1 files changed, 58 insertions, 0 deletions

diff --git a/src/main/scala/rsacomb/RDFoxAxiomConverter.scala b/src/main/scala/rsacomb/RDFoxAxiomConverter.scala
new file mode 100644
index 0000000..0a6272f
--- /dev/null
+++ b/src/main/scala/rsacomb/RDFoxAxiomConverter.scala
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+package rsacomb
+
+import org.semanticweb.owlapi.model.{OWLAxiom, OWLSubClassOfAxiom, OWLEquivalentClassesAxiom}
+import org.semanticweb.owlapi.model.OWLAxiomVisitorEx
+
+import tech.oxfordsemantic.jrdfox.logic.Rule
+import tech.oxfordsemantic.jrdfox.logic.{Atom, Term, Literal, Individual}
+
+import scala.collection.JavaConverters._
+
+import rsacomb.SkolemStrategy
+import rsacomb.RDFoxRuleShards
+
+object RDFoxAxiomConverter {
+
+  def apply(term : Term, skolem : SkolemStrategy) : RDFoxAxiomConverter =
+        new RDFoxAxiomConverter(term, skolem)
+
+  def apply(term : Term) : RDFoxAxiomConverter =
+        new RDFoxAxiomConverter(term, SkolemStrategy.None)
+
+} // object RDFoxAxiomConverter
+
+class RDFoxAxiomConverter(term : Term, skolem : SkolemStrategy)
+  extends OWLAxiomVisitorEx[List[Rule]]
+{
+
+  override
+  def visit(axiom : OWLSubClassOfAxiom) : List[Rule] = {
+    // Skolemization is needed only for the head of an axiom
+    val subVisitor = new RDFoxClassExprConverter(term,SkolemStrategy.None)
+    val superVisitor = new RDFoxClassExprConverter(term, skolem)
+    // Each visitor returns a `RDFoxRuleShards`, a tuple (res,ext):
+    // - the `res` List is a list of atoms resulting from the conversion
+    //   of the axiom.
+    // - for some Class Expressions appearing in the head of an Axiom,
+    //   the conversion might produce atoms that need to appear in the
+    //   body (and not in the head) of the rule. This is what the `ext`
+    //   List is for.
+    val sub = axiom.getSubClass.accept(subVisitor)
+    val sup = axiom.getSuperClass.accept(superVisitor)
+    val head = sup.res.asJava
+    val body = (sub.res ++ sup.ext).asJava
+    List(Rule.create(head,body))
+  }
+
+  override
+  def visit(axiom : OWLEquivalentClassesAxiom) : List[Rule] = {
+        for {
+          axiom1 <- axiom.asPairwiseAxioms.asScala.toList
+          axiom2 <- axiom1.asOWLSubClassOfAxioms.asScala.toList
+          rule   <- axiom2.accept(this)
+        } yield rule
+  }
+
+  def doDefault(axiom : OWLAxiom) : List[Rule] = List()
+
+} // class RDFoxAxiomConverter