ont-api: fix SWRLObjectPropertyAtom#getSimplified() (issue #17), add tests + minor changes in several places (comments, tests)

Author: sszuev

src/main/java/com/github/owlcs/ontapi/internal/objects/ONTSWRLAtomImpl.java

@@ -14,7 +14,6 @@
 
 package com.github.owlcs.ontapi.internal.objects;
 
-import com.github.owlcs.ontapi.DataFactory;
 import com.github.owlcs.ontapi.OntApiException;
 import com.github.owlcs.ontapi.internal.ModelObjectFactory;
 import com.github.owlcs.ontapi.internal.ONTObject;
@@ -681,20 +680,7 @@ public OntSWRL.Atom.WithObjectProperty asRDFNode() {
         @FactoryAccessor
         @Override
         public SWRLObjectPropertyAtom getSimplified() {
-            OWLObjectPropertyExpression p = getPredicate();
-            OWLObjectPropertyExpression ps = p.getSimplified();
-            if (ps.equals(p)) {
-                return eraseModel();
-            }
-            // p always equals ps (v5.1.11) - so the following code just in case:
-            DataFactory df = getDataFactory();
-            ps = eraseModel(ps);
-            SWRLIArgument f = eraseModel(getFirstArgument());
-            SWRLIArgument s = eraseModel(getSecondArgument());
-            if (ps.isAnonymous()) {
-                return df.getSWRLObjectPropertyAtom(ps.getInverseProperty(), s, f);
-            }
-            return df.getSWRLObjectPropertyAtom(ps, f, s);
+            return eraseModel().getSimplified();
         }
 
         @Override

src/main/java/com/github/owlcs/ontapi/owlapi/axioms/OWLInverseFunctionalObjectPropertyAxiomImpl.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of the ONT API.
  * The contents of this file are subject to the LGPL License, Version 3.0.
- * Copyright (c) 2019, The University of Manchester, owl.cs group.
+ * Copyright (c) 2020, The University of Manchester, owl.cs group.
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
@@ -13,8 +13,8 @@
  */
 package com.github.owlcs.ontapi.owlapi.axioms;
 
-import org.semanticweb.owlapi.model.*;
 import com.github.owlcs.ontapi.owlapi.objects.ce.OWLObjectMaxCardinalityImpl;
+import org.semanticweb.owlapi.model.*;
 
 import javax.annotation.Nonnull;
 import java.util.Collection;
@@ -50,13 +50,12 @@ public OWLInverseFunctionalObjectPropertyAxiomImpl getAxiomWithoutAnnotations()
     @SuppressWarnings("unchecked")
     @Override
     public <T extends OWLAxiom> T getAnnotatedAxiom(@Nonnull Stream<OWLAnnotation> anns) {
-        return (T) new OWLInverseFunctionalObjectPropertyAxiomImpl(getProperty(),
-                mergeAnnotations(this, anns));
+        return (T) new OWLInverseFunctionalObjectPropertyAxiomImpl(getProperty(), mergeAnnotations(this, anns));
     }
 
     @Override
     public OWLSubClassOfAxiom asOWLSubClassOfAxiom() {
-        return new OWLSubClassOfAxiomImpl(OWL_THING, new OWLObjectMaxCardinalityImpl(getProperty().getInverseProperty()
-                .getSimplified(), 1, OWL_THING), NO_ANNOTATIONS);
+        return new OWLSubClassOfAxiomImpl(OWL_THING,
+                new OWLObjectMaxCardinalityImpl(getProperty().getInverseProperty(), 1, OWL_THING), NO_ANNOTATIONS);
     }
 }

src/main/java/com/github/owlcs/ontapi/owlapi/axioms/OWLInverseObjectPropertiesAxiomImpl.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of the ONT API.
  * The contents of this file are subject to the LGPL License, Version 3.0.
- * Copyright (c) 2019, The University of Manchester, owl.cs group.
+ * Copyright (c) 2020, The University of Manchester, owl.cs group.
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
@@ -81,11 +81,9 @@ public OWLObjectPropertyExpression getSecondProperty() {
 
     @Override
     public Collection<OWLSubObjectPropertyOfAxiom> asSubObjectPropertyOfAxioms() {
-        Set<OWLSubObjectPropertyOfAxiom> axs = new HashSet<>();
-        axs.add(new OWLSubObjectPropertyOfAxiomImpl(first,
-                second.getInverseProperty().getSimplified(), NO_ANNOTATIONS));
-        axs.add(new OWLSubObjectPropertyOfAxiomImpl(second,
-                first.getInverseProperty().getSimplified(), NO_ANNOTATIONS));
-        return axs;
+        Set<OWLSubObjectPropertyOfAxiom> res = new HashSet<>();
+        res.add(new OWLSubObjectPropertyOfAxiomImpl(first, second.getInverseProperty(), NO_ANNOTATIONS));
+        res.add(new OWLSubObjectPropertyOfAxiomImpl(second, first.getInverseProperty(), NO_ANNOTATIONS));
+        return res;
     }
 }

src/main/java/com/github/owlcs/ontapi/owlapi/axioms/OWLObjectPropertyAssertionAxiomImpl.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of the ONT API.
  * The contents of this file are subject to the LGPL License, Version 3.0.
- * Copyright (c) 2019, The University of Manchester, owl.cs group.
+ * Copyright (c) 2020, The University of Manchester, owl.cs group.
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
@@ -13,9 +13,9 @@
  */
 package com.github.owlcs.ontapi.owlapi.axioms;
 
