Option value class, to avoid allocations for optional sender

akka-actor/src/main/scala/akka/util/OptionVal.scala

@@ -0,0 +1,69 @@
+/**
+ * Copyright (C) 2016 Lightbend Inc. <http://www.lightbend.com>
+ */
+package akka.util
+
+/**
+ * INTERNAL API
+ */
+private[akka] object OptionVal {
+
+  def apply[A >: Null](x: A): OptionVal[A] = new OptionVal(x)
+
+  object Some {
+    def apply[A >: Null](x: A): OptionVal[A] = new OptionVal(x)
+    def unapply[A >: Null](x: OptionVal[A]): OptionVal[A] = x
+  }
+
+  /**
+   * Represents non-existent values, `null` values.
+   */
+  val None = new OptionVal[Null](null)
+}
+
+/**
+ * INTERNAL API
+ * Represents optional values similar to `scala.Option`, but
+ * as a value class to avoid allocations.
+ *
+ * Note that it can be used in pattern matching without allocations
+ * because it has name based extractor using methods `isEmpty` and `get`.
+ * See http://hseeberger.github.io/blog/2013/10/04/name-based-extractors-in-scala-2-dot-11/
+ */
+private[akka] final class OptionVal[+A >: Null](val x: A) extends AnyVal {
+
+  /**
+   * Returns true if the option is `OptionVal.None`, false otherwise.
+   */
+  def isEmpty: Boolean =
+    x == null
+
+  /**
+   * Returns true if the option is `OptionVal.None`, false otherwise.
+   */
+  def isDefined: Boolean = !isEmpty
+
+  /**
+   * Returns the option's value if the option is nonempty, otherwise
+   * return `default`.
+   */
+  def getOrElse[B >: A](default: B): B =
+    if (x == null) default else x
+
+  /**
+   *  Returns the option's value if it is nonempty, or `null` if it is empty.
+   */
+  def orNull[A1 >: A](implicit ev: Null <:< A1): A1 = this getOrElse ev(null)
+
+  /**
+   * Returns the option's value.
+   * @note The option must be nonEmpty.
+   * @throws java.util.NoSuchElementException if the option is empty.
+   */
+  def get: A =
+    if (x == null) throw new NoSuchElementException("OptionVal.None.get")
+    else x
+
+  override def toString: String =
+    if (x == null) "None" else s"Some($x)"
+}

akka-bench-jmh/src/main/scala/akka/remote/artery/CodecBenchmark.scala

@@ -5,13 +5,10 @@ package akka.remote.artery
 
 import java.nio.ByteBuffer
 import java.nio.ByteOrder
-
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
-
 import scala.concurrent.Await
 import scala.concurrent.duration._
-
 import akka.NotUsed
 import akka.actor.ActorSystem
 import akka.actor.ExtendedActorSystem
@@ -28,6 +25,7 @@ import akka.stream.ActorMaterializerSettings
 import akka.stream.scaladsl._
 import com.typesafe.config.ConfigFactory
 import org.openjdk.jmh.annotations._
+import akka.util.OptionVal
 
 @State(Scope.Benchmark)
 @OutputTimeUnit(TimeUnit.MILLISECONDS)
@@ -127,7 +125,7 @@ class CodecBenchmark {
       Flow.fromGraph(new Encoder(uniqueLocalAddress, system, compression, envelopePool))
 
     Source.fromGraph(new BenchTestSourceSameElement(N, "elem"))
-      .map(_ ⇒ Send(payload, None, remoteRefB, None))
+      .map(_ ⇒ Send(payload, OptionVal.None, remoteRefB, None))
       .via(encoder)
       .map(envelope => envelopePool.release(envelope))
       .runWith(new LatchSink(N, latch))(materializer)
@@ -193,7 +191,7 @@ class CodecBenchmark {
         resolveActorRefWithLocalAddress, compression, envelopePool))
 
