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

[Matt Benson]

On Mon, Nov 21, 2016 at 8:18 AM, Gunnar Morling <gunnar at hibernate.org> wrote:
> 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.

+1

Matt (with apologies for not having participated earlier in the spec
2.0 process)

>
> 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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>
>
>
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