Hibernate Validator Annotation Processor not checking @Min

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

The Hibernate Validator site says the annotation processor will catch "Annotated strings with @Min to specify a minimum length even though you should have used @Size". This isn't the case, because in this code:

Code:

public class SomeObject {

    @Size(min = 10, max = 20)
    String foo;

    @Min(20)             // not marked as an error
    String foo3;

    @Valid                 // correctly marked as an error
    boolean foo2;
}

Is this an oversight, or is there a reason the check isn't being performed?

Thanks,
Emerson

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

Emerson,

thanks for your report.

I checked with the implemention (annotation processor and Hibernate Validator runtime) and was a bit surprised myself :-) Hibernate Validator actually supports @Min (and also @Max) for Strings (in addition to what is demanded by the Bean Validation specification), though not for checking the length of Strings, but for checking that the number represented by a given String is larger/smaller than the value given in the annotation. Therefore the annotation processor does not mark Strings annotated with @Min as an error.

The misunderstanding that @Min can be used for restricting the length of a String still could happen of course. I created HV-442 for improving the documentation on that matter.

Gunnar

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

Thanks. That makes sense. It's misleading because of the added type support, but it makes sense and as you suggested, is probably best clarified using the documentation. Maybe a "strict" option on the annotation processor can be added that warns the user when HV imports are being used instead of BV imports of the same name, to highlight these differences?

On a related note, would @Min return a ConstraintViolation if the String isn't numeric? And would the string be treated as an int, a double, a long, ...? I can't dig around the source right now, but I'm curious. :)

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

Quote:

... that warns the user when HV imports are being used instead of BV imports of the same name

Not sure, I'm following. To which import do you refer here? The @Min constraint is the one from javax.validation.constraints, it's just that HV supports this constraint for more data types than required by the specification.

The @Min validator for Strings uses new BigDecimal(String) for parsing, so any number format understood by BigDecimal is supported. If a NumberFormatException occurs during parsing due to an invalid number format a ConstraintViolation would be the result.

In case you want to have a look at the sources, you can find them at GitHub.