Java Code Examples for org.apache.jena.query.QuerySolutionMap#add()

private String injectTarget(String sparqlQuery, ShapeTarget target) {
    String changedQuery = sparqlQuery;

    if (target.getTargetType().equals(ShapeTargetType.NodeTarget)) {
        changedQuery = sparqlQuery
                .replaceFirst("[\\$\\?]this", thisVar )
                .replaceAll("(?i)BOUND\\s*\\(\\s*[\\$\\?]this\\s*\\)", "BOUND\\("+ thisVar+"\\)")
                .replaceAll("(?i)GROUP\\s+BY\\s+[\\$\\?]this", "GROUP BY "+ thisVar);

        QuerySolutionMap qsm = new QuerySolutionMap();
        qsm.add(CommonNames.This, target.getNode());
        ParameterizedSparqlString pq = new ParameterizedSparqlString(changedQuery, qsm);
        changedQuery = pq.toString();

        changedQuery = changedQuery
                .replaceFirst(thisVar, "\\$this")
                .replaceAll("(?i)BOUND\\("+ thisVar+"\\)", "BOUND\\(\\?this\\)")
                .replaceAll("(?i)GROUP BY "+ thisVar, "GROUP BY \\$this");
    }

    return injectSparqlSnippet(changedQuery, target.getPattern());
}
 

private static Resource mboxForAgent(Resource agentResource) {
	logger.fine("Finding mbox of " + agentResource);
	String queryStr = sparqlPrefixes + "SELECT ?mbox WHERE { \n"
			+ "		{ ?agent foaf:mbox ?mbox } \n" + "	UNION  \n"
			+ "		{ ?agent vcard:hasEmail ?mbox } \n" + "	UNION  \n"
			+ "		{ ?agent vcard:email ?email .  \n"
			+ "       BIND(IRI(CONCAT(\"mbox:\", ?email)) AS ?mbox) \n" // legacy
			+ "	    } \n" + "} \n";
	logger.finer(QueryFactory.create(queryStr).toString());
	QueryExecution qexec = QueryExecutionFactory.create(queryStr,
			agentResource.getModel());
	QuerySolutionMap binding = new QuerySolutionMap();
	binding.add("agent", agentResource);
	qexec.setInitialBinding(binding);
	ResultSet select = qexec.execSelect();
	if (select.hasNext()) {
		Resource mbox = select.next().getResource("mbox");
		logger.fine("Found mbox: " + mbox);
		return mbox;
	}
	logger.fine("mbox not found");
	return null;
}
 

private static List<RDFNode> creatingAgentsFor(Resource r) {
	logger.fine("Finding creator of " + r);
	String queryStr = sparqlPrefixes + "SELECT ?agent WHERE { \n" + " { \n"
			+ "  ?r dct:creator [ \n" + "	    rdfs:member ?agent \n"
			+ "  ] \n" + " } UNION { \n" + "   ?r dct:creator ?agent .\n "
			+ "   FILTER NOT EXISTS { ?agent rdfs:member ?member } \n"
			+ " } \n" + "} \n";
	logger.finer(QueryFactory.create(queryStr).toString());
	QueryExecution qexec = QueryExecutionFactory.create(queryStr,
			r.getModel());
	QuerySolutionMap binding = new QuerySolutionMap();
	binding.add("r", r);
	qexec.setInitialBinding(binding);
	ResultSet select = qexec.execSelect();
	List<RDFNode> agents = new ArrayList<>();

	while (select.hasNext()) {
		RDFNode agent = select.next().get("agent");
		logger.fine("Found: " + agent);
		agents.add(agent);
	}
	return agents;
}
 

