Scala example source code file (FutureInstances.scala)

This example Scala source code file (FutureInstances.scala) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Scala by Example" ^TM.

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Java - Scala tags/keywords

comonad, duration, executioncontext, futureinstances1, monoid

The FutureInstances.scala Scala example source code

package scalaz
package std

import scala.concurrent.{Await, ExecutionContext, Future}
import scala.concurrent.duration.Duration

trait FutureInstances extends FutureInstances1 {
  /**
   * Requires explicit usage as the use of `Await.result`. Can throw an exception, which is inherently bad.
   */
  def futureComonad(duration: Duration)(implicit executionContext: ExecutionContext): Comonad[Future] = new FutureInstance with Comonad[Future] {
    def copoint[A](f: Future[A]): A = Await.result(f, duration)
  }

  implicit def futureMonoid[A](implicit g: Monoid[A], ec: ExecutionContext): Monoid[Future[A]] =
    Monoid.liftMonoid[Future, A]
}