CODEWITHSUNDEEP
scala
Jan Goyvaerts
Jan Goyvaerts

Reputation: 3033

Introspect a Scala class for traits?

Is there an introspection api somewhere in Scala to find the traits a class is implementing ?

For Scala 2.9.2 that is.

Upvotes: 2

Views: 158

Answers (2)

Donald.McLean
Donald.McLean

Reputation: 899

Note that the example Kim Stebel used does not work if the trait is implemented by a superclass. Here is a more general form:

  def implementsInterface(target: Class[_], someInterface: Class[_]): Boolean = {
    val i = target.getInterfaces
    i.foreach((c: Class[_]) => if (c == someInterface) return true)

    val s = target.getSuperclass

    if (s == null) false
    else implementsInterface(s, someInterface)
  }

Upvotes: 0

Kim Stebel
Kim Stebel

Reputation: 42047

Trait in Scala translate to interfaces in Java, so you can use Java's reflection library to find out which traits are implemented. Here is an example:

trait Foo
class Bar extends Foo 

val b = new Bar
b.getClass.getInterfaces.foreach(println)

This prints:

interface Foo
interface scala.ScalaObject

Upvotes: 2

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