@Override
public boolean contains(Dataset dataset, RDFNode node) {
	QuerySolutionMap bindings = new QuerySolutionMap();
	bindings.add(SH.thisVar.getVarName(), node);
	if(parameterizableTarget != null) {
		parameterizableTarget.addBindings(bindings);
	}
	if(query.isAskType()) {
		try(QueryExecution qexec = SPARQLSubstitutions.createQueryExecution(query, dataset, bindings)) {
		    return qexec.execAsk();
		}
	}
	else {
		try(QueryExecution qexec = SPARQLSubstitutions.createQueryExecution(query, dataset, bindings)) {
		    ResultSet rs = qexec.execSelect();
		    return rs.hasNext();
		}
	}
}
 

public QuerySolutionMap getQuerySolutionMap()
{
    QuerySolutionMap qsm = new QuerySolutionMap();
    
    org.spinrdf.model.TemplateCall spinTemplateCall = SPINFactory.asTemplateCall(getTemplate().getQuery());
    if (spinTemplateCall != null)
    {
        qsm = spinTemplateCall.getInitialBinding();
        
        List<org.spinrdf.model.Argument> spinArgs = spinTemplateCall.getTemplate().getArguments(false);
        // add SPIN Arguments that match LDT Arguments (by predicate)
        for (org.spinrdf.model.Argument spinArg : spinArgs)
            if (getTemplate().getParameters().containsKey(spinArg.getPredicate()) && hasArgument(spinArg.getPredicate()))
            {
                Parameter param = getTemplate().getParameters().get(spinArg.getPredicate());
                qsm.add(param.getVarName(), getArgumentProperty(param.getPredicate()).getObject());
            }
    }
            
    return qsm;
}
 

@Override
   protected Collection<RDFNode> getValueNodes(ValidationEngine validationEngine, Constraint constraint, QuerySolutionMap bindings, RDFNode focusNode) {
	SHConstraintComponent component = constraint.getComponent();
	Resource context = constraint.getContext();
	Resource validatorResource = component.getValidator(SH.JSValidator, context);
	if(SH.PropertyShape.equals(context)) {
		if(component.hasProperty(SH.propertyValidator, validatorResource)) {
			bindings.add("path", constraint.getShapeResource().getRequiredProperty(SH.path).getObject());
			List<RDFNode> valueNodes = new ArrayList<>();
			valueNodes.add(null);
			return valueNodes;
		}
		else {
			return validationEngine.getValueNodes(constraint, focusNode);
		}
	}
	else {
		bindings.add("value", focusNode);
		return Collections.singletonList(focusNode);
	}
}
 

@Override
public void execute(RuleEngine ruleEngine, List<RDFNode> focusNodes, Shape shape) {
	ProgressMonitor monitor = ruleEngine.getProgressMonitor();
	for(RDFNode focusNode : focusNodes) {
		
		if(monitor != null && monitor.isCanceled()) {
			return;
		}

		QuerySolutionMap bindings = new QuerySolutionMap();
		bindings.add(SH.thisVar.getVarName(), focusNode);
		try(QueryExecution qexec = ARQFactory.get().createQueryExecution(query, ruleEngine.getDataset(), bindings)) {
			Iterator<Triple> it = qexec.execConstructTriples();
			while(it.hasNext()) {
				Triple triple = it.next();
				ruleEngine.infer(triple, this, shape);
			}
		}
	}
}
 

/**
 * Gets any locally-defined label for a given property.
 * The labels are expected to be attached to shapes associated with a given
 * context resource (instance).
 * That context resource may for example be the subject of the current UI form.
 * @param property  the property to get the label of
 * @param context  the context instance
 * @return the local label or null if it should fall back to a global label
 */
public static String getLocalPropertyLabel(Resource property, Resource context) {
	QuerySolutionMap binding = new QuerySolutionMap();
	binding.add("arg1", property);
	binding.add("arg2", context);
	try(QueryExecution qexec = ARQFactory.get().createQueryExecution(propertyLabelQuery, property.getModel(), binding)) {
	    ResultSet rs = qexec.execSelect();
	    if(rs.hasNext()) {
	        return rs.next().get("label").asLiteral().getLexicalForm();
	    }
	}
	return null;
}
 

