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Posted to dev@jena.apache.org by "Dave Reynolds (JIRA)" <ji...@apache.org> on 2017/11/02 08:57:02 UTC
[jira] [Comment Edited] (JENA-1415) ConversionException for
individuals
[ https://issues.apache.org/jira/browse/JENA-1415?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16235417#comment-16235417 ]
Dave Reynolds edited comment on JENA-1415 at 11/2/17 8:56 AM:
--------------------------------------------------------------
The conversion to Individual by Jena only tests whether the Model containing the Resource is an OntModel and that the OntModel profile says the conversion is OK (isSupported).
So either SparqlDLExecutionFactory is returning resources that aren't in the expected model (e.g. created by ResourceFactory) or the Pellet OntModel spec is rejecting that Resource as an Individual.
The answer on Galigator suggests the former. You could test this by trying:
{code:java}
Individual in = qs.getResource("x").inModel(m).as(Individual.class);
{code}
However, either way the issue is with OpenPellet.
was (Author: der):
The conversion to Individual by Jena only tests whether the Model containing the Resource is in is an OntModel and that the OntModel profile says the conversion is OK (isSupported).
So either SparqlDLExecutionFactory is returning resources that aren't in the expected model (e.g. created by ResourceFactory) or the Pellet OntModel spec is rejecting that Resource as an Individual.
The answer on Galigator suggests the former. You could test this by trying:
{code:java}
Individual in = qs.getResource("x").inModel(m).as(Individual.class);
{code}
However, either way the issue is with OpenPellet.
> ConversionException for individuals
> -----------------------------------
>
> Key: JENA-1415
> URL: https://issues.apache.org/jira/browse/JENA-1415
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ, Jena
> Affects Versions: Jena 3.4.0
> Environment: Linux, Maven, Openllet Reasoner
> Reporter: Christian Bay
> Priority: Minor
>
> Hey there,
> I'm getting a _ConversionException_ when converting a resource to an individual by using _as_.
> [EDIT] Edited this report because I could reproduce this error in a little example.
> Jena throws a _ConversionErrorException_ when trying to cast a Resource with _as_ to an individual. The resource is received by a query as suggested here [https://github.com/Galigator/openllet/blob/integration/examples/src/main/java/openllet/examples/SPARQLDLExample.java]
> This is the test code:
> {code:java}
> package bug;
> import openllet.jena.PelletReasonerFactory;
> import openllet.query.sparqldl.jena.SparqlDLExecutionFactory;
> import org.apache.jena.ontology.OntModel;
> import org.apache.jena.query.Query;
> import org.apache.jena.query.QueryExecution;
> import org.apache.jena.query.QueryFactory;
> import org.apache.jena.query.QuerySolution;
> import org.apache.jena.query.ResultSet;
> import org.apache.jena.query.ResultSetFormatter;
> import org.apache.jena.rdf.model.ModelFactory;
> import org.apache.jena.ontology.Individual;
> import org.apache.jena.ontology.OntClass;
> import org.apache.jena.util.iterator.ExtendedIterator;
> import java.util.ArrayList;
> public class SPARQLDLBug
> {
> // The ontology loaded as dataset
> private static final String ontology = "ontologies/simple.owl";
> private static final String query = "query.sparql";
> public void run()
> {
> // First create a Jena ontology model backed by the Pellet reasoner
> // (note, the Pellet reasoner is required)
> final OntModel m = ModelFactory.createOntologyModel(PelletReasonerFactory.THE_SPEC);
> // Then read the _data from the file into the ontology model
> m.read(ontology);
> // Now read the query file into a query object
> final Query q = QueryFactory.read(query);
> // Create a SPARQL-DL query execution for the given query and
> // ontology model
> final QueryExecution qe = SparqlDLExecutionFactory.create(q, m);
> // We want to execute a SELECT query, do it, and return the result set
> final ResultSet rs = qe.execSelect();
> ArrayList<String> result = new ArrayList<String>();
> while(rs.hasNext()){
> QuerySolution qs = rs.next();
> // The Bug occurs in the next line
> Individual in = qs.getResource("x").as(Individual.class);
> ExtendedIterator<OntClass> it = in.listOntClasses(true);
> String className = "";
> while(it.hasNext()){
> className = it.next().toString();
> }
> result.add(className);
> }
> qe.close();
> }
> public static void main(final String[] args)
> {
> final SPARQLDLBug app = new SPARQLDLBug();
> app.run();
> }
> }
> {code}
> The error message is:
> {code}
> Exception in thread "main" org.apache.jena.ontology.ConversionException: Cannot convert node http://www8.cs.fau.de/research:cgm/schizophrenia#R_AcuteSchizophrenia to Individual
> at org.apache.jena.ontology.impl.IndividualImpl$1.wrap(IndividualImpl.java:61)
> at org.apache.jena.enhanced.EnhNode.convertTo(EnhNode.java:152)
> at org.apache.jena.enhanced.EnhNode.convertTo(EnhNode.java:31)
> at org.apache.jena.enhanced.Polymorphic.asInternal(Polymorphic.java:62)
> at org.apache.jena.enhanced.EnhNode.as(EnhNode.java:107)
> at bug.SPARQLDLBug.run(SPARQLDLBug.java:58)
> at bug.SPARQLDLBug.main(SPARQLDLBug.java:75)
> {code}
> This Query is:
> {code:xml}
> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
> PREFIX owl: <http://www.w3.org/2002/07/owl#>
> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
> PREFIX bio: <http://www8.cs.fau.de/research:cgm/schizophrenia#>
> SELECT ?x
> WHERE { ?x rdf:type bio:AcuteSchizophrenia }
> {code}
> And the Ontology consist only of a class and one individual.
> {code:xml}
> <?xml version="1.0"?>
> <rdf:RDF xmlns="http://www8.cs.fau.de/research:cgm/schizophrenia#"
> xml:base="http://www8.cs.fau.de/research:cgm/schizophrenia"
> xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
> xmlns:owl="http://www.w3.org/2002/07/owl#"
> xmlns:xml="http://www.w3.org/XML/1998/namespace"
> xmlns:swrlb="http://www.w3.org/2003/11/swrlb#"
> xmlns:swrl="http://www.w3.org/2003/11/swrl#"
> xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
> xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
> xmlns:dc="http://purl.org/dc/elements/1.1/">
> <owl:Ontology rdf:about="http://www8.cs.fau.de/research:cgm/schizophrenia">
> </owl:Ontology>
> <!-- http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral -->
> <rdfs:Datatype rdf:about="http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral"/>
> <owl:Class rdf:about="http://www8.cs.fau.de/research:cgm/schizophrenia#AcuteSchizophrenia">
> <rdfs:label xml:lang="en">Acute schizophrenia</rdfs:label>
> </owl:Class>
> <owl:NamedIndividual rdf:about="http://www8.cs.fau.de/research:cgm/schizophrenia#R_AcuteSchizophrenia">
> <rdf:type rdf:resource="http://www8.cs.fau.de/research:cgm/schizophrenia#AcuteSchizophrenia"/>
> </owl:NamedIndividual>
> </rdf:RDF>
> {code}
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