owlapi-version5/tools/src/main/java/org/semanticweb/owlapi/modularity/locality/SyntacticLocalityEvaluator.java
/* This file is part of the OWL API.
 * The contents of this file are subject to the LGPL License, Version 3.0.
 * Copyright 2020, Marc Robin Nolte
 * 
 * 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.
 * You should have received a copy of the GNU General Public License along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Alternatively, the contents of this file may be used under the terms of the Apache License, Version 2.0 in which case, the provisions of the Apache License Version 2.0 are applicable instead of those above.
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */
package org.semanticweb.owlapi.modularity.locality;
/*
 * Following com.clarkparsia.owlapi.modularity.locality.SyntacticLocalityEvaluator, and
 * modified for a more modern, thread safe and maintainable implementation. Original Copyright is:
 *
 * This file is part of the OWL API.
 * The contents of this file are subject to the LGPL License, Version 3.0.
 * Copyright 2011, Clark & Parsia, LLC
 *
 * 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.
 * You should have received a copy of the GNU General Public License along with this program.  If not, see http://www.gnu.org/licenses/.
 *
 * Alternatively, the contents of this file may be used under the terms of the Apache License, Version 2.0 in which case, the provisions of the Apache License Version 2.0 are applicable instead of those above.
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
 */

import static org.semanticweb.owlapi.util.OWLAPIStreamUtils.asList;

import java.util.Collection;
import java.util.Iterator;
import java.util.Objects;

import javax.annotation.Nonnull;

import org.semanticweb.owlapi.model.OWLAsymmetricObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLAxiom;
import org.semanticweb.owlapi.model.OWLAxiomVisitor;
import org.semanticweb.owlapi.model.OWLClass;
import org.semanticweb.owlapi.model.OWLClassAssertionAxiom;
import org.semanticweb.owlapi.model.OWLClassExpression;
import org.semanticweb.owlapi.model.OWLClassExpressionVisitor;
import org.semanticweb.owlapi.model.OWLDataAllValuesFrom;
import org.semanticweb.owlapi.model.OWLDataExactCardinality;
import org.semanticweb.owlapi.model.OWLDataHasValue;
import org.semanticweb.owlapi.model.OWLDataMaxCardinality;
import org.semanticweb.owlapi.model.OWLDataMinCardinality;
import org.semanticweb.owlapi.model.OWLDataPropertyAssertionAxiom;
import org.semanticweb.owlapi.model.OWLDataRange;
import org.semanticweb.owlapi.model.OWLDataSomeValuesFrom;
import org.semanticweb.owlapi.model.OWLDatatype;
import org.semanticweb.owlapi.model.OWLDatatypeDefinitionAxiom;
import org.semanticweb.owlapi.model.OWLDifferentIndividualsAxiom;
import org.semanticweb.owlapi.model.OWLDisjointClassesAxiom;
import org.semanticweb.owlapi.model.OWLDisjointDataPropertiesAxiom;
import org.semanticweb.owlapi.model.OWLDisjointObjectPropertiesAxiom;
import org.semanticweb.owlapi.model.OWLEntity;
import org.semanticweb.owlapi.model.OWLEquivalentClassesAxiom;
import org.semanticweb.owlapi.model.OWLEquivalentDataPropertiesAxiom;
import org.semanticweb.owlapi.model.OWLEquivalentObjectPropertiesAxiom;
import org.semanticweb.owlapi.model.OWLFunctionalDataPropertyAxiom;
import org.semanticweb.owlapi.model.OWLFunctionalObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLHasKeyAxiom;
import org.semanticweb.owlapi.model.OWLInverseFunctionalObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLInverseObjectPropertiesAxiom;
import org.semanticweb.owlapi.model.OWLIrreflexiveObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLNaryPropertyAxiom;
import org.semanticweb.owlapi.model.OWLNegativeDataPropertyAssertionAxiom;
import org.semanticweb.owlapi.model.OWLNegativeObjectPropertyAssertionAxiom;
import org.semanticweb.owlapi.model.OWLObjectAllValuesFrom;
import org.semanticweb.owlapi.model.OWLObjectComplementOf;
import org.semanticweb.owlapi.model.OWLObjectExactCardinality;
import org.semanticweb.owlapi.model.OWLObjectHasSelf;
import org.semanticweb.owlapi.model.OWLObjectHasValue;
import org.semanticweb.owlapi.model.OWLObjectIntersectionOf;
import org.semanticweb.owlapi.model.OWLObjectMaxCardinality;
import org.semanticweb.owlapi.model.OWLObjectMinCardinality;
import org.semanticweb.owlapi.model.OWLObjectOneOf;
import org.semanticweb.owlapi.model.OWLObjectPropertyAssertionAxiom;
import org.semanticweb.owlapi.model.OWLObjectPropertyDomainAxiom;
import org.semanticweb.owlapi.model.OWLObjectPropertyRangeAxiom;
import org.semanticweb.owlapi.model.OWLObjectSomeValuesFrom;
import org.semanticweb.owlapi.model.OWLObjectUnionOf;
import org.semanticweb.owlapi.model.OWLPropertyExpression;
import org.semanticweb.owlapi.model.OWLReflexiveObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLSameIndividualAxiom;
import org.semanticweb.owlapi.model.OWLSubClassOfAxiom;
import org.semanticweb.owlapi.model.OWLSubObjectPropertyOfAxiom;
import org.semanticweb.owlapi.model.OWLSubPropertyChainOfAxiom;
import org.semanticweb.owlapi.model.OWLSymmetricObjectPropertyAxiom;
import org.semanticweb.owlapi.model.OWLTransitiveObjectPropertyAxiom;
import org.semanticweb.owlapi.model.SWRLRule;

