How to set script template in SearchRequestBuilder for elasticsearch version 6.6.1

Question

I was able to set the template in es 2.4.1 but this feature is no more present in es 6.6.1. What is an alternative to this?

Template template = new Template(esReqParams.getTemplateName(), esReqParams.getScriptType(),
        esReqParams.getLang(), esReqParams.getXContentType(), esReqParams.getParams());

SearchRequestBuilder searchRequestBuilder = esClient.prepareSearch(esReqParams.getIndexes())
.setTypes(esReqParams.getDocTypes())
.setTemplate(template);

1. org.elasticsearch.script.Template is not present in es6
2. Method setTemplate is not present as well.