     Source.fromGraph(new BenchTestSourceSameElement(N, "elem"))
-      .map(_ ⇒ Send(payload, None, remoteRefB, None))
+      .map(_ ⇒ Send(payload, OptionVal.None, remoteRefB, None))
       .via(encoder)
       .via(decoder)
       .runWith(new LatchSink(N, latch))(materializer)

akka-bench-jmh/src/main/scala/akka/remote/artery/SendQueueBenchmark.scala

@@ -34,7 +34,8 @@ class SendQueueBenchmark {
 
   val config = ConfigFactory.parseString(
     """
-    """)
+    """
+  )
 
   implicit val system = ActorSystem("SendQueueBenchmark", config)
 

akka-remote/src/main/scala/akka/remote/Endpoint.scala

@@ -27,6 +27,8 @@ import scala.concurrent.duration.{ Deadline }
 import scala.util.control.NonFatal
 import java.util.concurrent.locks.LockSupport
 import scala.concurrent.Future
+import akka.util.OptionVal
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -36,7 +38,7 @@ private[remote] trait InboundMessageDispatcher {
     recipient:         InternalActorRef,
     recipientAddress:  Address,
     serializedMessage: SerializedMessage,
-    senderOption:      Option[ActorRef]): Unit
+    senderOption:      OptionVal[ActorRef]): Unit
 }
 
 /**
@@ -53,7 +55,7 @@ private[remote] class DefaultMessageDispatcher(
     recipient:         InternalActorRef,
     recipientAddress:  Address,
     serializedMessage: SerializedMessage,
-    senderOption:      Option[ActorRef]): Unit = {
+    senderOption:      OptionVal[ActorRef]): Unit = {
 
     import provider.remoteSettings._
 

akka-remote/src/main/scala/akka/remote/RemoteActorRefProvider.scala

@@ -11,15 +11,14 @@ import akka.event.{ EventStream, Logging, LoggingAdapter }
 import akka.event.Logging.Error
 import akka.serialization.{ Serialization, SerializationExtension }
 import akka.pattern.pipe
-
 import scala.util.control.NonFatal
 import akka.actor.SystemGuardian.{ RegisterTerminationHook, TerminationHook, TerminationHookDone }
-
 import scala.util.control.Exception.Catcher
 import scala.concurrent.Future
 import akka.ConfigurationException
 import akka.dispatch.{ RequiresMessageQueue, UnboundedMessageQueueSemantics }
 import akka.remote.artery.ArteryTransport
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -528,13 +527,13 @@ private[akka] class RemoteActorRef private[akka] (
         //Unwatch has a different signature, need to pattern match arguments against InternalActorRef
         case Unwatch(watchee: InternalActorRef, watcher: InternalActorRef) if isWatchIntercepted(watchee, watcher) ⇒
           provider.remoteWatcher ! RemoteWatcher.UnwatchRemote(watchee, watcher)
-        case _ ⇒ remote.send(message, None, this)
+        case _ ⇒ remote.send(message, OptionVal.None, this)
       }
     } catch handleException
 
   override def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit = {
     if (message == null) throw new InvalidMessageException("Message is null")
-    try remote.send(message, Option(sender), this) catch handleException
+    try remote.send(message, OptionVal(sender), this) catch handleException
   }
 
   override def provider: RemoteActorRefProvider = remote.provider

akka-remote/src/main/scala/akka/remote/RemoteTransport.scala

@@ -11,6 +11,7 @@ import akka.event.{ LoggingAdapter }
 import scala.collection.immutable
 import scala.concurrent.Future
 import scala.util.control.NoStackTrace
+import akka.util.OptionVal
 
 /**
  * RemoteTransportException represents a general failure within a RemoteTransport,
@@ -68,7 +69,7 @@ private[akka] abstract class RemoteTransport(val system: ExtendedActorSystem, va
   /**
    * Sends the given message to the recipient supplying the sender() if any
    */
-  def send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef): Unit
+  def send(message: Any, senderOption: OptionVal[ActorRef], recipient: RemoteActorRef): Unit
 
   /**
    * Sends a management command to the underlying transport stack. The call returns with a Future that indicates

akka-remote/src/main/scala/akka/remote/Remoting.scala

@@ -24,6 +24,7 @@ import akka.remote.transport.AkkaPduCodec.Message
 import java.util.concurrent.ConcurrentHashMap
 import akka.dispatch.{ RequiresMessageQueue, UnboundedMessageQueueSemantics }
 import akka.util.ByteString.UTF_8
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -209,7 +210,7 @@ private[remote] class Remoting(_system: ExtendedActorSystem, _provider: RemoteAc
     }
   }
 
