Re: JESS: Java objects
Noel Huebers wrote (defquery searchcontext (declare (variables ?name ?task ?val)) (context (username ?name) (action Bewertet) (task ?task) (value ?val))) Now I want to delete the some facts. How do I get a fact from the queryresult '?result' ? ;(deffunction delformerattempts(?n ?t ?v) ;(bind ?results (run-query* searchcontext ?n ?t ?v)) ;(while (?results next)) ;(retract ?results get)) All you have to do is extend the pattern in the query with a binding for the entire fact: (defquery searchcontext (declare (variables ?name ?task ?val)) ?context - (context (username ?name) (action Bewertet) (task ?task) (value ?val))) And then you access it with the get method: (deffunction delformerattempts (?n ?t ?v) (bind ?results (run-query* searchcontext ?n ?t ?v)) (while (?results next) (retract (?results get context But wouldn't it be more convenient to rearrange things so that the context fact maintains a counter, with new Bewertet events being counted right there. Here's how: (clear) (deftemplate Base (slot username)(slot action)(slot value)(slot task)) (deftemplate Context extends Base (slot count (default 1))) (deftemplate Event extends Base (slot stamp )) (defrule IncrementCount ?event - (Event (username ?s)(action Bewertet)(value ?v)(task ?t)) ?context - (Context (username ?s)(action Bewertet)(value ?v)(task ?t)(count ?c)) = (modify ?context (count (++ ?c))) (retract ?event) ) (defrule FirstTime ?event - (Event (username ?s)(action Bewertet)(value ?v)(task ?t)) (not (Context (username ?s)(action Bewertet)(value ?v)(task ?t))) = (assert (Context (username ?s)(action Bewertet)(value ?v)(task ?t))) (retract ?event) ) (deffacts ecs (Event (username Max)(action Bewertet)(value 3)(task Thesis)(stamp 1)) (Event (username Max)(action Bewertet)(value 3)(task Thesis)(stamp 2)) (Event (username Max)(action Bewertet)(value 3)(task Thesis)(stamp 3)) ) (reset) (run) kr Wolfgang To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED]
Re: JESS: Java objects
Noël Huebers wrote: Hi, I'm new to the Jess language and have some questions. 1. I work with Java object. I stored them in Jess with store and assert/fetch commands. But I could not call there member in the lhs of my rule. No function calls allowed, right? So, for every object I made a rule to insert a Jess template. This works fine, but is this way of mapping Java objects to Jess facts and then discarding the object the best way to work with java objects? store and fetch are just a way of storing and retrieving arbitrary data. If you want to use Java objects in rules, look into the topic of shadow facts, see section 5.3. Shadow facts: reasoning about Java objects. 2. I am trying to implement a counter-logic for specific slot combinations. First, everytime a fact is inserted I check if there is already a procounter fact. If not I create one. This works fine. The next rule should recognize when a fact (EContext) is inserted and the counter (procounter) already exists. In this case, the count slot should only be modified. I try to compare bounded vars ?s ?v ?t from EContext to procounter slots, but I think Jess simply overwrites the binding. Can you help me with the correct syntax? Is there a better logic to implement a counter? If you have one fact (EContext (studentname Max) (action bewertet)(value 3)(task Thesis)) it won't be possible to ever assert another fact just like this one. This might be the cause of modpro failing to fire. Consider adding another slot to EContext such as a date or time stamp, and then you might see an increase. Notice that the rule might benefit from adding the option (declare (no-loop TRUE)). Best regards, Noel Huebers ***CODE*** (defrule modpro ; counter erhöhen (and (EContext (studentname ?s) (action bewertet) (value ?v) (task ?t)) ?pro - (procounter (name ?s) (task ?t) (val ?v) (count ?x)) ) = (modify ?pro (count (+ ?x 1))) ;increase counter (printout t Counter für ?s ?t ?v erhöhen!!! crlf)) To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED]
JESS: Java objects
