public static <MK, K, V> FineGrainedAtomicMap<K, V> getFineGrainedAtomicMap(Cache<MK, ?> cache, MK key) {
      return getFineGrainedAtomicMap(cache, key, true);
   }
public static < MK , K , V > FineGrainedAtomicMap < K , V > getFineGrainedAtomicMap ( Cache < MK , ? > cache , MK key ) { return getFineGrainedAtomicMap ( cache , key , true ) ; }
Retrieves a fine grained atomic map from a given cache, stored under a given key. If a fine grained atomic map did
not exist, one is created and registered in an atomic fashion.

@param cache underlying cache
@param key   key under which the atomic map exists
@param <MK>  key param of the cache
@param <K>   key param of the AtomicMap
@param <V>   value param of the AtomicMap
@return an AtomicMap