PerformanceCachingGoogleCloudStorage extends ForwardingGoogleCloudStorage { @Override public List<GoogleCloudStorageItemInfo> listBucketInfo() throws IOException { List<GoogleCloudStorageItemInfo> result = super.listBucketInfo(); for (GoogleCloudStorageItemInfo item : result) { cache.putItem(item); } return result; } PerformanceCachingGoogleCloudStorage(
      GoogleCloudStorage delegate, PerformanceCachingGoogleCloudStorageOptions options); @VisibleForTesting  PerformanceCachingGoogleCloudStorage(
      GoogleCloudStorage delegate,
      PrefixMappedItemCache cache); @Override WritableByteChannel create(StorageResourceId resourceId); @Override void deleteBuckets(List<String> bucketNames); @Override void deleteObjects(List<StorageResourceId> resourceIds); @Override List<GoogleCloudStorageItemInfo> listBucketInfo(); @Override List<String> listObjectNames(String bucketName, String objectNamePrefix); @Override List<String> listObjectNames(
      String bucketName, String objectNamePrefix, ListObjectOptions listOptions); @Override List<GoogleCloudStorageItemInfo> listObjectInfo(String bucketName, String objectNamePrefix); @Override List<GoogleCloudStorageItemInfo> listObjectInfo(
      String bucketName, String objectNamePrefix, ListObjectOptions listOptions); @Override ListPage<GoogleCloudStorageItemInfo> listObjectInfoPage(
      String bucketName, String objectNamePrefix, ListObjectOptions listOptions, String pageToken); @Override GoogleCloudStorageItemInfo getItemInfo(StorageResourceId resourceId); @Override List<GoogleCloudStorageItemInfo> getItemInfos(List<StorageResourceId> resourceIds); @Override List<GoogleCloudStorageItemInfo> updateItems(List<UpdatableItemInfo> itemInfoList); @Override void close(); @Override GoogleCloudStorageItemInfo composeObjects(
      List<StorageResourceId> sources, StorageResourceId destination, CreateObjectOptions options); @VisibleForTesting void invalidateCache();  }
@Test public void testListBucketInfo() throws IOException { List<GoogleCloudStorageItemInfo> expected = Lists.newArrayList(ITEM_A, ITEM_B); List<GoogleCloudStorageItemInfo> result = gcs.listBucketInfo(); verify(gcsDelegate).listBucketInfo(); assertThat(result).containsExactlyElementsIn(expected); assertThat(cache.getAllItemsRaw()).containsExactlyElementsIn(expected); }