-  override def send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef): Unit = endpointManager match {
+  override def send(message: Any, senderOption: OptionVal[ActorRef], recipient: RemoteActorRef): Unit = endpointManager match {
     case Some(manager) ⇒ manager.tell(Send(message, senderOption, recipient), sender = senderOption getOrElse Actor.noSender)
     case None          ⇒ throw new RemoteTransportExceptionNoStackTrace("Attempted to send remote message but Remoting is not running.", null)
   }
@@ -249,7 +250,7 @@ private[remote] object EndpointManager {
   final case class Listen(addressesPromise: Promise[Seq[(AkkaProtocolTransport, Address)]]) extends RemotingCommand
   case object StartupFinished extends RemotingCommand
   case object ShutdownAndFlush extends RemotingCommand
-  final case class Send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef, seqOpt: Option[SeqNo] = None)
+  final case class Send(message: Any, senderOption: OptionVal[ActorRef], recipient: RemoteActorRef, seqOpt: Option[SeqNo] = None)
     extends RemotingCommand with HasSequenceNumber {
     override def toString = s"Remote message $senderOption -> $recipient"
 

akka-remote/src/main/scala/akka/remote/artery/ArteryTransport.scala

@@ -77,6 +77,7 @@ import akka.actor.Cancellable
 import scala.collection.JavaConverters._
 import akka.stream.ActorMaterializerSettings
 import scala.annotation.tailrec
+import akka.util.OptionVal
 /**
  * INTERNAL API
  */
@@ -84,7 +85,7 @@ private[akka] final case class InboundEnvelope(
   recipient:        InternalActorRef,
   recipientAddress: Address,
   message:          AnyRef,
-  senderOption:     Option[ActorRef],
+  senderOption:     OptionVal[ActorRef],
   originUid:        Long)
 
 /**
@@ -111,11 +112,10 @@ private[akka] trait InboundContext {
 
   /**
    * Lookup the outbound association for a given UID.
-   * Will return `null` if the UID is unknown, i.e.
+   * Will return `OptionVal.None` if the UID is unknown, i.e.
-   * handshake not completed. `null` is used instead of `Optional`
+   * handshake not completed.
-   * to avoid allocations.
    */
-  def association(uid: Long): OutboundContext
+  def association(uid: Long): OptionVal[OutboundContext]
 
   def completeHandshake(peer: UniqueAddress): Unit
 
@@ -603,7 +603,7 @@ private[remote] class ArteryTransport(_system: ExtendedActorSystem, _provider: R
   override def sendControl(to: Address, message: ControlMessage) =
     association(to).sendControl(message)
 
-  override def send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef): Unit = {
+  override def send(message: Any, senderOption: OptionVal[ActorRef], recipient: RemoteActorRef): Unit = {
     val cached = recipient.cachedAssociation
 
     val a =
@@ -620,7 +620,7 @@ private[remote] class ArteryTransport(_system: ExtendedActorSystem, _provider: R
   override def association(remoteAddress: Address): Association =
     associationRegistry.association(remoteAddress)
 
-  override def association(uid: Long): Association =
+  override def association(uid: Long): OptionVal[Association] =
     associationRegistry.association(uid)
 
   override def completeHandshake(peer: UniqueAddress): Unit = {

akka-remote/src/main/scala/akka/remote/artery/Association.scala

@@ -4,7 +4,6 @@
 package akka.remote.artery
 
 import java.util.Queue
-
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.CopyOnWriteArrayList
 import java.util.concurrent.CountDownLatch
@@ -36,6 +35,7 @@ import akka.stream.scaladsl.Keep
 import akka.stream.scaladsl.Source
 import akka.util.{ Unsafe, WildcardTree }
 import org.agrona.concurrent.ManyToOneConcurrentArrayQueue
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -158,7 +158,7 @@ private[remote] class Association(
   override def sendControl(message: ControlMessage): Unit =
     outboundControlIngress.sendControlMessage(message)
 
-  def send(message: Any, senderOption: Option[ActorRef], recipient: RemoteActorRef): Unit = {
+  def send(message: Any, senderOption: OptionVal[ActorRef], recipient: RemoteActorRef): Unit = {
     // allow ActorSelectionMessage to pass through quarantine, to be able to establish interaction with new system
     // FIXME where is that ActorSelectionMessage check in old remoting?
     if (message.isInstanceOf[ActorSelectionMessage] || !associationState.isQuarantined() || message == ClearSystemMessageDelivery) {
@@ -224,7 +224,7 @@ private[remote] class Association(
                   "Association to [{}] with UID [{}] is irrecoverably failed. Quarantining address. {}",
                   remoteAddress, u, reason)
                 // end delivery of system messages to that incarnation after this point
-                send(ClearSystemMessageDelivery, None, dummyRecipient)
+                send(ClearSystemMessageDelivery, OptionVal.None, dummyRecipient)
                 // try to tell the other system that we have quarantined it
                 sendControl(Quarantined(localAddress, peer))
               } else
@@ -408,8 +408,8 @@ private[remote] class AssociationRegistry(createAssociation: Address ⇒ Associa
     }
   }
 