/**
 * Thread safe class for checking syntactic locality.
 *
 * @author Marc Robin Nolte (modified version)
 *
 */
public enum SyntacticLocalityEvaluator implements LocalityEvaluator {

    /**
     * The {@link SyntacticLocalityEvaluator} for \bottom-locality: Locality class obtained when
     * concepts and roles not present in the signature are given empty interpretations. In the
     * literature, $\emptyset$ for semantic and $\bottom$ for syntactic locality.
     */
    BOTTOM {
        @Override
        protected LocalityAxiomVisitor createLocalityAxiomVisitor(OWLAxiom axiom,
            Collection<OWLEntity> signature) {
            return new BottomLocalityAxiomVisitor(axiom, signature);
        }
    },

    /**
     * The {@link SyntacticLocalityEvaluator} for \top-locality: Locality class obtained when
     * concepts not present in the signature are given top concept interpretation, roles not present
     * are universal role interpretation. In the literature, $\Delta$ for semantic and $\top$ for
     * syntactic locality.
     */
    TOP {
        @Override
        protected LocalityAxiomVisitor createLocalityAxiomVisitor(OWLAxiom axiom,
            Collection<OWLEntity> signature) {
            return new TopLocalityAxiomVisitor(axiom, signature);
        }
    };

    /**
     * Class implementing the syntactic \bottom-locality check using the visitor-pattern. Needs to
     * be instantiated for thread safety.
     *
     * @author Marc Robin Nolte (modified version)
     *
     */
    private final class BottomLocalityAxiomVisitor extends LocalityAxiomVisitor {

        /**
         * Class to determine if class expressions are syntactically equivalent to \bottom for
         * \bottom-locality.
         *
         * @author Marc Robin Nolte (modified version)
         */
        final class BottomLocalityBottomEquivalenceEvaluator
            extends AbstractBottomEquivalenceEvaluator {

            @Override
            public void visit(OWLClass ce) {
                isEquivalent = ce.isOWLNothing() || !ce.isOWLThing() && !signature.contains(ce);
            }

            @Override
            public void visit(OWLDataAllValuesFrom ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataExactCardinality ce) {
                isEquivalent = ce.getCardinality() > 0
                    && !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataHasValue ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataMaxCardinality ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataMinCardinality ce) {
                isEquivalent = ce.getCardinality() > 0
                    && !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataSomeValuesFrom ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectAllValuesFrom ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectExactCardinality ce) {
                isEquivalent = ce.getCardinality() > 0
                    && (!signature.contains(ce.getProperty().getNamedProperty())
                        || isEquivalent(ce.getFiller()));
            }

