private boolean getNextClosure(
      NFAGraph nfaGraph, Closure curClosure, Closure nextClosure, IFATransition transfer) {
    boolean isEmpty = true;
    for (IFAState state : curClosure.getStates()) {
      if (state != null) {
        for (IFAState nextState : nfaGraph.getTransitions(transfer, state)) {
          nextClosure.addState(nextState);
          isEmpty = false;
        }
      }
    }
    return isEmpty;
  }
get next closure

@param nfaGraph
@param curClosure
@param transfer
@return if empty. return true
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/path/fa/dfa/graph/DFAGraph.java