-  def association(uid: Long): Association =
+  def association(uid: Long): OptionVal[Association] =
-    associationsByUid.get(uid)
+    OptionVal(associationsByUid.get(uid))
 
   def setUID(peer: UniqueAddress): Association = {
     val a = association(peer.address)

akka-remote/src/main/scala/akka/remote/artery/BufferPool.scala

@@ -97,6 +97,7 @@ sealed trait HeaderBuilder {
   def senderActorRef: String
 
   def setNoSender(): Unit
+  def isNoSender: Boolean
 
   def recipientActorRef_=(ref: String): Unit
   def recipientActorRef: String
@@ -135,6 +136,9 @@ private[remote] final class HeaderBuilderImpl(val compressionTable: LiteralCompr
     _senderActorRefIdx = EnvelopeBuffer.DeadLettersCode
   }
 
+  def isNoSender: Boolean =
+    (_senderActorRef eq null) && _senderActorRefIdx == EnvelopeBuffer.DeadLettersCode
+
   def senderActorRef: String = {
     if (_senderActorRef ne null) _senderActorRef
     else {

akka-remote/src/main/scala/akka/remote/artery/Codecs.scala

@@ -1,7 +1,6 @@
 package akka.remote.artery
 
 import scala.util.control.NonFatal
-
 import akka.actor.{ ActorRef, InternalActorRef }
 import akka.actor.ActorSystem
 import akka.actor.ExtendedActorSystem
@@ -11,6 +10,7 @@ import akka.remote.artery.SystemMessageDelivery.SystemMessageEnvelope
 import akka.serialization.{ Serialization, SerializationExtension }
 import akka.stream._
 import akka.stream.stage.{ GraphStage, GraphStageLogic, InHandler, OutHandler }
+import akka.util.OptionVal
 
 // TODO: Long UID
 class Encoder(
@@ -34,7 +34,6 @@ class Encoder(
       private val serialization = SerializationExtension(system)
       private val serializationInfo = Serialization.Information(localAddress, system)
 
-      private val noSender = system.deadLetters.path.toSerializationFormatWithAddress(localAddress)
       private val senderCache = new java.util.HashMap[ActorRef, String]
       private var recipientCache = new java.util.HashMap[ActorRef, String]
 
@@ -57,7 +56,8 @@ class Encoder(
         headerBuilder.recipientActorRef = recipientStr
 
         send.senderOption match {
-          case Some(sender) ⇒
+          case OptionVal.None => headerBuilder.setNoSender()
+          case OptionVal.Some(sender) =>
             val senderStr = senderCache.get(sender) match {
               case null ⇒
                 val s = sender.path.toSerializationFormatWithAddress(localAddress)
@@ -69,9 +69,6 @@ class Encoder(
               case s ⇒ s
             }
             headerBuilder.senderActorRef = senderStr
-          case None ⇒
-            //headerBuilder.setNoSender()
-            headerBuilder.senderActorRef = noSender
         }
 
         try {
@@ -124,7 +121,7 @@ class Decoder(
       private val serialization = SerializationExtension(system)
 
       private val recipientCache = new java.util.HashMap[String, InternalActorRef]
-      private val senderCache = new java.util.HashMap[String, Option[ActorRef]]
+      private val senderCache = new java.util.HashMap[String, ActorRef]
 
       override protected def logSource = classOf[Decoder]
 
@@ -146,16 +143,20 @@ class Decoder(
           case ref ⇒ ref
         }
 
-        val senderOption: Option[ActorRef] = senderCache.get(headerBuilder.senderActorRef) match {
+        val senderOption =
+          if (headerBuilder.isNoSender)
+            OptionVal.None
+          else {
+            senderCache.get(headerBuilder.senderActorRef) match {
               case null ⇒
                 val ref = resolveActorRefWithLocalAddress(headerBuilder.senderActorRef)
                 // FIXME this cache will be replaced by compression table
                 if (senderCache.size() >= 1000)
                   senderCache.clear()
-            val refOpt = Some(ref)
+                senderCache.put(headerBuilder.senderActorRef, ref)
-            senderCache.put(headerBuilder.senderActorRef, refOpt)
+                OptionVal(ref)
-            refOpt
+              case ref ⇒ OptionVal(ref)
-          case refOpt ⇒ refOpt
+            }
           }
 
         try {
@@ -166,7 +167,7 @@ class Decoder(
             recipient,
             localAddress, // FIXME: Is this needed anymore? What should we do here?
             deserializedMessage,
-            senderOption, // FIXME: No need for an option, decode simply to deadLetters instead
+            senderOption,
             headerBuilder.uid)
 
           push(out, decoded)

akka-remote/src/main/scala/akka/remote/artery/Control.scala

@@ -18,6 +18,7 @@ import akka.stream.stage.GraphStageWithMaterializedValue
 import akka.stream.stage.InHandler
 import akka.stream.stage.OutHandler
 import akka.remote.UniqueAddress
+import akka.util.OptionVal
 
