[bv-dev] On the support for Optional (was Re: Support for constraints on container values (e.g. Collection<@Email String>))

[Gunnar Morling]

Yes, probably we should not support Optional for fields. Also parameters
are dubious (the JDK team discourages that afaik). But supporting it for
return values (and getter-based properties) seems reasonable.

2016-11-21 14:32 GMT+01:00 Emmanuel Bernard <emmanuel at hibernate.org>:

>
> On 7 Nov 2016, at 23:42, Hendrik Ebbers <hendrik.ebbers at me.com> wrote:
>
> I don’t think that support for Optional is that important since having a
> field of type Optional looks like an anti-pattern to me. Normally Optional
> should be used as a method return type and not as a type for a field.
> Supporting it in the bean validation might end in strange model classes.
>
> Example:
>
> The following model looks good to me:
>
> public class Model {
>
> @NotNull
> private String name;
>
> public String getName() { return name; }
>
> public void setName(String name) { this.name = name; }
>
> public Optional<String> name() { return Optional.ofNullable(name);}
>
> }
>
> On the other hand this looks like an anti-pattern to me:
>
> public class Model {
>
> @NotNull
> private Optional<String> name;
>
> public Optional<String> getName() { return name; }
>
> public void setName(String name) { this.name = Optional.ofNullable(name);
> }
>
> }
>
>
> Yes Optional on a property is deemed an anti pattern by the JDK team but
> since Bean Validation supports contraints on method parameters and return
> values, this is still a valid use case
>
> Optional<@Email String> getUserEmail(@NotNull UUID userId);
>
> Emmanuel
>
>
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