From ba4a3b7f65aac8fff6f43c4406734fb2df22dec8 Mon Sep 17 00:00:00 2001
From: Viktor Klang <viktor.klang@gmail.com>
Date: Wed, 25 Apr 2012 18:34:16 +0200
Subject: [PATCH] #1973 - Adding support for a mechanism to create Futures that
 will have a result after a specified duration.

---
 .../test/scala/akka/pattern/PatternSpec.scala | 19 ++++++++++++++-
 .../akka/pattern/FutureTimeoutSupport.scala   | 23 +++++++++++++++++++
 .../main/scala/akka/pattern/Patterns.scala    | 22 ++++++++++++++++--
 .../src/main/scala/akka/pattern/package.scala |  2 +-
 4 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 akka-actor/src/main/scala/akka/pattern/FutureTimeoutSupport.scala

diff --git a/akka-actor-tests/src/test/scala/akka/pattern/PatternSpec.scala b/akka-actor-tests/src/test/scala/akka/pattern/PatternSpec.scala
index ce1b9db201..2776beabce 100644
--- a/akka-actor-tests/src/test/scala/akka/pattern/PatternSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/pattern/PatternSpec.scala
@@ -8,9 +8,10 @@ import akka.testkit.AkkaSpec
 import akka.actor.Props
 import akka.actor.Actor
 import akka.actor.ActorTimeoutException
-import akka.dispatch.Await
 import akka.util.Duration
 import akka.util.duration._
+import akka.dispatch.{ Future, Promise, Await }
+import java.lang.IllegalStateException
 
 object PatternSpec {
   case class Work(duration: Duration)
@@ -49,4 +50,20 @@ class PatternSpec extends AkkaSpec {
       }
     }
   }
+
+  "pattern.after" must {
+    "be completed successfully eventually" in {
+      val f = after(1 second, using = system.scheduler)(Promise.successful(5))
+
+      val r = Future.firstCompletedOf(Seq(Promise[Int](), f))
+      Await.result(r, remaining) must be(5)
+    }
+
+    "be completed abnormally eventually" in {
+      val f = after(1 second, using = system.scheduler)(Promise.failed(new IllegalStateException("Mexico")))
+
+      val r = Future.firstCompletedOf(Seq(Promise[Int](), f))
+      intercept[IllegalStateException] { Await.result(r, remaining) }.getMessage must be("Mexico")
+    }
+  }
 }
diff --git a/akka-actor/src/main/scala/akka/pattern/FutureTimeoutSupport.scala b/akka-actor/src/main/scala/akka/pattern/FutureTimeoutSupport.scala
new file mode 100644
index 0000000000..25bc199ff5
--- /dev/null
+++ b/akka-actor/src/main/scala/akka/pattern/FutureTimeoutSupport.scala
@@ -0,0 +1,23 @@
+package akka.pattern
+
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+import akka.util.Duration
+import akka.actor._
+import akka.dispatch.{ ExecutionContext, Promise, Future }
+
+trait FutureTimeoutSupport {
+  /**
+   * Returns a [[akka.dispatch.Future]] that will be completed with the success or failure of the provided value
+   * after the specified duration.
+   */
+  def after[T](duration: Duration, using: Scheduler)(value: ⇒ Future[T])(implicit ec: ExecutionContext): Future[T] =
+    if (duration.isFinite() && duration.length < 1) value else {
+      val p = Promise[T]()
+      val c = using.scheduleOnce(duration) { p completeWith value }
+      p onComplete { _ ⇒ c.cancel() }
+      p
+    }
+}
\ No newline at end of file
diff --git a/akka-actor/src/main/scala/akka/pattern/Patterns.scala b/akka-actor/src/main/scala/akka/pattern/Patterns.scala
index 7167775b29..b58e9a8fc1 100644
--- a/akka-actor/src/main/scala/akka/pattern/Patterns.scala
+++ b/akka-actor/src/main/scala/akka/pattern/Patterns.scala
@@ -3,10 +3,14 @@
  */
 package akka.pattern
 
+import akka.actor.Scheduler
+import akka.dispatch.ExecutionContext
+import java.util.concurrent.Callable
+
 object Patterns {
   import akka.actor.{ ActorRef, ActorSystem }
   import akka.dispatch.Future
-  import akka.pattern.{ ask ⇒ scalaAsk, pipe ⇒ scalaPipe }
+  import akka.pattern.{ ask ⇒ scalaAsk, pipe ⇒ scalaPipe, gracefulStop ⇒ scalaGracefulStop, after ⇒ scalaAfter }
   import akka.util.{ Timeout, Duration }
 
   /**
@@ -99,5 +103,19 @@ object Patterns {
    * is completed with failure [[akka.actor.ActorTimeoutException]].
    */
   def gracefulStop(target: ActorRef, timeout: Duration, system: ActorSystem): Future[java.lang.Boolean] =
-    akka.pattern.gracefulStop(target, timeout)(system).asInstanceOf[Future[java.lang.Boolean]]
+    scalaGracefulStop(target, timeout)(system).asInstanceOf[Future[java.lang.Boolean]]
+
+  /**
+   * Returns a [[akka.dispatch.Future]] that will be completed with the success or failure of the provided Callable
+   * after the specified duration.
+   */
+  def after[T](duration: Duration, scheduler: Scheduler, context: ExecutionContext, value: Callable[Future[T]]): Future[T] =
+    scalaAfter(duration, scheduler)(value.call())(context)
+
+  /**
+   * Returns a [[akka.dispatch.Future]] that will be completed with the success or failure of the provided value
+   * after the specified duration.
+   */
+  def after[T](duration: Duration, scheduler: Scheduler, context: ExecutionContext, value: Future[T]): Future[T] =
+    scalaAfter(duration, scheduler)(value)(context)
 }
diff --git a/akka-actor/src/main/scala/akka/pattern/package.scala b/akka-actor/src/main/scala/akka/pattern/package.scala
index ec4786a4c0..f467ca72f2 100644
--- a/akka-actor/src/main/scala/akka/pattern/package.scala
+++ b/akka-actor/src/main/scala/akka/pattern/package.scala
@@ -40,6 +40,6 @@ import akka.util.{ Timeout, Duration }
  * ask(actor, message);
  * }}}
  */
-package object pattern extends PipeToSupport with AskSupport with GracefulStopSupport {
+package object pattern extends PipeToSupport with AskSupport with GracefulStopSupport with FutureTimeoutSupport {
 
 }
\ No newline at end of file