@Test
public void testGetQuerySolutionMap()
{
    QuerySolutionMap qsm = new QuerySolutionMap();
    qsm.add(predicate1.getLocalName(), QUERY_BINDING);
    
    assertEquals(qsm.asMap(), call.getQuerySolutionMap().asMap());
}
 

@Override
public ExtendedIterator<RDFNode> eval(RDFNode focusNode, NodeExpressionContext context) {
	List<RDFNode> focusNodes;
	NodeExpression input = getInput();
	if(input != null) {
		focusNodes = input.eval(focusNode, context).toList();
	}
	else {
		focusNodes = Collections.singletonList(focusNode);
	}
	List<RDFNode> results = new LinkedList<>();
	for(RDFNode f : focusNodes) {
		QuerySolutionMap binding = new QuerySolutionMap();
		binding.add(SH.thisVar.getName(), f);
		try(QueryExecution qexec = ARQFactory.get().createQueryExecution(query, focusNode.getModel(), binding)) {
			if(query.isAskType()) {
				results.add(qexec.execAsk() ? JenaDatatypes.TRUE : JenaDatatypes.FALSE);
			}
			else {
				ResultSet rs = qexec.execSelect();
				String varName = rs.getResultVars().get(0);
				while(rs.hasNext()) {
					RDFNode node = rs.next().get(varName);
					if(node != null) {
						results.add(node);
					}
				}
			}
		}
	}
	return WrappedIterator.create(results.iterator());
}
 

@Override
public void addBindings(QuerySolutionMap bindings) {
	for(SHParameter arg : getParameterizable().getParameters()) {
		Statement s = getProperty(arg.getPredicate());
		if(s != null) {
			bindings.add(arg.getVarName(), s.getObject());
		}
	}
}
 

/**
 * Turns a Binding into a QuerySolutionMap.
 * @param binding  the Binding to convert
 * @return a QuerySolutionMap
 */
public static QuerySolutionMap asQuerySolutionMap(Binding binding) {
	QuerySolutionMap map = new QuerySolutionMap();
	Iterator<Var> vars = binding.vars();
	while(vars.hasNext()) {
		Var var = vars.next();
		Node node = binding.get(var);
		if(node != null) {
			map.add(var.getName(), dummyModel.asRDFNode(node));
		}
	}
	return map;
}
 

/**
 * Take an existing {@link CypherEntity} and adds the properties that can be mapped from the underlining TDB by means 
 * of a property query, like {@link CyNodeLoadingHandler#getNodePropsSparql()}, or 
 * {@link CyRelationLoadingHandler#getRelationPropsSparql()}.
 * 
 * It doesn't do anything if the query is null.
 * 
 */
protected void addCypherProps ( CypherEntity cyEnt, String propsSparql )
{
	ensureOpen ();		
	Dataset dataSet = this.getDataSet ();
	
	QuerySolutionMap params = new QuerySolutionMap ();
	params.add ( "iri", dataSet.getUnionModel().getResource ( cyEnt.getIri () ) );

	// It may be omitted, if you don't have any property except the IRI.
	if ( propsSparql == null ) return;
	
	Query qry = SparqlUtils.getCachedQuery ( propsSparql );
	Function<String, String> propIdConverter = this.getCyPropertyIdConverter ();
	
	boolean wasInTnx = dataSet.isInTransaction ();
	if ( !wasInTnx ) dataSet.begin ( ReadWrite.READ );
	try
	{
		QueryExecution qx = QueryExecutionFactory.create ( qry, dataSet, params );
		qx.execSelect ().forEachRemaining ( row ->
		{
			String propName = this.getCypherId ( row.get ( "name" ), propIdConverter );
			if ( propName == null ) throw new IllegalArgumentException ( 
				"Null property name for " + cyEnt.getIri () 
			);
			
