[bv-dev] Value extraction open issue #5: Should value extractors be discoverable via the service loader?

[Christian Kaltepoth]

Hey Gunnar,

+1 for your proposal. I also think that this overriding scheme is
sufficient and covers all the real world use cases.

Christian

2017-02-20 18:57 GMT+01:00 Michael Nascimento <misterm at gmail.com>:

> Gunnar,
>
> Agreed.
>
> Regards,
> Michael
>
> On Mon, Feb 20, 2017 at 12:54 PM, Gunnar Morling <gunnar at hibernate.org>
> wrote:
>
>> Hi,
>>
>> I think there already was agreement essentially that value extractors
>> should be discoverable using the service loader mechanism.
>>
>> This will allow providers of custom collection types (e.g. Google
>> Guava) to bundle a value extractor with their library and have it
>> being picked up automatically, allowing application developer to put
>> @Valid to these types without any further configuration.
>>
>> So I've prepared a change for that:
>>
>>     https://github.com/beanvalidation/beanvalidation-spec/pull/140
>>
>> The open question was how value extractors should be
>> overridden/disabled. I've foreseen the following sources for value
>> extractors, in descending order of precedence:
>>
>> * ValidatorContext#addValueExtractor(ValueExtractor<?>)
>> * Configuration#addValueExtractor(ValueExtractor<?>)
>> * META-INF/validation.xml
>> * META-INF/services/javax.validation.valueextraction.ValueExtractor
>>
>> If an extractor for a specific type (e.g. java.util.List) and type
>> parameter (e.g. "E") is given at one level (e.g. ValidatorContext) it
>> will override any extractors for the same type and type parameter
>> given at the lower levels and the built-in extractor for that type and
>> type parameter, if any.
>>
>> I don't think there's a way needed to explicitly disable an extractor
>> without providing an alternative implementation. I.e. I cannot see a
>> use case why one would want to disable cascaded validation let's say
>> for List. Hence the proposed overriding scheme.
>>
>> Can you please let me know what you think of this by the end of the week?
>>
>> Thanks,
>>
>> --Gunnar
>> _______________________________________________
>> beanvalidation-dev mailing list
>> beanvalidation-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/beanvalidation-dev
>>
>
>
> _______________________________________________
> beanvalidation-dev mailing list
> beanvalidation-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/beanvalidation-dev
>



-- 
Christian Kaltepoth
Blog: http://blog.kaltepoth.de/
Twitter: http://twitter.com/chkal
GitHub: https://github.com/chkal
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/beanvalidation-dev/attachments/20170221/9e54de0e/attachment.html