Thanks for the reply Ernest.
I have a thread calling Rete.run(). Inside the jess script I create a
hardware interface and hardware monitor much the same as your example
in the temperature controller in your book - chap 14. The hardware
sensor opens a data source which are timestamped instantaneous values
and the monitor class (like the thermometer class) gets data values
from the hardware interface inside a run() method and fires events for
Jess to reason with. This all works fine.
My rules also rely on time periods. I classify data into categories
depending on their values and initiate the relevant category using a
rule. A rule input by the user might have the following semantics:
"Determine if there are any periods of time 20 seconds or more where
data values are greater than 143."
(defrule Initiates
(mon (reading ?r&:(>= ?r 143))
(tstamp ?t&:(> ?t 0)))
(pTime(running ?run&:(= ?run FALSE)))
=>
(printout t ">>>>>>>Initiates: Data "?r" bpm, timestamp "?t", Fluent
truth val: "?run crlf)
;; start the timer which also functions as a flag to indicate
;; that this category is active
(call ?pT startPropTimer))
So if the category hasn't been activated before (running is false) and
the data value is > 143 then I initiate the time dependent category by
starting the propTimer. Property 'running' and method startPropTimer()
are in a class called PropTimer. This class is connected to Jess
using:
(defclass pTime PropTime)
(bind ?pT (new PropTime)
(definstance pTime ?pT)
The Initiates rule works OK.
The terminates rule is a problem. It's function ius to terminate the
category due to the propTimer expiring.
(defrule Terminates
;Terminate when timer reaches 7000, example only
(pTime(elapsedTime ?et&:(>= ?et 7000)))
=>
(printout t ">>>>>>>Terminates: Elapsed time: "?et crlf)
(call ?pT stopPropTimer))
I will use some kind of flag to indicate the start and end times of
the category and may even save all the data in between these times to
a file or something.
So I guess, in response to your prompt, I have only one thread; the
one that starts the rete engine. The timer events are simply fired
from within a loop inside calcTime() - the facts are picked up by Jess
but the terminates rule won't act on them. I have a trace as follows
from watch facts:
<=> f-0 (MAIN::pTime (class <Java-Object:java.lang.Class>)
(elapsedTime 5860) (running TRUE) (OBJECT <Java-Object:PropTime>))
<=> f-0 (MAIN::pTime (class <Java-Object:java.lang.Class>)
(elapsedTime 5875) (running TRUE) (OBJECT <Java-Object:PropTime>))
<=> f-0 (MAIN::pTime (class <Java-Object:java.lang.Class>)
(elapsedTime 5891) (running TRUE) (OBJECT <Java-Object:PropTime>))
etc...
These facts appear after the Initiates rule has fired and before the
terminates rule fires. But, as I mentioned originally, terminates only
fires when the loop inside calcTime() finishes.
I hope this is clearer now?
Thanks again.
Mike
----- Original Message -----
From: "Ernest Friedman-Hill" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, January 05, 2007 1:50 PM
Subject: Re: JESS: Shadow facts not working
: Off the top of my head, I'm not sure Jess (or other clients of your
: class) will react to change events being fired during a call to a
: getter method; not only calcTime(), but also presumably Jess will be
: calling getElapsedTime(), and the results might be odd.
:
: But from your description, I suspect the problem is more pedestrian.
: How many threads are involved? For it to work the way you're
: expecting, there would need to be two: one calling calcTime(), and
: the other calling Rete.run() (or the equivalent.) It sounds to me as
: if you just have one that calls run() after calling calcTime(). If
: I'm wrong, then will you please describe what you're doing?
:
: On Jan 4, 2007, at 7:37 PM, Mike Stacey wrote:
:
: > I have a java class which is a bean and fires events when
properties
: > change. My rules fire when this property attains certain values.
The
: > property is a timer which calculates the elapsed time since some
: > previous event happened. This is implemented in a loop within the
: > java class. My jess rule needs to fire when the timer gets to a
: > particular elapsed time.
: >
: > Problem: The rule doesn't fire until the method returns, by which
: > time the timer has run further than it needs to. I have checked
with
: > watch facts and the facts are being asserted in jess continuously
but
: > yet the rule doesn't fire until the caclTime() method exits.
: >
: > In the examle below, when the Terminates rule fires the timer has
: > reached a bit over 10000 instead of 7000. Any suggestions would be
: > greatly appreciated of course. I hope the following is clear
enough
: > to follow...
: >
: > The java code
: > -------------
: > Class PropTime
: >
: > public void calcTime()
: > {
: > long etime = getElapsedTime();
: > // Loop condition only for test purposes at the moment
: > while(etime < 10000)
: > {
: > etime = getElapsedTime();
: > }
: > }
: >
: > /** Returns elapsed time in milliseconds.
: > * PROBLEM: 'Terminates' rule not firing until calcTime()
returns
: > */
: >
: > public long getElapsedTime()
: > {
: > if (startTime == -1)
: > {
: > elapsedTime = 0;
: > System.out.println("0");
: > }
: > if (running)
: > {
: > oldElapsedTime = elapsedTime;
: > elapsedTime = System.currentTimeMillis() - startTime;
: > // Terminate rule should fire when this reaches a given
: > value
: > eventSupport.firePropertyChange("elapsedTime", new
: > Long(oldElapsedTime), new Long(elapsedTime));
: > }
: > else
: > {
: > elapsedTime = stopTime-startTime;
: > }
: > return elapsedTime;
: > }
: >
: > The jess code
: > -------------
: >
: > (defclass pTime PropTime);; create deftemplate from javabean
: > (bind ?pT (new PropTime));; create bean
: > (definstance pTime ?pT);; add bean (shadow fact) to jess memory
: >
: > ; PROBLEM: This rule doesn't fire until the calcTime() method
: > ; finishes
: >
: > (defrule Terminates
: > ; Terminate when timer reaches 7000
: > (pTime(elapsedTime ?et&:(>= ?et 7000)))
: > =>
: > (printout t ">>>>>>>Terminates: Elapsed time: "?et crlf)
: > (call ?pT stopPropTimer))
: >
: >
: >
:
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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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