import scala.concurrent._
import ExecutionContext.Implicits.global
import scala.util.{Success, Failure}

object Demo {
    def main(args: Array[String]){

        // ---------------------------------------------------
        // This shows taking a value of a future and operating on it to give another future.

        val b2: Future[List[Int]] = Future {
            List(1,2)
        }

        val c2:Future[List[Int]] = b2.map( x => x.map( _*3 ) )

        // Note how in this case the two `map` do not have the same meaning.

        c2 onComplete {
          case Success(value) => println(s"Value: $value")
          case Failure(t) => println("An error has occured: " + t.getMessage)
        }

        // Outputs: Value: 2

        Thread.sleep(2000)

    }
}