[bv-dev] Container element validation for arrays
guillaume.smet at gmail.com
Wed Apr 19 06:28:05 EDT 2017
FWIW, the main issue with BV 1.1 compatibility is that BV 1.1 supports:
@Size(min = 2)
private String array;
which was the way to write that the array should have a minimum length of 2
(and was perfectly valid if the @Size constraint does not have a TYPE_USE
If we consider TYPE_USE support for arrays, according to the JLS, it should
in fact be written:
private String @Size(min = 2)  array;
And the main compatibility issue is that the meaning of [Example 1] would
not be compatible with the BV 1.1 behavior: it should mean that the String
inside the array must have a minimum length of 2.
See the class I used as a playground here:
On Wed, Apr 19, 2017 at 10:27 AM, Gunnar Morling <gunnar at hibernate.org>
> Guillaume made an important observation concerning the validation of
> array elements. So far we envisioned to support this:
> String @Email  emails;
> That looks nice (provided that @Email supports TYPE_USE), only that
> it's getting semantics of type annotations for arrays wrong.
> As per the JLS , the @Email annotation here applies to the array
> type String, not the component type String. This example from the
> JLS clarifies the intent:
> @C int @A  @B  f;
> "@A applies to the array type int, @B applies to its component
> type int,
> and @C applies to the element type int."
> So according to that, our example would have to be:
> @Email String emails;
> But obviously this conflicts with the existing semantics of applying
> constraints to arrays (not their elements) in BV 1.1.
> So based on that, I don't see a good way for supporting container
> element constraints for arrays. Hence my suggestion is to not support
> them in the BV 2.0 spec (the validation of container elements of
> generic containers - List<@Email String> - is not affected). Specific
> implementations may explore ways around it (e.g. specifying the target
> via payload()) and we may revisit it in 2.1.
> Any thoughts?
>  https://docs.oracle.com/javase/specs/jls/se8/html/jls-9.html#jls-9.7.4
> beanvalidation-dev mailing list
> beanvalidation-dev at lists.jboss.org
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