As soon as you have more than one thread, you have to be *very
careful* with your definitions of words like "when" and "finished".
The method "runUntilHalt()" just does something like this
while (!halt) {
while there are activated rules and halt is false
fire a rule
wait for halt to become true or there to be new activations
}
So when you call "runUntilHalt()", Jess can potentially be "done"
lots of times. If you want to do something special at that time, then
don't call runUntilHalt() -- write your own equivalent method which
is based on the same loop, but does something special. For example
while (!halt) {
while there are activated rules and halt is false
fire a rule
// At this point, either there are no rules to fire, or "halt"
has been called
// This is, I think, what you're calling "a safe spot to call
halt", although, of course,
// it's always safe to do so
if (mySpecialHaltFlag)
break;
wait for halt to become true or there to be new activations
}
On Feb 12, 2007, at 7:44 AM, Shi Paul wrote:
Hi Henrique and others,
Ernest's reply is only good for single thread execution, while I
have at least 2 threads running. It's kinda like reproducer/
consumer scenario. I have Jess running in its own thread (consumer
thread), I have my other threads running as facts-collecting
threads (producer thread). So once those facts-collecting threads
stop running, I need to stop Jess thread but the problem is when I
call Rete.halt() I don't know if it's still busy.
I tried Rete.listActivations() before stopping it, it seems doesn't
work as well (the test result revealed that). I didn't try Scott's
suggestion since I want the solution in the API level instead of
adding a new rule in the knowledge base as I think the solution
shouldn't be across 2 different domains. Does anybody has othe good
suggestions?
Thanks,
Paul
From: "Henrique Lopes Cardoso" <[EMAIL PROTECTED]>
Reply-To: jess-users@sandia.gov
To: jess-users@sandia.gov
Subject: Re: JESS: How do I determine Jess engine has finished
firing rules
Date: Mon, 12 Feb 2007 09:43:05 +0000
Why don't you use Rete.run() instead of runUntilHalt() and wait
for the method to return?
Read Ernest's reply.
Cheers,
Henrique
Shi Paul wrote:
Hmmm, I wouldn't say it's a nice solution although it might work.
I looked through the Rete api, there is a Rete.listActivations,
I'm wondering if I could count on that, before calling rete.halt
in the main thread, I'd use that API in a while loop and let main
thread sleep for a few seconds if that doesn't return 0.
From: "Krasnigor, Scott L (N-AST)" <[EMAIL PROTECTED]>
Reply-To: jess-users@sandia.gov
To: jess-users@sandia.gov
Subject: RE: JESS: How do I determine Jess engine has finished
firing rules
Date: Fri, 09 Feb 2007 15:59:11 -0500
The easiest thing to do is add a rule with a low salience (I use
-1000)
that will always match and add whatever action on the rhs that
you want
to use to signal all rules are done being processed. This rule will
always be added to the end of the agenda, so when it fires, you
know
there are no more rules waiting to be fired.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:owner-jess-
[EMAIL PROTECTED]
On Behalf Of Shi Paul
Sent: Friday, February 09, 2007 1:46 PM
To: jess-users@sandia.gov
Subject: Re: JESS: How do I determine Jess engine has finished
firing
rules
Hi,
Actually I have created its own thread and then in that thread I
call
rete.runUntilHalt. Then I run into this issue just mentioned,
can you
give
me some more specifics about the solution as how to determin if the
engine
is not busy and can safely be stopped? I'd imagine that the main
thread
could just wait on some semaphore the jess thread operates or
call into
some
API which does the same thing.
Thanks,
Paul
>From: "Ernest Friedman-Hill" <[EMAIL PROTECTED]>
>Reply-To: jess-users@sandia.gov
>To: jess-users@sandia.gov
>Subject: Re: JESS: How do I determine Jess engine has finished
firing
rules
>Date: Fri, 9 Feb 2007 13:19:29 -0500
>
>
>On Feb 9, 2007, at 12:15 PM, Shi Paul wrote:
>
>>Hi there,
>>Is there an API to determine the rule engine has completed
its work.
I'd
>>like to call rete.halt() to stop the engine, but I'm
wondering what
if
>>the engine is still firing rules when I call that. Can
anybody shed
some
>>lights on it?
>>
>
>Jess doesn't create any threads on its own. If you call rete.run
(),
then
>run() returns when, and only when, there are no more rules to
fire. If
you
>have multiple threads, then you can set up your own notification
scheme
>based on that.
>
>
>---------------------------------------------------------
>Ernest Friedman-Hill
>Advanced Software Research Phone: (925) 294-2154
>Sandia National Labs FAX: (925) 294-2234
>PO Box 969, MS 9012 [EMAIL PROTECTED]
>Livermore, CA 94550 http://www.jessrules.com
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