akka.pattern.AskSupport.scala Maven / Gradle / Ivy
/*
* Copyright (C) 2009-2019 Lightbend Inc.
*/
package akka.pattern
import java.util.concurrent.TimeoutException
import akka.actor._
import akka.annotation.InternalApi
import akka.dispatch.sysmsg._
import akka.util.{ Timeout, Unsafe }
import com.github.ghik.silencer.silent
import scala.annotation.tailrec
import scala.concurrent.{ ExecutionContext, Future, Promise }
import scala.language.implicitConversions
import scala.util.{ Failure, Success }
/**
* This is what is used to complete a Future that is returned from an ask/? call,
* when it times out. A typical reason for `AskTimeoutException` is that the recipient
* actor didn't send a reply.
*/
class AskTimeoutException(message: String, cause: Throwable) extends TimeoutException(message) {
def this(message: String) = this(message, null: Throwable)
override def getCause(): Throwable = cause
}
/**
* This object contains implementation details of the “ask” pattern.
*/
trait AskSupport {
/**
* Import this implicit conversion to gain `?` and `ask` methods on
* [[akka.actor.ActorRef]], which will defer to the
* `ask(actorRef, message)(timeout)` method defined here.
*
* {{{
* import akka.pattern.ask
*
* val future = actor ? message // => ask(actor, message)
* val future = actor ask message // => ask(actor, message)
* val future = actor.ask(message)(timeout) // => ask(actor, message)(timeout)
* }}}
*
* All of the above use an implicit [[akka.util.Timeout]].
*/
implicit def ask(actorRef: ActorRef): AskableActorRef = new AskableActorRef(actorRef)
/**
* Sends a message asynchronously and returns a [[scala.concurrent.Future]]
* holding the eventual reply message; this means that the target actor
* needs to send the result to the `sender` reference provided.
*
* The Future will be completed with an [[akka.pattern.AskTimeoutException]] after the
* given timeout has expired; this is independent from any timeout applied
* while awaiting a result for this future (i.e. in
* `Await.result(..., timeout)`). A typical reason for `AskTimeoutException` is that the
* recipient actor didn't send a reply.
*
* Warning:
* When using future callbacks, inside actors you need to carefully avoid closing over
* the containing actor’s object, i.e. do not call methods or access mutable state
* on the enclosing actor from within the callback. This would break the actor
* encapsulation and may introduce synchronization bugs and race conditions because
* the callback will be scheduled concurrently to the enclosing actor. Unfortunately
* there is not yet a way to detect these illegal accesses at compile time.
*
* Recommended usage:
*
* {{{
* val f = ask(worker, request)(timeout)
* f.map { response =>
* EnrichedMessage(response)
* } pipeTo nextActor
* }}}
*
*/
def ask(actorRef: ActorRef, message: Any)(implicit timeout: Timeout): Future[Any] =
actorRef.internalAsk(message, timeout, ActorRef.noSender)
def ask(actorRef: ActorRef, message: Any, sender: ActorRef)(implicit timeout: Timeout): Future[Any] =
actorRef.internalAsk(message, timeout, sender)
/**
* Import this implicit conversion to gain `?` and `ask` methods on
* [[akka.actor.ActorSelection]], which will defer to the
* `ask(actorSelection, message)(timeout)` method defined here.
*
* {{{
* import akka.pattern.ask
*
* val future = selection ? message // => ask(selection, message)
* val future = selection ask message // => ask(selection, message)
* val future = selection.ask(message)(timeout) // => ask(selection, message)(timeout)
* }}}
*
* All of the above use an implicit [[akka.util.Timeout]].
*/
implicit def ask(actorSelection: ActorSelection): AskableActorSelection = new AskableActorSelection(actorSelection)
/**
* Sends a message asynchronously and returns a [[scala.concurrent.Future]]
* holding the eventual reply message; this means that the target actor
* needs to send the result to the `sender` reference provided.
*
* The Future will be completed with an [[akka.pattern.AskTimeoutException]] after the
* given timeout has expired; this is independent from any timeout applied
* while awaiting a result for this future (i.e. in
* `Await.result(..., timeout)`). A typical reason for `AskTimeoutException` is that the
* recipient actor didn't send a reply.
