@Override
  public CloseableIterator<IndexStoreEntry> descendingIterator(Object start, boolean startInclusive,
      Object end, boolean endInclusive, Collection keysToRemove) {
    // @todo change to descending once it is supported
    return new MapIndexStoreIterator(indexMap.iterator(start, startInclusive, end, endInclusive),
        keysToRemove, indexOnValues, indexOnRegionKeys);
  }
Implementation of IndexStorage that is backed by an IndexMap
geode-core/src/main/java/org/apache/geode/cache/query/internal/index/MapIndexStore.java