Hi, I'm new to the Jess language and have some questions. 1. I work with Java object. I stored them in Jess with store and assert/fetch commands. But I could not call there member in the lhs of my rule. No function calls allowed, right? So, for every object I made a rule to insert a Jess template. This works fine, but is this way of mapping Java objects to Jess facts and then discarding the object the best way to work with java objects? 2. I am trying to implement a counter-logic for specific slot combinations. First, everytime a fact is inserted I check if there is already a procounter fact. If not I create one. This works fine. The next rule should recognize when a fact (EContext) is inserted and the counter (procounter) already exists. In this case, the count slot should only be modified. I try to compare bounded vars ?s ?v ?t from EContext to procounter slots, but I think Jess simply overwrites the binding. Can you help me with the correct syntax? Is there a better logic to implement a counter? Best regards, Noel Huebers ***CODE*** (defrule modpro ; counter erhöhen (and (EContext (studentname ?s) (action bewertet) (value ?v) (task ?t)) ?pro - (procounter (name ?s) (task ?t) (val ?v) (count ?x)) ) = (modify ?pro (count (+ ?x 1))) ;increase counter (printout t Counter für ?s ?t ?v erhöhen!!! crlf))
Re: JESS: Java objects
On Aug 14, 2007, at 5:20 AM, Noël Huebers wrote: Hi, I'm new to the Jess language and have some questions. 1. I work with Java object. I stored them in Jess with store and assert/fetch commands. But I could not call there member in the lhs of my rule. No function calls allowed, right? So, for every object I made a rule to insert a Jess template. This works fine, but is this way of mapping Java objects to Jess facts and then discarding the object the best way to work with java objects? I'm afraid I don't quite understand what you're asking. If you're pointing out that in Jess, you have to add objects to working memory (insert a Jess template) before rules can act directly on them, then yes, that's correct. I'm not sure what you mean about discarding something. 2. I am trying to implement a counter-logic for specific slot combinations. First, everytime a fact is inserted I check if there is already a procounter fact. If not I create one. This works fine. The next rule should recognize when a fact (EContext) is inserted and the counter (procounter) already exists. In this case, the count slot should only be modified. I try to compare bounded vars ? s ?v ?t from EContext to procounter slots, but I think Jess simply overwrites the binding. Can you help me with the correct syntax? Is there a better logic to implement a counter? What you've shown looks correct; you probably want to include a (declare (no-loop TRUE)) to the rule to avoid an infinite loop. - Ernest Friedman-Hill Advanced Software Research Phone: (925) 294-2154 Sandia National LabsFAX: (925) 294-2234 PO Box 969, MS 9012 [EMAIL PROTECTED] Livermore, CA 94550 http://www.jessrules.com To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED]
Re: Fw: JESS: Java Objects
I think Aditya Deshpande wrote:
Hi,
I have to give a run every time I want the activation of rules to take
place. Is there any way that I can get the rule engine running all the
time
and the rules get automatically fired as and when the facts are loaded
into
the knowledge base.
The (run-until-halt) function is documented in the manual; see
http://herzberg.ca.sandia.gov/jess/docs/functions.html#run-until-halt .
Also I can't get the Rete.assert(Fact f) to start working.
Here is the code dump
fact.setSlotValue("ntype",new Value("email",RU.SLOT));
RU.SLOT was an internal type; the only mention of it in the Jess 5
manual is this line in a table:
final public static int SLOT = 16384; ; (internal use)
In Jess 6, it no longer even exists. If you want the ntype slot to
hold an atom, use RU.ATOM; if a String, RU.STRING.
Also any pointers on how to use Observer interface using the JessEvent and
JessEventListener.
Jess doesn't use the Observer interface. The manual (Jess 5 section
4.10) discusses using event listeners at some length.
Do you see a common theme to these answers? Not to be rude, but maybe
you need to make a cup of tea, put your feet up, lean back, and read
through the whole manual once.
