Can anyone tell why is this query not valid?

[Eduardo Born]

Hello!
I have criteria query that, when executed, results the following exception thrown:

java.lang.IllegalArgumentException: org.hibernate.QueryException: illegal syntax near collection: id [select generatedAlias0.permissions from temp.package.commons.user.Role as generatedAlias0 where generatedAlias0.id=2L]
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1222)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1168)
at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:320)
at org.hibernate.ejb.criteria.CriteriaQueryCompiler.compile(CriteriaQueryCompiler.java:227)
at org.hibernate.ejb.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:437)
at temp.package.dao.impl.DefaultDAOService.getProperties(DefaultDAOService.java:585)

The id attribute is the entity's attribute which was annotated with @Id @GeneratedValue. Basically I'm trying to load the attribute "permissions", which is a collection uninitialized at the time, for the role object whose id is 2. The id attribute is of long type.

Any ideas on why this query would fail?

It seems correct to me...

I can post the code that creates the criteria query here, but it is fairly complicated (as it generates based on a LDAP filter, etc), so I'm hoping the error will be visible from the generated query string and the exception. Please let me know if that's not the case.

Thanks!!
Eduardo Born

[Eduardo Born]

Some more information...

The criteria query that generated this error was built this way:

    EntityManager entityManager = getEntityManager();
    CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
    
    CriteriaQuery<Object> criteriaQuery = criteriaBuilder.createQuery();
    
    // queryScopeClass is assigned to type temp.pack.commons.user.Role
    Class<? extends T> queryScopeClass = role.getClass();
    
    Root<? extends T> from = criteriaQuery.from(queryScopeClass);
    
    Path<?> attributePath = from.get("permissions");
    Predicate predicate = criteriaBuilder.equal(attributePath, new Long(2));
    criteriaQuery.where(predicate);
    
    // attempting to get just the role's permissions
    CriteriaQuery<Object> select = criteriaQuery.select(attributePath);
    TypedQuery<Object> typedQuery = entityManager.createQuery(select);
    
    return typedQuery.getResultList();

The Role and Permission classes have been mapped with JPA and some Hibernate annotations like this:

   public abstract class Role implements Serializable {
    
     /**
      * The id of this role. Internal use only.
      * 
      * @since 1.0
      */
     @Id @GeneratedValue
     protected long id;
    
     /**
      * Set of permissions granted to this role.
      * 
      * @since 1.0
      */
     @OneToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, mappedBy="sourceRole")
     protected Set<Permission> permissions = new HashSet<Permission>();
    
    ...
    
    }
    
    public class Permission implements Serializable {
     private static final long serialVersionUID = 1L;
    
     /**
      * The id of this permission. Used internally for persistence.
      * 
      * @since 1.0
      */
     @Id @GeneratedValue
     @Column(name = "PERMISSION_ID")
     protected long id;
    
     /**
      * The group to which the owner of this permission is being granted permission to.
      * 
      * @since 1.0
      */
     @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
     @JoinColumn(name = "TARGET_ROLE_ID")
     @ForeignKey(name = "FK_TARGET_GROUP_PERMISSION_ID",
       inverseName = "FK_PERMISSION_ID_TARGET_GROUP")
     protected Group targetGroup;
    
     /**
      * The role that has been granted this permission.
      * 
      * @since 1.0
      */
     @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
     @JoinColumn(name = "SOURCE_ROLE_ID")
     @ForeignKey(name = "FK_SOURCE_GROUP", inverseName = "FK_GROUP_PERMISSIONS")
     private Role sourceRole;
    
    ...
    
    }

I was expecting the call to typedQuery.getResultList() to return a list of collections with just one element: the collection of permission objects for the role with id = 2. This is an attempt to select just the "permissions" collection from the object role with id = 2.

I'm new to criteria queries and I'm having a hard time finding what's wrong with it.

What would be the correct criteria query to accomplish this?

Thank you!!

Eduardo