@Override
    public boolean equals(Object o) {
      if (this == o) return true;
      if (o == null || getClass() != o.getClass()) return false;
      LRUCacheEntry<?, ?> that = (LRUCacheEntry<?, ?>) o;
      return Objects.equals(secondKey, that.secondKey)
          && Objects.equals(cacheEntryGroup, that.cacheEntryGroup);
    }
This class implements the cache entry manager with LRU policy.

@param <FK> The first key of cache value.
@param <SK> The second key of cache value.
@param <V> The cache value.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/analyze/cache/schema/dualkeycache/impl/LRUCacheEntryManager.java