Predefined groups and JPA integration

javierpaniza · **Posted:** Fri Apr 18, 2008 1:00 pm

The groups feature of JSR-303 is a really great idea, and I think that useful for a lot of cases.
But, there is a typical case in business applications that is a validation to be enforced on creation but not on update. In fact, OpenXava validation annotations have a onlyOnCreate attribute for this case, look at:
http://www.gestion400.com/OpenXavaDoc/a ... dator.html
http://www.gestion400.com/OpenXavaDoc/a ... dator.html

My proposal is to add standard (or predefined) groups to JSR-303 that can be understood by JPA implementations, in this way;

Code:

@ForbiddenPrice(groups=JPAGroups.ON_PERSIST)
private BigDecimal price;

In this case ForbiddenPrice is only enforced on persist, not on update.
With these standard groups we can develop more portable applications.

What do you think ?

emmanuel · **Posted:** Wed Apr 23, 2008 8:39 pm

Those group definitions should be part of JPA 2 rather than JSR 303. I noted the point.
Can you give me a use case though

javierpaniza · **Posted:** Wed May 07, 2008 12:59 pm

emmanuel wrote:

Those group definitions should be part of JPA 2 rather than JSR 303. I noted the point.

Thanks

Quote:

Can you give me a use case though

The next code is from an existing OpenXava application:

Code:

@Entity
@EntityValidator(value=ValidadorNoDuplicarHojaPadronal.class, 
      onlyOnCreate=true
)
public class HojaPadronal {

This using Bean validation would be:

Code:

@Entity
@NoDuplicarHojaPadronal(groups=JPAGroups.ON_PERSIST)
public class HojaPadronal {

Look also at this thread:
http://forum.hibernate.org/viewtopic.php?t=986527

emmanuel · **Posted:** Tue Jun 03, 2008 3:24 pm

ValidadorNoDuplicarHojaPadronal test based on some data in the database?

This is the typical bad use case for validation unless you use a Serializable transaction isolation :)

javierpaniza · **Posted:** Thu Jun 05, 2008 2:38 pm

emmanuel wrote:

ValidadorNoDuplicarHojaPadronal test based on some data in the database?

Of course.
Do you mean that JSR-303 will not allow to read database from the constraint logic?

emmanuel wrote:

This is the typical bad use case for validation unless you use a Serializable transaction isolation :)

"bad use case": Let me to decide if it's bad or good.
There are nothing perfect. All options, even the better ones, have its inconvenients.
I think that to forbid access to database from a validator is a great mistake.

emmanuel · **Posted:** Thu Jun 05, 2008 4:57 pm

It is not forbidden to use a database in a constraint validator implementation, people are free to shoot themselves in the foot.
But I would be reinsured if you needed the group feature on a non flawed use case :)

emmanuel · **Posted:** Thu Jun 05, 2008 6:10 pm

Nevermind, there is a use case here. http://forum.hibernate.org/viewtopic.php?t=986527