Hello everybody,
I have one "Template" shadow-fact and two "Trigger" shadow-facts. I have a
rule ("MAIN::triggers-template") activated by both "Trigger" shadow-facts.
This rule is pre-emptive. So once fired by a first "Trigger" fact, it won't
be fired by the second one. Each of the "Trigger" shadow-facts have a unique
slot named "key".
Generally the output of the Jess program (a simple clp file) looks like
this:
------------------------------------------
Jess, the Rule Engine for the Java Platform
Copyright (C) 2006 Sandia Corporation
Jess Version 7.0p1 12/21/2006
[Activation: MAIN::triggers-template f-3, f-2, ; time=4 ; salience=0]
[Activation: MAIN::triggers-template f-3, f-1, ; time=4 ; salience=0]
For a total of 2 activations in module MAIN.
f-0 (MAIN::initial-fact)
f-1 (MAIN::Trigger (class <Java-Object:java.lang.Class>) (dynamicSlot 0)
(key 1) (priority 0) (template <Java-Object:trigger.Template>) (templateKey
1) (OBJECT <Java-Object:trigger.Trigger>))
f-2 (MAIN::Trigger (class <Java-Object:java.lang.Class>) (dynamicSlot 0)
(key 2) (priority 0) (template <Java-Object:trigger.Template>) (templateKey
1) (OBJECT <Java-Object:trigger.Trigger>))
f-3 (MAIN::Template (class <Java-Object:java.lang.Class>) (key 1) (state
0) (OBJECT <Java-Object:trigger.Template>))
For a total of 4 facts in module MAIN.
******* Trigger [key 2] (Fact Id 2) triggers template [key 1]
------------------------------------------
However, sometimes the shadow-facts doesn't have the same order in the
working memory. It is really strange, because I am using the same clp file.
So the shadow-facts are added in the same order. As you can see below,
instead to be fired by the [key 2] shadow-facts (Fact Id 2), the rule is
fired by [key 1] shadow-facts (Fact Id 3). See the last line of the output
with "*******".
------------------------------------------
Jess, the Rule Engine for the Java Platform
Copyright (C) 2006 Sandia Corporation
Jess Version 7.0p1 12/21/2006
[Activation: MAIN::triggers-template f-1, f-3, ; time=4 ; salience=0]
[Activation: MAIN::triggers-template f-1, f-2, ; time=4 ; salience=0]
For a total of 2 activations in module MAIN.
f-0 (MAIN::initial-fact)
f-1 (MAIN::Template (class <Java-Object:java.lang.Class>) (key 1) (state
0) (OBJECT <Java-Object:trigger.Template>))
f-2 (MAIN::Trigger (class <Java-Object:java.lang.Class>) (dynamicSlot 0)
(key 2) (priority 0) (template <Java-Object:trigger.Template>) (templateKey
1) (OBJECT <Java-Object:trigger.Trigger>))
f-3 (MAIN::Trigger (class <Java-Object:java.lang.Class>) (dynamicSlot 0)
(key 1) (priority 0) (template <Java-Object:trigger.Template>) (templateKey
1) (OBJECT <Java-Object:trigger.Trigger>))
For a total of 4 facts in module MAIN.
******* Trigger [key 1] (Fact Id 3) triggers template [key 1]
------------------------------------------
This strange behavior seems to occur randomly. Sometimes it happens only
after many attempts. In the beginning, I thought that it was caused by a
rule ("INIT::modify-trigger-1") that modified a "Template" shadow-facts.
This rule was called before the pre-emptive rule
("MAIN::triggers-template"). But I commented the "modify-trigger-1" rule and
its module (INIT) and the problem occurs still. Here is the source code:
------------------------------------------
(import trigger.Template)
(import trigger.Trigger)
(deftemplate MAIN::Trigger
(declare (slot-specific TRUE) (from-class trigger.Trigger)))
(deftemplate MAIN::Template
(declare (slot-specific TRUE) (from-class trigger.Template)))
(defglobal ?*idle* = 0)
(defglobal ?*triggered* = 1)
; Constructor : Template(int aKey, int aState)
(bind ?template (new trigger.Template 1 ?*idle*))
(add ?template)
; Constructor : Trigger(int aKey, int aPriority, int aTemplateKey, int
aDynamicSlot, Template aTemplate)
(bind ?trigger1 (new trigger.Trigger 1 0 (?template getKey) 0 ?template))
(add ?trigger1)
(bind ?trigger2 (new trigger.Trigger 2 0 (?template getKey) 0 ?template))
(add ?trigger2)
;(bind ?trigger3 (new trigger.Trigger 3 1 (?template getKey) 0 ?template))
;(add ?trigger3)
(reset)
;(defmodule INIT)
;
;(defrule INIT::modify-trigger-1
; ?triggerFact <-
; (MAIN::Trigger
; (key 1)
; )
; =>
; (printout t "******* Facts before modification." crlf)
; (facts)
; (modify ?triggerFact (dynamicSlot 1))
; (printout t "******* Facts after modification." crlf)
; (facts)
; (printout t "******* Trigger [key 1] dynamicSlot has been modified."
crlf)
; )
(defrule MAIN::triggers-template
?templateFact <-
(MAIN::Template
(key ?templateKey)
(state ?*idle*)
(OBJECT ?template))
?triggerFact <-
(MAIN::Trigger
(key ?key)
(priority ?p1)
(template ?template))
(not
(MAIN::Trigger
(priority ?p2&:(< ?p2 ?p1))
(template ?template)))
=>
(facts)
(printout t "******* Trigger [key " ?key "] (Fact Id " (?triggerFact
getFactId) ") triggers "
"template [key " ?templateKey "]" crlf)
(modify ?templateFact (state ?*triggered*))
)
;(focus INIT)
(agenda)
(run)
------------------------------------------
I would be glad, if anybody could help me to figure out something.
Thanks in advance,
NicolasF
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