I would prefer option 3 if possible. But would this require XA transactions (two phase commit) because JPA would trigger the ID validation after the record has been created and if invalid needs to rollback the commit. Seb On 15.05.2012 10:22, Emmanuel Bernard wrote: > There is an annoyance when using JPA and Bean Validation today. I worked out a proposal. Please let me know what you think > > http://beanvalidation.org/proposals/BVAL-234/ > > --- (copied here for convenience) --- > > [Link to JIRA ticket][jira] > See also [NetBeans issue][netbeans] > > ## Problem description > > Today when a property marked @Id @GeneratedValue is also marked @NotNull, it will fail if the identity generation is post-insert > in the database. This can be the case if the underlying table is using column id generation for example. > > The id property is thus null when Bean Validation is executed during the pre-persist phase and a constraint > violation is raised. > > ## Solutions > > ### 1. User adjusts > > One option is to stay put and consider the behavior valid. The user can work around that by: > > - creating a `com.acme.groups.Created` group > - marking the `@NotNull` annotation as belonging to the group > - override the groups in `persistence.xml` to validate `Created` accordingly > > Here is the snipped of the `persistence.xml` file > > <property name="javax.persistence.validation.group.pre-persist" > value="javax.validation.groups.Default"/> > <property name="javax.persistence.validation.group.pre-update" > value="javax.validation.groups.Default,com.acme.groups.Created"/> > > > ### 2 User adjusts with some help > > We could use option 1 but have JPA provide the created group: `javax.persistence.validation.groups.Created` > > ### 3. Have JPA disable validation of id properties at pre-persist > > JPA could disable validation on id properties if in pre-persist and if the generated value is not created yet. > Note that we disable all validations - not simply `@NotNull` - as it does not make much sense to execute other > validations when a property is null. > > `TraversableResolver` can be used to solve the problem as `isReachable` can stop the processing of a property. > > ### Conclusions > > Option 3 seems the most reasonable but it could be complicated at the JPA level. > Before going to the JPA EG, let's discuss the situation here. > > ### Questions remaining > > - should the `Created` groups be renamed? > - is that correct to sneakily disable @NotNull constraint validation? > > > [netbeans]: http://netbeans.org/bugzilla/show_bug.cgi?id=197845#c3 > [jira]: https://hibernate.onjira.com/browse/BVAL-234 > _______________________________________________ > beanvalidation-dev mailing list > beanvalidation-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/beanvalidation-dev _______________________________________________ beanvalidation-dev mailing list beanvalidation-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/beanvalidation-dev

Is option #3 even possible within the JPA spec? One would need meta information about the id property (which generation type and how exactly this type behaves regarding the id generation time). I don't think there is a way to do this with the JPA api. Also JPA does not even explicitly define the behavior of the different strategies.

Disabling the validation per default can also backfire in the cases where a user "knows" that a certain strategy will generate the id pre insert. In this case it would be valid to add @NotNull.

I also find disabling validation of @NotNull by default problematic. If I'm for instance using sequences for id generation, then @NotNull should be validated upon insertion. But relying on sequences is IMO per se not portable; so when deciding to use them, I'd also expect @NotNull to be validated.

2012/5/21 Emmanuel Bernard <emmanuel(a)hibernate.org&gt;: > > On 15 mai 2012, at 19:50, Gunnar Morling wrote: > >> I also find disabling validation of @NotNull by default problematic. >> If I'm for instance using sequences for id generation, then @NotNull >> should be validated upon insertion. But relying on sequences is IMO >> per se not portable; so when deciding to use them, I'd also expect >> @NotNull to be validated. > > I think you misunderstood something. If sequence, table generation or any in memory generation logic is used, then @NoNull will indeed be validated in option #3. In fact, database trigger and column id generations are the only one that would disable validation. Ah, I see. Indeed I thought that you meant to disable validation of @NotNull in any case. If the behavior depends on the applied id generation strategy, #3 makes more sense. I'm not sure, does the JPA spec define that sequence values are always to be prefetched? Otherwise I could imagine situations where an allocation size of 1 is used, which would allow to fetch the sequence just within the INSERT statement. In that case I think the constraints again couldn't be validated.