public int indexDocs(final int numOfDoc) throws Exception {
   for (int doc = 0; doc < numOfDoc; doc++) {
     final IndexRequest indexRequest =
         new IndexRequest(index.getName(), "type", Integer.toString(docId.incrementAndGet()))
             .source("{}");
     final IndexResponse response = index(indexRequest);
     assertEquals(DocWriteResponse.Result.CREATED, response.getResult());
   }
   return numOfDoc;
 }