-
Ernest Friedman-Hill
Distributed Systems ResearchPhone: (925) 294-2154
Sandia National LabsFAX: (925) 294-2234
Org. 8920, MS 9012 [EMAIL PROTECTED]
PO Box 969 http://herzberg.ca.sandia.gov
Livermore, CA 94550
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JESS: Java Objects
How do I do this in JESS:Implement factory kind of a pattern wherein based on the property of ajavabean I get a class from JESS returneRegardsAditya
Re: JESS: Java Objects
Do you just mean something like: (deffunction make-widget (?bean) (bind ?type (get ?bean aProperty)) (if (eq ?type "FOO") then (return (new Foo)) else (if (eq ?type "BAR") then (return (new Bar)) else (if (eq ?type "BAZ") then (return (new Baz) (return (new NoneOfTheAbove))) Pretty much exactly as you would do it in Java, yes? I think Aditya Deshpande wrote: [Charset iso-8859-1 unsupported, filtering to ASCII...] How do I do this in JESS: Implement factory kind of a pattern wherein based on the property of a javabean I get a class from JESS returne Regards Aditya - Ernest Friedman-Hill Distributed Systems ResearchPhone: (925) 294-2154 Sandia National LabsFAX: (925) 294-2234 Org. 8920, MS 9012 [EMAIL PROTECTED] PO Box 969 http://herzberg.ca.sandia.gov Livermore, CA 94550 - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] -
Re: JESS: Java Objects
Precisely. Thanks. need to know is that do I need to store this object using "store" to be retreived by the Java Application or is there a direct way of doing this. The basic need is to create an object based on a certain pattern and return it to tha Java Program which has invoked JESS. Regards Aditya - Original Message - From: [EMAIL PROTECTED] To: Aditya Deshpande [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Sent: Monday, August 14, 2000 6:18 PM Subject: Re: JESS: Java Objects Do you just mean something like: (deffunction make-widget (?bean) (bind ?type (get ?bean aProperty)) (if (eq ?type "FOO") then (return (new Foo)) else (if (eq ?type "BAR") then (return (new Bar)) else (if (eq ?type "BAZ") then (return (new Baz) (return (new NoneOfTheAbove))) Pretty much exactly as you would do it in Java, yes? I think Aditya Deshpande wrote: [Charset iso-8859-1 unsupported, filtering to ASCII...] How do I do this in JESS: Implement factory kind of a pattern wherein based on the property of a javabean I get a class from JESS returne Regards Aditya - Ernest Friedman-Hill Distributed Systems ResearchPhone: (925) 294-2154 Sandia National LabsFAX: (925) 294-2234 Org. 8920, MS 9012 [EMAIL PROTECTED] PO Box 969 http://herzberg.ca.sandia.gov Livermore, CA 94550 - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] - - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list (use your own address!) List problems? Notify [EMAIL PROTECTED] -
Re: JESS: java objects in Jess not updating
Something that I forgot to mention in the previous post is that a
(reset) fails with an 'error in routine Rete.broadcastEvent while
executing (reset) while executing (batch diag.clp)...'
I am sending the propertyChangeEvents after I modify the appropriate
properties, as shown in these two set procs (below). I was not using
the static keyword, and adding dynamic to my defclass statements does
not change things.
Is there anything else that could be causing this behavior?
Thanks,
Erik Huestis
public void setSalary(float f)
{
Float old = new Float(this.salary);
this.salary = f;
this.pcs.firePropertyChange("salary", old, new Float(f));
}
public void setQualification(String s)
{
String old = this.qualification;
this.qualification = s;
System.out.println("Changing qualification to " + s + " and firing
propertyChange event...old=" + old + ", new=" + s);
this.pcs.firePropertyChange("qualification", old, s);
}
[EMAIL PROTECTED] wrote:
Two possibilities.
1) Jess only works properly if you write your PropertyChangeEvents
"correctly." The letter of the law is, according to the Java Beans
spec, that at the time the event is received, the property in the Bean
has already been changed. Jess depends on this. Unfortunately the most
convenient way to implement PropertyChangedEvents sets the Bean's
property AFTER the event is sent. Use a temporary variable to stash
the old value, then set the new one, then send the event.
2) If you've got that right, you might have used (defclass X static)
for some reason. The 'static' here implies that updated values will
only be fetched from a Bean at (reset) time.
I think Erik Huestis wrote:
I have a program set up in which several java objects are shadowed in
Jess, and there are several rules set up to modify those objects.
However, after the modify command executes, a (facts) command does not
show the updated values. A java getXXX command gives the updated
values.
The object does firePropertyChange when appropriate. I am certain that
there is something blatantly obvious which I am overlooking. Any ideas
would be much appreciated.
