In my previous post I have detailed how you can create a local Ontotext GraphDB repository using RDF4J. I indicated that there are some problems when creating a local repository. Therefore, in this post I will detail how to create a remote Ontotext GraphDB repository using RDF4J. As with creating a local repository, there are three steps:
- Create a configuration file, which is as for local repositories.
- Create
pom.xmlfile, which is as for local repositories. - Create the Java code.
The benefit of creating a remote repository is that it will be under the control of the Ontotext GraphDB Workbench. Hence, you will be able to monitor your repository from the Workbench.
Java Code
package org.graphdb.rdf4j.tutorial;
import java.io.FileInputStream;
import java.io.InputStream;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Iterator;
import org.eclipse.rdf4j.model.Model;
import org.eclipse.rdf4j.model.Resource;
import org.eclipse.rdf4j.model.Statement;
import org.eclipse.rdf4j.model.impl.TreeModel;
import org.eclipse.rdf4j.model.util.Models;
import org.eclipse.rdf4j.model.vocabulary.RDF;
import org.eclipse.rdf4j.repository.Repository;
import org.eclipse.rdf4j.repository.RepositoryConnection;
import org.eclipse.rdf4j.repository.config.RepositoryConfig;
import org.eclipse.rdf4j.repository.config.RepositoryConfigSchema;
import org.eclipse.rdf4j.repository.http.config.HTTPRepositoryConfig;
import org.eclipse.rdf4j.repository.manager.RemoteRepositoryManager;
import org.eclipse.rdf4j.repository.manager.RepositoryManager;
import org.eclipse.rdf4j.repository.manager.RepositoryProvider;
import org.eclipse.rdf4j.rio.RDFFormat;
import org.eclipse.rdf4j.rio.RDFParser;
import org.eclipse.rdf4j.rio.Rio;
import org.eclipse.rdf4j.rio.helpers.StatementCollector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
public class CreateRemoteRepository {
private static Logger logger = LoggerFactory.getLogger(CreateRemoteRepository.class);
// Why This Failure marker
private static final Marker WTF_MARKER = MarkerFactory.getMarker("WTF");
public static void main(String[] args) {
try {
Path path = Paths.get(".").toAbsolutePath().normalize();
String strRepositoryConfig = path.toFile().getAbsolutePath() + "/src/main/resources/repo-defaults.ttl";
String strServerUrl = "http://localhost:7200";
// Instantiate a local repository manager and initialize it
RepositoryManager repositoryManager = RepositoryProvider.getRepositoryManager(strServerUrl);
repositoryManager.initialize();
repositoryManager.getAllRepositories();
// Instantiate a repository graph model
TreeModel graph = new TreeModel();
// Read repository configuration file
InputStream config = new FileInputStream(strRepositoryConfig);
RDFParser rdfParser = Rio.createParser(RDFFormat.TURTLE);
rdfParser.setRDFHandler(new StatementCollector(graph));
rdfParser.parse(config, RepositoryConfigSchema.NAMESPACE);
config.close();
// Retrieve the repository node as a resource
Resource repositoryNode = Models.subject(graph
.filter(null, RDF.TYPE, RepositoryConfigSchema.REPOSITORY))
.orElseThrow(() -> new RuntimeException(
"Oops, no <http://www.openrdf.org/config/repository#> subject found!"));
// Create a repository configuration object and add it to the repositoryManager
RepositoryConfig repositoryConfig = RepositoryConfig.create(graph, repositoryNode);
repositoryManager.addRepositoryConfig(repositoryConfig);
// Get the repository from repository manager, note the repository id
// set in configuration .ttl file
Repository repository = repositoryManager.getRepository("graphdb-repo");
// Open a connection to this repository
RepositoryConnection repositoryConnection = repository.getConnection();
// ... use the repository
// Shutdown connection, repository and manager
repositoryConnection.close();
repository.shutDown();
repositoryManager.shutDown();
} catch (Throwable t) {
logger.error(WTF_MARKER, t.getMessage(), t);
}
}
}
Conclusion
In this post I detailed how you can create remote repository for Ontotext GraphDB using RDF4J, as well as the benefit of creating a remote repository rather than a local repository. You can find the complete code of this example on github.