How to use

Context

in

org.apache.jena.sparql.util

  private static Context setupContext(Context context, DatasetGraph dataset)
  {
    // To many copies?
    if ( context == null )      // Copy of global context to protect against change.
      context = ARQ.getContext() ;
    context = context.copy() ;

    if ( dataset.getContext() != null )
      context.putAll(dataset.getContext()) ;
    
    context.set(ARQConstants.sysCurrentTime, NodeFactoryExtra.nowAsDateTime()) ;
    return context ; 
  }
}

public static DescribeHandlerRegistry get(Context context)
{
  if ( context == null )
    return null ;
  return (DescribeHandlerRegistry)ARQ.getContext().get(ARQConstants.registryDescribeHandlers) ;
}

/**
 * Get the value a string (uses .toString() if the value is not null) -
 * supply a default string value
 */
public String getAsString(Symbol property, String defaultValue) {
  String x = getAsString(property) ;
  if ( x == null )
    return defaultValue ;
  return x ;
}

@Override
public String toString() {
  String x = "" ;
  String sep = "" ;
  for ( Symbol s : keys() ) {
    Object value = get(s) ;
    x = x + sep + s + " = " + value ;
    sep = "\n" ;
  }
  return x ;
}

/** Store a named value - overwrites any previous set value */
public void set(Symbol property, boolean value) {
  if ( value )
    setTrue(property) ;
  else
    setFalse(property) ;
}

/** Merge an outer (global) and local context to produce a new context
 * The new context is always a separate copy.  
 */
public static Context mergeCopy(Context contextGlobal, Context contextLocal) {
  if ( contextGlobal == null )
    contextGlobal = ARQ.getContext();
  Context context = contextGlobal.copy();
  if ( contextLocal != null )
    // Copy per-dataset settings.
    context.putAll(contextLocal);
  return context ;
}

public static List<URI> getAcceptedEvents(final Dataset messageDataset) {
  List<URI> acceptedEvents = new ArrayList<>();
  String queryString =
      "prefix msg:   <http://purl.org/webofneeds/message#>\n" +
          "prefix agr:   <http://purl.org/webofneeds/agreement#>\n" +
          "SELECT ?eventUri where {\n" +
          " graph ?g {"+
          "  ?s agr:accepts ?eventUri .\n" +
          "}}";
  Query query = QueryFactory.create(queryString);
  try (QueryExecution qexec = QueryExecutionFactory.create(query, messageDataset)) {
    qexec.getContext().set(TDB.symUnionDefaultGraph, true);
    ResultSet rs = qexec.execSelect();
    if (rs.hasNext()) {
      QuerySolution qs = rs.nextSolution();
      String eventUri = rdfNodeToString(qs.get("eventUri"));
      if(eventUri != null) {
        acceptedEvents.add(URI.create(eventUri));
      }
    }
  }
  return acceptedEvents;
}

@Test public void special3()
{
  Dataset ds = create() ;
  load1(ds.getDefaultModel()) ;
  load2(ds.getNamedModel("http://example/graph1")) ;
  load3(ds.getNamedModel("http://example/graph2")) ;
  
  Model m = ModelFactory.createDefaultModel() ;
  load2(m) ;
  load3(m) ;
  
  String qs = "CONSTRUCT {?s ?p ?o } WHERE { ?s ?p ?o }" ;
  Query q = QueryFactory.create(qs) ;
  QueryExecution qExec = QueryExecutionFactory.create(q, ds) ;
  qExec.getContext().set(TDB.symUnionDefaultGraph, true) ;
  Model m2 = qExec.execConstruct() ;
  if ( ! m.isIsomorphicWith(m2) )
  {
    System.out.println("---- ----") ;
    SSE.write(ds.asDatasetGraph()) ;
    System.out.println("-- Expected") ;
    m.write(System.out, "TTL") ;
    System.out.println("-- Actual") ;
    m2.write(System.out, "TTL") ;
    System.out.println("---- ----") ;
  }
  assertTrue(m.isIsomorphicWith(m2)) ;
}

private void test2(ReadWrite mode)
{
  ds.begin(mode) ;
  Query q = QueryFactory.create("SELECT * { { ?s ?p ?o } UNION { GRAPH ?g { ?s ?p ?o }}}") ;
  QueryExecution qExec = QueryExecutionFactory.create(q, ds) ;
  qExec.getContext().setTrue(TDB.symUnionDefaultGraph) ;
  long count = ResultSetFormatter.consume(qExec.execSelect()) ;
  ds.commit() ;
  ds.end() ;
  assertEquals(2, count) ;
}

@Test
public void timeout_22()
{
  String qs = prefix + "SELECT * { ?s ?p ?o }" ;
  ARQ.getContext().set(ARQ.queryTimeout, "-1") ;
  try(QueryExecution qExec = QueryExecutionFactory.create(qs, ds)) {
    ResultSet rs = qExec.execSelect() ;
    ResultSetFormatter.consume(rs) ;
  }
}