*
* Warning:
* When using future callbacks, inside actors you need to carefully avoid closing over
* the containing actor’s object, i.e. do not call methods or access mutable state
* on the enclosing actor from within the callback. This would break the actor
* encapsulation and may introduce synchronization bugs and race conditions because
* the callback will be scheduled concurrently to the enclosing actor. Unfortunately
* there is not yet a way to detect these illegal accesses at compile time.
*
* Recommended usage:
*
* {{{
* val f = ask(worker, request)(timeout)
* f.map { response =>
* EnrichedMessage(response)
* } pipeTo nextActor
* }}}
*
*/
def ask(actorSelection: ActorSelection, message: Any)(implicit timeout: Timeout): Future[Any] =
actorSelection.internalAsk(message, timeout, ActorRef.noSender)
def ask(actorSelection: ActorSelection, message: Any, sender: ActorRef)(implicit timeout: Timeout): Future[Any] =
actorSelection.internalAsk(message, timeout, sender)
}
/**
* This object contains implementation details of the “ask” pattern,
* which can be combined with "replyTo" pattern.
*/
trait ExplicitAskSupport {
/**
* Import this implicit conversion to gain `?` and `ask` methods on
* [[akka.actor.ActorRef]], which will defer to the
* `ask(actorRef, askSender => message)(timeout)` method defined here.
*
* {{{
* import akka.pattern.ask
*
* // same as `ask(actor, askSender => Request(askSender))`
* val future = actor ? { askSender => Request(askSender) }
*
* // same as `ask(actor, Request(_))`
* val future = actor ? (Request(_))
*
* // same as `ask(actor, Request(_))(timeout)`
* val future = actor ? (Request(_))(timeout)
* }}}
*
* All of the above use a required implicit [[akka.util.Timeout]] and optional implicit
* sender [[akka.actor.ActorRef]].
*/
implicit def ask(actorRef: ActorRef): ExplicitlyAskableActorRef = new ExplicitlyAskableActorRef(actorRef)
/**
* Sends a message asynchronously and returns a [[scala.concurrent.Future]]
* holding the eventual reply message; this means that the target actor
* needs to send the result to the `sender` reference provided.
*
* The Future will be completed with an [[akka.pattern.AskTimeoutException]] after the
* given timeout has expired; this is independent from any timeout applied
* while awaiting a result for this future (i.e. in
* `Await.result(..., timeout)`). A typical reason for `AskTimeoutException` is that the
* recipient actor didn't send a reply.
*
* Warning:
* When using future callbacks, inside actors you need to carefully avoid closing over
* the containing actor’s object, i.e. do not call methods or access mutable state
* on the enclosing actor from within the callback. This would break the actor
* encapsulation and may introduce synchronization bugs and race conditions because
* the callback will be scheduled concurrently to the enclosing actor. Unfortunately
* there is not yet a way to detect these illegal accesses at compile time.
*
* Recommended usage:
*
* {{{
* val f = ask(worker, replyTo => Request(replyTo))(timeout)
* f.map { response =>
* EnrichedMessage(response)
* } pipeTo nextActor
* }}}
*/
def ask(actorRef: ActorRef, messageFactory: ActorRef => Any)(implicit timeout: Timeout): Future[Any] =
actorRef.internalAsk(messageFactory, timeout, ActorRef.noSender)
def ask(actorRef: ActorRef, messageFactory: ActorRef => Any, sender: ActorRef)(
implicit timeout: Timeout): Future[Any] =
actorRef.internalAsk(messageFactory, timeout, sender)
/**
* Import this implicit conversion to gain `?` and `ask` methods on
* [[akka.actor.ActorSelection]], which will defer to the
* `ask(actorSelection, message)(timeout)` method defined here.
*
* {{{
* import akka.pattern.ask
*
* // same as `ask(selection, askSender => Request(askSender))`
* val future = selection ? { askSender => Request(askSender) }
*
* // same as `ask(selection, Request(_))`
* val future = selection ? (Request(_))
*
* // same as `ask(selection, Request(_))(timeout)`
* val future = selection ? (Request(_))(timeout)
* }}}
*
* All of the above use a required implicit [[akka.util.Timeout]] and optional implicit
* sender [[akka.actor.ActorRef]].
