JESS: Would like to know why runQueryStar would not return any results

Hi all,

I am wondering if someone could help me understand why runQueryStar would
not work for me in a certain scenario. Thank you in advance!

First, I have the following script. It works as expected:

(deftemplate DimmerSwitch (slot label) (slot brightness))
(defquery search-dimmer-switch
   (declare (variables ?lbl))
   (DimmerSwitch (label ?lbl) (brightness ?b))
)
(defrule set-brightness-to-10-and-15
   (not (DimmerSwitch))
   =>
   (assert (DimmerSwitch (label "Ceiling Light") (brightness 10)))
   (assert (DimmerSwitch (label "Bathroom Light") (brightness 5)))
)

(reset)
(run)
(facts)
(bind ?result (run-query* search-dimmer-switch "Ceiling Light"))
(while (?result next)
   (printout t (?result getString lbl) " | " (?result getInt b) crlf)
   )

The output is as follows. No problem there.

f-0 (MAIN::initial-fact)

f-1 (MAIN::DimmerSwitch (label "Ceiling Light") (brightness 10))

f-2 (MAIN::DimmerSwitch (label "Bathroom Light") (brightness 5))

For a total of 3 facts in module MAIN.

Ceiling Light | 10

-----------------------------------------------------------

Then I delete the portion of the script from (reset) on down, with just the
following:
(deftemplate DimmerSwitch (slot label) (slot brightness))
(defquery search-dimmer-switch
(declare (variables ?lbl))
(DimmerSwitch (label ?lbl) (brightness ?b))
)
(defrule set-brightness-to-10-and-15
(not (DimmerSwitch))
=>
(assert (DimmerSwitch (label "Ceiling Light") (brightness 10)))
(assert (DimmerSwitch (label "Bathroom Light") (brightness 5)))
)

Then I use java to run the query as follows. "test.clp" contains the above
script obviously.

package control;
import jess.*;
public class TestApp {
 public static void main(String[] args) throws JessException {
  Rete engine = new Rete();
  engine.batch("C:\\Users\\Administrator\\workspace\\ShadowFactTest\\src\\control\\test.clp");
  engine.reset();

  engine.eval("(facts)");
  engine.run();

  engine.eval("(facts)");

  QueryResult result = engine.runQueryStar("search-dimmer-switch", new
ValueVector().add("Ceiling Light"));
  while (result.next()) {
   System.out.println(result.getString("lbl") + " | " + result.getInt("b"));
  }
 }
}

The output is as follows. The Rete Engine ran fine. The rule fired. But
there's nothing coming back from runQueryStar.

f-0 (MAIN::initial-fact)

For a total of 1 facts in module MAIN.

f-0 (MAIN::initial-fact)

f-1 (MAIN::DimmerSwitch (label "Ceiling Light") (brightness 10))

f-2 (MAIN::DimmerSwitch (label "Bathroom Light") (brightness 5))

For a total of 3 facts in module MAIN.

---------------------------------------------------------

Now I change the query parameter to "brightness", an integer field.

(deftemplate DimmerSwitch (slot label) (slot brightness))
(defquery search-dimmer-switch
    (declare (variables ?b))
    (DimmerSwitch (label ?lbl) (brightness ?b))
)
(defrule set-brightness-to-10-and-15
    (not (DimmerSwitch))
    =>
    (assert (DimmerSwitch (label "Ceiling Light") (brightness 10)))
    (assert (DimmerSwitch (label "Bathroom Light") (brightness 5)))
)

---------------------

and use the following java program instead:

package control;

import jess.*;

public class TestApp {

 public static void main(String[] args) throws JessException {
  Rete engine = new Rete();
  engine.batch("C:\\Users\\Administrator\\workspace\\ShadowFactTest\\src\\control\\test.clp");
  engine.reset();

  engine.eval("(facts)");
  engine.run();

  engine.eval("(facts)");

  QueryResult result = engine.runQueryStar("search-dimmer-switch", new
ValueVector().add(10));

  while (result.next()) {
   System.out.println(result.getString("lbl") + " | " + result.getInt("b"));
  }
 }
}

---------------

Now the output looks normal:

f-0   (MAIN::initial-fact)
For a total of 1 facts in module MAIN.
f-0   (MAIN::initial-fact)
f-1   (MAIN::DimmerSwitch (label "Ceiling Light") (brightness 10))
f-2   (MAIN::DimmerSwitch (label "Bathroom Light") (brightness 5))
For a total of 3 facts in module MAIN.
Ceiling Light | 10

--------------------------

Could someone explain why this query won't work?

QueryResult result = engine.runQueryStar("search-dimmer-switch", new
ValueVector().add("Ceiling Light"));

Many thanks.

Felix