			String propValue = JENAUTILS.literal2Value ( row.getLiteral ( "value" ) ).get ();
			cyEnt.addPropValue ( propName, propValue );
		});
	}
	finally {
		if ( !wasInTnx && dataSet.isInTransaction () ) dataSet.end ();
	}
}
 

/**
 * Uses the underlining TDB and mapping queries to create a new {@link CyNode} instance.
 * 
 * @param nodeRes the RDF/Jena resource correspnding to the Cypher node. This provides the ?iri paramter in the queries below.
 * @param labelsSparql the node labels query, which is usually taken from {@link CyNodeLoadingHandler#getLabelsSparql()}.
 * @param propsSparql the node properties query, which is usually taken from {@link CyNodeLoadingHandler#getNodePropsSparql()}.
 */
public CyNode getCyNode ( Resource nodeRes, String labelsSparql, String propsSparql )
{
	ensureOpen ();
	
	QuerySolutionMap params = new QuerySolutionMap ();
	params.add ( "iri", nodeRes );

	CyNode cyNode = new CyNode ( nodeRes.getURI () );
	
	// The node's labels
	if ( labelsSparql != null )
	{
		// If it's omitted, it will get the default label.
		Query qry = SparqlUtils.getCachedQuery ( labelsSparql );
		Function<String, String> labelIdConverter = this.getCyNodeLabelIdConverter ();
		
		boolean wasInTnx = dataSet.isInTransaction ();
		if ( !wasInTnx ) dataSet.begin ( ReadWrite.READ );
		try {
			QueryExecution qx = QueryExecutionFactory.create ( qry, this.getDataSet(), params );
			qx.execSelect ().forEachRemaining ( row ->
				cyNode.addLabel ( this.getCypherId ( row.get ( "label" ), labelIdConverter ) )
			);
		}
		finally {
			if ( !wasInTnx && dataSet.isInTransaction () ) dataSet.end ();
		}
	}
	
	// and the properties
	this.addCypherProps ( cyNode, propsSparql );
	
	return cyNode;
}
 

public QuerySolution createQuerySolution( String varName, Node n ) {
	final RDFNode nn = ModelFactory.createDefaultModel().asRDFNode(n);
	final QuerySolutionMap s = new QuerySolutionMap();
	s.add(varName, nn);
	return s;
}
 

@Override
public void executeConstraint(Constraint constraint, ValidationEngine validationEngine, Collection<RDFNode> focusNodes) {
	
	JSScriptEngine jsEngine = SHACLScriptEngineManager.getCurrentEngine();
	
	Dataset dataset = validationEngine.getDataset();
	URI shapesGraphURI = validationEngine.getShapesGraphURI();
	String functionName = null;
	JSGraph shapesJSGraph = new JSGraph(validationEngine.getShapesModel().getGraph(), jsEngine);
	Model dataModel = dataset.getDefaultModel();
	Object oldSHACL = jsEngine.get(SHACL);
	jsEngine.put(SHACL, new SHACLObject(validationEngine.getShapesGraph(), shapesGraphURI, dataset));
	JSGraph dataJSGraph = new JSGraph(dataModel.getGraph(), jsEngine);
	try {
		
		jsEngine.put(SH.JS_SHAPES_VAR, shapesJSGraph);
		jsEngine.put(SH.JS_DATA_VAR, dataJSGraph);
		
		QuerySolutionMap bindings = new QuerySolutionMap();
		bindings.add(SH.currentShapeVar.getName(), constraint.getShapeResource());
		addBindings(constraint, bindings);

