if (resultSetNodes.size() != 1) {
throw new RDFHandlerException("Expected 1 subject of type ResultSet, found: "
+ resultSetNodes.size());
}
Resource resultSetNode = resultSetNodes.iterator().next();
Set<Value> resultValues = model.filter(resultSetNode, BOOLEAN, null).objects();
if (resultValues.size() != 1) {
throw new RDFHandlerException("Expected 1 boolean result value, found: " + resultValues.size());
}