Forward RETE and redundant deduction

[Sébastien Boulet [intactile DESIGN]]

Hello,

I have two rules which could produce the same triple:

        String rules = "[r1: (?a eg:p ?b) -> (?a, eg:q, ?b)]" +
                       "[r2: (?a eg:r ?b) -> (?a, eg:q, ?b)]";

i have configured a GenericRuleReasoner in FORWARD_RETE mode.

        GenericRuleReasoner reasoner = new 
GenericRuleReasoner(Rule.parseRules(rules));
        reasoner.setMode(GenericRuleReasoner.FORWARD_RETE);
        InfModel model = ModelFactory.createInfModel(reasoner, 
ModelFactory.createDefaultModel());

When a triple satisfy the first rule and another triple satisfy the second rule:

                 Resource subject = model.createResource();
        Property predicateP = model.getProperty("urn:x-hp:eg/p");
        Literal literalA = model.createTypedLiteral("A");
        Property predicateR = model.getProperty("urn:x-hp:eg/r");

        model.add(subject, predicateP, literalA);
        model.add(subject, predicateR, literalA);

only one triple is deduced:

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
    xmlns:j.0="urn:x-hp:eg/" > 
  <rdf:Description rdf:nodeID="A0">
    <j.0:r rdf:datatype="http://www.w3.org/2001/XMLSchema#string";>A</j.0:r>
    <j.0:p rdf:datatype="http://www.w3.org/2001/XMLSchema#string";>A</j.0:p>
    <j.0:q rdf:datatype="http://www.w3.org/2001/XMLSchema#string";>A</j.0:q>
  </rdf:Description>
</rdf:RDF>

When i remove the fist triple:

        model.remove(subject, predicateP, literalA);

 the sole deduced triple is removed even if the second rule is still satisfied:

<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
    xmlns:j.0="urn:x-hp:eg/" > 
  <rdf:Description rdf:nodeID="A0">
    <j.0:r rdf:datatype="http://www.w3.org/2001/XMLSchema#string";>A</j.0:r>
  </rdf:Description>
</rdf:RDF>

is it the expected behavior ?
is there a workaround to deduce twice the same triple or at least to don’t 
remove the sole deduction ?

Thanks


Sébastien BOULET
LEAD DÉVELOPPEUR

intactile DESIGN
Création d’interfaces + subtiles
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09 50 12 05 66
20 rue du carré du roi
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France
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