public void addFilterInfo(FilterInfo other) {
      if (other.cqs != null) {
        if (cqs == null) {
          cqs = new HashMap<>();
        }
        cqs.putAll(other.cqs);
      }
      if (other.interestedClients != null) {
        if (interestedClients == null) {
          interestedClients = new HashSet<>();
        }
        interestedClients.addAll(other.interestedClients);
      }
      if (other.interestedClientsInv != null) {
        if (interestedClientsInv == null) {
          interestedClientsInv = new HashSet<>();
        }
        interestedClientsInv.addAll(other.interestedClientsInv);
      }
    }
adds the content from another FilterInfo object.
geode-core/src/main/java/org/apache/geode/internal/cache/FilterRoutingInfo.java