class CacheInfo {

  @Nullable
  public static CacheInfo extractFromAsset(final Asset asset) {
    checkNotNull(asset);
    final NestedAttributesMap cache = asset.attributes().child(CACHE);
    final DateTime lastVerified = toDateTime(cache.get(LAST_VERIFIED, Date.class));
    if (lastVerified == null) {
      return null;
    }
    final String cacheToken = cache.get(CACHE_TOKEN, String.class);
    return new CacheInfo(lastVerified, cacheToken);
  }

  public  CacheInfo(final DateTime lastVerified, @Nullable final String cacheToken);

}