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From José Luis Cetina <maxtorz...@gmail.com>
Subject Re: Entity cant be refreshed with new list values
Date Fri, 18 Oct 2013 20:02:39 GMT
In the previous example i tried to set the list in the ejb, but if removed
and then put the list in the managed bean i get the same behavior


@Named
public class MyBean implements Serializable{

 @EJB
 private MyEJB ejb;

 public void anyMethod(){
   User user = ejb.getUserWithRoles();
    //i will create a list of role just for try to set any role the userJohn
      List<Role> roleList = new ArrayList<Role>(2);
      roleList.add(new Role(1,'ADMIN'); //creating and adding role 1
      roleList.add(new Role(2,'DEVELOPER');//creating and adding role 2

     user.setRoles(roleList);

    user.getRoles(); //<---- HERE THE LIST IS ALWAYS NULL
 }

}


2013/10/18 José Luis Cetina <maxtorzito@gmail.com>

>
> I have a "strange" behavior, with list properties of any kind of entity.
>
> When i try to set a non empty list to a retrieved entity that has a list
> value with null (because is not fetched) the entity doesnt "reflect" the
> new non-empty values that i set.
>
> Steps
> 1. Retrieve any entity (ex. user) from database in an ejb with criterias.
> 2. The retrieved entity has a OneToMany attribute (roles) by default is
> lazy thats why if i dont do a fetch (i dont) the list is null
> 3. Then try to fill the role list with a NON-EMPTY list
> 4. Here the list that i set has values but the user list has a null in the
> roles list attribute even though i set it in the step 3
>
>
> I dont know why this is happening, the only way i could fix this is
> cloning (using SerializationUtils from Apache commons.lang3) the user
> entity (see the steps) and with this work, but i dont know why.
>
> 1. Retrieve any entity (ex. user) from database in an ejb with criterias.
> 2. Clone retrieved entity and asig to new one User clonedUser =
> SerializationUtils.clone(originalRetrivedUser);
> 3. Then try to fill the role list with a NON-EMPTY list to the clonedUser
> 4. The list of clonedUser has the correct values
>
>
> Why i need to clone? why i cannot set a list to the entity if is not
> cloned?
>
>
> Im using Apache TomEE 1.6.0-SNAPSHOT (with the openjpa version embedded)
>
>
> Scenario:
>
> ***** ENTITIES *****
> @Entity
> public class User implements Serializable{
>
>    @Id
>    private int id;
>    private String userName;
>    private String password;
>    @OneToMany(mappedBy = "user")
>    private List<Role> roles;
>
>    //getters and setters..
>
> }
>
>
> @Entity
> public class Role implements Serializable{
>
>    @Id
>    private int id;
>    private String roleName;
>    @ManyToOne
>    @JoinColumn(name = "user_id")
>    private User user;
>
>   //getters and setters..
> }
>
>
> **** EJB CLASS ****
> @Stateless
> public class MyEJB{
>
>     @PersistenceContext(unitName ="ANY_NAME")
>     private EntityManager em;
>
>   public User getUserWithRoles(){
>
>         CriteriaBuilder cb = em.getCriteriaBuilder();
>         CriteriaQuery<User> cq = cb.createQuery(User.class);
>         Root<User> root = cq.from(User.class);
>
>         cq.where(cb.equal(root.get(User_.userName),"john"));
>
>        User userJohn = em.createQuery(cq).getSingleResult();  // if i want
> this work i have to do User userJohn =
> SerializationUtils.clone(em.createQuery(cq).getSingleResult());  [1*]
>
>
>        //i will create a list of role just for try to set any role the
> userJohn
>       List<Role> roleList = new ArrayList<Role>(2);
>       roleList.add(new Role(1,'ADMIN'); //creating and adding role 1
>       roleList.add(new Role(2,'DEVELOPER');//creating and adding role 2
>
>      //setting the list of roles created to the user, as you can see the
> list has 2 values but the value roles of userJohn always is set to null, my
> setters and getters are correct
>      userJohn.setRoles(roleList);
>
>      return userJohn;
>   }
>
> }
>
> *** MANAGED BEAN ****
>
> @Named
> public class MyBean implements Serializable{
>
>  @EJB
>  private MyEJB ejb;
>
>  public void anyMethod(){
>    User user = ejb.getUserWithRoles();
>     user.getRoles(); //<---- HERE THE LIST IS ALWAYS NULL but if i use
> clone in the ejb method (see 1*) i can get the corrected values.
>
>  }
>
>
> }
>
> I know i can get the values fetching but im trying to not do it
>



-- 
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*SCJA. José Luis Cetina*
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