How get generic parameter in scala

Question

I would like to be able to perform the following code:

abstract class A[T <: AnyRef]{
  def whichClass: Class[_] = classOf[T]
}

case class X()

object B extends A[X]

object Main{
  def main(args: Array[String]){
    B.whichClass //should return classOf[X]
  }
}

Clearly, it doesn't work in this form, since classOf[T] can be only assignged to class, not type. A got an error:

error: class type required but T found
def whichClass: Class[_] = classOf[T]

Any idea how solve this problem in another way?

missingfaktor · Accepted Answer · 2012-02-02 08:40:12Z

9

Use ClassManifest.

abstract class A[T <: AnyRef : ClassManifest] {
  def whichClass = classManifest[T].erasure
}

case class X()

object B extends A[X]

object Main{
  def main(args: Array[String]): Unit = {
    println(B.whichClass) // prints 'class X'
  }
}

answered Feb 2, 2012 at 8:40

missingfaktor

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1 Comment

virtualeyes Over a year ago

@missing, any idea if this approach will change with new reflection in 2.10?

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