how to get the sub aggregation from elasticsearch

Question

I want to get the sub aggregation.

    "size" :0 ,
     "aggs": {
            "classification of day": {
               "date_histogram": {
                  "field": "ALARM DATE",
                   "format" : "dd/MM/yyyy",
                  "interval": "day"

               },
               "aggs": {
                  "classification1": {
                     "terms": {
                        "field": "CLASSIFICATION",
                         "keyed":true
                     }
                  }
               }
            }
         }

above json query returns the following output.

    "aggregations": {
          "classification of day": {
             "buckets": [
                {
                   "key_as_string": "25/02/2016",
                   "key": 1456358400000,
                   "doc_count": 166,
                   "classification1": {
                      "doc_count_error_upper_bound": 0,
                      "sum_other_doc_count": 0,
                      "buckets": [
                         {
                            "key": "attack",
                            "doc_count": 58
                         },
                         {
                            "key": "compromise",
                            "doc_count": 30
                         },
                         {
                            "key": "error",
                            "doc_count": 24
                         },
                         {
                            "key": "reconnaissance",
                            "doc_count": 20
                         },
                         {
                            "key": "suspicious",
                            "doc_count": 19
                         },
                         {
                            "key": "warning",
                            "doc_count": 14
                         },
                         {
                            "key": "misuse",
                            "doc_count": 2
                         }
                      ]
                   }
                },
                {
                   "key_as_string": "26/02/2016",
                   "key": 1456444800000,
...

Java code I tried,

String aggregations1 = "CLASSIFICATION";
        String field1 = "ALARM DATE";
        DateHistogramInterval interval1 = DateHistogramInterval.DAY;

        SearchResponse response = client.prepareSearch(index).setTypes(type)
                .addAggregation(AggregationBuilders.dateHistogram("classification of day").field(field1)
                        .interval(interval1).format("dd/MM/yyyy")
                        .subAggregation(AggregationBuilders.terms("terms").field(aggregations1)))
                .execute().actionGet();

        Iterator<Aggregation> iter = response.getAggregations().iterator();// get("");

        while (iter.hasNext()) {
            Aggregation aggs=iter.next();
            System.out.println(aggs.getName());
            //aggs.
        }

Issue is I get the aggregation values. here dates but I don't get the subaggregation. Basically I want to extract the CLASSIFICATION by date to a object.

Answer 1

I managed to get this working. In case, someone find this helpful, I add my answer here.

String aggregations1 = "CLASSIFICATION";
        String field1 = "ALARM DATE";
        DateHistogramInterval interval1 = DateHistogramInterval.DAY;

        SearchResponse sr = client.prepareSearch(index).setTypes(type)
                .addAggregation(AggregationBuilders.dateHistogram("classification of day").field(field1)
                        .interval(interval1).format("dd/MM/yyyy")
                        .subAggregation(AggregationBuilders.terms("classifications").field(aggregations1)))
                .execute().actionGet();





        // sr is here your SearchResponse object
        Histogram agg = sr.getAggregations().get("classification of day");

        Collection<Histogram.Bucket> buckets = (Collection<Histogram.Bucket>) agg.getBuckets();
        // For each entry

        for (Histogram.Bucket bucket : buckets) {

            if (bucket.getDocCount() != 0) {

                System.out.println((int) bucket.getDocCount());
                System.out.println(bucket.getKeyAsString());
                Terms terms =bucket.getAggregations().get("classifications");
                Collection<Terms.Bucket> bkts = terms.getBuckets();
                for (Bucket b : bkts) {

                    if (b.getDocCount() != 0) {
                        //ESClassification classificaiton = new ESClassification();
                        System.out.println((int) b.getDocCount());
                        System.out.println(b.getKeyAsString());

                    } else {
                        //list = Collections.<ESClassification> emptyList();
                    }

                }


            } else {
                //list = Collections.<ESClassification> emptyList();
            }

        }