addToCache(entry);
      return entry.value;
    }
    return null;
  }

  @Override
  void clearCache() {
    super.clearCache();
    cacheEntry1 = null;
    cacheEntry2 = null;
  }

  private void addToCache(K key, V value) {
    addToCache(new CacheEntry<K, V>(key, value));
  }

  private void addToCache(CacheEntry<K, V> entry) {