This example shows the SPARQL query from Example5.java: SPARQL query with JOIN_METHOD with additional features including a PLAN setting (PLAN=encoded_plan), where you can specify the execution plan associated to the query patterns of this query. Further details on query hints can be found in Query hints.
import com.hp.hpl.jena.query.*;
import org.openjena.riot.Lang;
import com.hp.hpl.jena.sparql.core.DatasetImpl;
import java.net.URLEncoder;
import oracle.rdf.kv.client.jena.*;
public class Example5g
{
public static void main(String[] args) throws Exception
{
String szStoreName = args[0];
String szHostName = args[1];
String szHostPort = args[2];
// Create connection
OracleNoSqlConnection conn
= OracleNoSqlConnection.createInstance(szStoreName,
szHostName,
szHostPort);
// Create datasetgraph
OracleGraphNoSql graph = new OracleGraphNoSql(conn);
DatasetGraphNoSql datasetGraph = DatasetGraphNoSql.createFrom(graph);
// Close graph, as it is no longer needed
graph.close();
// Clear dataset
datasetGraph.clearRepository();
// Load data from file into the dataset
DatasetGraphNoSql.load("example.nt", Lang.NQUADS, conn,
"http://example.com");
Dataset ds = DatasetImpl.wrap(datasetGraph);
String plan = URLEncoder.encode("((qp2 qp3 NLJ) qp1 NLJ)", "UTF-8");
String queryString =
" PREFIX ORACLE_SEM_HT_NS: " +
" <http://oracle.com/semtech#plan=" + plan + ">" +
" PREFIX foaf: <http://xmlns.com/foaf/0.1/>" +
" SELECT ?name1 ?name2 " +
" WHERE { " +
" graph <http://example.org/alice/foaf.rdf> { " +
" ?person1 foaf:knows ?person2 . " +
" ?person1 foaf:name ?name1 . " +
" ?person2 foaf:name ?name2 . " +
" } } ";
System.out.println("Execute query " + queryString);
Query query = QueryFactory.create(queryString);
QueryExecution qexec = QueryExecutionFactory.create(query, ds);
try {
ResultSet results = qexec.execSelect();
ResultSetFormatter.out(System.out, results, query);
}
finally {
qexec.close();
}
ds.close();
conn.dispose();
}
}
The following are the commands to compile and run this example, as well as the expected output of the java command.
javac -classpath ./:./jena-core-2.7.4.jar:./jena-arq-2.9.4.jar: \ ./sdordfnosqlclient.jar:./kvclient.jar:./xercesImpl-2.10.0.jar: \ ./slf4j-api-1.6.4.jar:./slf4j-log4j12-1.6.4.jar:./log4j/1.2.16.jar: \ ./jena-iri-0.9.4.jar:./xml-apis-1.4.01.jar Example5g.java javac -classpath ./:./jena-core-2.7.4.jar:./jena-arq-2.9.4.jar: \ ./sdordfnosqlclient.jar:./kvclient.jar:./xercesImpl-2.10.0.jar: \ ./slf4j-api-1.6.4.jar:./slf4j-log4j12-1.6.4.jar:./log4j/1.2.16.jar: \ ./jena-iri-0.9.4.jar:./xml-apis-1.4.01.jar Example5g <store_name> \ <host_name> <host_port> ------------------- | name1 | name2 | =================== | "Alice" | "Bob" | -------------------