code: public static long getTransactorMaxCacheSize(FluoConfiguration conf) {
      long size = conf.getLong(TRANSACTOR_MAX_CACHE_SIZE, TRANSACTOR_MAX_CACHE_SIZE_DEFAULT);
      if (size <= 0) {
        throw new IllegalArgumentException(
            "Cache size must be positive for " + TRANSACTOR_MAX_CACHE_SIZE);
      }
      return size;
    }
docs: Gets the specified number of entries the cache can contain, this gets the value of
  {@value #TRANSACTOR_MAX_CACHE_SIZE} if set, the default
  {@value #TRANSACTOR_CACHE_TIMEOUT_DEFAULT} otherwise
  
  @param conf The FluoConfiguration
  @return The maximum number of entries permitted in this cache