org.eclipse.rdf4j.spin.function.spif.Name Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2015 Eclipse RDF4J contributors, Aduna, and others.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Distribution License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*******************************************************************************/
package org.eclipse.rdf4j.spin.function.spif;
import java.util.stream.Stream;
import org.eclipse.rdf4j.model.Literal;
import org.eclipse.rdf4j.model.Resource;
import org.eclipse.rdf4j.model.Value;
import org.eclipse.rdf4j.model.ValueFactory;
import org.eclipse.rdf4j.model.vocabulary.RDFS;
import org.eclipse.rdf4j.model.vocabulary.SPIF;
import org.eclipse.rdf4j.query.QueryEvaluationException;
import org.eclipse.rdf4j.query.algebra.evaluation.QueryPreparer;
import org.eclipse.rdf4j.query.algebra.evaluation.ValueExprEvaluationException;
import org.eclipse.rdf4j.query.algebra.evaluation.function.Function;
import org.eclipse.rdf4j.query.algebra.evaluation.util.TripleSources;
import org.eclipse.rdf4j.spin.function.AbstractSpinFunction;
public class Name extends AbstractSpinFunction implements Function {
public Name() {
super(SPIF.NAME_FUNCTION.stringValue());
}
@Override
public Value evaluate(ValueFactory valueFactory, Value... args) throws ValueExprEvaluationException {
if (args.length != 1) {
throw new ValueExprEvaluationException(
String.format("%s requires 1 argument, got %d", getURI(), args.length));
}
if (args[0] instanceof Literal) {
return valueFactory.createLiteral(((Literal) args[0]).getLabel());
} else {
QueryPreparer qp = getCurrentQueryPreparer();
try {
try (Stream stream = TripleSources
.getObjectLiterals((Resource) args[0], RDFS.LABEL, qp.getTripleSource())
.stream()) {
return stream.findFirst().orElseGet(() -> valueFactory.createLiteral(args[0].stringValue()));
}
} catch (QueryEvaluationException e) {
throw new ValueExprEvaluationException(e);
}
}
}
}