            @Override
            public void visit(OWLObjectHasSelf ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty());
            }

            @Override
            public void visit(OWLObjectHasValue ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty());
            }

            @Override
            public void visit(OWLObjectMaxCardinality ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectMinCardinality ce) {
                isEquivalent = ce.getCardinality() > 0
                    && (!signature.contains(ce.getProperty().getNamedProperty())
                        || isEquivalent(ce.getFiller()));
            }

            @Override
            public void visit(OWLObjectSomeValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty())
                    || isEquivalent(ce.getFiller());
            }
        }

        /**
         * Class to determine if class expressions are syntactically equivalent to \top for a
         * \bottom-locality.
         *
         * @author Marc Robin Nolte (modified version)
         */
        final class BottomLocalityTopEquivalenceEvaluator extends AbstractTopEquivalenceEvaluator {

            @Override
            public void visit(OWLClass ce) {
                isEquivalent = ce.isOWLThing();
            }

            @Override
            public void visit(OWLDataAllValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty())
                    || ce.getFiller().isTopDatatype();
            }

            @Override
            public void visit(OWLDataExactCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    && !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataHasValue ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataMaxCardinality ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataMinCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    || ce.getCardinality() == 1
                        && !signature.contains(ce.getProperty().asOWLDataProperty())
                        && isTopOrBuiltInDatatype(ce.getFiller())
                    || ce.getCardinality() > 1
                        && !signature.contains(ce.getProperty().asOWLDataProperty())
                        && isTopOrBuiltInInfiniteDatatype(ce.getFiller());
            }

            @Override
            public void visit(OWLDataSomeValuesFrom ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectAllValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty())
                    || isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectExactCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    && (!signature.contains(ce.getProperty().getNamedProperty())
                        || getBottomEquivalenceEvaluator().isEquivalent(ce.getFiller()));
            }

            @Override
            public void visit(OWLObjectHasSelf ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectHasValue ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectMaxCardinality ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty())
                    || getBottomEquivalenceEvaluator().isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectMinCardinality ce) {
                isEquivalent = ce.getCardinality() == 0;
            }

            @Override
            public void visit(OWLObjectSomeValuesFrom ce) {
                isEquivalent = false;
            }

        }

        /**
         * Instantiates a new {@link BottomLocalityAxiomVisitor}.
         *
         * @param axiom     the axiom to test
         * @param signature the signature to test against
         */
        BottomLocalityAxiomVisitor(OWLAxiom axiom, Collection<OWLEntity> signature) {
            super(axiom, signature);
        }

        protected boolean checkIfLocalProperties(
            OWLNaryPropertyAxiom<? extends OWLPropertyExpression> axiom) {
            Collection<? extends OWLPropertyExpression> disjs = asList(axiom.properties());
            int size = disjs.size();
            if (size > 1) {
                boolean nonBottomEquivPropFound = false;
                for (OWLPropertyExpression dpe : disjs) {
                    if (dpe.isOWLDataProperty() && signature.contains(dpe.asOWLDataProperty())
                        || dpe.isOWLObjectProperty()
                            && signature.contains(dpe.asOWLObjectProperty())) {
                        if (nonBottomEquivPropFound) {
                            return false;
                        } else {
                            nonBottomEquivPropFound = true;
                        }
                    }
                }
            }
            return true;
        }

        @Override
        protected BottomLocalityBottomEquivalenceEvaluator createBottomEquivalenceEvaluator() {
            return new BottomLocalityBottomEquivalenceEvaluator();
        }

        @Override
        protected BottomLocalityTopEquivalenceEvaluator createTopEquivalenceEvaluator() {
            return new BottomLocalityTopEquivalenceEvaluator();
        }

        @Override
        public void visit(OWLAsymmetricObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLDataPropertyAssertionAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLDisjointDataPropertiesAxiom axiom) {
            isLocal = checkIfLocalProperties(axiom);
        }

