/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.gom.alchemy.owl;
import org.openrdf.model.vocabulary.OWL;
import org.openrdf.model.vocabulary.RDF;
import org.openrdf.model.vocabulary.RDFS;
import com.bigdata.gom.gpo.BasicSkin;
import com.bigdata.gom.gpo.IGPO;
import com.bigdata.gom.gpo.IGenericSkin;
/**
* The OWLClassSkin returns Iterator<OWLPropertySkin> with the
* getProperties method using the RDFS.DOMAIN URI.
*
* So a property has a domain, an RDF.TYPE and an RDFS.RANGE that
* defines the datatype of the property of an instance.
*
* A confusion is the RDF.TYPE which is one of the main following types:
*
* DatatypeProperty, ObjectProperty, FunctionalProperty
*
* (there are also a few more inverse/transitive etc)
*
* It seems to me that FunctionalProperty is slightly problematic since
* it appears to be used to indicate 0 or 1 data values. But also
* often means unique.
*
* There also seems to be an oddity around whether a property is, say,
* an owl:datatypeProperty with rdf:type owl:functionalProperty or an
* owl:functionalProperty with rdf:type owl.datatypeProperty.
*
* It all looks very odd.
*
* The inverseOf property is interesting, but the example from univ-bench
* doesn't look like an true inverse to me, more like an alias.
*
* Alias, or equivalent properties
*
* <owl:ObjectProperty rdf:ID="degreeFrom">
* <rdfs:label>has a degree from</rdfs:label>
* <rdfs:domain rdf:resource="#Person" />
* <rdfs:range rdf:resource="#University" />
* <owl:inverseOf rdf:resource="#hasAlumnus"/>
* </owl:ObjectProperty>
*
* <owl:ObjectProperty rdf:ID="hasAlumnus">
* <rdfs:label>has as an alumnus</rdfs:label>
* <rdfs:domain rdf:resource="#University" />
* <rdfs:range rdf:resource="#Person" />
* <owl:inverseOf rdf:resource="#degreeFrom"/>
* </owl:ObjectProperty>
*
* The inverse of "degreeFrom" should be "degreeTo". The idea *should* be
* to normalize the data, to allow the assertion of <uni, degreeTo student>
* and transform to <student, degreeFrom, uni>. Not to support both
* types of statements. ...and of course to transform queries that
* use the inverse predicate.
*
* So, to clarify, there should *not* be two properties defined, just one
* with an "inverseOf" annotation.
*
* @author Martyn Cutcher
*
*/
public class OWLPropertySkin extends BasicSkin implements IGenericSkin {
public OWLPropertySkin(IGPO gpo) {
super(gpo);
}
public String getName() {
return m_gpo.getId().stringValue();
}
public boolean isAssociation() {
return m_gpo.getValue(RDF.TYPE) == OWL.OBJECTPROPERTY;
}
/**
* Note that this can be null. The univ-bench.owl does not define
* types of Literal values.
*
* @return type of property
*/
public IGPO getType() {
return this.getGPOValue(RDFS.RANGE);
}
}