JPA Eclipselink Subquery in where clause with between, CriteriaBuilder and metamodel - subquery

Question

I want to do this query with metamodel but I can't!! I dont know how to do this.
MYSQL QUERY (with this query I want to get all the rows from the Clases table that are teaching in this moment):
SELECT * FROM clases cl
WHERE CURRENT_TIME() BETWEEN
(SELECT ml2.inicio FROM modulos ml2 WHERE cl.modulo_id=ml2.modulo_id ) AND
(SELECT ml2.fin FROM modulos ml2 WHERE cl.modulo_id=ml2.modulo_id) AND
cl.fecha=CURRENT_DATE();
These are my entities:
ENTITY MODULOS
#Entity
#Table(name = "modulos")
public class Modulos implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "modulo_id")
private Integer moduloId;
#Basic(optional = false)
#Column(name = "inicio")
#Temporal(TemporalType.TIME)
private Date inicio;
#Basic(optional = false)
#Column(name = "fin")
#Temporal(TemporalType.TIME)
private Date fin;
#Basic(optional = false)
#Column(name = "modulo")
private String modulo;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "modulos")
private List<GruposHorarioHasModulos> gruposHorarioHasModulosList;
//getters and setters...
}
ENTITY CLASES
#Entity
#Table(name = "clases")
public class Clases implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "clase_id")
private Integer claseId;
#Basic(optional = false)
#Column(name = "aula")
private String aula;
#Basic(optional = false)
#Column(name = "fusion")
private boolean fusion = false;
#Basic(optional = false)
#Column(name = "clase_numero")
private Integer claseNumero;
#Basic(optional = false)
#Column(name = "clase_impartida")
private boolean claseImpartida = false;
#JoinColumn(name = "modulo_id", referencedColumnName = "modulo_id")
#ManyToOne(optional = false)
private Modulos modulos;
//getters and setters...
}
I have this:
EntityManager em1 = Persistence.createEntityManagerFactory("myPU").createEntityManager();
CriteriaBuilder cb = em1.getCriteriaBuilder();
CriteriaQuery cq = cb.createQuery();
Root<Clases> root = cq.from(Clases.class);
cq.select(root.get(Clases_.claseId));
Subquery<Date> sqOne = cq.subquery(Date.class);
Root<Modulos> root2 = sqOne.from(Modulos.class);
sqOne.select(root2.get(Modulos_.inicio));
Subquery<Date> horaInicio = sqOne.select(root2.get(Modulos_.inicio)).where(
cb.equal(
root2.get(Modulos_.moduloId),
root.get(Clases_.modulos).get(Modulos_.moduloId)
)
);
Subquery<Date> sqTwo = cq.subquery(Date.class);
Root<Modulos> root3 = sqTwo.from(Modulos.class);
Subquery<Date> horaFin = sqTwo.select(root3.get(Modulos_.fin)).where(
cb.equal(
root3.get(Modulos_.moduloId),
root.get(Clases_.modulos).get(Modulos_.moduloId)
)
);
cq.where(cb.between(cb.currentTime(), horaInicio, horaFin));
em1.createQuery(cq).getResultList();
This code gives me the following exception:
Exception in thread "main" java.lang.ClassCastException:
org.eclipse.persistence.internal.jpa.querydef.SubQueryImpl cannot be
cast to org.eclipse.persistence.internal.jpa.querydef.ExpressionImpl
If i change the where clause for this one...
cq.where(cb.between(cb.currentTime(), new Date(), new Date()));
... it works but without my Subquery, then i can see the error came from my subquery, but I don't know why, if I change the where clause for this one...
cq.where(cb.greaterThan(cb.currentTime(), horaInicio));
... I get this:
SELECT t0.clase_id FROM clases t0, clases t1 WHERE (CURRENT_TIME > (SELECT t2.inicio FROM modulos t3, modulos t2 WHERE ((t2.modulo_id = t3.modulo_id) AND (t3.modulo_id = t0.modulo_id))))
I can see the problem are the 2 subqueries in the between clause.
Please I need help with this, I spent 2 weeks looking for an answer but... nothing... help.
I'm using JPA 2.0 with Netbeans and EclipseLink with metamodel generator and Java 6.
I want to do it with metamodels and criteriasbuilder and criteriasquerys
As you can see i need to do a subquery in the where clause and in that where clause I need to do a between where each parameter have a subquery, like this:
SELECT * FROM X WHERE CURRENT_TIME BETWEEN **MY_SUBQUERY_ONE** AND **MY_SUBQUERY_TWO**

Answer 1

Abit late answer but..
Subquery<Date> sqOne = cq.subquery(Date.class);
Root<Modulos> root2 = sqOne.from(Modulos.class);
sqOne.select(root2.get(Modulos_.inicio));
Subquery<Date> horaInicio = sqOne.select(root2.get(Modulos_.inicio)).where(
cb.equal(
root2.get(Modulos_.moduloId),
root.get(Clases_.modulos).get(Modulos_.moduloId)
)
);
Not sure what you are trying to do here, and it might or might not be related to your error. You create sqOne and make a selection. Then you redo the selection, replacing the previous one and copy the result to horaInicio. What is the purpose of this? You might aswell skip sqOne.select(root2.get(Modulos_.inicio)); and keep using sqOne instead of horaInicio.
Also, I'm not sure you can mix and match Roots created from different queries.