        @Override
        public void visit(OWLDisjointObjectPropertiesAxiom axiom) {
            isLocal = checkIfLocalProperties(axiom);
        }

        @Override
        public void visit(OWLFunctionalDataPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().asOWLDataProperty());
        }

        @Override
        public void visit(OWLFunctionalObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLInverseFunctionalObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLIrreflexiveObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLNegativeDataPropertyAssertionAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().asOWLDataProperty());
        }

        @Override
        public void visit(OWLNegativeObjectPropertyAssertionAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLObjectPropertyAssertionAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLObjectPropertyDomainAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty())
                || getTopEquivalenceEvaluator().isEquivalent(axiom.getDomain());
        }

        @Override
        public void visit(OWLObjectPropertyRangeAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty())
                || getTopEquivalenceEvaluator().isEquivalent(axiom.getRange());
        }

        @Override
        public void visit(OWLReflexiveObjectPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLSubObjectPropertyOfAxiom axiom) {
            isLocal = !signature.contains(axiom.getSubProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLSubPropertyChainOfAxiom axiom) {
            // Axiom is local iff at least one prop in the chain is
            // bot-equiv
            isLocal = axiom.getPropertyChain().stream()
                .anyMatch(ope -> !signature.contains(ope.getNamedProperty()));
        }

    }

    /**
     * Abstract superclass for classes implementing the syntactic locality check using the
     * visitor-pattern. Needs to be instantiated for thread safety.
     *
     * @author Marc Robin Nolte (modified version)
     *
     */
    protected abstract class LocalityAxiomVisitor implements OWLAxiomVisitor {

        /**
         * Abstract superclass for class that determine if class expressions are syntactically
         * equivalent to \bottom for a specific locality class.
         *
         * @author Marc Robin Nolte (modified version)
         */
        protected abstract class AbstractBottomEquivalenceEvaluator
            extends AbstractEquivalenceEvaluator {

            @Override
            public final void visit(OWLObjectComplementOf ce) {
                isEquivalent = getTopEquivalenceEvaluator().isEquivalent(ce.getOperand());
            }

            @Override
            public final void visit(OWLObjectOneOf ce) {
                isEquivalent = ce.individuals().count() == 0;
            }

        }

        /**
         * Abstract superclass for class that determine if class expressions are syntactically
         * equivalent to another one for a specific locality class.
         *
         * @author Marc Robin Nolte (modified version)
         */
        protected abstract class AbstractEquivalenceEvaluator implements OWLClassExpressionVisitor {

            /**
             * Whether the {@link OWLClassExpression} to test is equivalent to the expression
             * represented by this evaluator. This value will be manipulated during the evaluation.
             */
            protected boolean isEquivalent;

            /**
             * Checks if the given class expression is equivalent to the expression represented by
             * this evaluator.
             *
             * @param classExpression The {@link OWLClassExpression} to test
             * @return <code>true</code>, if the class expression is equivalent to the expression
             *         represented by this evaluator; <code>false</code> otherwise
             */
            protected final synchronized boolean isEquivalent(OWLClassExpression classExpression) {
                Objects
                    .requireNonNull(classExpression, "The given class expression may not be null")
                    .accept(this);
                return isEquivalent;
            }

            @Override
            public final void visit(OWLObjectIntersectionOf ce) {
                isEquivalent = !ce.operands().anyMatch(this::isEquivalent);
            }

            @Override
            public final void visit(OWLObjectUnionOf ce) {
                isEquivalent = ce.operands().anyMatch(this::isEquivalent);
            }
        }

        /**
         * Abstract superclass for class that determine if class expressions are syntactically
         * equivalent to \top for a specific locality class.
         *
         * @author Marc Robin Nolte (modified version)
         */
        protected abstract class AbstractTopEquivalenceEvaluator
            extends AbstractEquivalenceEvaluator {

            @Override
            public final void visit(OWLObjectComplementOf ce) {
                isEquivalent = getBottomEquivalenceEvaluator().isEquivalent(ce.getOperand());
            }

            @Override
            public final void visit(OWLObjectOneOf ce) {
                isEquivalent = false;
            }