 /**
  * INTERNAL API: Marker trait for reply messages
@@ -197,7 +198,7 @@ private[akka] class OutboundControlJunction(outboundContext: OutboundContext)
       }
 
       private def wrap(message: ControlMessage): Send =
-        Send(message, None, outboundContext.dummyRecipient, None)
+        Send(message, OptionVal.None, outboundContext.dummyRecipient, None)
 
       setHandlers(in, out, this)
     }

akka-remote/src/main/scala/akka/remote/artery/Handshake.scala

@@ -5,7 +5,6 @@ package akka.remote.artery
 
 import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
-
 import akka.remote.EndpointManager.Send
 import akka.remote.UniqueAddress
 import akka.stream.Attributes
@@ -17,6 +16,7 @@ import akka.stream.stage.GraphStageLogic
 import akka.stream.stage.InHandler
 import akka.stream.stage.OutHandler
 import akka.stream.stage.TimerGraphStageLogic
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -123,7 +123,7 @@ private[akka] class OutboundHandshake(outboundContext: OutboundContext, timeout:
       private def pushHandshakeReq(): Unit = {
         injectHandshakeTickScheduled = true
         scheduleOnce(InjectHandshakeTick, injectHandshakeInterval)
-        push(out, Send(HandshakeReq(outboundContext.localAddress), None, outboundContext.dummyRecipient, None))
+        push(out, Send(HandshakeReq(outboundContext.localAddress), OptionVal.None, outboundContext.dummyRecipient, None))
       }
 
       private def handshakeCompleted(): Unit = {
@@ -215,7 +215,7 @@ private[akka] class InboundHandshake(inboundContext: InboundContext, inControlSt
 
       private def isKnownOrigin(originUid: Long): Boolean = {
         // FIXME these association lookups are probably too costly for each message, need local cache or something
-        (inboundContext.association(originUid) ne null)
+        inboundContext.association(originUid).isDefined
       }
 
       // OutHandler

akka-remote/src/main/scala/akka/remote/artery/InboundQuarantineCheck.scala

@@ -12,6 +12,7 @@ import akka.stream.stage.GraphStageLogic
 import akka.stream.stage.InHandler
 import akka.stream.stage.OutHandler
 import akka.remote.UniqueAddress
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -28,10 +29,10 @@ private[akka] class InboundQuarantineCheck(inboundContext: InboundContext) exten
       override def onPush(): Unit = {
         val env = grab(in)
         inboundContext.association(env.originUid) match {
-          case null ⇒
+          case OptionVal.None =>
             // unknown, handshake not completed
             push(out, env)
-          case association ⇒
+          case OptionVal.Some(association) =>
             if (association.associationState.isQuarantined(env.originUid)) {
               inboundContext.sendControl(
                 association.remoteAddress,

akka-remote/src/main/scala/akka/remote/artery/MessageDispatcher.scala

@@ -16,6 +16,7 @@ import akka.dispatch.sysmsg.SystemMessage
 import akka.event.Logging
 import akka.remote.RemoteActorRefProvider
 import akka.remote.RemoteRef
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -31,7 +32,7 @@ private[akka] class MessageDispatcher(
     recipient:        InternalActorRef,
     recipientAddress: Address,
     message:          AnyRef,
-    senderOption:     Option[ActorRef]): Unit = {
+    senderOption:     OptionVal[ActorRef]): Unit = {
 
     import provider.remoteSettings._
 

akka-remote/src/main/scala/akka/remote/transport/AkkaPduCodec.scala

@@ -10,6 +10,7 @@ import akka.remote._
 import akka.util.ByteString
 import akka.protobuf.InvalidProtocolBufferException
 import akka.protobuf.{ ByteString ⇒ PByteString }
+import akka.util.OptionVal
 
