private RDFWriter createWriter(StringWriter writer) {
RDFWriter result = null;
if (format.equals(Format.TURTLE)) {
result = new TurtlePrettyPrinter(new MemValueFactory().createURI(baseURI.toString()), writer);
} else {
RDFWriterRegistry registry = RDFWriterRegistry.getInstance();
RDFFormat rawFormat = Rio.getWriterFormatForMIMEType(format.getMime(), RDFFormat.RDFXML);
RDFWriterFactory factory = registry.get(rawFormat);
result = factory.getWriter(writer);
if (format.equals(Format.JSON_LD)) {
result.getWriterConfig().set(JSONLDSettings.JSONLD_MODE, JSONLDMode.FLATTEN);
result.getWriterConfig().set(BasicWriterSettings.PRETTY_PRINT, true);
}
}
return result;
}
public void test_query() throws Exception {
final BigdataSail sail = getSail();
try {
sail.initialize();
if (!((BigdataSail) sail).database.getStatementIdentifiers()) {
log.warn("Statement identifiers are not enabled");
return;
}
/*
* Load data into the sail.
*/
{
final DataLoader dataLoader = sail.database.getDataLoader();
dataLoader.loadData(
"/com/bigdata/rdf/sail/provenance01.ttlx",
"" /*baseURL*/,
ServiceProviderHook.TURTLE_RDR);
}
/*
* Serialize as RDF/XML.
*
* Note: This is just for debugging.
*/
if (log.isInfoEnabled()) {
final BigdataStatementIterator itr = sail.database.getStatements(null, null, null);
final String rdfXml;
try {
final Writer w = new StringWriter();
// final RDFXMLWriter rdfWriter = new RDFXMLWriter(w);
final RDFWriterFactory writerFactory =
RDFWriterRegistry.getInstance().get(RDFFormat.RDFXML);
assertNotNull(writerFactory);
final RDFWriter rdfWriter = writerFactory.getWriter(w);
rdfWriter.startRDF();
while (itr.hasNext()) {
final BigdataStatementImpl stmt = (BigdataStatementImpl) itr.next();
// only write the explicit statements.
if (!stmt.isExplicit()) continue;
rdfWriter.handleStatement(stmt);
}
rdfWriter.endRDF();
rdfXml = w.toString();
} finally {
itr.close();
}
// write the rdf/xml
log.info(rdfXml);
}
final SailConnection conn = sail.getConnection();
try {
final URI y = new URIImpl("http://www.foo.org/y");
final URI B = new URIImpl("http://www.foo.org/B");
final URI dcCreator = new URIImpl("http://purl.org/dc/terms/creator");
final Literal bryan = new LiteralImpl("bryan");
final Literal mike = new LiteralImpl("mike");
/*
* This is a hand-coded query.
*
* Note: When statement identifiers are enabled, the only way to
* bind the context position is to already have a statement on hand -
* there is no index which can be used to look up a statement by its
* context and the context is always a blank node.
*/
// final TupleExpr tupleExpr =
// new Projection(
// new Join(//
// new StatementPattern(//
// new Var("X", y),//
// new Var("1", RDF.TYPE),//
// new Var("2", B),//
// new Var("SID")),// unbound.
// new StatementPattern(//
// new Var("SID"),//
// new Var("3", dcCreator),//
// new Var("Y"))),
// new ProjectionElemList(new ProjectionElem[] { new ProjectionElem( "Y"
// )}));
// final String q = "select ?Y where { ?SID <"+dcCreator+"> ?Y . graph ?SID {
// <"+y+"> <"+RDF.TYPE+"> <"+B+"> . } }";
final String q =
"select ?Y where { <<<"
+ y
+ "> <"
+ RDF.TYPE
+ "> <"
+ B
+ ">>> <"
+ dcCreator
+ "> ?Y . }";
/*
* Create a data set consisting of the contexts to be queried.
*
* Note: a [null] DataSet will cause context to be ignored when the
* query is processed.
*/
// final DatasetImpl dataSet = null; //new DatasetImpl();
//
// final BindingSet bindingSet = new QueryBindingSet();
//
// final CloseableIteration<? extends BindingSet, QueryEvaluationException> itr =
// conn
// .evaluate(tupleExpr, dataSet, bindingSet, true/* includeInferred */);
final TupleQuery tq =
new BigdataSailRepository(sail)
.getReadOnlyConnection()
.prepareTupleQuery(QueryLanguage.SPARQL, q);
final TupleQueryResult itr = tq.evaluate();
if (log.isInfoEnabled()) log.info("Verifying query.");
/*
* These are the expected results for the query (the bindings for Y).
*/
final Set<Value> expected = new HashSet<Value>();
expected.add(bryan);
expected.add(mike);
/*
* Verify that the query results is the correct solutions.
*/
final int nresults = expected.size();
try {
int i = 0;
while (itr.hasNext()) {
final BindingSet solution = itr.next();
if (log.isInfoEnabled()) log.info("solution[" + i + "] : " + solution);
final Value actual = solution.getValue("Y");
assertTrue("Not expecting Y=" + actual, expected.remove(actual));
i++;
}
assertEquals("#results", nresults, i);
} finally {
itr.close();
}
} finally {
conn.close();
}
} finally {
sail.__tearDownUnitTest();
}
}