 March 2007 15:29
To: Rules Users List
Subject: RE: [rules-users] Rules Engine always running

Mike,

Thanks for you rresponse, however I'm not sure based on what we are wanting to do that we should use a single working memory. The proposed approach is:

a rule has been added to the rule base, then a Fact (object) comes along and we instantiate a working memory and fire all rules relative to this working memory. The outcome from Drools is evaluated by another sw component, and it is decided to try a different rule with a given Fact.

So, a new rule, rule #2, comes along with slightly different specifics on what it is supposed to match, so it is added to the rule base. Then, Fact #2 comes down the pipeline. A new working memory #2 is instantiated against the existing rulebase, Fact #2 is asserted, and fireAllRules() called against the working memory #2.

The desired behavior is that only rule #2 is actually kicked into action (against Fact #2), since the first rule and fact is done with. We don't want the previous rules/facts in the rule base operating any longer.

Maybe I just don't know enough about the proper application of rules when solving particular problems to ask the right questions -- my task is to expose JBoss rules as a service so I'm trying to understand a bit about it's operation.

Thanks,

aj

--------------------------------------------
Alan R Jones
Boeing S&IS Mission Systems
Denver Engineering Center (BDEC)
303.307.3415

From: Anstis, Michael (M.) [mailto:manstis1@ford.com]
Sent: Wednesday, March 28, 2007 2:23 AM
To: Rules Users List
Subject: RE: [rules-users] Rules Engine always running

Hi Alan,

A working memory is in essence always available\running whilst there is a reference to it; other than the "main" thread (on which your public static void main executes) you don't need to use other threads (but this obviously depends upon what exactly you're trying to achieve). The Rulebase can contain all of your production rules (in fact this is probably the recommended approach as, assuming some rules share a common pattern, the resulting RETE network will be optimised); and you can feed incoming objects (Facts in JBoss Rules terms) into one working memory created from the one Rulebase. As objects are asserted patterns (LHS) defining the rules are matched and, once fully matched, rules are activated for execution (RHS). Unfortunately I don't have any experience of JBoss Rules in a multi-threaded environment.

For example:-

public static void main(String args[]) {

    Rulebase rb = loadRuleBase();

    WorkingMemory wm = rb.newWorkingMemory();

    while (!exit()) {

        Collection c = getObjectsFromWherever();

        assertObjectsIntoWorkingMemory(c, wm);

        wm.fireAllRules();

                try {

                    Thread.sleep(1000);

                }

                catch(InterruptedException ie) {

        }

    }

}

With kind regards,

Mike

From: rules-users-bounces@lists.jboss.org [mailto: rules-users-bounces@lists.jboss.org] On Behalf Of Jones, Alan R
Sent: 27 March 2007 19:05
To: Rules Users List
Subject: [rules-users] Rules Engine always running

Kind of new to JBoss Rules...I'm trying to fiigure out from what i have read so far if the following scenario is possible:

1. Start up an instance of a working memory (say, with dummy rule?) and keep it running, feeding it data objects to operate on from time to time.

2. As needed, kick off as many instance of working memory within the single rule base (in a separate thread) and keep them going as in step 1

The idea is to keep the rules engine running constantly, but kick off separate working-memory threads for the injection of various incoming rule sets and the objects those rule sets work on as needed. Can anyone provide some insight to this? Pointers to examples, perhaps?

Alan J.

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