java - How count a mongodb collection with ReactiveMongoTemplate without any query filter?

Question

I would like to determine mongodb collection size in my java spring application. I know that reactive rective Mongo Template has a count() method what does that, however it needs a query param.

So my solution is:

public Mono<Long> collectionSize(){
    Criteria criteria = Criteria.where("_id").exists(true);
    return this.reactiveMongoTemplate.count(Query.query(criteria),MY_COLLECTION_NAME);
}

However I dont like this solution, because I have to use a captain obvious criteria.

Is there any better solution for this problem?

Thanks!

Answer 1

Criteria has an empty constructor.

public Mono<Long> collectionSize(){
    Criteria criteria = new Criteria();
    return this.reactiveMongoTemplate.count(Query.query(criteria),MY_COLLECTION_NAME);
}

Reference

And all of the variants of count requires a query param as documented here

Query doesn't need criteria, you can just supply the query param. Reference

public Mono<Long> collectionSize(){
        return this.reactiveMongoTemplate.count(new Query(),MY_COLLECTION_NAME);
    }