Add findAll method supporting pagination and dynamic fetch paths to EntityViewAwareRepository

[Mobe91]

Consider adding the following method to EntityViewAwareRepository.

Page<E> findAll(Specification<E> specification, Pageable pageable, boolean includeTotalCount,
                    String... fetch);

Potential implementation:

    @Override
    public Page<E> findAll(Specification<E> specification, Pageable pageable, boolean includeTotalCount,
                           String... fetch) {
        BlazeCriteriaQuery<E> query = BlazeCriteria.get(cbf, entityInformation.getJavaType());
        BlazeRoot<E> root = query.from(entityInformation.getJavaType());
        BlazeCriteriaBuilder criteriaBuilder = query.getCriteriaBuilder();
        Predicate predicate = specification.toPredicate(root, query,
            criteriaBuilder);

        if (predicate != null) {
            query.where(predicate);
        }

        Sort sort = pageable.getSort();
        if (sort.isSorted()) {
            query.orderBy(toOrders(sort, root, criteriaBuilder));
        }

        CriteriaBuilder<E> cb = query.createCriteriaBuilder(em);
        List<E> entities;
        LongSupplier totalCountSupplier;
        if (pageable.isPaged()) {
            PagedList<E> pagedEntities = cb.page((int) pageable.getOffset(), pageable.getPageSize())
                .withCountQuery(includeTotalCount)
                .getResultList();
            totalCountSupplier = pagedEntities::getTotalSize;
            entities = pagedEntities;
        } else {
            entities = cb.getResultList();
            totalCountSupplier = entities::size;
        }

        return PageableExecutionUtils.getPage(entities, pageable, totalCountSupplier);
    }

This would be useful when one wants to do pagination on entities with dynamic fetches.

This would require fixing the following bugs first:

• https://github.com/Blazebit/blaze-persistence/issues/1770
• https://github.com/Blazebit/blaze-persistence/issues/2095