/*
* This file is part of the OWL API.
*
* The contents of this file are subject to the LGPL License, Version 3.0.
*
* Copyright (C) 2011, The University of Manchester
*
* 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.
*
* Copyright 2011, University of Manchester
*
* 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.normalform;
import org.semanticweb.owlapi.model.OWLClassExpression;
import org.semanticweb.owlapi.model.OWLDataFactory;
import org.semanticweb.owlapi.util.NNF;
/**
* Author: Matthew Horridge<br>
* The University Of Manchester<br>
* Bio-Health Informatics Group<br>
* Date: 24-Sep-2007<br><br>
*/
public class NegationalNormalFormConverter implements NormalFormRewriter {
private NNF nnf;
private OWLObjectComplementOfExtractor extractor;
public NegationalNormalFormConverter(OWLDataFactory dataFactory) {
nnf = new NNF(dataFactory);
extractor = new OWLObjectComplementOfExtractor();
}
public boolean isInNormalForm(OWLClassExpression classExpression) {
// The classExpression is in negational normal form if negations
// only appear in front of named concepts
extractor.getComplementedClassExpressions(classExpression);
for (OWLClassExpression desc : extractor.getComplementedClassExpressions(classExpression)) {
if (desc.isAnonymous()) {
return false;
}
}
return true;
}
public OWLClassExpression convertToNormalForm(OWLClassExpression classExpression) {
nnf.reset();
return classExpression.accept(nnf);
}
}