Retrieving the joined Entity with a Criteria

luther.blisset · **Joined:** Thu Oct 09, 2008 7:56 am **Posts:** 4

Hi folks,

I've two Entity (called Price and RentalUnit) with a monodirectional ManyToMany relationship.
Here the code:

Code:

@Entity
public class Price {
  @ManyToMany
  @JoinTable(name = "price_rental_unit",
      joinColumns = {@JoinColumn(name = "price_id") },
      inverseJoinColumns = {@JoinColumn(name = "rental_unit_id") }
   )
   @IndexColumn (name = "index_column")
   private List<RentalUnit> rentalUnits;
}

@Entity
public class RentlaUnit {
    ......
}

I'm writing a DAO method using Criteria Hibernate to retrieve all rentalUnits entities that have the same price.
My method would return a List<RentalUnit> from a join between Price and RentalUnit.
I wrote a Criteria like this:

Code:

DetachedCriteria criteria = DetachedCriteria.forClass(Price.class);
criteria.add(Restrictions.idEq(price.getId()));
criteria.createAlias("rentalUnits", "rentalUnit")
   .setProjection(Projections.projectionList().add(Projections.property("rentalUnit.name")));

thus I can retrieve the name of RentalUnit but I would like to retrieve the Entity!
Have you any idea to solve this?
Thanks!

gonzao_diaz · **Joined:** Mon Nov 26, 2007 2:29 pm **Posts:** 443

No need to do a projection.
Apply a result transformer

Code:

criteria.setResultTransformer(CriteriaSpecification.DISTINCT_ROOT_ENTITY)

so that the prices don't duplicate for each child, and then access with java code the getRentalUnits() of each price.

luther.blisset · **Joined:** Thu Oct 09, 2008 7:56 am **Posts:** 4

Thanks to reply Gonzalo,
I found other solution with a ResultTransformer:

Code:

DetachedCriteria criteria = DetachedCriteria.forClass(Price.class);
criteria.add(Restrictions.idEq(price.getId()));
criteria.createAlias("rentalUnits", "rentalUnit")
   .setResultTransformer(CriteriaSpecification.ALIAS_TO_ENTITY_MAP);

List result = criteria.getExecutableCriteria(delegatedDao.getHibernateSession()).list();
List<RentalUnit> rentalUnits = new ArrayList<RentalUnit>();

for (Object aResult :result) {
   Map map = (Map) aResult;
   RentalUnit rentalUnit = (RentalUnit) map.get("rentalUnit");
   if (!rentalUnits.contains(rentalUnit))
      rentalUnits.add(rentalUnit);
}
return rentalUnits;

thus I must not to use getPrices().
Thanks a lot.