Jena Virtuoso Load Model

Question

I read different tutorials explaining how to load a Model to a Virtuoso SPARQL endpoint using Java Apache Jena (eg https://jena.apache.org/documentation/rdfconnection/ ), but I am not able to make it.

I tried this function:

public void uploader(){ 
String myVirtuosoEndpoint = "http://10.1.22.17:8890/"; //my Virtuoso endpoint IP

Model model = ModelFactory.createDefaultModel() ; //the Model I want to upload
model.createResource("https://example.org").addProperty(RDF.type, "http://myType");
try (RDFConnection conn = RDFConnectionFactory.connect(myVirtuosoEndpoint)) {
                conn.begin(ReadWrite.WRITE);
                conn.load("http://myGraph", model);
                conn.commit();
                conn.end();
        }
}

I also tried this other function, leveraging Jena's Txn library ( https://jena.apache.org/documentation/txn/txn.html ).

try (RDFConnection conn = RDFConnectionFactory.connect(myVirtuosoEndpoint)) {
        Txn.executeWrite(conn, ()-> {
             conn.load(targetGraph, model);
        }) ;
}

I am using a OpenLink Virtuoso Server version 07.20.3217. As for the Jena dependencies I am using the following:

    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>apache-jena-libs</artifactId>
        <type>pom</type>
        <version>3.1.0</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.apache.jena/jena-rdfconnection -->
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-rdfconnection</artifactId>
        <version>3.10.0</version>
    </dependency>

It seems that code works as I don't get any error, but the graph where I want to upload the model does not change. I am verifying it by simply executing a SPARQL query against the Graph after executing the code.

Anyone with the same problem?

Thanks

Answer 1

I am trying another new approach to update the content of an RDF graph in Virtuoso.

Code:

//Connect to Virtuoso
VirtModel virtualModel = VirtModel.openDatabaseModel(GRAPH_NAME, endpoint, USERNAME, PASSWORD);
long modelInitialSize = virtualModel.size();

//Add model
virtualModel.add(model);
long modelNewSize = virtualModel.size();

virtualModel.close();

Where the endpoint is similar to jdbc:virtuoso://10.1.22.xxx:1111

I am using these dependencies in the pom.xml :

    <!-- https://mvnrepository.com/artifact/org.apache.jena/jena-tdb -->
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>jena-tdb</artifactId>
        <version>3.9.0</version>
    </dependency>


    <!-- https://mvnrepository.com/artifact/org.apache.jena/apache-jena-libs -->
    <dependency>
        <groupId>org.apache.jena</groupId>
        <artifactId>apache-jena-libs</artifactId>
        <version>3.9.0</version>
        <type>pom</type>
    </dependency>

Furthermore, I am using the virt_jena3.jar and virtjdbc4.jar dependencies from Virtuoso webapge

Now I am getting the following error when trying to get the VirtModel's size with the command long modelNewSize = virtualModel.size(); :

org.apache.jena.shared.JenaException: virtuoso.jdbc4.VirtuosoException: Problem during serialization : Software caused connection abort: socket write error .

Besides, once this error appears, it seems like the Virtuoso server goes down, and I need to restart the Virtual Machine to fix it.

The tricky part is is that with dependencies available here , the same code works perfectly...