-import org.semanticweb.owlapi.model.*;
 import com.github.owlcs.ontapi.owlapi.objects.ce.OWLObjectHasValueImpl;
 import com.github.owlcs.ontapi.owlapi.objects.ce.OWLObjectOneOfImpl;
+import org.semanticweb.owlapi.model.*;
 
 import javax.annotation.Nonnull;
 import java.util.Collection;
@@ -67,11 +67,10 @@ public <T extends OWLAxiom> T getAnnotatedAxiom(@Nonnull Stream<OWLAnnotation> a
     public OWLObjectPropertyAssertionAxiom getSimplified() {
         if (!getProperty().isAnonymous()) {
             return this;
-        } else {
-            OWLObjectInverseOf property = (OWLObjectInverseOf) getProperty();
-            OWLObjectPropertyExpression invProp = property.getInverse();
-            return new OWLObjectPropertyAssertionAxiomImpl(getObject(), invProp, getSubject(), NO_ANNOTATIONS);
         }
+        // OWL2 does not allow assertion with anonymous property in model,
+        // but OWLDataFactory allows such constructions
+        return new OWLObjectPropertyAssertionAxiomImpl(getObject(), getProperty().getNamedProperty(), getSubject(), NO_ANNOTATIONS);
     }
 
     @Override

src/main/java/com/github/owlcs/ontapi/owlapi/axioms/OWLSymmetricObjectPropertyAxiomImpl.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of the ONT API.
  * The contents of this file are subject to the LGPL License, Version 3.0.
- * Copyright (c) 2019, The University of Manchester, owl.cs group.
+ * Copyright (c) 2020, The University of Manchester, owl.cs group.
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
@@ -39,11 +39,11 @@ public OWLSymmetricObjectPropertyAxiomImpl(OWLObjectPropertyExpression property,
 
     @Override
     public Set<OWLSubObjectPropertyOfAxiom> asSubPropertyAxioms() {
-        Set<OWLSubObjectPropertyOfAxiom> result = new HashSet<>(2);
+        Set<OWLSubObjectPropertyOfAxiom> res = new HashSet<>(2);
         OWLObjectPropertyExpression p = getProperty();
-        result.add(new OWLSubObjectPropertyOfAxiomImpl(p, p.getInverseProperty().getSimplified(), NO_ANNOTATIONS));
-        result.add(new OWLSubObjectPropertyOfAxiomImpl(p.getInverseProperty().getSimplified(), p, NO_ANNOTATIONS));
-        return result;
+        res.add(new OWLSubObjectPropertyOfAxiomImpl(p, p.getInverseProperty(), NO_ANNOTATIONS));
+        res.add(new OWLSubObjectPropertyOfAxiomImpl(p.getInverseProperty(), p, NO_ANNOTATIONS));
+        return res;
     }
 
     @SuppressWarnings("unchecked")

src/main/java/com/github/owlcs/ontapi/owlapi/objects/swrl/SWRLObjectPropertyAtomImpl.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of the ONT API.
  * The contents of this file are subject to the LGPL License, Version 3.0.
- * Copyright (c) 2019, The University of Manchester, owl.cs group.
+ * Copyright (c) 2020, The University of Manchester, owl.cs group.
  *
  * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
  * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
@@ -40,15 +40,11 @@ public OWLObjectPropertyExpression getPredicate() {
 
     @Override
     public SWRLObjectPropertyAtom getSimplified() {
-        OWLObjectPropertyExpression prop = getPredicate().getSimplified();
-        if (prop.equals(getPredicate())) {
+        // See https://github.com/owlcs/ont-api/issues/17 & https://github.com/owlcs/owlapi/issues/882
+        OWLObjectPropertyExpression p = getPredicate();
+        if (p.isNamed()) {
             return this;
-        } else if (prop.isAnonymous()) {
-            // Flip
-            return new SWRLObjectPropertyAtomImpl(prop.getInverseProperty().getSimplified(), getSecondArgument(), getFirstArgument());
-        } else {
-            // No need to flip
-            return new SWRLObjectPropertyAtomImpl(prop, getFirstArgument(), getSecondArgument());
         }
+        return new SWRLObjectPropertyAtomImpl(p.getInverseProperty(), getSecondArgument(), getFirstArgument());
     }
 }

src/test/java/com/github/owlcs/ontapi/tests/TestFactory.java

@@ -958,6 +958,29 @@ public OWLObject create(OWLDataFactory df) {
                         return df.getSWRLRule(body, head, annotations);
                     }
                 }
+                , new AxiomData() {
+                    @Override
+                    public AxiomType getType() {
+                        return AxiomType.SWRL_RULE;
+                    }
+
+                    @Override
+                    public String toString() {
+                        // to test https://github.com/owlcs/ont-api/issues/17
+                        return "SWRLRule Axiom single object property atom";
+                    }
+
+                    @Override
+                    public OWLObject create(OWLDataFactory df) {
+                        OWLObjectPropertyExpression p = df.getOWLObjectInverseOf(df.getOWLObjectProperty("P"));
+                        SWRLIArgument a1 = df.getSWRLVariable("V");
+                        SWRLIArgument a2 = df.getSWRLIndividualArgument(df.getOWLAnonymousIndividual("_:bx"));
+
+                        List<? extends SWRLAtom> body = Collections.singletonList(df.getSWRLObjectPropertyAtom(p, a1, a2));
+                        List<? extends SWRLAtom> head = Collections.emptyList();
+                        return df.getSWRLRule(body, head);
+                    }
+                }
                 , new NamedRange() {
                     @Override
                     public OWLObject create(OWLDataFactory df) {