Scala - ambiguous reference to overloaded definition -- with varargs

Question

Possible Duplicate:
How do I disambiguate in Scala between methods with vararg and without

I am currently porting part of an application to scala and it uses the Oval library. The method is question is the Validator.validate method. It has two signatures:

List<ConstraintViolation> validate(Object validatedObject)
List<ConstraintViolation> validate(Object validatedObject, String... profiles)

The scala code looks generally like this:

def validate(toValidate: AnyRef) = {
  val validator = createValidator
  validator.validate(toValidate)
}

And the error message:

error: ambiguous reference to overloaded definition,
[INFO] both method validate in class Validator of type (x$1: Any,x$2: <repeated...>[java.lang.String])java.util.List[net.sf.oval.ConstraintViolation]
[INFO] and  method validate in class Validator of type (x$1: Any)java.util.List[net.sf.oval.ConstraintViolation]
[INFO] match argument types (AnyRef)
[INFO]       this.validator.validate(toValidate)

How can I get this be be unambiguous?

It does appear to be an ambiguous reference to an overloaded definition question on stack overflow. Should I delete this post? Although Rex Kerr did give an answer that wasn't on the original. — Travis Stevens, Jun 02 '11 at 16:16
I recreated my answer there, and expanded it in two ways: a short form for what I wrote for methods, and an alternate that works for constructors. — Rex Kerr, Jun 02 '11 at 18:10

score 12 · Accepted Answer · edited May 23 '17 at 12:09

12

I think that this could be a duplicate of How do I disambiguate in Scala between methods with vararg and without

Basically, it is a known java-scala-interop problem, and the only workarounds involve extra Java adapters to make accessible in Scala.

edited May 23 '17 at 12:09

Community

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answered Jun 02 '11 at 00:37

jkl

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Sometimes you can avoid the Java adapter by explicitly creating a `Seq` and using the [`_*` type annotation](https://stackoverflow.com/a/6051356/14379), eg `validator.validate(toValidate, Array[String](): _*)`. See answers by Yawar and Teimuraz in the [duplicate question](https://stackoverflow.com/q/3313929/14379). – seanf Jul 01 '19 at 06:32

score 5 · Answer 2 · edited Sep 16 '14 at 09:20

5

The only way I know of is to use reflection:

val ambiguous = validator.getClass.getMethods.filter(_.getName == "validate")
val wanted = ambiguous.find(_.getParameterTypes.length == 1).get
wanted.invoke(validator, toValidate).asInstanceOf[java.util.List[ConstraintViolation]]

edited Sep 16 '14 at 09:20

zellus

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answered Jun 02 '11 at 00:42

Rex Kerr

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Scala - ambiguous reference to overloaded definition -- with varargs

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