public Answer executeQuery(Graph graph, QueryEngine queryEngine) {
checkNotNull(graph, queryEngine);
long timeStarted = System.currentTimeMillis();
EvaluatedRelation result = getResult(graph, queryEngine);
LinkedHashSet<Attribute> heading = getHeading(result);
return new SelectAnswerImpl(heading, result, System.currentTimeMillis() - timeStarted, hasProjected());
}