*/
implicit def ask(actorSelection: ActorSelection): ExplicitlyAskableActorSelection =
new ExplicitlyAskableActorSelection(actorSelection)
/**
* Sends a message asynchronously and returns a [[scala.concurrent.Future]]
* holding the eventual reply message; this means that the target actor
* needs to send the result to the `sender` reference provided.
*
* The Future will be completed with an [[akka.pattern.AskTimeoutException]] after the
* given timeout has expired; this is independent from any timeout applied
* while awaiting a result for this future (i.e. in
* `Await.result(..., timeout)`). A typical reason for `AskTimeoutException` is that the
* recipient actor didn't send a reply.
*
* Warning:
* When using future callbacks, inside actors you need to carefully avoid closing over
* the containing actor’s object, i.e. do not call methods or access mutable state
* on the enclosing actor from within the callback. This would break the actor
* encapsulation and may introduce synchronization bugs and race conditions because
* the callback will be scheduled concurrently to the enclosing actor. Unfortunately
* there is not yet a way to detect these illegal accesses at compile time.
*
* Recommended usage:
*
* {{{
* val f = ask(worker, replyTo => Request(replyTo))(timeout)
* f.map { response =>
* EnrichedMessage(response)
* } pipeTo nextActor
* }}}
*
*/
def ask(actorSelection: ActorSelection, messageFactory: ActorRef => Any)(implicit timeout: Timeout): Future[Any] =
actorSelection.internalAsk(messageFactory, timeout, ActorRef.noSender)
def ask(actorSelection: ActorSelection, messageFactory: ActorRef => Any, sender: ActorRef)(
implicit timeout: Timeout): Future[Any] =
actorSelection.internalAsk(messageFactory, timeout, sender)
}
object AskableActorRef {
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def ask$extension(actorRef: ActorRef, message: Any, timeout: Timeout): Future[Any] =
actorRef.internalAsk(message, timeout, ActorRef.noSender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def $qmark$extension(actorRef: ActorRef, message: Any, timeout: Timeout): Future[Any] =
actorRef.internalAsk(message, timeout, ActorRef.noSender)
private def messagePartOfException(message: Any, sender: ActorRef): String = {
val msg = if (message == null) "unknown" else message
val wasSentBy = if (sender == ActorRef.noSender) "" else s" was sent by [$sender]"
s"Message of type [${msg.getClass.getName}]$wasSentBy."
}
/**
* INTERNAL API
*/
@InternalApi private[akka] def negativeTimeoutException(
recipient: Any,
message: Any,
sender: ActorRef): IllegalArgumentException = {
new IllegalArgumentException(
s"Timeout length must be positive, question not sent to [$recipient]. " +
messagePartOfException(message, sender))
}
/**
* INTERNAL API
*/
@InternalApi private[akka] def recipientTerminatedException(
recipient: Any,
message: Any,
sender: ActorRef): AskTimeoutException = {
new AskTimeoutException(
s"Recipient [$recipient] had already been terminated. " +
messagePartOfException(message, sender))
}
/**
* INTERNAL API
*/
@InternalApi private[akka] def unsupportedRecipientType(
recipient: Any,
message: Any,
sender: ActorRef): IllegalArgumentException = {
new IllegalArgumentException(
s"Unsupported recipient type, question not sent to [$recipient]. " +
messagePartOfException(message, sender))
}
}
/*
* Implementation class of the “ask” pattern enrichment of ActorRef
*/
final class AskableActorRef(val actorRef: ActorRef) extends AnyVal {
/**
* INTERNAL API: for binary compatibility
*/
protected def ask(message: Any, timeout: Timeout): Future[Any] =
internalAsk(message, timeout, ActorRef.noSender)
def ask(message: Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
protected def ?(message: Any)(implicit timeout: Timeout): Future[Any] =
internalAsk(message, timeout, ActorRef.noSender)
def ?(message: Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def internalAsk(message: Any, timeout: Timeout, sender: ActorRef) = actorRef match {
case ref: InternalActorRef if ref.isTerminated =>
actorRef ! message
Future.failed[Any](AskableActorRef.recipientTerminatedException(actorRef, message, sender))
case ref: InternalActorRef =>
if (timeout.duration.length <= 0)
Future.failed[Any](AskableActorRef.negativeTimeoutException(actorRef, message, sender))
else {
val a = PromiseActorRef(ref.provider, timeout, targetName = actorRef, message.getClass.getName, sender)