The initialization steps that I go through look like:
this.engine = new Rete();
this.engine.addUserpackage(new MiscFunctions());
this.engine.addUserpackage(new jess.ReflectFunctions());
this.engine.executeCommand("(batch " + DEFAULT_LIBRARY + ")");
this.engine.reset();
I then go on to take a set of defclass statements from an Enumeration
and execute them.
for...
{
...
this.engine.executeCommand(cmd);
...
}
I then send a reset.
...
this.engine.executeCommand("(reset)");
...
I then batch a file containing a bunch of rules.
...
this.engine.executeCommand("(batch " + this.fileName + ")");
...
I then reset again just for good measure.
...
this.engine.executeCommand("(reset)");
...
I then execute a whole bunch of definstance Funcalls taken from an
Enumeration.
for ...
{
try
{
Funcall cmd = (Funcall) en.nextElement();
cmd.execute(this.engine.getGlobalContext());
}
...
I then send a run command.
...
this.engine.run();
...
My rules look like:
(defrule new-engineer
"for all engineers, set properties"
?emp - (Employee (qualification "Engineer"))
=
(modify ?emp (salary (float 5)))
(printout t "Engineer salary changed to 5" crlf))
Thank You Much,
Erik Huestis
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Ernest Friedman-Hill
Distributed Systems ResearchPhone: (925) 294-2154
Sandia National LabsFAX: (925) 294-2234
Org. 8920, MS 9012 [EMAIL PROTECTED]
PO Box 969 http://herzberg.ca.sandia.gov
Livermore, CA 94550
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Re: JESS: Java objects and Jess facts.
"Ernest" == Ernest Friedman-Hill [EMAIL PROTECTED] writes: Ernest Hi Lewis, Thanks for the example - this might well explain the Ernest other problem you were having. The problem here lies in the Ernest way that your property mutators are written... Along similar lines, the Java objects in our expert system have properties that complex containers (hash tables, lists), rather than "atoms" (int, String). Since changing one of these properties is really a matter of adding or removing elements from the container, it isn't clear to me how the property-change mechanism should be handled. Could you please clarify the technique? Thanks much. Regards, -- - David E. Young Fujitsu Network Communications "I claim not to have controlled ([EMAIL PROTECTED])events, but confess plainly that events have controlled me." -- Abraham Lincoln (1864) "Apology is Policy" - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list. List problems? Notify [EMAIL PROTECTED] -
Re: JESS: Java objects and Jess facts.
"Ernest" == Ernest Friedman-Hill [EMAIL PROTECTED] writes: Ernest Hi David, Well, the Java Beans spec includes the notion of Ernest 'indexed properties', or properties which are arrays that are Ernest accessed one-element-at-a-time, but Jess doesn't do anything Ernest with these; I'm actually not sure how the mapping would work... Hello Ernest. In our particular case, Jess' current behavior is innocuous (even desirable); i.e. the fact that modifying the contents of a Hashtable property doesn't trigger the property change mechanism is just dandy with me. However, I can envision situations where such changes might be of interest to certain rules that would like to rely on the semantics of 'modify'. I can't at this time offer a suggestion, but I will be thinking about it. If anyone else has any ideas, I'd love to hear about them. Thanks for your help. Regards, -- - David E. Young Fujitsu Network Communications "I claim not to have controlled ([EMAIL PROTECTED])events, but confess plainly that events have controlled me." -- Abraham Lincoln (1864) "Apology is Policy" - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list. List problems? Notify [EMAIL PROTECTED] -
Re: JESS: Java objects and Jess facts.
