Aggregations in Java client through JSON query - without AggregationBuilder - elasticsearch

Question

I am able to implement aggregation functionality via JSON query in HTTP based JEST client but not in TCP based Java client.
Through JEST client (HTTP REST based) it is possible to implement aggregation through query String.
JEST sample code:
JestClientFactory factory = new JestClientFactory();
HttpClientConfig httpClientConfig = new HttpClientConfig
.Builder("http://localhost:9201")
.build();
factory.setHttpClientConfig(httpClientConfig);
JestClient client = factory.getObject();
String queryString ="{\"query\":{\"match_all\": {}},\"aggs\":{\"avg1\":{\"avg\":{\"field\":\"age\"} } }}";
Search.Builder searchBuilder = new Search.Builder(queryString)
.addIndex("st1index")
.addType("st1type");
SearchResult response = client.execute(searchBuilder.build());
System.out.println(response.getJsonString());
client.shutdownClient();
Printing response of JEST client shows aggregation results.
Using TCP client in elasticsearch, aggregation is possible through AggregationBuilder.
When I tried to implement JSON query in TCP, it did not return aggregation results.
Is there any reason why TCP do not support aggregation through query string but supports with adding aggregation options?
TCP Java client sample code:
Edited
Removed WrapperQueryBuilder surrounding the queryString.
Settings settings = ImmutableSettings.settingsBuilder()
.put("cluster.name", "javaEscluster")
.put("node.name", "arivu").build();
Client client = new TransportClient(settings)
.addTransportAddress(new InetSocketTransportAddress("localhost", 9303));
String queryString ="{\"match_all\": {},\"aggs\":{\"avg1\":{\"avg\":{\"field\":\"age\"} } }}";
SearchResponse response = client.prepareSearch("st1index").setTypes("st1type").setQuery(queryString).execute().actionGet();
System.out.println("Getresponse-->" +"Index-->"+ response.toString());
//closing node
client.close();
System.out.println("completed");
This code retrieves only search results and empty aggregation result data.
Edited:
Any reference material which explains the reason would be great.

Answer 1

In the main documentation of the WrapperQueryBuilder class, it is stated:
A Query builder which allows building a query given JSON string or binary data provided as input. This is useful when you want to use the Java Builder API but still have JSON query strings at hand that you want to combine with other query builders.
The keyword in here is the word query, i.e. the part named query in the request you send to the ES _search endpoint, i.e.:
{
"sort": {
... <--- whatever sorting definition you have goes here
},
"_source": {
... <--- whatever source definition you have goes here
},
"query": {
... <--- this is the content you can use with WrapperQueryBuilder
},
"aggs": {
... <--- whatever aggs definition you have goes here
}
}
WrapperQueryBuilder will only ever consider whatever you can fit inside that query section, so as you can see that doesn't include aggregations, which are in another top-level section of the request.
So, in the JSON query string you give, only the match_all will be considered, because that's the only valid token that is allowed to appear in the query section, the aggs:{...} part is not.
"{\"match_all\": {},\"aggs\":{\"avg1\":{\"avg\":{\"field\":\"age\"} } }}"
^ ^
| |
this is valid this is NOT valid