ClosableMap<Long, ClosableMap<Long, ClosableMap<Long, Set<Long>>>> subIndex = index.get(first);
if (subIndex != null) {
ClosableMap<Long, ClosableMap<Long, Set<Long>>> map = subIndex.get(second);
if (map != null) {
Iterator<Map.Entry<Long, ClosableMap<Long, Set<Long>>>> entryIterator = map.entrySet().iterator();
return new FlatteningThreeLongClosableIterator(
new ClosableIteratorImpl<Map.Entry<Long, ClosableMap<Long, Set<Long>>>>(entryIterator));
}
}
return new LongArrayEmptyClosableIterator();
}