private static void addRefSet(
      SolrInputDocument doc, Collection<? extends DcsEntityReference> set, SolrName field) {

    if (set == null || set.size() == 0) {
      return;
    }

    for (DcsEntityReference ref : set) {
      setadd(doc, field, ref.getRef());
    }
  }
  private static Set<DcsEntityReference> getEntityRefSet(SolrDocument doc, EventField field) {
    Set<DcsEntityReference> set = new HashSet<DcsEntityReference>();

    for (String s : setgetAll(doc, field)) {
      DcsEntityReference ref = new DcsEntityReference();

      if (s != null) {
        ref.setRef(s);
      }

      set.add(ref);
    }

    return set;
  }