JPA CriteriaQuery implements Spring Data Pageable.getSort()

Question

I used JPA CriteriaQuery to build my dynamic Query and pass in a Spring Data Pageable object:

sort=name,desc

At the backend I have a method in my Repository to support dynamic query:

public Page<User> findByCriteria(String username, Pageable page) {
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<User> cq = cb.createQuery(User.class);
    Root<User> iRoot = cq.from(User.class);
    List<Predicate> predicates = new ArrayList<Predicate>();

    if (StringUtils.isNotEmpty(username)) {
        predicates.add(cb.like(cb.lower(iRoot.<String>get("username")), "%" + username.toLowerCase() + "%"));
    }

    Predicate[] predArray = new Predicate[predicates.size()];
    predicates.toArray(predArray);

    cq.where(predArray);

    TypedQuery<User> query = em.createQuery(cq);

    int totalRows = query.getResultList().size();

    query.setFirstResult(page.getPageNumber() * page.getPageSize());
    query.setMaxResults(page.getPageSize());

    Page<User> result = new PageImpl<User>(query.getResultList(), page, totalRows);

    return result;
}

Note: I put only one param for demo purpose.

However the returned data is unsorted therefore I would like to ask is that any way to implement Pageable in CriteriaQuery.

Answer 1

A complete example that uses JpaSpecificationExecutor and encapsulate it in a class:

First define the repository as an extension of JpaRepository and JpaSpecificationExecutor for SomeEntity:

interface SomeEntityRepositoryPaged extends JpaRepository<SomeEntity, Integer>, JpaSpecificationExecutor<SomeEntity> {
 Page<SomeEntity> findAll(Specification<SomeEntity> spec, Pageable pageable);

}

FindByCriteria class:

class FindByCriteria{
     FindByCriteria() {
            ApplicationContext appCtx = ApplicationContextUtils.getApplicationContext();
            repository = appCtx.getBean(SomeEntityRepositoryPaged.class);
        }
    
        private SomeEntityRepositoryPaged repository;
        
        public Page<SomeEntity> searchBy(Client client, SearchParams params,Pageable page){
            return repository.findAll(getCriteria(params), page);
        }
        private Specification<SomeEntity> getCriteria(SearchParams params){
              return (paymentRoot, query, cb)-> 
              { 
                    List<Predicate> predicates = new ArrayList<>(5);
            
                    filterByParams(params, cb, paymentRoot, predicates);

                    query.where(predicates.toArray(new Predicate[] {}));

                    //IMPORTANT: the order specify should be deterministic, meaning rows can never change order in 2 subsequent calls.
                    
                    List<Order> orders = new ArrayList<>(1);
                    orders.add(cb.asc(paymentRoot.get("date")));
                    
                    query.orderBy(orders);
                    
                    return  null;
              };
            }

        private void filterByParams(SearchParams params, CriteriaBuilder cb, Root<SomeEntity> payment,
                List<Predicate> predicates) {
        
            if (params.getInitialDate() != null)
                predicates.add(cb.greaterThan(payment.get("paymentDate"), params.getInitialDate()));

            if (params.getFinalDate() != null)
                predicates.add(cb.lessThanOrEqualTo(payment.get("paymentDate"), params.getFinalDate()));

            if (params.getState() != null)
                predicates.add(cb.equal(payment.get("state"), params.getState()));
            //... add here any criteria needed bases on params object
        }
    }

}

To invoke simple call:

@Test pagedQueryTest
{
     var page = PageRequest.of(2, 10);
     var params = new SearchParams (...);
     var list = new FindByCriteria().searchBy(params, page);
     assert...
     //The generated native query should be optimized.
     //For mssql the native query should end with "offset ? rows fetch first ? rows only" 
     //and that means the store engine will only fetch the rows after first parameter (=page*size), and to the max of the page size.
}

Answer 2

Both Op question and Angelo's answer won't work in a real-life scenario. If that table/query returns thousand of records this approach will perform slowly and you could also could create memory issues.

Why?

• int totalRows = query.getResultList().size();
• new PageImpl(query.getResultList(), page, totalRows);

both resultsets will run same query twice and mantain a full table/query data in those colections, just to be counted or sliced, which makes no sense when you need to show few records in your front-end.

My suggestion for Spring Data is to extend JpaSpecificationExecutor interface in your repository

@Repository
public interface UserRepository extends JpaRepository<User, Integer>,
        JpaSpecificationExecutor {
}

This interface will enable your repository to use findAll(Specification, Pageable) method.

After that, all is quite easy. You only need to create a Java closure to inject predicates into a dynamic jpa query.

public Page<User> listUser( String name, int pageNumber, int pageSize ) {

Sort sort = Sort.by("id").ascending();
Pageable pageable = PageRequest.of(pageNumber, pageSize, sort);


return this.reservationRepository.findAll((root, query, builder) -> {
            List<Predicate> predicates = new ArrayList<>();
            if name!= null ) {
                predicates.add(builder.equal(root.get("name"), name));
            }
            // More simple/complex conditions can be added to 
            // predicates collection if needed.

            return builder.and(predicates.toArray(new Predicate[]{}));

        }, pageable);

}

As you can see here, this solution supports Sorting/Filtering and database side pagination.

Answer 3

 CriteriaBuilder cb = em.getCriteriaBuilder();
 CriteriaQuery<User> cq = cb.createQuery(User.class);
 Root<User> iRoot = cq.from(User.class);
 List<Predicate> predicates = new ArrayList<Predicate>();

 if (StringUtils.isNotEmpty(username)) {
     predicates.add(cb.like(cb.lower(iRoot.<String>get("username")), "%" + 
     username.toLowerCase() + "%"));
 }


 Predicate[] predArray = new Predicate[predicates.size()];
 predicates.toArray(predArray);

 cq.where(predArray);

 cq.orderBy(cb.desc(user.get("name")));

 TypedQuery<User> query = em.createQuery(cq);
 Page<User> result = new PageImpl<User>(query.getResultList(), page, totalRows);

 return result;

Answer 4

You can add sorting using QueryUtils from spring: query.orderBy(QueryUtils.toOrders(pageable.getSort(), root, builder));

Answer 5

In your criteria query i see no sort information I'd write in this way:

     CriteriaBuilder cb = em.getCriteriaBuilder();
     CriteriaQuery<User> cq = cb.createQuery(User.class);
     Root<User> iRoot = cq.from(User.class);
     List<Predicate> predicates = new ArrayList<Predicate>();

     if (StringUtils.isNotEmpty(username)) {
         predicates.add(cb.like(cb.lower(iRoot.<String>get("username")), "%" + username.toLowerCase() + "%"));
     }

     Predicate[] predArray = new Predicate[predicates.size()];
     predicates.toArray(predArray);

     cq.where(predArray);

     List<Order> orders = new ArrayList<Order>(2);
     orders.add(cb.asc(iRoot.get("name")));
     orders.add(cb.asc(iRoot.get("desc")));

     cq.orderBy(orders);
     TypedQuery<User> query = em.createQuery(cq);
     Page<User> result = new PageImpl<User>(query.getResultList(), page, totalRows);

     return result;

I didn't test it but it should work

Angelo