		SHJSExecutable executable = getExecutable(constraint);
		functionName = executable.getFunctionName();
		jsEngine.executeLibraries(executable);
		
		long startTime = System.currentTimeMillis();
		for(RDFNode theFocusNode : focusNodes) {
			validationEngine.checkCanceled();
			Object resultObj;
			bindings.add(SH.thisVar.getVarName(), theFocusNode);
			
			for(RDFNode valueNode : getValueNodes(validationEngine, constraint, bindings, theFocusNode)) {
				bindings.add("value", valueNode);
				resultObj = jsEngine.invokeFunction(functionName, bindings);
				handleJSResultObject(resultObj, validationEngine, constraint, theFocusNode, valueNode, executable, bindings);
			}
		}
		if(ExecStatisticsManager.get().isRecording()) {
			long endTime = System.currentTimeMillis();
			long duration = endTime - startTime;
			String label = getLabel(constraint);
			ExecStatistics stats = new ExecStatistics(label, null, duration, startTime, constraint.getComponent().asNode());
			ExecStatisticsManager.get().add(Collections.singletonList(stats));
		}
	}
	catch(Exception ex) {
		ex.printStackTrace();
		Resource result = validationEngine.createResult(DASH.FailureResult, constraint, null);
		result.addProperty(SH.resultMessage, "Could not execute JavaScript constraint");
		if(SH.JSConstraintComponent.equals(constraint.getComponent())) {
			result.addProperty(SH.sourceConstraint, constraint.getParameterValue());
		}
		FailureLog.get().logFailure("Could not execute JavaScript function \"" + functionName + "\": " + ex);
	}
	finally {
		dataJSGraph.close();
		shapesJSGraph.close();
		jsEngine.put(SHACL, oldSHACL);
	}
}
 

@Override
public void executeConstraint(Constraint constraint, ValidationEngine engine, Collection<RDFNode> focusNodes) {
	
	QuerySolutionMap bindings = new QuerySolutionMap();
	addBindings(constraint, bindings);
	bindings.add(SH.currentShapeVar.getVarName(), constraint.getShapeResource());
	bindings.add(SH.shapesGraphVar.getVarName(), ResourceFactory.createResource(engine.getShapesGraphURI().toString()));
	
	Resource path = constraint.getShapeResource().getPath();
	if(path != null && path.isURIResource()) {
		bindings.add(SH.PATHVar.getName(), path);
	}
	
	URI oldShapesGraphURI = HasShapeFunction.getShapesGraphURI();
	ShapesGraph oldShapesGraph = HasShapeFunction.getShapesGraph();
	if(!engine.getShapesGraphURI().equals(oldShapesGraphURI)) {
		HasShapeFunction.setShapesGraph(engine.getShapesGraph(), engine.getShapesGraphURI());
	}
	
	Model oldNestedResults = HasShapeFunction.getResultsModel();
	Model nestedResults = JenaUtil.createMemoryModel();
	HasShapeFunction.setResultsModel(nestedResults);
	
	try {
		long startTime = System.currentTimeMillis();
		Resource messageHolder = getSPARQLExecutable(constraint);
		for(RDFNode focusNode : focusNodes) {
			bindings.add(SH.thisVar.getVarName(), focusNode); // Overwrite any previous binding
			QueryExecution qexec = SPARQLSubstitutions.createQueryExecution(query, engine.getDataset(), bindings);
			executeSelectQuery(engine, constraint, messageHolder, nestedResults, focusNode, qexec, bindings);
			engine.checkCanceled();
		}			
		if(ExecStatisticsManager.get().isRecording()) {
			long endTime = System.currentTimeMillis();
			long duration = endTime - startTime;
			String label = getLabel(constraint);
			Iterator<String> varNames = bindings.varNames();
			if(varNames.hasNext()) {
				queryString += "\nBindings:";
				while(varNames.hasNext()) {
					String varName = varNames.next();
					queryString += "\n- ?" + varName + ": " + bindings.get(varName);
				}
			}
			ExecStatistics stats = new ExecStatistics(label, queryString, duration, startTime, constraint.getComponent().asNode());
			ExecStatisticsManager.get().add(Collections.singletonList(stats));
		}
	}
	finally {
		HasShapeFunction.setShapesGraph(oldShapesGraph, oldShapesGraphURI);
		HasShapeFunction.setResultsModel(oldNestedResults);
	}
}
 

