Search API using aggregation

[Raghuveer_SJ (Raghuveer)]

I have started learning JAVA search APIs on elasticsearch 6.3.2 and want to be compatible for future use, i don't want to use TransportClient. I would like to run a query using aggregation something in SQL world would look like :

Select count(logLevel) from table where logLevel="ERROR" and responseCode like "500" and timestamp between ("2018-8-11", "2018-8-12")

Actually I want a dynamic date range of 3 days from current to past 3 days.

using the aggregation code as below :

SearchSourceBuilder ssb = new SearchSourceBuilder();
        ssb.query(QueryBuilders.termQuery("responseCode", 500)); 
// only with this code the total hits I see is 0...!!
        TermsAggregationBuilder termAgg = AggregationBuilders.terms("ERROR")
                .field("logLevel.keyword");
        RangeAggregationBuilder rangeAgg = AggregationBuilders.range("dating").field("timestamp.keyword");
// how to put a dynamic date range here ?
        ssb.aggregation(rangeAgg);
        ssb.aggregation(termAgg);

I am not sure of what data format the responseCode is stored as. I want to get a hold of the queries before I go further. Kindly answer the comment section in the code. kindly suggest.