Failing fast with composite constraints

mers · **Joined:** Wed Sep 12, 2007 1:58 pm **Posts:** 12

Hi,

I'm wondering if there's a way to make the validation of a composite constraint fail fast (or short circuit) if the validation of a meta constraint fails. In my case, I have two constraints @NullHostileCollection for Collection<?> and composite @NumberList for List<? extends Number>, which look like

Code:

@Target({METHOD, FIELD, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = NullHostileCollectionValidator.class)
@Documented
public @interface NullHostileCollection {

Code:

@Target({METHOD, FIELD, ANNOTATION_TYPE})
@Retention(RUNTIME)
@Constraint(validatedBy = NumberListValidator.class)
@Documented
@NullHostileCollection
@ReportAsSingleViolation
public @interface NumberList {

When I validate a number list which contains null values, the NullHostileCollectionValidator correctly considers the list invalid. However, validation then continues to the NumberListValidator instad of short circuiting. As a result, the NumberListValidator can't assume anything about the list and has to have extra checks to avoid NPEs, etc. Is it possible to make the validation short circuit? This behaviour makes even more sense when reporting as a single violation, IMO.

Thanks,
Emerson

Gunnar · **Joined:** Sat Jan 24, 2009 12:46 pm **Posts:** 388

Hi,

The Bean Validation spec says

Quote:

[If] a composed constraint is marked as @ReportAsSingleViolation, the evaluation of the composing constraints stops at the first failing constraint and the error report corresponding to the composed constraint is generated and returned.

Hibernate Validator validates the composing constraints before the composed constraint. Based on that I'd expect that the NumberListValidator is not invoked when @NullHostileCollection is violated (since you have annotated @NumberList with @ReportAsSingleViolation). Is this not the case, i.e. is the number list validator invoked in this case?

--Gunnar