Hi, I am away on home leave in the US. If this E-mail is private, it will automatically forwarded to my private E-mail address: [EMAIL PROTECTED] Thanks - Original Text From: Ernest Friedman-Hill [EMAIL PROTECTED], on 7/6/98 10:47 AM: I think [EMAIL PROTECTED] wrote: ... When an instance of a fact, created using definstance, is modified, the old fact is retracted, _but_ the modified fact is never asserted. In the excerpt below, when the modify is executed the DM_Query fact is lost. Hi Lewis, As the following excerpt shows, a trivial test case works for me: -- Jess, the Java Expert System Shell Copyright (C) 1998 E.J. Friedman Hill and the Sandia Corporation Jess Version 4.1b3 7/1/98 Jess (defclass simple jess.examples.simple.Simple) jess.examples.simple.Simple Jess (definstance simple (new jess.examples.simple.Simple "Foo")) TRUE Jess (defrule test-rule ?f - (simple) = (modify ?f (truth TRUE))) TRUE Jess (reset) TRUE Jess (facts) f-0 (initial-fact) f-1 (simple (truth FALSE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess (run) TRUE Jess (facts) f-0 (initial-fact) f-2 (simple (truth TRUE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess -- The same thing happens regardless of how the fact is modified, as above using (set ?qfr record ?srr), or calling setRecord() in Java. 4.1b3 fixed a bug whereby modifying a definstance fact using a bogus property name could cause the fact to be retracted without the new version being asserted... are you using 4.1b3? If you are not, download it and give it a try. In any case, make sure that there really is a public method named getRecord() with no arguments that returns non-void in the class you're matching, and make sure Jess knows about it (run the 'facts' command and look at all the slots in the definstance facts.) Let me know what you find out. The RHS of some rules call user functions which use aReteEngine.executeCommand(theCommand); to assert new facts. Could this be causing problems in the rete code or data structures? This should be OK; it's equivalent to calling (assert) on the RHS of a rule, which is perfectly legal. Now if you're doing it on the -LHS- of a rule, or if you're calling functions that modify a matched object on the LHS of a rule, well, I think the README warns about that... - Ernest Friedman-Hill Distributed Systems ResearchPhone: (510) 294-2154 Sandia National LabsFAX: (510) 294-2234 Org. 8920, MS 9214 [EMAIL PROTECTED] PO Box 969 http://herzberg.ca.sandia.gov Livermore, CA 94550 - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list. List problems? Notify [EMAIL PROTECTED] - - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list. List problems? Notify [EMAIL PROTECTED] -
Re[2]: JESS: Java objects and Jess facts.
I was not able to reproduce the problem in a simple example, however, something appears to be happening that I don't understand. The Java and rule files used in the trial below are attached. (Note the java files should be Thing1.java and Thing2.java, cc-mail does not like long file names). The problem is that the modification to the (definstance... created facts does not seem to be permanent. The ShowMe rule clearly show that the source and record field have been set in Java, but the last (facts) output show that those slots are nil in Jess. This is a similar problem, perhaps they are related. Jess, the Java Expert System Shell Copyright (C) 1998 E.J. Friedman Hill and the Sandia Corporation Jess Version 4.1b3 7/1/98 Jess (batch "rules.clp") TRUE Jess (reset) TRUE Jess (facts) f-0 (initial-fact) f-1 (Thing2 (source nil) (class External-Address:java.lang.Class) (OBJECT External-Address:Thing2)) f-2 (Thing1 (source nil) (class External-Address:java.lang.Class) (record nil) (OBJECT External-Address:Thing1)) For a total of 3 facts. TRUE Jess (run) (Query (Source Thing1) (Record (Query (Source Thing2) )) ) (Query (Source Thing2) )TRUE Jess (facts) f-0 (initial-fact) f-4 (Thing2 (source nil) (class External-Address:java.lang.Class) (OBJECT External-Address:Thing2)) f-5 (Thing1 (source nil) (class External-Address:java.lang.Class) (record nil) (OBJECT External-Address:Thing1)) For a total of 3 facts. TRUE Jess Opinions are strictly those of the author and do not necessarily reflect those of GRCI. __ Lewis Hart GRC International 703-506-5938 1900 Gallows Rd [EMAIL PROTECTED] Vienna, VA 22182 __ Reply Separator _ Subject: Re: JESS: Java objects and Jess facts. Author: Ernest Friedman-Hill [EMAIL PROTECTED] at GRC_INET Date:7/6/98 10:47 AM I think [EMAIL PROTECTED] wrote: ... When an instance of a fact, created using definstance, is modified, the old fact is retracted, _but_ the modified fact is never