jena-examples/src/main/java/rdfconnection/examples/RDFConnectionExample1.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
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 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *   SPDX-License-Identifier: Apache-2.0
 */

package rdfconnection.examples;

import org.apache.jena.query.*;
import org.apache.jena.rdfconnection.RDFConnection;
import org.apache.jena.system.Txn;

/** RDF Connection example */
public class RDFConnectionExample1 {
    public static void main(String ...args) {
        Query query = QueryFactory.create("SELECT * { {?s ?p ?o } UNION { GRAPH ?g { ?s ?p ?o } } }");
        Dataset dataset = DatasetFactory.createTxnMem();
        RDFConnection conn = RDFConnection.connect(dataset);

        Txn.executeWrite(conn, () ->{
            System.out.println("Load a file");
            conn.load("data.ttl");
            conn.load("http://example/g0", "data.ttl");
            System.out.println("In write transaction");
            conn.queryResultSet(query, ResultSetFormatter::out);
        });
        // And again - implicit READ transaction.
        System.out.println("After write transaction");
        conn.queryResultSet(query, ResultSetFormatter::out);
    }
}