public Page<Item> testAgg(){
NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder();
queryBuilder.withSourceFilter(new FetchSourceFilter(new String[]{""}, null));
queryBuilder.addAggregation(
AggregationBuilders.terms("brands").field("brand.keyword"));
AggregatedPage<Item> aggPage = (AggregatedPage<Item>) this.itemRepository.search(queryBuilder.build());
StringTerms agg = (StringTerms) aggPage.getAggregation("brands");
List<StringTerms.Bucket> buckets = agg.getBuckets();
for (StringTerms.Bucket bucket : buckets) {
System.out.println(bucket.getKeyAsString());
System.out.println(bucket.getDocCount());
}
return
}