 /**
  * INTERNAL API
@@ -38,7 +39,7 @@ private[remote] object AkkaPduCodec {
     recipient: InternalActorRef,
     recipientAddress: Address,
     serializedMessage: SerializedMessage,
-    senderOption:      Option[ActorRef],
+    senderOption: OptionVal[ActorRef],
     seqOption: Option[SeqNo]) extends HasSequenceNumber {
 
     def reliableDeliveryEnabled = seqOption.isDefined
@@ -97,7 +98,7 @@ private[remote] trait AkkaPduCodec {
     localAddress: Address,
     recipient: ActorRef,
     serializedMessage: SerializedMessage,
-    senderOption:      Option[ActorRef],
+    senderOption: OptionVal[ActorRef],
     seqOption: Option[SeqNo] = None,
     ackOption: Option[Ack] = None): ByteString
 
@@ -121,7 +122,7 @@ private[remote] object AkkaPduProtobufCodec extends AkkaPduCodec {
     localAddress: Address,
     recipient: ActorRef,
     serializedMessage: SerializedMessage,
-    senderOption:      Option[ActorRef],
+    senderOption: OptionVal[ActorRef],
     seqOption: Option[SeqNo] = None,
     ackOption: Option[Ack] = None): ByteString = {
 
@@ -130,7 +131,11 @@ private[remote] object AkkaPduProtobufCodec extends AkkaPduCodec {
     val envelopeBuilder = RemoteEnvelope.newBuilder
 
     envelopeBuilder.setRecipient(serializeActorRef(recipient.path.address, recipient))
-    senderOption foreach { ref ⇒ envelopeBuilder.setSender(serializeActorRef(localAddress, ref)) }
+    senderOption match {
+      case OptionVal.Some(sender) => envelopeBuilder.setSender(serializeActorRef(localAddress, sender))
+      case OptionVal.None         =>
+    }
+
     seqOption foreach { seq ⇒ envelopeBuilder.setSeq(seq.rawValue) }
     ackOption foreach { ack ⇒ ackAndEnvelopeBuilder.setAck(ackBuilder(ack)) }
     envelopeBuilder.setMessage(serializedMessage)
@@ -193,8 +198,8 @@ private[remote] object AkkaPduProtobufCodec extends AkkaPduCodec {
         recipientAddress = AddressFromURIString(msgPdu.getRecipient.getPath),
         serializedMessage = msgPdu.getMessage,
         senderOption =
-          if (msgPdu.hasSender) Some(provider.resolveActorRefWithLocalAddress(msgPdu.getSender.getPath, localAddress))
+          if (msgPdu.hasSender) OptionVal(provider.resolveActorRefWithLocalAddress(msgPdu.getSender.getPath, localAddress))
-          else None,
+          else OptionVal.None,
         seqOption =
           if (msgPdu.hasSeq) Some(SeqNo(msgPdu.getSeq)) else None))
     } else None

akka-remote/src/test/scala/akka/remote/artery/InboundControlJunctionSpec.scala

@@ -4,7 +4,6 @@
 package akka.remote.artery
 
 import scala.concurrent.duration._
-
 import akka.actor.Address
 import akka.actor.InternalActorRef
 import akka.remote.UniqueAddress
@@ -18,6 +17,7 @@ import akka.stream.testkit.scaladsl.TestSource
 import akka.testkit.AkkaSpec
 import akka.testkit.ImplicitSender
 import akka.testkit.TestProbe
+import akka.util.OptionVal
 
 object InboundControlJunctionSpec {
   case object Control1 extends ControlMessage
@@ -42,7 +42,7 @@ class InboundControlJunctionSpec extends AkkaSpec with ImplicitSender {
       val recipient = null.asInstanceOf[InternalActorRef] // not used
 
       val ((upstream, controlSubject), downstream) = TestSource.probe[AnyRef]
-        .map(msg ⇒ InboundEnvelope(recipient, addressB.address, msg, None, addressA.uid))
+        .map(msg ⇒ InboundEnvelope(recipient, addressB.address, msg, OptionVal.None, addressA.uid))
         .viaMat(new InboundControlJunction)(Keep.both)
         .map { case InboundEnvelope(_, _, msg, _, _) ⇒ msg }
         .toMat(TestSink.probe[Any])(Keep.both)

