code: @Override
      public void write(List<? extends SnapshotContentItem> items) throws Exception {
          for (SnapshotContentItem item : items) {
              Map<String, String> props = PropertiesSerializer.deserialize(item.getMetadata());
              String contentId = item.getContentId();
              String checksum = props.get(ContentStore.CONTENT_CHECKSUM);
  
              // verify that manifest contains every item from the database except
              // SNAPSHOT_PROPS_FILENAME
              if (!contentId.equals(Constants.SNAPSHOT_PROPS_FILENAME)) {
                  if (!this.manifestSet.contains(ManifestFileHelper.formatManifestSetString(contentId, checksum))) {
                      addError(MessageFormat.format("Content item {0} with checksum {1} not found in manifest "
                                                    + "for snapshot {2}", contentId, checksum, this.snapshotName));
                  }
              }
          }
      }
docs: /*
  (non-Javadoc)
  
  @see org.springframework.batch.item.ItemWriter#write(java.util.List)