GET dss_checkin_index/_search
{
  "size": 0,
  "query": {
    "bool": {
      "must": [
        {
          "range": {
            "checkInTime": {
              "gte": "2015-06-01 00:00:00 000",
              "lt": "2015-07-01 00:00:00 000"
            }
          }
        }
      ]
    }
  },
  "aggs": {
    "name": {
      "terms": {
        "field": "user.keyword"
      },
      "aggs": {
        "top_users": {
          "top_hits": {
            "size": 100
          }
        }
      }
    }
  }
}

TopHitsBuilder thb=  AggregationBuilders.topHits("top_users");