Play Framework/Scala example source code file (Promise.scala)

This example Play Framework source code file (Promise.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Play Framework (and Scala) source code examples by using tags.

All credit for the original source code belongs to Play Framework; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Play Framework tags/keywords

a, api, collection, concurrent, core, executioncontext, future, long, play, play framework, promise, spromise, timeunit, utilities

The Promise.scala Play Framework example source code

/*
 * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
 */
package play.api.libs.concurrent

import scala.language.higherKinds

import play.core._
import play.api._

import scala.concurrent.duration.{ FiniteDuration, Duration }

import java.util.concurrent.{ TimeUnit }

import scala.concurrent.{ Future, ExecutionContext, Promise => SPromise }
import scala.collection.mutable.Builder
import scala.collection._
import scala.collection.generic.CanBuildFrom
import java.util.concurrent.TimeoutException
import play.core.Execution.internalContext
import scala.util.Try
import scala.util.control.NonFatal

/**
 * useful helper methods to create and compose Promises
 */
object Promise {

  /**
   * Constructs a Future which will contain value "message" after the given duration elapses.
   * This is useful only when used in conjunction with other Promises
   * @param message message to be displayed
   * @param duration duration for the scheduled promise
   * @return a scheduled promise
   */
  def timeout[A](message: => A, duration: scala.concurrent.duration.Duration)(implicit ec: ExecutionContext): Future[A] = {
    timeout(message, duration.toMillis)
  }

  /**
   * Constructs a Future which will contain value "message" after the given duration elapses.
   * This is useful only when used in conjunction with other Promises
   * @param message message to be displayed
   * @param duration duration for the scheduled promise
   * @return a scheduled promise
   */
  def timeout[A](message: => A, duration: Long, unit: TimeUnit = TimeUnit.MILLISECONDS)(implicit ec: ExecutionContext): Future[A] = {
    val p = SPromise[A]()
    import play.api.Play.current
    Akka.system.scheduler.scheduleOnce(FiniteDuration(duration, unit)) {
      p.complete(Try(message))
    }
    p.future
  }

}