Dear Alfredo and Juan, obviously there is an hidden problem with my code i simply do not see. Could you please have a short look at these 3 classes (full code) and tell me what am I doing wrong here:
https://dl.dropboxusercontent.com/u/2983671/JPA_Problem/JPA_Problem.zip Please note: Everything works fine as log as I do not try to make any changes to the Tradesman entity (its parameters). When is set new password or any other parameter, i get an error message of type: Detected attempt to establish Company(no-id-yet) as the parent of Tradesman(358) but the entity identified by Tradesman(358) has already been persisted without a parent. A parent cannot be established or changed once an object has been persisted. I am using: JPA with DataNucleus on Google Datastore. (Standard setting that come with GWT 2.5) Thank you in advance for your help!! Best regards: Nermin Am Dienstag, 21. Mai 2013 18:29:54 UTC+2 schrieb Alfredo Quiroga-Villamil: > > Or use a cascade persist, merge to force creation or merge respectively > > Sent from my iPhone > > On May 21, 2013, at 7:02 AM, Juan Pablo Gardella > <gardella...@gmail.com<javascript:>> > wrote: > > You should persist company before persist Tradesman or attach to an > existent company. This relation should be explicit. Create > company.addTrademan(Trademan t) method: > > company.addTrademan(Trademan t){ > users.add(t); > t.setCompany(this); > } > > Call this in a transactional method. > > Juan > > > > > > > 2013/5/21 Nermin <use...@gmx.de <javascript:>> > >> 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(**enti**ty.getPassword(), >>> BCrypt.gensalt()); >>> } >>> >>> And then check where are you persisting Tradesman without company. >>> >>> >>> >>> 2013/5/21 Thomas Broyer <t.br...@gmail.com> >>> >>>> >>>> >>>> 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(**enti**ty.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<https://developers.google.com/appengine/community> >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Google Web Toolkit" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to google-web-toolkit+**unsubscr...@googlegroups.com. >>>> To post to this group, send email to google-we...@**googlegroups.com. >>>> Visit this group at http://groups.google.com/** >>>> group/google-web-toolkit?hl=en<http://groups.google.com/group/google-web-toolkit?hl=en> >>>> **. >>>> For more options, visit >>>> https://groups.google.com/**groups/opt_out<https://groups.google.com/groups/opt_out> >>>> . >>>> >>>> >>>> >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "Google Web Toolkit" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to google-web-toolkit+unsubscr...@googlegroups.com <javascript:>. >> To post to this group, send email to >> google-we...@googlegroups.com<javascript:> >> . >> Visit this group at >> http://groups.google.com/group/google-web-toolkit?hl=en. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to google-web-toolkit+unsubscr...@googlegroups.com <javascript:>. > To post to this group, send email to > google-we...@googlegroups.com<javascript:> > . > Visit this group at > http://groups.google.com/group/google-web-toolkit?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > > > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. 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