actorRef.tell(message, a)
a.result.future
}
case _ => Future.failed[Any](AskableActorRef.unsupportedRecipientType(actorRef, message, sender))
}
}
/*
* Implementation class of the “ask” with explicit sender pattern enrichment of ActorRef
*/
final class ExplicitlyAskableActorRef(val actorRef: ActorRef) extends AnyVal {
def ask(message: ActorRef => Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
def ?(message: ActorRef => Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def internalAsk(messageFactory: ActorRef => Any, timeout: Timeout, sender: ActorRef): Future[Any] =
actorRef match {
case ref: InternalActorRef if ref.isTerminated =>
val message = messageFactory(ref.provider.deadLetters)
actorRef ! message
Future.failed[Any](AskableActorRef.recipientTerminatedException(actorRef, message, sender))
case ref: InternalActorRef =>
if (timeout.duration.length <= 0) {
val message = messageFactory(ref.provider.deadLetters)
Future.failed[Any](AskableActorRef.negativeTimeoutException(actorRef, message, sender))
} else {
val a = PromiseActorRef(ref.provider, timeout, targetName = actorRef, "unknown", sender)
val message = messageFactory(a)
a.messageClassName = message.getClass.getName
actorRef.tell(message, a)
a.result.future
}
case _ if sender eq null =>
Future.failed[Any](
new IllegalArgumentException(
"No recipient for the reply was provided, " +
s"question not sent to [$actorRef]."))
case _ =>
val message =
if (sender == null) null else messageFactory(sender.asInstanceOf[InternalActorRef].provider.deadLetters)
Future.failed[Any](AskableActorRef.unsupportedRecipientType(actorRef, message, sender))
}
}
object AskableActorSelection {
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def ask$extension(actorSel: ActorSelection, message: Any, timeout: Timeout): Future[Any] =
actorSel.internalAsk(message, timeout, ActorRef.noSender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def $qmark$extension(actorSel: ActorSelection, message: Any, timeout: Timeout): Future[Any] =
actorSel.internalAsk(message, timeout, ActorRef.noSender)
}
/*
* Implementation class of the “ask” pattern enrichment of ActorSelection
*/
final class AskableActorSelection(val actorSel: ActorSelection) extends AnyVal {
/**
* INTERNAL API: for binary compatibility
*/
protected def ask(message: Any, timeout: Timeout): Future[Any] =
internalAsk(message, timeout, ActorRef.noSender)
def ask(message: Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
protected def ?(message: Any)(implicit timeout: Timeout): Future[Any] =
internalAsk(message, timeout, ActorRef.noSender)
def ?(message: Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def internalAsk(message: Any, timeout: Timeout, sender: ActorRef): Future[Any] =
actorSel.anchor match {
case ref: InternalActorRef =>
if (timeout.duration.length <= 0)
Future.failed[Any](AskableActorRef.negativeTimeoutException(actorSel, message, sender))
else {
val a = PromiseActorRef(ref.provider, timeout, targetName = actorSel, message.getClass.getName, sender)
actorSel.tell(message, a)
a.result.future
}
case _ => Future.failed[Any](AskableActorRef.unsupportedRecipientType(actorSel, message, sender))
}
}
/*
* Implementation class of the “ask” with explicit sender pattern enrichment of ActorSelection
*/
final class ExplicitlyAskableActorSelection(val actorSel: ActorSelection) extends AnyVal {
def ask(message: ActorRef => Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
def ?(message: ActorRef => Any)(implicit timeout: Timeout, sender: ActorRef = Actor.noSender): Future[Any] =
internalAsk(message, timeout, sender)
/**
* INTERNAL API: for binary compatibility
*/
private[pattern] def internalAsk(messageFactory: ActorRef => Any, timeout: Timeout, sender: ActorRef): Future[Any] =
actorSel.anchor match {
case ref: InternalActorRef =>
if (timeout.duration.length <= 0) {
val message = messageFactory(ref.provider.deadLetters)
Future.failed[Any](AskableActorRef.negativeTimeoutException(actorSel, message, sender))
} else {
val a = PromiseActorRef(ref.provider, timeout, targetName = actorSel, "unknown", sender)
val message = messageFactory(a)
a.messageClassName = message.getClass.getName
actorSel.tell(message, a)
a.result.future
}
case _ if sender eq null =>
Future.failed[Any](
new IllegalArgumentException(
"No recipient for the reply was provided, " +
s"question not sent to [$actorSel]."))