        }

        /**
         * The used {@link AbstractBottomEquivalenceEvaluator} to test for equivalence with \bottom.
         */
        private final @Nonnull AbstractBottomEquivalenceEvaluator bottomEquivalenceEvaluator;

        /**
         * Whether the axiom is local w.r.t the current signature. This value is manipulated during
         * the evaluation.
         */
        protected boolean isLocal;

        /**
         * The signature the axiom should be checked against.
         */
        protected final @Nonnull Collection<OWLEntity> signature;

        /**
         * The used {@link AbstractTopEquivalenceEvaluator} to test for equivalence with \top.
         */
        private final @Nonnull AbstractTopEquivalenceEvaluator topEquivalenceEvaluator;

        /**
         * Instantiates a new {@link LocalityAxiomVisitor} and tests whether the given axiom is
         * local w.r.t the given signature. The result may be retrieved calling
         * {@link LocalityAxiomVisitor#isLocal()}.
         *
         * @param axiom     the axiom to test
         * @param signature the signature to test against
         */
        protected LocalityAxiomVisitor(OWLAxiom axiom, Collection<OWLEntity> signature) {
            this.signature = signature;
            isLocal = false;
            bottomEquivalenceEvaluator = createBottomEquivalenceEvaluator();
            topEquivalenceEvaluator = createTopEquivalenceEvaluator();
            axiom.accept(this);
        }

        /**
         * Instantiates a new {@link AbstractBottomEquivalenceEvaluator} to test equivalence with
         * \bottom.
         *
         * @return A new {@link AbstractBottomEquivalenceEvaluator}
         */
        protected abstract AbstractBottomEquivalenceEvaluator createBottomEquivalenceEvaluator();

        /**
         * Instantiates a new {@link AbstractTopEquivalenceEvaluator} to test equivalence with \top.
         *
         * @return A new {@link AbstractTopEquivalenceEvaluator}
         */
        protected abstract AbstractTopEquivalenceEvaluator createTopEquivalenceEvaluator();

        /**
         * Returns the used {@link AbstractEquivalenceEvaluator} to test equivalence with \bottom.
         *
         * @return The used {@link AbstractEquivalenceEvaluator} to test equivalence with \bottom
         */
        protected final @Nonnull AbstractEquivalenceEvaluator getBottomEquivalenceEvaluator() {
            return bottomEquivalenceEvaluator;
        }

        /**
         * Returns the used {@link AbstractEquivalenceEvaluator} to test for equivalence with top.
         *
         * @return The used {@link AbstractEquivalenceEvaluator} to test for equivalence with top
         */
        protected final @Nonnull AbstractEquivalenceEvaluator getTopEquivalenceEvaluator() {
            return topEquivalenceEvaluator;
        }

        /**
         * Returns whether the axiom is local w.r.t the current signature.
         *
         * @return Whether the axiom is local w.r.t the current signature.
         */
        protected final boolean isLocal() {
            return isLocal;
        }

        private boolean isLocal(OWLEquivalentClassesAxiom axiom) {
            Iterator<OWLClassExpression> eqs = axiom.classExpressions().iterator();
            OWLClassExpression first = eqs.next();
            // axiom is local if it contains a single class expression
            if (!eqs.hasNext()) {
                return true;
            }
            // axiom is local iff either all class expressions evaluate to TOP or all
            // evaluate to BOTTOM check if first class expr. is BOTTOM
            boolean isBottom = getBottomEquivalenceEvaluator().isEquivalent(first);
            // if not BOTTOM or not TOP then this axiom is non-local
            if (!isBottom && !getTopEquivalenceEvaluator().isEquivalent(first)) {
                return false;
            }
            // unless we find a non-locality, process all the class expressions
            while (eqs.hasNext()) {
                if (isBottom ? !getBottomEquivalenceEvaluator().isEquivalent(eqs.next())
                    : !getTopEquivalenceEvaluator().isEquivalent(eqs.next())) {
                    // first class expr. was BOTTOM (TOP), so this one should be BOTTOM (TOP) too
                    return false;
                }
            }
            return true;
        }

