private static Map<Class<? extends StoreFileTracker>, Trackers> reverse() {
    Map<Class<? extends StoreFileTracker>, Trackers> map = new HashMap<>();
    for (Trackers tracker : Trackers.values()) {
      map.put(tracker.clazz, tracker);
    }
    return Collections.unmodifiableMap(map);
  }
Maps between configuration names for trackers and implementation classes.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/storefiletracker/StoreFileTrackerFactory.java