:; bin/scala -i util/util-app -i finagle/finagle-core jammer.scala Made some tasty jam: cranapple, banana, cherry, durian

jammer.scala

import com.twitter.finagle.{Filter, Service}
import com.twitter.util.{Await, Future}

case class Fruit(flavor: String)
case class Jam(flavor: String)

object Jammer extends Service[Fruit, Jam] {
  def apply(fruit: Fruit) =
    Future value Jam(fruit.flavor)
}

object AppleToCranapple extends Filter[Fruit, Jam, Fruit, Jam] {
  def apply(fruit: Fruit, jammer: Service[Fruit, Jam]) = {
    fruit match {
      case Fruit("apple") => jammer(Fruit("cranapple"))
      case fruit          => jammer(fruit)
    }
  }
}

val fruits = "apple" :: "banana" :: "cherry" :: "durian" :: Nil
val jammer = AppleToCranapple andThen Jammer

try {
  val jams = Await result {
    Future collect {
      fruits map { Fruit(_) } map {
        jammer(_) map { _.flavor }
      }
    }
  }

  println("Made some tasty jam: %s".format(jams.mkString(", ")))
} catch { case e =>
  println("Error: %s".format(e.getMessage))
}