Question

In my application, I have an @ApplicationScoped CDI bean to store some information from the database:

@Named
@ApplicationScoped
public class MrBean {
   @EJB
   private SoyaBean soyaBean;
   private List<Toys> myToys;

   @PostConstruct
   public void prepareMrBean() {
      this.myToys = soyaBean.getToys();
   }

   public void updateToys() {
      this.myToys = soyaBean.getToys();
   }
}

I also have a AddToy.xhtml page which would simply add a toy to the database. The backing bean is as following:

@Named
@RequestScoped
public class MrsBean {
   @EJB
   private SoyaBean soyaBean;
   @Inject
   private MrBean mrBean;

   public void addToy() {
      this.soyaBean.addToy();
      this.mrBean.updateToys();
   }
}

Since there is a new toy added to the database, I wanted to update the list of toys in mrBean. However, even though mrsBean called mrBean.updateToys(), the list of toys in mrBean is not updated at all. I have another ViewToys.xhtml with a @RequestScoped backing bean to view the list of toys and I didn’t see the list get updated.

I’d be very grateful if someone could give me an advice on how to tackle this problem.

UPDATE: This is my SoyaBean implementation:

@Stateless
public class SoyaBeanImpl implements SoyaBean {
   @PersistenceContext()
   private EntityManager em;

   @Override
   public List<Toys> getToys() {
      Query q = em.createQuery("SELECT T from Toys T");
      return (List<Toys>) q.getResultList();
   }

   @Override
   public void addToy() {
      Toys newToy = new Toys();
      em.persist(newToy);
   }
}

UPDATE 2 I’d also really appreciate if someone could show me how I can achieve the same goal in any ways other than my troubling way.

Best regards,

James Tran

Answer 1

The problem was that the results of all SQL queries were cached. Hence, even though I tried to refresh the list of toys, it only received the old result. I solved this problem by setting the option Shared Cache Mode in the file persistence.xml to None.

I believe not using cache at all is not a good option. Hence, I’d be very grateful if someone could show me how I can achieve the same result without having to turn off cache.