code: final public void addIdAndRef(Integer id, Long ref, int additionalId,
        long additionalRef) {
      if (id != null) {
        MtasTreeNodeId tnId = new MtasTreeNodeId(ref, additionalId,
            additionalRef);
        ids.put(id, tnId);
      }
    }
docs: Adds the id and ref.
  
  @param id the id
  @param ref the ref
  @param additionalId the additional id
  @param additionalRef the additional ref