code: public boolean isRdfResource(final Graph graph,
                                   final Node subject,
                                   final String namespace,
                                   final String resource) {
          LOGGER.trace("Is RDF Resource? s:{}, ns:{}, r:{}, g:{}", subject, namespace, resource, graph);
          return graph.find(subject, type.asNode(),
                  createResource(namespace + resource).asNode()).hasNext();
      }
docs: Determines whether the subject is kind of RDF resource
  @param graph the graph
  @param subject the subject
  @param namespace the namespace
  @param resource the resource
  @return whether the subject is kind of RDF resource