akka-remote/src/test/scala/akka/remote/artery/InboundHandshakeSpec.scala

@@ -5,7 +5,6 @@ package akka.remote.artery
 
 import scala.concurrent.Await
 import scala.concurrent.duration._
-
 import akka.actor.Address
 import akka.actor.InternalActorRef
 import akka.remote.UniqueAddress
@@ -22,6 +21,7 @@ import akka.stream.testkit.scaladsl.TestSource
 import akka.testkit.AkkaSpec
 import akka.testkit.ImplicitSender
 import akka.testkit.TestProbe
+import akka.util.OptionVal
 
 object InboundHandshakeSpec {
   case object Control1 extends ControlMessage
@@ -41,7 +41,7 @@ class InboundHandshakeSpec extends AkkaSpec with ImplicitSender {
   private def setupStream(inboundContext: InboundContext, timeout: FiniteDuration = 5.seconds): (TestPublisher.Probe[AnyRef], TestSubscriber.Probe[Any]) = {
     val recipient = null.asInstanceOf[InternalActorRef] // not used
     TestSource.probe[AnyRef]
-      .map(msg ⇒ InboundEnvelope(recipient, addressB.address, msg, None, addressA.uid))
+      .map(msg ⇒ InboundEnvelope(recipient, addressB.address, msg, OptionVal.None, addressA.uid))
       .via(new InboundHandshake(inboundContext, inControlStream = true))
       .map { case InboundEnvelope(_, _, msg, _, _) ⇒ msg }
       .toMat(TestSink.probe[Any])(Keep.both)

akka-remote/src/test/scala/akka/remote/artery/OutboundControlJunctionSpec.scala

@@ -4,7 +4,6 @@
 package akka.remote.artery
 
 import scala.concurrent.duration._
-
 import akka.actor.Address
 import akka.remote.EndpointManager.Send
 import akka.remote.RemoteActorRef
@@ -17,6 +16,7 @@ import akka.stream.testkit.scaladsl.TestSink
 import akka.stream.testkit.scaladsl.TestSource
 import akka.testkit.AkkaSpec
 import akka.testkit.ImplicitSender
+import akka.util.OptionVal
 
 object OutboundControlJunctionSpec {
   case object Control1 extends ControlMessage
@@ -41,7 +41,7 @@ class OutboundControlJunctionSpec extends AkkaSpec with ImplicitSender {
       val destination = null.asInstanceOf[RemoteActorRef] // not used
 
       val ((upstream, controlIngress), downstream) = TestSource.probe[String]
-        .map(msg ⇒ Send(msg, None, destination, None))
+        .map(msg ⇒ Send(msg, OptionVal.None, destination, None))
         .viaMat(new OutboundControlJunction(outboundContext))(Keep.both)
         .map { case Send(msg, _, _, _) ⇒ msg }
         .toMat(TestSink.probe[Any])(Keep.both)

akka-remote/src/test/scala/akka/remote/artery/OutboundHandshakeSpec.scala

@@ -4,7 +4,6 @@
 package akka.remote.artery
 
 import scala.concurrent.duration._
-
 import akka.actor.Address
 import akka.remote.EndpointManager.Send
 import akka.remote.RemoteActorRef
@@ -22,6 +21,7 @@ import akka.stream.testkit.scaladsl.TestSource
 import akka.testkit.AkkaSpec
 import akka.testkit.ImplicitSender
 import akka.testkit.TestProbe
+import akka.util.OptionVal
 
 class OutboundHandshakeSpec extends AkkaSpec with ImplicitSender {
 
@@ -38,7 +38,7 @@ class OutboundHandshakeSpec extends AkkaSpec with ImplicitSender {
 
     val destination = null.asInstanceOf[RemoteActorRef] // not used
     TestSource.probe[String]
-      .map(msg ⇒ Send(msg, None, destination, None))
+      .map(msg ⇒ Send(msg, OptionVal.None, destination, None))
       .via(new OutboundHandshake(outboundContext, timeout, retryInterval, injectHandshakeInterval))
       .map { case Send(msg, _, _, _) ⇒ msg }
       .toMat(TestSink.probe[Any])(Keep.both)

akka-remote/src/test/scala/akka/remote/artery/SystemMessageDeliverySpec.scala

@@ -4,10 +4,8 @@
 package akka.remote.artery
 
 import java.util.concurrent.ThreadLocalRandom
-
 import scala.concurrent.Await
 import scala.concurrent.duration._
-
 import akka.NotUsed
 import akka.actor.ActorIdentity
 import akka.actor.ActorSystem
@@ -33,6 +31,7 @@ import akka.testkit.ImplicitSender
 import akka.testkit.TestActors
 import akka.testkit.TestProbe
 import com.typesafe.config.ConfigFactory
+import akka.util.OptionVal
 