private static String nameForAgent(Resource agentResource) {
	logger.fine("Finding name of " + agentResource);
	String queryStr = sparqlPrefixes
			+ "SELECT ?name WHERE { \n"
			+ "		{ ?agent foaf:name ?name } \n"
			+ "	UNION  \n"
			+ "		{ ?agent vcard:fn ?name } \n"
			+ "	UNION  \n"
			+ "		{ ?agent vcard:FN ?name } \n"
			+ // legacy
			"	UNION  \n"
			+ "		{ ?agent rdfs:label ?name } \n"
			+ " UNION  \n"
			+ "     { \n"
			+ "         { ?agent vcard:n ?n } UNION { ?agent vcard:hasName ?n } \n"
			+ "         ?n vcard:family-name ?family ; \n"
			+ "            vcard:given-name ?given . \n"
			+ "          BIND(CONCAT(?given, \" \", ?family) AS ?name) \n"
			+ "     } \n" + " UNION \n" + "     { "
			+ "         ?agent foaf:givenName ?given ; \n"
			+ "                foaf:familyName ?family \n"
			+ "          BIND(CONCAT(?given, \" \", ?family) AS ?name) \n"
			+ "     } \n" + " UNION \n" + "     { "
			+ "         ?agent foaf:firstName ?given ; \n"
			+ "                foaf:surname ?family \n"
			+ "          BIND(CONCAT(?given, \" \", ?family) AS ?name) \n"
			+ "     } \n" + "	}  \n";
	logger.finer(QueryFactory.create(queryStr).toString());
	QueryExecution qexec = QueryExecutionFactory.create(queryStr,
			agentResource.getModel());
	QuerySolutionMap binding = new QuerySolutionMap();
	binding.add("agent", agentResource);
	qexec.setInitialBinding(binding);
	ResultSet select = qexec.execSelect();
	if (select.hasNext()) {
		String name = select.next().getLiteral("name").getString();
		logger.fine(name);
		return name;
	}
	logger.fine("(null)");
	return null;
}
 

/**
 *
 * @param subject
 * @param predicate
 * @param object
 * @param offset
 * @param limit
 * @return
 */
@Override
protected ILinkedDataFragment createFragment(
           final ITriplePatternElement<RDFNode,String,String> subject,
           final ITriplePatternElement<RDFNode,String,String> predicate,
           final ITriplePatternElement<RDFNode,String,String> object,
           final long offset,
           final long limit )
{
    // FIXME: The following algorithm is incorrect for cases in which
    //        the requested triple pattern contains a specific variable
    //        multiple times;
    //        e.g., (?x foaf:knows ?x ) or (_:bn foaf:knows _:bn)
    // see https://github.com/LinkedDataFragments/Server.Java/issues/24

    Model model;
    if (defaultGraph == null) {
        model = tdb.getDefaultModel();
    } else {
        model = tdb.getNamedModel(defaultGraph);
    }

    QuerySolutionMap map = new QuerySolutionMap();
    if ( ! subject.isVariable() ) {
        map.add("s", subject.asConstantTerm());
    }
    if ( ! predicate.isVariable() ) {
        map.add("p", predicate.asConstantTerm());
    }
    if ( ! object.isVariable() ) {
        map.add("o", object.asConstantTerm());
    }

    query.setOffset(offset);
    query.setLimit(limit);

    Model triples = ModelFactory.createDefaultModel();

    try (QueryExecution qexec = QueryExecutionFactory.create(query, model, map)) {
        qexec.execConstruct(triples);
    }

    if (triples.isEmpty()) {
        return createEmptyTriplePatternFragment();
    }

    // Try to get an estimate
    long size = triples.size();
    long estimate = -1;

    try (QueryExecution qexec = QueryExecutionFactory.create(countQuery, model, map)) {
        ResultSet results = qexec.execSelect();
        if (results.hasNext()) {
            QuerySolution soln = results.nextSolution() ;
            Literal literal = soln.getLiteral("count");
            estimate = literal.getLong();
        }
    }