asserted. In the excerpt below, when the modify is executed the DM_Query fact is lost. Hi Lewis, As the following excerpt shows, a trivial test case works for me: -- Jess, the Java Expert System Shell Copyright (C) 1998 E.J. Friedman Hill and the Sandia Corporation Jess Version 4.1b3 7/1/98 Jess (defclass simple jess.examples.simple.Simple) jess.examples.simple.Simple Jess (definstance simple (new jess.examples.simple.Simple "Foo")) TRUE Jess (defrule test-rule ?f - (simple) = (modify ?f (truth TRUE))) TRUE Jess (reset) TRUE Jess (facts) f-0 (initial-fact) f-1 (simple (truth FALSE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess (run) TRUE Jess (facts) f-0 (initial-fact) f-2 (simple (truth TRUE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess -- The same thing happens regardless of how the fact is modified, as above using (set ?qfr record ?srr), or calling setRecord() in Java. 4.1b3 fixed a bug whereby modifying a definstance fact using a bogus property name could cause the fact to be retracted without the new version being asserted... are you using 4.1b3? If you are not, download it and give it a try. In any case, make sure that there really is a public method named getRecord() with no arguments that returns non-void in the class you're matching, and make sure Jess knows about it (run the 'facts' command and look at all the slots in the definstance facts.) Let me know what you find out. The RHS of some rules call user functions which use aReteEngine.executeCommand(theCommand); to assert new facts. Could this be causing problems in the rete code or data structures? This should be OK; it's equivalent to calling (assert) on the RHS of a rule, which is perfectly legal. Now if you're doing it on the -LHS- of a rule, or if you're calling functions that modify a matched object on the LHS of a rule, well, I think the README warns about that... - Ernest Friedman-Hill Distributed Systems ResearchPhone: (510) 294-2154 Sandia National LabsFAX: (510) 294-2234 Org. 8920, MS 9214 [EMAIL PROTECTED] PO Box 969 http://herzberg.ca.sandia.gov Livermore, CA 94550 -
Re: JESS: Java objects and Jess facts.
I think [EMAIL PROTECTED] wrote: ... When an instance of a fact, created using definstance, is modified, the old fact is retracted, _but_ the modified fact is never asserted. In the excerpt below, when the modify is executed the DM_Query fact is lost. Hi Lewis, As the following excerpt shows, a trivial test case works for me: -- Jess, the Java Expert System Shell Copyright (C) 1998 E.J. Friedman Hill and the Sandia Corporation Jess Version 4.1b3 7/1/98 Jess (defclass simple jess.examples.simple.Simple) jess.examples.simple.Simple Jess (definstance simple (new jess.examples.simple.Simple "Foo")) TRUE Jess (defrule test-rule ?f - (simple) = (modify ?f (truth TRUE))) TRUE Jess (reset) TRUE Jess (facts) f-0 (initial-fact) f-1 (simple (truth FALSE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess (run) TRUE Jess (facts) f-0 (initial-fact) f-2 (simple (truth TRUE) (class External-Address:java.lang.Class) (name "Foo") (fraction 0.0) (serial 0) (OBJECT External-Address:jess.examples.simple.Simple)) For a total of 2 facts. TRUE Jess -- The same thing happens regardless of how the fact is modified, as above using (set ?qfr record ?srr), or calling setRecord() in Java. 4.1b3 fixed a bug whereby modifying a definstance fact using a bogus property name could cause the fact to be retracted without the new version being asserted... are you using 4.1b3? If you are not, download it and give it a try. In any case, make sure that there really is a public method named getRecord() with no arguments that returns non-void in the class you're matching, and make sure Jess knows about it (run the 'facts' command and look at all the slots in the definstance facts.) Let me know what you find out. The RHS of some rules call user functions which use aReteEngine.executeCommand(theCommand); to assert new facts. Could this be causing problems in the rete code or data structures? This should be OK; it's equivalent to calling (assert) on the RHS of a rule, which is perfectly legal. Now if you're doing it on the -LHS- of a rule, or if you're calling functions that modify a matched object on the LHS of a rule, well, I think the README warns about that... - Ernest Friedman-Hill Distributed Systems ResearchPhone: (510) 294-2154 Sandia National LabsFAX: (510) 294-2234 Org. 8920, MS 9214 [EMAIL PROTECTED] PO Box 969 http://herzberg.ca.sandia.gov Livermore, CA 94550 - To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]' in the BODY of a message to [EMAIL PROTECTED], NOT to the list. List problems? Notify [EMAIL PROTECTED] -
