code: private void doBatchMessage(final JsonObject message) {
      String batchID = message.getString("batch");
      if (currentBatch != null && currentBatch.id().equals(batchID)) {
        Object value = deserializer.deserialize(message);
        if (value != null) {
          if (log.isDebugEnabled()) {
            log.debug(String.format("%s - Batch received: Batch[batch=%s, id=%d, message=%s]", this, batchID, message.getLong("id"), value));
          }
          currentBatch.handleMessage(value);
        }
      }
    }
docs: Handles a batch message.