Add OWL{Data,Object}MinCardinality and OWLHasValue expression support

2 files changed, 81 insertions, 5 deletions

diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/converter/RDFoxConverter.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/converter/RDFoxConverter.scala
index e3c44c6..dadc81c 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/converter/RDFoxConverter.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/converter/RDFoxConverter.scala
@@ -1,6 +1,7 @@
 package uk.ac.ox.cs.rsacomb.converter
 
 import java.util.stream.Collectors
+import org.semanticweb.owlapi.apibinding.OWLManager
 import org.semanticweb.owlapi.model._
 import scala.collection.JavaConverters._
 import tech.oxfordsemantic.jrdfox.logic.datalog.{
@@ -40,6 +41,15 @@ trait RDFoxConverter {
     */
   import uk.ac.ox.cs.rsacomb.implicits.RDFox._
 
+  /** Factory used for converting expressions when needed.
+    *
+    * @note most of the time this is used to perform some kind of
+    * normalization on axioms. In later versions it might be worth
+    * moving the normalization code in its own independent step.
+    */
+  private val manager = OWLManager.createOWLOntologyManager()
+  private val factory = manager.getOWLDataFactory()
+
   /** Represents the result of the conversion of a
     * [[org.semanticweb.owlapi.model.OWLClassExpression OWLClassExpression]].
     *
@@ -228,14 +238,11 @@ trait RDFoxConverter {
     * - [[org.semanticweb.owlapi.model.OWLDataAllValuesFrom OWLDataAllValuesFrom]]
     * - [[org.semanticweb.owlapi.model.OWLDataExactCardinality OWLDataExactCardinality]]
     * - [[org.semanticweb.owlapi.model.OWLDataMaxCardinality OWLDataMaxCardinality]]
-    * - [[org.semanticweb.owlapi.model.OWLDataMinCardinality OWLDataMinCardinality]]
     * - [[org.semanticweb.owlapi.model.OWLDataHasValue OWLDataHasValue]]
     * - [[org.semanticweb.owlapi.model.OWLObjectAllValuesFrom OWLObjectAllValuesFrom]]
     * - [[org.semanticweb.owlapi.model.OWLObjectComplementOf OWLObjectComplementOf]]
     * - [[org.semanticweb.owlapi.model.OWLObjectExactCardinality OWLObjectExactCardinality]]
     * - [[org.semanticweb.owlapi.model.OWLObjectHasSelf OWLObjectHasSelf]]
-    * - [[org.semanticweb.owlapi.model.OWLObjectHasValue OWLObjectHasValue]]
-    * - [[org.semanticweb.owlapi.model.OWLObjectMinCardinality OWLObjectMinCardinality]]
     * - [[org.semanticweb.owlapi.model.OWLObjectUnionOf OWLObjectUnionOf]]
     *
     * Moreover:
@@ -365,6 +372,60 @@ trait RDFoxConverter {
         (List(eq), res.flatten ++ props)
       }
 
+      /** Minimum cardinality restriction class
+        *
+        * @note we only admit classes with cardinality set to 1 because
+        * they are equivalent to existential quantification.
+        *
+        * @throws `RuntimeException` when dealing with a restriction
+        * with cardinality != 1.
+        *
+        * @see [[https://www.w3.org/TR/owl2-syntax/#Minimum_Cardinality]]
+        */
+      case e: OWLObjectMinCardinality => {
+        if (e.getCardinality != 1)
+          throw new RuntimeException(
+            s"Class expression '$e' has cardinality restriction != 1."
+          )
+        val filler = e.getFiller
+        val property = e.getProperty
+        val expr = factory.getOWLObjectSomeValuesFrom(property, filler)
+        convert(expr, term, unsafe, skolem, suffix)
+      }
+
+      /** Minimum cardinality restriction class
+        *
+        * @note we only admit classes with cardinality set to 1 because
+        * they are equivalent to existential quantification.
+        *
+        * @throws `RuntimeException` when dealing with a restriction
+        * with cardinality != 1.
+        *
+        * @see [[http://www.w3.org/TR/owl2-syntax/#Minimum_Cardinality_2]]
+        */
+      case e: OWLDataMinCardinality => {
+        if (e.getCardinality != 1)
+          throw new RuntimeException(
+            s"Class expression '$e' has cardinality restriction != 1."
+          )
+        val filler = e.getFiller
+        val property = e.getProperty
+        val expr = factory.getOWLDataSomeValuesFrom(property, filler)
+        convert(expr, term, unsafe, skolem, suffix)
+      }
+
+      /** Existential quantification with singleton filler
+        *
+        * @see
+        * [[http://www.w3.org/TR/owl2-syntax/#Individual_Value_Restriction]]
+        */
+      case e: OWLObjectHasValue => {
+        val term1: Term = e.getFiller match {
+          case i: OWLNamedIndividual     => i.getIRI
+          case i: OWLAnonymousIndividual => i.getID
+        }
+        (List(convert(e.getProperty, term, term1, suffix)), List())
+      }
       /** Catch-all case for all unhandled class expressions. */
       case e =>
         throw new RuntimeException(
diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/implicits/RDFox.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/implicits/RDFox.scala
index 35bf25c..0407ae9 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/implicits/RDFox.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/implicits/RDFox.scala
@@ -1,8 +1,17 @@
 package uk.ac.ox.cs.rsacomb.implicits
 
 import tech.oxfordsemantic.jrdfox.logic.Datatype
-import tech.oxfordsemantic.jrdfox.logic.expression.{IRI => RDFoxIRI, Literal}
-import org.semanticweb.owlapi.model.{IRI => OWLIRI, OWLLiteral, OWLDatatype}
+import tech.oxfordsemantic.jrdfox.logic.expression.{
+  BlankNode,
+  IRI => RDFoxIRI,
+  Literal
+}
+import org.semanticweb.owlapi.model.{
+  IRI => OWLIRI,
+  NodeID,
+  OWLLiteral,
+  OWLDatatype
+}
 import org.semanticweb.owlapi.vocab.OWL2Datatype
 
 object RDFox {
@@ -13,6 +22,12 @@ object RDFox {
   implicit def owlapiToRdfoxIri(iri: OWLIRI): RDFoxIRI =
     RDFoxIRI.create(iri.getIRIString())
 
+  implicit def nodeIdToBlankNode(node: NodeID): BlankNode =
+    BlankNode.create(node.getID)
+
+  implicit def blankNodeToNodeId(node: BlankNode): NodeID =
+    NodeID.getNodeID(node.getID)
+
   implicit def stringToRdfoxIri(iri: String): RDFoxIRI =
     RDFoxIRI.create(iri)