Creating a Hibernate Method Validator in Scala

Question

I'm trying to convert this Java code into Scala, and I am failing:

Java (which compiles without error):

Validation.byProvider(HibernateValidator.class).configure().
    buildValidatorFactory().getValidator().unwrap(MethodValidator.class);

Scala:

Validation.byProvider(classOf[HibernateValidator]).configure.
    buildValidatorFactory.getValidator.unwrap( classOf[MethodValidator] )

Scala error:

inferred type arguments [Nothing,org.hibernate.validator.HibernateValidator] do 
  not conform to method byProvider's type parameter bounds [T <: 
  javax.validation.Configuration[T],U <: 
  javax.validation.spi.ValidationProvider[T]]

What am I doing wrong?

I am using Scala 2.10 and have JBoss 7.1.0 on the classpath.

Answer 1

It looks like scala is having a little trouble infering some types. This should work:

Validation.byProvider[HibernateValidatorConfiguration, HibernateValidator](classOf[HibernateValidator])
   .configure.buildValidatorFactory.getValidator.unwrap(classOf[MethodValidator])

If you look at the source of byProvider you'll find this:

public static <T extends javax.validation.Configuration<T>, 
    U extends javax.validation.spi.ValidationProvider<T>>  
    javax.validation.bootstrap.ProviderSpecificBootstrap<T> 
    byProvider(java.lang.Class<U> providerType)

So scala should pick up that HibernateValidator has HibernateValidatorConfiguration implemented, but it doesn't.