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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
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*/
package tdb.examples;
import com.hp.hpl.jena.query.Dataset ;
import com.hp.hpl.jena.query.Query ;
import com.hp.hpl.jena.query.QueryExecution ;
import com.hp.hpl.jena.query.QueryExecutionFactory ;
import com.hp.hpl.jena.query.QueryFactory ;
import com.hp.hpl.jena.query.QuerySolution ;
import com.hp.hpl.jena.query.ResultSet ;
import com.hp.hpl.jena.tdb.TDBFactory ;
/** Example of creating a TDB-backed model.
* The preferred way is to create a dataset then get the mode required from the dataset.
* The dataset can be used for SPARQL query and update
* but the Model (or Graph) can also be used.
*
* All the Jena APIs work on the model.
*
* Calling TDBFactory is the only place TDB-specific code is needed.
*
* See also ExTDB_Txn1 for use with transactions.
*/
public class ExTDB5
{
public static void main(String... argv)
{
// Direct way: Make a TDB-back Jena model in the named directory.
String directory = "MyDatabases/DB1" ;
Dataset dataset = TDBFactory.createDataset(directory) ;
// Potentially expensive query.
String sparqlQueryString = "SELECT (count(*) AS ?count) { ?s ?p ?o }" ;
// See http://incubator.apache.org/jena/documentation/query/app_api.html
Query query = QueryFactory.create(sparqlQueryString) ;
QueryExecution qexec = QueryExecutionFactory.create(query, dataset) ;
try {
ResultSet results = qexec.execSelect() ;
for ( ; results.hasNext() ; )
{
QuerySolution soln = results.nextSolution() ;
int count = soln.getLiteral("count").getInt() ;
System.out.println("count = "+count) ;
}
} finally { qexec.close() ; }
// Close the dataset.
dataset.close();
}
}