@SuppressWarnings("unchecked")
@Test
public void query_service_context_application_05() {
  // This test requires us to set that GZip and Deflate are permitted
  Map<String, Context> serviceContextMap = (Map<String, Context>) ARQ.getContext().get(Service.serviceContext);
  if (serviceContextMap == null) {
    ARQ.getContext().put(Service.serviceContext, new HashMap<String, Context>());
    serviceContextMap = (Map<String, Context>) ARQ.getContext().get(Service.serviceContext);
  }
  if (serviceContextMap.get(SERVICE) == null) {
    serviceContextMap.put(SERVICE, new Context(ARQ.getContext()));
  }
  Context serviceContext = serviceContextMap.get(SERVICE);
  try {
    serviceContext.put(Service.queryCompression, false);
    Query q = QueryFactory.create("ASK { }");
    QueryEngineHTTP engine = QueryExecutionFactory.createServiceRequest(SERVICE, q);
    Assert.assertNotNull(engine);
    // Check that no settings were changed
    Assert.assertEquals(-1, engine.getTimeout1());
    Assert.assertEquals(-1, engine.getTimeout2());
    Assert.assertFalse(engine.getAllowCompression());
    Assert.assertNull(engine.getClient());
  } finally {
    serviceContext.remove(Service.queryCompression);
  }
}

@Test public void uniontxn_ds_ww()
{
  ds.begin(WRITE) ;
  ds.commit(); 
  ds.end() ;
  
  ds.getContext().setTrue(TDB.symUnionDefaultGraph) ;
  test(ReadWrite.WRITE) ;
  //ds.getContext().unset(TDB.symUnionDefaultGraph) ;
}

/**
 * Add data access control information on a {@link DatasetGraph}. This modifies the
 * {@link DatasetGraph}'s {@link Context}.
 */
private static void addAuthorizatonService(DatasetGraph dsg, AuthorizationService authService) {
  //dsg.getContext().set(symControlledAccess, true);
  dsg.getContext().set(symAuthorizationService, authService);
}

@Test public void sparql_update_unionGraph()
{
  // JENA-344
  Dataset ds = TDBFactory.createDataset() ;
  ds.asDatasetGraph().add(SSE.parseQuad("(<g> <s> <p> 123)")) ;
  ds.getContext().setTrue(TDB.symUnionDefaultGraph) ;
  String us = StrUtils.strjoinNL(
    "INSERT { GRAPH <http://example/g2> { ?s ?p 'NEW' } }",
    "WHERE { ",
       "?s ?p 123",
    " }" ) ;
                    UpdateRequest req = UpdateFactory.create(us) ;
  UpdateAction.execute(req, ds) ;
  
  Model m = ds.getNamedModel("http://example/g2") ;
  assertEquals("Did not find 1 statement in named graph", 1, m.size()) ;
}

@Test
public void query_service_context_application_01() {
  // This test requires no service context to be set
  @SuppressWarnings("unchecked")
  Map<String, Context> serviceContextMap = (Map<String, Context>) ARQ.getContext().get(Service.serviceContext);
  if (serviceContextMap != null) {
    serviceContextMap.remove(SERVICE);
  }
  Query q = QueryFactory.create("ASK { }");
  QueryEngineHTTP engine = QueryExecutionFactory.createServiceRequest(SERVICE, q);
  Assert.assertNotNull(engine);
  // Check that no settings were changed
  Assert.assertEquals(-1, engine.getTimeout1());
  Assert.assertEquals(-1, engine.getTimeout2());
  Assert.assertTrue(engine.getAllowCompression());
  Assert.assertNull(engine.getClient());
}

private QueryExecution createQueryExecution(Query query, Model model) {
  QueryExecution result = QueryExecutionFactory.create(query, model);
  PrefixMappingImpl prefixes = new PrefixMappingImpl();
  prefixes.setNsPrefixes(tq.getPrologue().getPrefixMapping());
  prefixes.setNsPrefix("tarql", tarql.NS);
  result.getContext().set(ExpandPrefixFunction.PREFIX_MAPPING, prefixes);
  return result;
}

public void setup() {
  DatasetGraph dsg = TDBFactory.createDatasetGraph();
  dsg.getContext().set(TDB.symUnionDefaultGraph, true);
  Dataset myDataset = DatasetFactory.wrap(dsg);
  baseModel = myDataset.getNamedModel("http://example.com/baseModel");
  baseModel = QueryEngineTest.populateModel(baseModel);
  dftModel = Factory.getInstance(eval, "http://example.com/securedModel", baseModel);
  dataset = DatasetFactory.create();
  dataset.setDefaultModel(dftModel);
}

public static NodeValue eval(Expr expr, Binding binding)
{
  Context context = ARQ.getContext().copy() ;
  context.set(ARQConstants.sysCurrentTime, NodeFactoryExtra.nowAsDateTime()) ;
  FunctionEnv env = new ExecutionContext(context, null, null, null) ; 
  NodeValue r = expr.eval(binding, env) ;
  return r ;
}

public Dataset retrieveDataset(String graphName) {
 DatasetGraph dsg = TDBFactory.createDatasetGraph();
 dsg.getContext().set(TDB.symUnionDefaultGraph, new NodeValueBoolean(true));
 Dataset ds = DatasetFactory.create(dsg);
 Model model = retrieveModel(graphName);
 ds.addNamedModel(graphName, model);
 return ds;
}

private static EnvJavaScript setupJS() {
  Context cxt = ARQ.getContext().copy();
  cxt.set(EnvJavaScript.symJavaScriptFunctions, CamelCaseJS);
  cxt.set(EnvJavaScript.symJavaScriptLibFile, JS_LIB_FILE);
  return EnvJavaScript.create(cxt);
}