Any Sample Java API client dynamic nested aggregation query building

Elastic Stack Elasticsearch
1

Hi Team,

I have below query with me for which I am trying to build dynamically using Java API client.

{
"aggs": {
    "country_aggr": {
      "terms": {
        "field": "country",
        "size": 1000
      },
      "aggs": {
        "state_aggr": {
          "terms": {
            "field": "state",
              "size": 1000
          },
          "aggs": {
            "city_aggr": {
              "terms": {
                "field": "city",
                "size": 1000
              }
            }
          }
        }
      }
    }
  }
}

Any help would be appreciated.

Thanks,
Ram Prasad

2

Have a look at Switching from the Java High Level Rest Client to the new Java API Client | Elastic Blog

This might help you to find how to build your code.

An example of on agg in Java is also available at:

If you don't succeed, let us know and share what you did so far so we can iterate from that.

3

Hi dadoonet,

We are using Java API client. Currently we are preparing parent-child hierarchy based aggregation upfront using String (its not a recommended way) for different levels.
We tried to build this hierarchy dynamically based on the total number of fields, like below.

Aggregation aggr = Aggregation.of(t0 -> t0.terms(f0 -> f0.field(fields[0]).size(fieldSize[0])).aggregations(fields[1],
				t1 -> t1.terms(f1 -> f1.field(fields[1]).size(fieldSize[1])).aggregations(fields[2],
						t2 -> t2.terms(f2 -> f2.field(fields[2]).size(fieldSize[2])))));

But our requirement is, sub-aggregation should be appended to main aggregation within the iteration of fields.

Kindly let me know if my requirement is not clear.

Thanks,
Ram Prasad G

4

How should this look like using the QueryDSL?

5

It should look something like this,

Aggregation cityAggr = new Aggregation.Builder()
		.terms(new TermsAggregation.Builder().field(CITY).build())
		.build();
Map<String, Aggregation> cityAggrMap = new HashMap<>();
cityAggrMap.put(CITY_AGGR, cityAggr);

Aggregation stateAggr = new Aggregation.Builder()
		.terms(new TermsAggregation.Builder().field(STATE).build()).aggregations(cityAggrMap)
		.build();
Map<String, Aggregation> stateAggrMap = new HashMap<>();
stateAggrMap.put(STATE_AGGR, stateAggr);

Aggregation countryAggr = new Aggregation.Builder()
		.terms(new TermsAggregation.Builder().field(COUNTRY).build()).aggregations(stateAggrMap)
		.build();
Map<String, Aggregation> countryAggrMap = new HashMap<>();
countryAggrMap.put(COUNTRY_AGGR, countryAggr);

SearchRequest searchReq = SearchRequest.Builder().index(collection_name).size(0)
		.aggregations(countryAggrMap)
		.build();

In the above code, I am framing manually for 3 level of nested aggregation. This I need to frame dynamically.

Thanks,
Ram Prasad G

6

So you want something like this:

SearchResponse<Void> response = client.search(sr -> sr
                .index(indexName)
                .aggregations("country", a -> a.terms(ta -> ta.field("country"))
                        .aggregations("state", sa -> sa.terms(ta -> ta.field("state"))
                                .aggregations("city", ca -> ca.terms(ta -> ta.field("city")))
                        )
                )
        , Void.class);

But built depending on some conditions?