public void limitValuesToBlankNodeID(BlankNodeID id) {
if (isEmpty) return;
if (!blankNodeIDs.isEmpty()) {
BlankNodeID first = (BlankNodeID) blankNodeIDs.iterator().next();
if (!first.classMapID().equals(id.classMapID())) {
limitToEmptySet();
}
}
blankNodeIDs.add(id);
}