Totalhits support for ReactiveSearchOperations

[aleksanderlech]

Hello,

I need to have total count while searching and would like to avoid making two searches in Elasticsearch.
For non-reactive version of SearchOperations I could use the following method:

<T> SearchHits<T> search(Query query, Class<T> clazz);

But I miss the corresponding method in ReactiveSearchOperations. It would be very convenient to have something similar in ReactiveSearchOperations like:

<T> ReactiveSearchHits<T> search(Query query, Class<T> clazz);

where the ReactiveSearchHits is a reactive version of SearchHits returning Flux instead of List.

Is this possible to deliver such an API or are there any alternative ways for doing that in the reactive world?

I am using Spring Boot 2.5.6 with Spring Data ElasticSearch 4.0.4. Thank you in advance for your help!

[sothawo]

I thought I had left a comment on this issue last Friday, sorry if I didn't do.

We need a new name for the search method, because we cannot use the same name/arguments with a different return type.

What I have in a branch is:

public interface ReactiveSearchHits<T> {

	Mono<AggregationsContainer<?>> getAggregations();

	float getMaxScore();

	Flux<SearchHit<T>> getSearchHits();

	long getTotalHits();

	TotalHitsRelation getTotalHitsRelation();

	boolean hasAggregations();

	boolean hasSearchHits();

	@Nullable
	Suggest getSuggest();

	boolean hasSuggest();
}

and the additional methods in ReactiveSearchOperations like:

<T> Mono<ReactiveSearchHits<T>> searchForHits(Query query, Class<T> entityType)

Usage example:

public Flux<SearchHit<Person>> test() {
	
       Query query = new CriteriaQuery(new Criteria("lastName").is("Moeller")).setPageable(PageRequest.of(0, 5));

	return operations.searchForHits(query, Person.class)
		.flatMapMany(reactiveSearchHits -> {
			LOGGER.info("total number of hits: {}", reactiveSearchHits.getTotalHits());
			return reactiveSearchHits.getSearchHits();
		});
}

I used a pageable here to see the difference in the total number of hits and the count of the flux.

Would that be what you had in mind?

[aleksanderlech]

Hello @sothawo,

First of all many thanks for the super fast reaction! I am impressed. And yes, that would be something that would definitely work for me.