    /*GraphStatisticsHandler stats = model.getGraph().getStatisticsHandler();
    if (stats != null) {
        Node s = (subject != null) ? subject.asNode() : null;
        Node p = (predicate != null) ? predicate.asNode() : null;
        Node o = (object != null) ? object.asNode() : null;
        estimate = stats.getStatistic(s, p, o);
    }*/

    // No estimate or incorrect
    if (estimate < offset + size) {
        estimate = (size == limit) ? offset + size + 1 : offset + size;
    }

    // create the fragment
    final boolean isLastPage = ( estimate < offset + limit );
    return createTriplePatternFragment( triples, estimate, isLastPage );
}
 

/**
 *
 * @param subject
 * @param predicate
 * @param object
 * @param offset
 * @param limit
 * @return
 */
@Override
protected ILinkedDataFragment createFragment(
           final ITriplePatternElement<RDFNode,String,String> subject,
           final ITriplePatternElement<RDFNode,String,String> predicate,
           final ITriplePatternElement<RDFNode,String,String> object,
           final long offset,
           final long limit )
{
    // FIXME: The following algorithm is incorrect for cases in which
    //        the requested triple pattern contains a specific variable
    //        multiple times;
    //        e.g., (?x foaf:knows ?x ) or (_:bn foaf:knows _:bn)
    // see https://github.com/LinkedDataFragments/Server.Java/issues/24

    QuerySolutionMap map = new QuerySolutionMap();
    if ( ! subject.isVariable() ) {
        map.add("s", subject.asConstantTerm());
    }
    if ( ! predicate.isVariable() ) {
        map.add("p", predicate.asConstantTerm());
    }
    if ( ! object.isVariable() ) {
        map.add("o", object.asConstantTerm());
    }

    query.setOffset(offset);
    query.setLimit(limit);

    Model triples = ModelFactory.createDefaultModel();

    // Build the SPARQL-endpoint
    URIBuilder uriBuilder = new URIBuilder(endpointURI);
    addCredentials(uriBuilder);

    final String endpoint;
    try {
        endpoint = uriBuilder.build().toString();
    } catch (URISyntaxException e) {
        throw new RuntimeException(e);
    }

    ParameterizedSparqlString queryWithParams = new ParameterizedSparqlString(query.serialize(), map);

    try (QueryExecution qexec = QueryExecutionFactory.sparqlService(endpoint, queryWithParams.asQuery())) {
        qexec.execConstruct(triples);
    }

    if (triples.isEmpty()) {
        return createEmptyTriplePatternFragment();
    }

    // Try to get an estimate
    long size = triples.size();
    long estimate = -1;

    ParameterizedSparqlString countQueryWithParams = new ParameterizedSparqlString(countQuery.serialize(), map);

    try (QueryExecution qexec = QueryExecutionFactory.createServiceRequest(endpoint, countQueryWithParams.asQuery())) {
        ResultSet results = qexec.execSelect();
        if (results.hasNext()) {
            QuerySolution soln = results.nextSolution() ;
            Literal literal = soln.getLiteral("count");
            estimate = literal.getLong();
        }
    }

    /*GraphStatisticsHandler stats = model.getGraph().getStatisticsHandler();
    if (stats != null) {
        Node s = (subject != null) ? subject.asNode() : null;
        Node p = (predicate != null) ? predicate.asNode() : null;
        Node o = (object != null) ? object.asNode() : null;
        estimate = stats.getStatistic(s, p, o);
    }*/

    // No estimate or incorrect
    if (estimate < offset + size) {
        estimate = (size == limit) ? offset + size + 1 : offset + size;
    }

    // create the fragment
    final boolean isLastPage = ( estimate < offset + limit );
    return createTriplePatternFragment( triples, estimate, isLastPage );
}