Check this blog entry

Thanks for this nice JSR!
If you guys managed to work on the initial draft of the XML Deployment as well, please do post a preview.

thanks!

The XML will be mainly a transposition of the annotations model. That's why we left it for the end.

We have a propreitory web framework and we are strictly prohibited from creating too many objects (extremely high volume site ) and hence this question -

public interface Constraint<A extends Annotation> {
void initialize(A constraintAnnotation);
boolean isValid(Object value);
}

I'm a little confused with this interface. I wanted to check if i can work with a singleton instance of an implementation for a given constraint?

I understand that isValid() will be called everytime validation kicks in. What about initialize()?

I mean does it make sense to have

boolean isValid(Object value,A constraintAnnotation); ?

Your response would be very helpful when i talk to my web architect about relevance of jsr303 to our propreitory web framework.

thanks,
Karthik

You are the second person asking for that http://forum.hibernate.org/viewtopic.php?t=985983

For each constraint impl, initialize is called once (slightly after instantiation).

Usually one constraint impl object is instantiated per annotation. The number of constraint is fairly limited, let's say 2000 on a 300 entity model.

In the example of @Max, I imagine the instance would take around 100 bytes in memory, so we are talking about 200k of memory for 2000 constraints. Is it really useful to use a singleton approach?

That being said, the constraint is build by a ConstraintFactory, I imagine it's possible to tweak a ConstraintFactory to create singletons. But at that point I think you would use more CPU and have more scalability headaches than what 200k of memory is worth.