How to access Validator Annotation MetaData programatically?

razmataz · **Joined:** Sat May 05, 2007 8:11 am **Posts:** 2

Hibernate version:
hibernate-3.2, hibernate-annotations-3.3.0.GA,
hibernate-validator-3.0.0.GA

Mapping documents:
none (annotations)

Hi everyone,

For testing I have made an annotated class like so:

Code:

import javax.persistence.*;
import org.hibernate.validator.*;

@Entity
@Table(name="person")
public class Person
{
    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE)
    long id;
 
    @Column( length=128 )
    @Length( min=5, max=128 )
    @Email
    String email;
}

How would I go about obtaining the Annotation Metadata from this class from within my program?

I'd like to write a small presentation framework and that needs
to learn about the constraints for each field to do its thing.

I figured out how I can get at the basic Column's via Configuration.getClassMapping(..).getIdentityTable(..).getColumn(..).
But those only seem to give me the classname and @Column( length ),
most other getters return null for my little testclass (even getSqlType(), i wonder why?).

But how do I get the data for @Length( min/max ), @Email, @Id and
other Annotations?

Any help would be very appreciated.

christian · **Posted:** Sat May 05, 2007 10:00 am

With regular Java Reflection: class.getAnnotations() etc.

emmanuel · **Posted:** Sat May 05, 2007 11:05 am

In the meanwhile Christian is right, check the properties annotations annotated with @ClassValidator

The spec group is willing to provide a metadata API though, so it probably will be possible to avoid the manual annotation checking in the future.

razmataz · **Joined:** Sat May 05, 2007 8:11 am **Posts:** 2

Thank you christian and emmanuel.

I'll go for it with direct annotation access for now, not so nice imho because the annotation semantics may change in the future(?) but at least that's
gonna work in a reasonable straightforward fashion. :-)

I'm definately looking forward to the metadata API, that might ease the integration of other components with validator and hibernate in general.

Without knowing much about the specs that you're targeting I'd personally also like to see a more or less generic way to add own meta-data to be accessed via the same API. Maybe that's even possible already and I just don't know?

In my specific case I'd use such "meta-annotations" to provide hints
to the presentation layer about things like preferred size and order
of the input widgets and to further augment the available information
about field types with stuff like "isPassword" (to create a special password-dialog).

Anyways, thanks for the pointer, for now I'll move on with what we have today.

regards, raz