        @Override
        public void visit(OWLClassAssertionAxiom axiom) {
            isLocal = getTopEquivalenceEvaluator().isEquivalent(axiom.getClassExpression());
        }

        @Override
        public void visit(OWLDatatypeDefinitionAxiom axiom) {
            isLocal = true;
        }

        @Override
        public final void visit(OWLDifferentIndividualsAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLDisjointClassesAxiom axiom) {
            Collection<OWLClassExpression> disjs = asList(axiom.classExpressions());
            boolean nonBottomEquivDescFound = false;
            for (OWLClassExpression desc : disjs) {
                if (!getBottomEquivalenceEvaluator().isEquivalent(desc)) {
                    if (nonBottomEquivDescFound) {
                        isLocal = false;
                        return;
                    } else {
                        nonBottomEquivDescFound = true;
                    }
                }
            }
            isLocal = true;
        }

        @Override
        public final void visit(OWLEquivalentClassesAxiom axiom) {
            isLocal = isLocal(axiom);
        }

        @Override
        public final void visit(OWLEquivalentDataPropertiesAxiom axiom) {
            if (axiom.properties().count() < 2) {
                isLocal = true;
                return;
            }
            if (axiom.properties()
                .anyMatch(property -> signature.contains(property.asOWLDataProperty()))) {
                isLocal = false;
                return;
            }
            isLocal = true;
        }

        @Override
        public final void visit(OWLEquivalentObjectPropertiesAxiom axiom) {
            if (axiom.properties().count() < 2) {
                isLocal = true;
                return;
            }
            if (axiom.properties()
                .anyMatch(property -> signature.contains(property.getNamedProperty()))) {
                isLocal = false;
                return;
            }
            isLocal = true;

        }

        @Override
        public final void visit(OWLHasKeyAxiom axiom) {
            isLocal = true;
        }

        @Override
        public final void visit(OWLInverseObjectPropertiesAxiom axiom) {
            isLocal = !signature.contains(axiom.getFirstProperty().getNamedProperty())
                && !signature.contains(axiom.getSecondProperty().getNamedProperty());
        }

        @Override
        public final void visit(OWLSameIndividualAxiom axiom) {
            isLocal = false;
        }

        @Override
        public final void visit(OWLSubClassOfAxiom axiom) {
            isLocal = getBottomEquivalenceEvaluator().isEquivalent(axiom.getSubClass())
                || getTopEquivalenceEvaluator().isEquivalent(axiom.getSuperClass());
        }

        @Override
        public final void visit(OWLSymmetricObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public final void visit(OWLTransitiveObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public final void visit(SWRLRule rule) {
            // TODO: (TS) Can't we treat this in a more differentiated way?
            isLocal = false;
        }
    }

    /**
     * Class implementing the syntactic \top-locality check using the visitor-pattern. Needs to be
     * instantiated for thread safety.
     *
     * @author Marc Robin Nolte (modified version)
     *
     */
    private final class TopLocalityAxiomVisitor extends LocalityAxiomVisitor {

        /**
         * Class to determine if class expressions are syntactically equivalent to \bottom for
         * \top-locality.
         *
         * @author Marc Robin Nolte (modified version)
         */
        final class TopLocalityBottomEquivalenceEvaluator
            extends AbstractBottomEquivalenceEvaluator {

            @Override
            public void visit(OWLClass ce) {
                isEquivalent = ce.isOWLNothing();
            }

            @Override
            public void visit(OWLDataAllValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty())
                    && !ce.getFiller().isTopDatatype();
            }

            @Override
            public void visit(OWLDataExactCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    && !signature.contains(ce.getProperty().asOWLDataProperty())
                    && isTopOrBuiltInDatatype(ce.getFiller())
                    || ce.getCardinality() > 0
                        && !signature.contains(ce.getProperty().asOWLDataProperty())
                        && isTopOrBuiltInInfiniteDatatype(ce.getFiller());
            }

            @Override
            public void visit(OWLDataHasValue ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataMaxCardinality ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty())
                    && ce.getCardinality() <= 1 && isTopOrBuiltInDatatype(ce.getFiller());

