CODEWITHSUNDEEP
javasparqljenasemantic-webfuseki
Orazio Contarino
Orazio Contarino

Reputation: 103

Jena Fuseki API add new data to an exsisting dataset [java]

i was trying to upload an RDF/OWL file to my Sparql endpoint (given by Fuseki). Right now i'm able to upload a single file, but if i try to repeat the action, the new dataset will override the old one. I'm searching a way to "merge" the content of the data in the dataset with the new ones of the rdf file just uploaded. Anyone can help me? thanks.

Following the code to upload/query the endpoint (i'm not the author)

// Written in 2015 by Thilo Planz 
// To the extent possible under law, I have dedicated all copyright and related and neighboring rights 
// to this software to the public domain worldwide. This software is distributed without any warranty. 
// http://creativecommons.org/publicdomain/zero/1.0/

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ByteArrayOutputStream;

import org.apache.jena.query.DatasetAccessor;
import org.apache.jena.query.DatasetAccessorFactory;
import org.apache.jena.query.QueryExecution;
import org.apache.jena.query.QueryExecutionFactory;
import org.apache.jena.query.QuerySolution;
import org.apache.jena.query.ResultSet;
import org.apache.jena.query.ResultSetFormatter;
import org.apache.jena.rdf.model.Model;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.rdf.model.RDFNode;


class FusekiExample {

    public static void uploadRDF(File rdf, String serviceURI)
            throws IOException {

        // parse the file
        Model m = ModelFactory.createDefaultModel();
        try (FileInputStream in = new FileInputStream(rdf)) {
            m.read(in, null, "RDF/XML");
        }

        // upload the resulting model
        DatasetAccessor accessor = DatasetAccessorFactory.createHTTP(serviceURI);
        accessor.putModel(m);

    }

    public static void execSelectAndPrint(String serviceURI, String query) {
        QueryExecution q = QueryExecutionFactory.sparqlService(serviceURI,
                query);
        ResultSet results = q.execSelect();

        // write to a ByteArrayOutputStream
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        //convert to JSON format
        ResultSetFormatter.outputAsJSON(outputStream, results);
        //turn json to string
        String json = new String(outputStream.toByteArray());
        //print json string
        System.out.println(json);

    }

    public static void execSelectAndProcess(String serviceURI, String query) {
        QueryExecution q = QueryExecutionFactory.sparqlService(serviceURI,
                query);
        ResultSet results = q.execSelect();

        while (results.hasNext()) {
            QuerySolution soln = results.nextSolution();
            // assumes that you have an "?x" in your query
            RDFNode x = soln.get("x");
            System.out.println(x);
        }
    }

    public static void main(String argv[]) throws IOException {
        // uploadRDF(new File("test.rdf"), );

        uploadRDF(new File("test.rdf"), "http://localhost:3030/MyEndpoint/data");


    }
}

Upvotes: 0

Views: 1261

Answers (1)

Jeen Broekstra
Jeen Broekstra

Reputation: 22042

Use accessor.add(m) instead of putModel(m). As you can see in the Javadoc, putModel replaces the existing data.

Upvotes: 4

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