ここでは、「Example5.java: JOIN_METHODを使用するSPARQL問合せ」と同じSPARQL問合せに、PLAN設定(PLAN=encoded_plan)などの機能を追加した例を示します。この問合せの問合せパターンに関連付けられた実行プランを指定できます。問合せのヒントの詳細は、「問合せのヒント」を参照してください。

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();    
  }
}

この例をコンパイルして実行するコマンドと、想定されるJavaコマンドの出力は次のとおりです。

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" |
-------------------