            }

            @Override
            public void visit(OWLDataMinCardinality ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataSomeValuesFrom ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectAllValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty())
                    && isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectExactCardinality ce) {
                isEquivalent = ce.getCardinality() > 0 && (isEquivalent(ce.getFiller())
                    || !signature.contains(ce.getProperty().getNamedProperty())
                        && getTopEquivalenceEvaluator().isEquivalent(ce.getFiller()));
            }

            @Override
            public void visit(OWLObjectHasSelf ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectHasValue ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLObjectMaxCardinality ce) {
                isEquivalent = ce.getCardinality() > 0
                    && !signature.contains(ce.getProperty().getNamedProperty())
                    && getTopEquivalenceEvaluator().isEquivalent(ce.getFiller());

            }

            @Override
            public void visit(OWLObjectMinCardinality ce) {
                isEquivalent = ce.getCardinality() > 0 && isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectSomeValuesFrom ce) {
                isEquivalent = isEquivalent(ce.getFiller());
            }
        }

        /**
         * Class to determine if class expressions are syntactically equivalent to \top for
         * \top-locality.
         *
         * @author Marc Robin Nolte (modified version)
         */
        final class TopLocalityTopEquivalenceEvaluator extends AbstractTopEquivalenceEvaluator {

            @Override
            public void visit(OWLClass ce) {
                isEquivalent = ce.isOWLThing() || !ce.isOWLNothing() && !signature.contains(ce);
            }

            @Override
            public void visit(OWLDataAllValuesFrom ce) {
                isEquivalent = ce.getFiller().isTopDatatype();
            }

            @Override
            public void visit(OWLDataExactCardinality ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataHasValue ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty());
            }

            @Override
            public void visit(OWLDataMaxCardinality ce) {
                isEquivalent = false;
            }

            @Override
            public void visit(OWLDataMinCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    || ce.getCardinality() == 1
                        && !signature.contains(ce.getProperty().asOWLDataProperty())
                        && isTopOrBuiltInDatatype(ce.getFiller())
                    || ce.getCardinality() > 1
                        && !signature.contains(ce.getProperty().asOWLDataProperty())
                        && isTopOrBuiltInInfiniteDatatype(ce.getFiller());
            }

            @Override
            public void visit(OWLDataSomeValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().asOWLDataProperty())
                    && isTopOrBuiltInDatatype(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectAllValuesFrom ce) {
                isEquivalent = isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectExactCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    && getBottomEquivalenceEvaluator().isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectHasSelf ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty());
            }

            @Override
            public void visit(OWLObjectHasValue ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty());
            }

            @Override
            public void visit(OWLObjectMaxCardinality ce) {
                isEquivalent = getBottomEquivalenceEvaluator().isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectMinCardinality ce) {
                isEquivalent = ce.getCardinality() == 0
                    || !signature.contains(ce.getProperty().getNamedProperty())
                        && isEquivalent(ce.getFiller());
            }

            @Override
            public void visit(OWLObjectSomeValuesFrom ce) {
                isEquivalent = !signature.contains(ce.getProperty().getNamedProperty())
                    && isEquivalent(ce.getFiller());
            }

        }

        /**
         * Instantiates a new {@link TopLocalityAxiomVisitor}.
         *
         * @param axiom     the axiom to test
         * @param signature the signature to test against
         */
        TopLocalityAxiomVisitor(OWLAxiom axiom, Collection<OWLEntity> signature) {
            super(axiom, signature);
        }

        @Override
        protected TopLocalityBottomEquivalenceEvaluator createBottomEquivalenceEvaluator() {
            return new TopLocalityBottomEquivalenceEvaluator();
        }

        @Override
        protected TopLocalityTopEquivalenceEvaluator createTopEquivalenceEvaluator() {
            return new TopLocalityTopEquivalenceEvaluator();
        }

        @Override
        public void visit(OWLAsymmetricObjectPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLDataPropertyAssertionAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().asOWLDataProperty());
        }

