Can I use Slice with findAll method : Spring Data

Question

What i want : skip the count query that spring performs with findAll(Pageable).

I found that there is Slice datatype for such UIs (next based) where there is no need for total records/pages hence no need for count query.

I can use Slice return type for methods like findByName(Pageable) etc but if i use Slice for findAll(Pageable) then it still performs the count query.

Is there a workaround where i am able to use slice for findAll avoiding the count query?

P.S. : i want the features that slice provide like - hasNext, size etc and i don't need to use Specification as well.

Any help is appreciated.

Answer 1

It is possible to use Slice with findAll() - you just need to extend the correct Spring JPA Repository.

It won't work if you extend JpaRepository, because it extends PagingAndSortingRepository and there's already findAll(Pageable pageable) method defined in the Paging repository.

If you extend CrudRepository then you will be able to define method Slice<T> findAll(Pageable pageable) in your repository.

Answer 2

You can use query derivation for this. Based on a Spring Data JPA examples:

/**
 * Returns a {@link Slice} counting a maximum number of {@link Pageable#getPageSize()} users matching given criteria
 * starting at {@link Pageable#getOffset()} without prior count of the total number of elements available.
 * 
 * @param lastname
 * @param page
 * @return
 */
Slice<User> findByLastnameOrderByUsernameAsc(String lastname, Pageable page);

You can modify this to your needs by adding the following to your repository:

Slice<User> findBy(Pageable page);

Since it doesn't have any other condition it performs a findAll limited to a single page, but without a count query.