case _ =>
val message =
if (sender == null) null else messageFactory(sender.asInstanceOf[InternalActorRef].provider.deadLetters)
Future.failed[Any](AskableActorRef.unsupportedRecipientType(actorSel, message, sender))
}
}
/**
* Akka private optimized representation of the temporary actor spawned to
* receive the reply to an "ask" operation.
*
* INTERNAL API
*/
private[akka] final class PromiseActorRef private (
val provider: ActorRefProvider,
val result: Promise[Any],
_mcn: String)
extends MinimalActorRef {
import AbstractPromiseActorRef.{ stateOffset, watchedByOffset }
import PromiseActorRef._
// This is necessary for weaving the PromiseActorRef into the asked message, i.e. the replyTo pattern.
@volatile var messageClassName = _mcn
/**
* As an optimization for the common (local) case we only register this PromiseActorRef
* with the provider when the `path` member is actually queried, which happens during
* serialization (but also during a simple call to `toString`, `equals` or `hashCode`!).
*
* Defined states:
* null => started, path not yet created
* Registering => currently creating temp path and registering it
* path: ActorPath => path is available and was registered
* StoppedWithPath(path) => stopped, path available
* Stopped => stopped, path not yet created
*/
@volatile
@silent
private[this] var _stateDoNotCallMeDirectly: AnyRef = _
@volatile
@silent
private[this] var _watchedByDoNotCallMeDirectly: Set[ActorRef] = ActorCell.emptyActorRefSet
@inline
private[this] def watchedBy: Set[ActorRef] =
Unsafe.instance.getObjectVolatile(this, watchedByOffset).asInstanceOf[Set[ActorRef]]
@inline
private[this] def updateWatchedBy(oldWatchedBy: Set[ActorRef], newWatchedBy: Set[ActorRef]): Boolean =
Unsafe.instance.compareAndSwapObject(this, watchedByOffset, oldWatchedBy, newWatchedBy)
@tailrec // Returns false if the Promise is already completed
private[this] final def addWatcher(watcher: ActorRef): Boolean = watchedBy match {
case null => false
case other => updateWatchedBy(other, other + watcher) || addWatcher(watcher)
}
@tailrec
private[this] final def remWatcher(watcher: ActorRef): Unit = watchedBy match {
case null => ()
case other => if (!updateWatchedBy(other, other - watcher)) remWatcher(watcher)
}
@tailrec
private[this] final def clearWatchers(): Set[ActorRef] = watchedBy match {
case null => ActorCell.emptyActorRefSet
case other => if (!updateWatchedBy(other, null)) clearWatchers() else other
}
@inline
private[this] def state: AnyRef = Unsafe.instance.getObjectVolatile(this, stateOffset)
@inline
private[this] def updateState(oldState: AnyRef, newState: AnyRef): Boolean =
Unsafe.instance.compareAndSwapObject(this, stateOffset, oldState, newState)
@inline
private[this] def setState(newState: AnyRef): Unit = Unsafe.instance.putObjectVolatile(this, stateOffset, newState)
override def getParent: InternalActorRef = provider.tempContainer
def internalCallingThreadExecutionContext: ExecutionContext =
provider.guardian.underlying.systemImpl.internalCallingThreadExecutionContext
/**
* Contract of this method:
* Must always return the same ActorPath, which must have
* been registered if we haven't been stopped yet.
