public boolean isEmpty() {
      return interestMaps[NON_DURABLE].keysOfInterest == null
          && interestMaps[NON_DURABLE].keysOfInterestInv == null
          && interestMaps[NON_DURABLE].patternsOfInterest == null
          && interestMaps[NON_DURABLE].patternsOfInterestInv == null
          && interestMaps[NON_DURABLE].filtersOfInterest == null
          && interestMaps[NON_DURABLE].filtersOfInterestInv == null
          && interestMaps[DURABLE].patternsOfInterest == null
          && interestMaps[DURABLE].patternsOfInterestInv == null
          && interestMaps[DURABLE].filtersOfInterest == null
          && interestMaps[DURABLE].filtersOfInterestInv == null && cqs == null;
    }
Helper method to register the filters.
geode-core/src/main/java/org/apache/geode/internal/cache/InitialImageOperation.java