JPA criteria: count from multiselect query - jpa

Question

I want to implement a table component with pagination. The result in the table is retrieved by a multiselect-query like this:
SELECT DISTINCT t0.userId,
t0.userName,
t1.rolleName
FROM userTable t0
LEFT OUTER JOIN roleTable t1 ON t0.userId = t1.fkUser
WHERE(t0.userType = 'normalUser' AND t1.roleType = 'loginRole')
This result I can get via a multiselect-query.
Now for the pagination I have to retrieve the total rowcount at first.
Is there anybody who can define a criteriaquery for one of this sql? I failed because a subquery does not support multiselects and I do not know how to get this distinct into a count statement.
SELECT COUNT(*) FROM
(
SELECT DISTINCT t0.userId,
t0.userName,
t1.rolleName
FROM userTable t0
LEFT OUTER JOIN roleTable t1 ON t0.userId = t1.fkUser
WHERE(t0.userType = 'normalUser' AND t1.roleType = 'loginRole')
)
or
SELECT COUNT(DISTINCT t0.userId || t0.userName || t1.rolleName)
FROM userTable t0
LEFT OUTER JOIN roleTable t1 ON t0.userId = t1.fkUser
WHERE(t0.userType = 'normalUser' AND t1.roleType = 'loginRole')
Thanks in advance!
Btw. I am using OpenJpa on a WebSphere AppServer

Answer 1

The following is not tested but should work:
CriteriaBuilder builder = em.getCriteriaBuilder();
CriteriaQuery<Long> query = builder.createQuery(Long.class);
Root<User> t0 = query.from(User.class);
Join<User, Role> t1 = t0.join("roles", JoinType.LEFT);
query.select(builder.concat(t0.get(User_.userId), builder.concat(t0.get(User_.userName), t1.get(Role_.rolleName))).distinct(true);
query.where(cb.equal(t0.get("userType"), "normalUser"), cb.equal(t1.get("roleType"), "loginRole"));
TypedQuery<Long> tq = em.createQuery(query);

Answer 2

Due to known issue https://jira.spring.io/browse/DATAJPA-1532 Multiselect does not work with repo.findall method. I handled this by autowiring entity manager to service class.
#Autowired
EntityManager entityManager;
public List<?> getResults() throws ParseException
{
//ModelSpecification modelSpecification = new ModelSpecification();
CriteriaQuery<DAO> query = modelSpecification.getSpecQuery();
TypedQuery<DAO> typedQuery = entityManager.createQuery(query);
List<?> resultList = typedQuery.getResultList();
//List<DAO> allData = entityManager.createQuery(query).getResultList();
return resultList;
}
You can find working code here https://github.com/bsridharpatnaik/CriteriaMultiselectGroupBy