Dear Juan,
I tried *@ManyToOne(optional=false)*, unfortunately no changes.
In my current setting, the @PrePersist is called only once. (I see it on
system out) That means: no multiple attempts to persist Tradesman entity.
However, it looks to me that whenever I change parameters on the Tradesman
entity JPA creates/persists for some reason the Tradesman in the DB,
independently from the Company entity.
I use Standard GWT settings: GWT 2.5, DataNucleus on Appengine Datastore.
The scenario I am describing here is a standard scenario you will face when
using GWT with JPA. I am surprised that my code is not working.
@PrePersist works fine as long as the Entity is not in a owned relation
with other entities.
Does anyone has an idea what could be wrong here?
Thank you!!
Nermin
@Thomas: Thank you for the advise. I will
Am Dienstag, 21. Mai 2013 12:01:43 UTC+2 schrieb Juan Pablo Gardella:
>
> Update your entity as:
>
> @Entity
> public class Tradesman extends User{
> @ManyToOne(optional=false)
> private Company company;
>
> *@PrePersist*
> public void hashPassword(){
> setPassword(BCrypt.hashpw(**entity.getPassword(),
> BCrypt.gensalt());
> }
>
> And then check where are you persisting Tradesman without company.
>
>
>
> 2013/5/21 Thomas Broyer <t.br...@gmail.com <javascript:>>
>
>>
>>
>> On Tuesday, May 21, 2013 11:18:42 AM UTC+2, Nermin wrote:
>>>
>>> Dear GWT developers,
>>>
>>> I have a "probably simple" problem with my application which I am
>>> obviously not able to solve.
>>>
>>> Two Classes: Company, Tradesman
>>>
>>> @Entity
>>> public class Company {
>>> @OneToMany(cascade = CascadeType.ALL, mappedBy = "company")
>>> private List<Tradesman> users = new ArrayList<Tradesman>();
>>>
>>> ....
>>> }
>>>
>>>
>>> @Entity
>>> public class Tradesman extends User{
>>> @ManyToOne
>>> private Company company;
>>>
>>> *@PrePersist*
>>> public void hashPassword(){
>>> setPassword(BCrypt.hashpw(**entity.getPassword(),
>>> BCrypt.gensalt());
>>> }
>>>
>>> *JSR 303 validation on GWT is activated.*
>>>
>>> Here is the *error message:
>>> *Detected attempt to establish Company(no-id-yet) as the parent of
>>> Tradesman(356) but the entity identified by Tradesman(356) has already been
>>> persisted without a parent. A parent cannot be established or changed once
>>> an object has been persisted.
>>>
>>> My problem is obviously that when I change some parameters within the
>>> Tradesman entity within the *@PrePersist* method, a new child entity is
>>> created.
>>> In case I do not touch any parameter, in the @PrePersist, everything
>>> works fine.
>>>
>>> What am I doing wrong here?
>>>
>>
>> You're not reaching the appropriate group ;-)
>>
>> I suppose you're using AppEngine (form what I know of JPA, I can't see a
>> reason for that kind of message, unless you're using JPA on AppEngine), in
>> which case you can ask for support on StackOverflow:
>> https://developers.google.com/appengine/community
>>
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>>
>
>
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