SparqlQueryEvaluatorDefault.java

/*******************************************************************************
 * Copyright (c) 2022 Eclipse RDF4J contributors.
 *
 * 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.http.server.readonly.sparql;

import java.io.IOException;
import java.util.Arrays;

import org.eclipse.rdf4j.model.ValueFactory;
import org.eclipse.rdf4j.query.Dataset;
import org.eclipse.rdf4j.query.MalformedQueryException;
import org.eclipse.rdf4j.query.Query;
import org.eclipse.rdf4j.query.QueryLanguage;
import org.eclipse.rdf4j.query.impl.SimpleDataset;
import org.eclipse.rdf4j.repository.Repository;
import org.eclipse.rdf4j.repository.RepositoryConnection;
import org.springframework.stereotype.Component;

@Component
class SparqlQueryEvaluatorDefault implements SparqlQueryEvaluator {

	@Override
	public void evaluate(EvaluateResult result, Repository repository, String query,
			String acceptHeader, String[] defaultGraphUri, String[] namedGraphUris)
			throws MalformedQueryException, IOException, IllegalStateException {
		try (RepositoryConnection connection = repository.getConnection()) {
			Query preparedQuery = connection.prepareQuery(QueryLanguage.SPARQL, query);
			preparedQuery.setDataset(getQueryDataSet(defaultGraphUri, namedGraphUris, connection));
			for (QueryTypes qt : QueryTypes.values()) {
				if (qt.accepts(preparedQuery, acceptHeader)) {
					qt.evaluate(result, preparedQuery, acceptHeader);
				}
			}
		}
	}

	/**
	 * @param defaultGraphUri
	 * @param namedGraphUris
	 * @param connection
	 * @see <a href="https://www.w3.org/TR/sparql11-protocol/#dataset">protocol dataset</a>
	 */
	private Dataset getQueryDataSet(String[] defaultGraphUri, String[] namedGraphUris,
			RepositoryConnection connection) {
		SimpleDataset dataset = new SimpleDataset();

		ValueFactory valueFactory = connection.getValueFactory();
		if (defaultGraphUri != null) {
			Arrays.stream(defaultGraphUri)
					.map(valueFactory::createIRI)
					.forEach(dataset::addDefaultGraph);
		}

		if (namedGraphUris != null) {
			Arrays.stream(namedGraphUris)
					.map(valueFactory::createIRI)
					.forEach(dataset::addNamedGraph);
		}
		return dataset;
	}
}