net.sf.openschema

Class RDFOntology

java.lang.Object

net.sf.openschema.RDFOntology

All Implemented Interfaces:

Ontology

public class RDFOntology
extends Object
implements Ontology

An implementation of the Ontology interface from and RDF Schema (rdfs) file.

Author:

Pablo Ariel Duboue

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,Set<String>>	parentsOf Parents of a given concept, map from concept name to Set of parent concepts.

Constructor Summary

Constructors

Constructor and Description
RDFOntology(InputStream in, String base) Construct an ontology from an InputStream.
RDFOntology(com.hp.hpl.jena.rdf.model.Model model) Construct an ontology from an existing RDF Model.
RDFOntology(String url, String lang) Construct an ontology from an URL.

Method Summary

Modifier and Type	Method and Description
double	distance(Object concept1, Object concept2) Some notion of semantic distance between the two concepts.
protected void	extractTriples(com.hp.hpl.jena.rdf.model.Model model) Extract the triples from the Model into the ontology.
boolean	isA(Object child, Object parent) Whether a child concept is a sub-type of the parent.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

parentsOf

protected Map<String,Set<String>> parentsOf

Parents of a given concept, map from concept name to Set of parent concepts.

Constructor Detail

RDFOntology

public RDFOntology(com.hp.hpl.jena.rdf.model.Model model)

Construct an ontology from an existing RDF Model.

RDFOntology

public RDFOntology(InputStream in,
                   String base)
            throws IOException

Construct an ontology from an InputStream.

Throws:

IOException

RDFOntology

public RDFOntology(String url,
                   String lang)

Construct an ontology from an URL.

Method Detail

extractTriples

protected void extractTriples(com.hp.hpl.jena.rdf.model.Model model)

Extract the triples from the Model into the ontology.

isA

public boolean isA(Object child,
                   Object parent)

Whether a child concept is a sub-type of the parent.

Specified by:

isA in interface Ontology

distance

public double distance(Object concept1,
                       Object concept2)

Some notion of semantic distance between the two concepts. Currently, it returns Double.MAX_VALUE if any of the concepts is null or unknown to the ontology or if they are completely unrelated (they don't share any ancestor in common, something that cannot happen in RDF-based ontologies, all concepts derive from 'Class'). If the two concepts are the same, the distance is 0. If one is a parent of the other, the distance is 0.5 (nevermind the distance). Otherwise the distance is 0.5 plus 0.1 for each level up until a common ancestor is found.

Specified by:

distance in interface Ontology