Write query in CriteriaBuilder using Optional<T>-CodePudding

@Query(value = "select usd from UserDetail usd where usd.phoneNumber=:phoneNumber")
Optional<UserDetail> findByPhoneNumber(@Valid @Param("phoneNumber") String phoneNumber);

This is my JPQL query method and I am here using return type with Optional. I wonder how to write using CriteriaBuilder?

I wrote like this but I am getting an error.

@Override
public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
    Root<UserDetail> root = cq.from(UserDetail.class);
    cq.where(cb.equal(root.get("phoneNumber"), phoneNumber))
      .orderBy(cb.desc(root.get("phoneNumber")));
    return em.createQuery(cq).getResultList().get(3);
}

CodePudding user response：

If the method return type is Optional that is what exactly you must return.

The line em.createQuery(cq).getResultList().get(3) returns only UserDetail so you need to wrap it to Optional.of:

@Override
public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
    Root<UserDetail> root = cq.from(UserDetail.class);
    cq.where(cb.equal(root.get("phoneNumber"), phoneNumber))
      .orderBy(cb.desc(root.get("phoneNumber")));
    return Optional.of(em.createQuery(cq).getResultList().get(3));
}

By the way, are you sure the hardcoded .get(3) is what you want? If the list is empty or has less than 4 elements, it would throw a runtime exception.

CodePudding user response：

if a phone number is associated with only one person why are you trying to get a list ?

have a look to this :

@Override
        public Optional<UserDetail> findByCreatedDate(String phoneNumber) {
            CriteriaBuilder cb = em.getCriteriaBuilder();
            CriteriaQuery<UserDetail> cq = cb.createQuery(UserDetail.class);
            Root<UserDetail> root = cq.from(UserDetail.class);
            cq.where(cb.equal(root.get("phoneNumber"), phoneNumber)).orderBy(cb.desc(root.get("phoneNumber")));
            UserDetail ud = em.createQuery(cq).getSingleResult();
            return ud == null ? Optional.empty() : Optional.of(ud)
    
        }

Regards,