*/
@tailrec
def path: ActorPath = state match {
case null =>
if (updateState(null, Registering)) {
var p: ActorPath = null
try {
p = provider.tempPath()
provider.registerTempActor(this, p)
p
} finally {
setState(p)
}
} else path
case p: ActorPath => p
case StoppedWithPath(p) => p
case Stopped =>
// even if we are already stopped we still need to produce a proper path
updateState(Stopped, StoppedWithPath(provider.tempPath()))
path
case Registering => path // spin until registration is completed
}
override def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit = state match {
case Stopped | _: StoppedWithPath => provider.deadLetters ! message
case _ =>
if (message == null) throw InvalidMessageException("Message is null")
if (!(result.tryComplete(message match {
case Status.Success(r) => Success(r)
case Status.Failure(f) => Failure(f)
case other => Success(other)
}))) provider.deadLetters ! message
}
override def sendSystemMessage(message: SystemMessage): Unit = message match {
case _: Terminate => stop()
case DeathWatchNotification(a, ec, at) => this.!(Terminated(a)(existenceConfirmed = ec, addressTerminated = at))
case Watch(watchee, watcher) =>
if (watchee == this && watcher != this) {
if (!addWatcher(watcher))
// ➡➡➡ NEVER SEND THE SAME SYSTEM MESSAGE OBJECT TO TWO ACTORS ⬅⬅⬅
watcher.sendSystemMessage(
DeathWatchNotification(watchee, existenceConfirmed = true, addressTerminated = false))
} else System.err.println("BUG: illegal Watch(%s,%s) for %s".format(watchee, watcher, this))
case Unwatch(watchee, watcher) =>
if (watchee == this && watcher != this) remWatcher(watcher)
else System.err.println("BUG: illegal Unwatch(%s,%s) for %s".format(watchee, watcher, this))
case _ =>
}
@deprecated("Use context.watch(actor) and receive Terminated(actor)", "2.2")
override private[akka] def isTerminated: Boolean = state match {
case Stopped | _: StoppedWithPath => true
case _ => false
}
@tailrec
override def stop(): Unit = {
def ensureCompleted(): Unit = {
result.tryComplete(ActorStopResult)
val watchers = clearWatchers()
if (!watchers.isEmpty) {
watchers.foreach { watcher =>
// ➡➡➡ NEVER SEND THE SAME SYSTEM MESSAGE OBJECT TO TWO ACTORS ⬅⬅⬅
watcher
.asInstanceOf[InternalActorRef]
.sendSystemMessage(DeathWatchNotification(this, existenceConfirmed = true, addressTerminated = false))
}
}
}
state match {
case null => // if path was never queried nobody can possibly be watching us, so we don't have to publish termination either
if (updateState(null, Stopped)) ensureCompleted() else stop()
case p: ActorPath =>
if (updateState(p, StoppedWithPath(p))) {
try ensureCompleted()
finally provider.unregisterTempActor(p)
} else stop()
case Stopped | _: StoppedWithPath => // already stopped
case Registering => stop() // spin until registration is completed before stopping
}
}
}
/**
* INTERNAL API
*/
@InternalApi
private[akka] object PromiseActorRef {
private case object Registering
private case object Stopped
private final case class StoppedWithPath(path: ActorPath)
private val ActorStopResult = Failure(ActorKilledException("Stopped"))
private val defaultOnTimeout: String => Throwable = str => new AskTimeoutException(str)
def apply(
provider: ActorRefProvider,
timeout: Timeout,
targetName: Any,
messageClassName: String,
sender: ActorRef = Actor.noSender,
onTimeout: String => Throwable = defaultOnTimeout): PromiseActorRef = {
val result = Promise[Any]()
val scheduler = provider.guardian.underlying.system.scheduler
val a = new PromiseActorRef(provider, result, messageClassName)
implicit val ec = a.internalCallingThreadExecutionContext
val f = scheduler.scheduleOnce(timeout.duration) {
result.tryComplete {
val wasSentBy = if (sender == ActorRef.noSender) "" else s" was sent by [$sender]"
val messagePart = s"Message of type [${a.messageClassName}]$wasSentBy."
Failure(
onTimeout(
s"Ask timed out on [$targetName] after [${timeout.duration.toMillis} ms]. " +
messagePart +
" A typical reason for `AskTimeoutException` is that the recipient actor didn't send a reply."))
}
}
result.future.onComplete { _ =>
try a.stop()
finally f.cancel()
}
a
}
}
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