Type Signatures

A method's type signature comprises its name; the number, order, and types of its parameters, if any; and its result type. The type signature of a class, trait, or singleton object comprises its name, the type signatures of all of its members and constructors, and its declared inheritance and mixin relations.

In Java you declare a generic type within a <>, in Scala [] is used:

val z: List[String] = "Do" :: "Re" :: "Mi" :: "Fa" :: "So" :: "La" :: "Te" :: "Do" :: Nil

Most of the time, Scala will infer the type and [] are optional:

val z = "Do" :: "Re" :: "Mi" :: "Fa" :: "So" :: "La" :: "Te" :: "Do" :: Nil //Infers that the list assigned to variable is of type List[String]

A trait can be declared containing a type, where a concrete implementer will satisfy the type:

trait Randomizer[A] {
  def draw(): A
}

class IntRandomizer extends Randomizer[Int] {
  def draw() = {
    import util.Random
    Random.nextInt()
  }
}

val intRand = new IntRandomizer
(intRand.draw < Int.MaxValue) should be(res0)

Class meta-information can be retrieved by class name by using classOf[className]:

classOf[String].getCanonicalName should be(res0)
classOf[String].getSimpleName should be(res1)

Class meta-information can be derived from an object reference using getClass():

val zoom = "zoom"
zoom.isInstanceOf[String] should be(res0)
zoom.getClass.getCanonicalName should be(res1)
zoom.getClass.getSimpleName should be(res2)

isInstanceOf[className] is used to determine if an object reference is an instance of a given class:

trait Randomizer[A] {
  def draw(): A
}

class IntRandomizer extends Randomizer[Int] {
  def draw() = {
    import util.Random
    Random.nextInt()
  }
}

val intRand = new IntRandomizer
intRand.isInstanceOf[IntRandomizer] should be(res0)
intRand.isInstanceOf[Randomizer[Int]] should be(res1)
intRand.draw.isInstanceOf[Int] should be(res2)