"while there are activated rules and halt is false, fire a rule" is
also known as Rete.run().
"wait for halt to become true or there to be new activations" is also
known as Rete.waitForActivations().
The complete source for runUntilHalt() is something like
int runUntilHalt() throws JessException {
int count = 0;
do {
count += run();
synchronized (getActivationSemaphore()) {
if (isHalted())
break;
waitForActivations();
if (isHalted())
break;
}
} while (true);
return count;
}
All the Rete methods used here are public.
Note that most Jess licenses include the full source code.
On Feb 13, 2007, at 9:52 AM, Shi Paul wrote:
Hi Ernest,
You're so close to give me the right solution :-). Could you show
me the code as "while there are activated rules"? I don't think
it's "Rete.listActivations().hasMore()" since you mentioned in some
other posts that it's not for internal use, so I'd like to see what
you use internally so that I can apply the same theory.
Thanks,
Paul
From: "Ernest Friedman-Hill" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Re: JESS: How do I determine Jess engine has finished
firing rules
Date: Mon, 12 Feb 2007 19:33:10 -0700
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: [email protected]
To: [email protected]
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: [email protected]
To: [email protected]
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: [email protected]
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: [email protected]
>To: [email protected]
>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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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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