001    /**
002     * Copyright (C) 2007-2011, Jens Lehmann
003     *
004     * This file is part of DL-Learner.
005     *
006     * DL-Learner is free software; you can redistribute it and/or modify
007     * it under the terms of the GNU General Public License as published by
008     * the Free Software Foundation; either version 3 of the License, or
009     * (at your option) any later version.
010     *
011     * DL-Learner is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
014     * GNU General Public License for more details.
015     *
016     * You should have received a copy of the GNU General Public License
017     * along with this program.  If not, see <http://www.gnu.org/licenses/>.
018     */
019    
020    package org.dllearner.core.owl;
021    
022    import java.util.Map;
023    
024    /**
025     * Implementation of owl:Nothing/BOTTOM.
026     * 
027     * @author Jens Lehmann
028     *
029     */
030    public class Nothing extends Description {
031    
032            /**
033             * 
034             */
035            private static final long serialVersionUID = -3053885252153066318L;
036            public static final Nothing instance = new Nothing();   
037            
038        public String toString(String baseURI, Map<String,String> prefixes) {
039            return "BOTTOM";
040        }
041        
042        public String toKBSyntaxString(String baseURI, Map<String,String> prefixes) {
043            return "BOTTOM";
044        }
045    
046            /* (non-Javadoc)
047             * @see org.dllearner.core.owl.Description#toManchesterSyntaxString(java.lang.String, java.util.Map)
048             */
049            @Override
050            public String toManchesterSyntaxString(String baseURI, Map<String, String> prefixes) {
051                    // in Protege 3.3 owl:Nothing
052                    // in Protege 4.0 only Nothing
053                    //return "owl:Nothing";
054                    return "Nothing";
055            }           
056        
057            public int getLength() {
058                    return 1;
059            }
060    
061            @Override
062            public int getArity() {
063                    return 0;
064            }
065            
066            /* (non-Javadoc)
067             * @see org.dllearner.core.owl.Description#accept(org.dllearner.core.owl.DescriptionVisitor)
068             */
069            @Override
070            public void accept(DescriptionVisitor visitor) {
071                    visitor.visit(this);
072            }       
073            
074            public void accept(KBElementVisitor visitor) {
075                    visitor.visit(this);
076            }
077    
078    }