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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 20:04:25 GMT
I just want want to retrieve an entity add some info but i dont want to
persist that new info.

Im trying to use the detach method but nothing changes.





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

> 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
>>
>
>
>
> --
> -------------------------------------------------------------------
> *SCJA. José Luis Cetina*
> -------------------------------------------------------------------
>



-- 
-------------------------------------------------------------------
*SCJA. José Luis Cetina*
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