        @Override
        public void visit(OWLDisjointDataPropertiesAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLDisjointObjectPropertiesAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLFunctionalDataPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLFunctionalObjectPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLInverseFunctionalObjectPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLIrreflexiveObjectPropertyAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLNegativeDataPropertyAssertionAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLNegativeObjectPropertyAssertionAxiom axiom) {
            isLocal = false;
        }

        @Override
        public void visit(OWLObjectPropertyAssertionAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLObjectPropertyDomainAxiom axiom) {
            isLocal = getTopEquivalenceEvaluator().isEquivalent(axiom.getDomain());
        }

        @Override
        public void visit(OWLObjectPropertyRangeAxiom axiom) {
            isLocal = getTopEquivalenceEvaluator().isEquivalent(axiom.getRange());
        }

        @Override
        public void visit(OWLReflexiveObjectPropertyAxiom axiom) {
            isLocal = !signature.contains(axiom.getProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLSubObjectPropertyOfAxiom axiom) {
            isLocal = !signature.contains(axiom.getSuperProperty().getNamedProperty());
        }

        @Override
        public void visit(OWLSubPropertyChainOfAxiom axiom) {
            // Axiom is local iff RHS is top-equiv
            isLocal = !signature.contains(axiom.getSuperProperty().getNamedProperty());
        }

    }

    /**
     * This is a convenience method for determining whether a given data range expression is the top
     * datatype or a built-in datatype. This is used in the
     * {@link org.semanticweb.owlapi.modularity.locality.SyntacticLocalityEvaluator.BottomLocalityAxiomVisitor.BottomLocalityBottomEquivalenceEvaluator}
     * and
     * {@link org.semanticweb.owlapi.modularity.locality.SyntacticLocalityEvaluator.TopLocalityAxiomVisitor.TopLocalityTopEquivalenceEvaluator}
     * for treating cardinality restrictions.
     *
     * @param dataRange a data range expression
     * @return <code>true</code> if the specified data range expression is the top datatype or a
     *         built-in datatype; <code>false</code> otherwise
     */
    protected static boolean isTopOrBuiltInDatatype(OWLDataRange dataRange) {
        if (dataRange.isOWLDatatype()) {
            OWLDatatype dataType = dataRange.asOWLDatatype();
            return dataType.isTopDatatype() || dataType.isBuiltIn();
        }
        return false;
    }

    /**
     * This is a convenience method for determining whether a given data range expression is the top
     * datatype or a built-in infinite datatype. This is used in the
     * {@link org.semanticweb.owlapi.modularity.locality.SyntacticLocalityEvaluator.BottomLocalityAxiomVisitor.BottomLocalityBottomEquivalenceEvaluator}
     * and
     * {@link org.semanticweb.owlapi.modularity.locality.SyntacticLocalityEvaluator.TopLocalityAxiomVisitor.TopLocalityTopEquivalenceEvaluator}
     * for treating cardinality restrictions.
     *
     * @param dataRange a data range expression
     * @return <code>true</code> if the specified data range expression is the top datatype or a
     *         built-in infinite datatype; <code>false</code> otherwise
     */
    static boolean isTopOrBuiltInInfiniteDatatype(OWLDataRange dataRange) {
        if (dataRange.isOWLDatatype()) {
            OWLDatatype dataType = dataRange.asOWLDatatype();
            return dataType.isTopDatatype()
                || dataType.isBuiltIn() && !dataType.getBuiltInDatatype().isFinite();
        }
        return false;
    }

    /**
     * Creates the {@link LocalityAxiomVisitor} to check locality associated with the locality class
     * represented by this {@link SyntacticLocalityEvaluator}.
     *
     * @param axiom     The axiom to visit
     * @param signature The signature to check against
     * @return {@link LocalityAxiomVisitor} to check locality
     */
    protected abstract LocalityAxiomVisitor createLocalityAxiomVisitor(OWLAxiom axiom,
        Collection<OWLEntity> signature);

    @Override
    public final boolean isLocal(OWLAxiom axiom, Collection<OWLEntity> signature) {
        return !axiom.isLogicalAxiom() || createLocalityAxiomVisitor(
            Objects.requireNonNull(axiom, "The given axiom may not be null"),
            Objects.requireNonNull(signature, "The given signature may not be null")).isLocal();
    }

}