 object SystemMessageDeliverySpec {
 
@@ -68,7 +67,7 @@ class SystemMessageDeliverySpec extends AkkaSpec(SystemMessageDeliverySpec.confi
   private def send(sendCount: Int, resendInterval: FiniteDuration, outboundContext: OutboundContext): Source[Send, NotUsed] = {
     val remoteRef = null.asInstanceOf[RemoteActorRef] // not used
     Source(1 to sendCount)
-      .map(n ⇒ Send("msg-" + n, None, remoteRef, None))
+      .map(n ⇒ Send("msg-" + n, OptionVal.None, remoteRef, None))
       .via(new SystemMessageDelivery(outboundContext, resendInterval, maxBufferSize = 1000))
   }
 
@@ -77,7 +76,7 @@ class SystemMessageDeliverySpec extends AkkaSpec(SystemMessageDeliverySpec.confi
     Flow[Send]
       .map {
         case Send(sysEnv: SystemMessageEnvelope, _, _, _) ⇒
-          InboundEnvelope(recipient, addressB.address, sysEnv, None, addressA.uid)
+          InboundEnvelope(recipient, addressB.address, sysEnv, OptionVal.None, addressA.uid)
       }
       .async
       .via(new SystemMessageAcker(inboundContext))

akka-remote/src/test/scala/akka/remote/artery/TestContext.scala

@@ -6,11 +6,9 @@ package akka.remote.artery
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.CopyOnWriteArrayList
 import java.util.concurrent.ThreadLocalRandom
-
 import scala.concurrent.Future
 import scala.concurrent.Promise
 import scala.util.Success
-
 import akka.Done
 import akka.actor.ActorRef
 import akka.actor.Address
@@ -18,6 +16,7 @@ import akka.remote.RemoteActorRef
 import akka.remote.UniqueAddress
 import akka.remote.artery.InboundControlJunction.ControlMessageObserver
 import akka.remote.artery.InboundControlJunction.ControlMessageSubject
+import akka.util.OptionVal
 
 private[akka] class TestInboundContext(
   override val localAddress: UniqueAddress,
@@ -44,8 +43,8 @@ private[akka] class TestInboundContext(
       case existing ⇒ existing
     }
 
-  override def association(uid: Long): OutboundContext =
+  override def association(uid: Long): OptionVal[OutboundContext] =
-    associationsByUid.get(uid)
+    OptionVal(associationsByUid.get(uid))
 
   override def completeHandshake(peer: UniqueAddress): Unit = {
     val a = association(peer.address).asInstanceOf[TestOutboundContext]
@@ -85,7 +84,7 @@ private[akka] class TestOutboundContext(
 
   override def sendControl(message: ControlMessage) = {
     controlProbe.foreach(_ ! message)
-    controlSubject.sendControl(InboundEnvelope(null, remoteAddress, message, None, localAddress.uid))
+    controlSubject.sendControl(InboundEnvelope(null, remoteAddress, message, OptionVal.None, localAddress.uid))
   }
 
   // FIXME we should be able to Send without a recipient ActorRef

akka-remote/src/test/scala/akka/remote/transport/AkkaProtocolSpec.scala

@@ -14,6 +14,7 @@ import com.typesafe.config.ConfigFactory
 import scala.concurrent.duration._
 import scala.concurrent.{ Await, Promise }
 import java.util.concurrent.TimeoutException
+import akka.util.OptionVal
 
 object AkkaProtocolSpec {
 
@@ -66,7 +67,7 @@ class AkkaProtocolSpec extends AkkaSpec("""akka.actor.provider = "akka.remote.Re
   val codec = AkkaPduProtobufCodec
 
   val testMsg = WireFormats.SerializedMessage.newBuilder().setSerializerId(0).setMessage(PByteString.copyFromUtf8("foo")).build
-  val testEnvelope = codec.constructMessage(localAkkaAddress, testActor, testMsg, None)
+  val testEnvelope = codec.constructMessage(localAkkaAddress, testActor, testMsg, OptionVal.None)
   val testMsgPdu: ByteString = codec.constructPayload(testEnvelope)
 
   def testHeartbeat = InboundPayload(codec.constructHeartbeat)

project/MiMa.scala

@@ -853,6 +853,14 @@ object MiMa extends AutoPlugin {
         ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.Remoting.useUntrustedMode"),
         ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.RemoteTransport.useUntrustedMode"),
         
+        // Use OptionVal in remote Send envelope
+        FilterAnyProblemStartingWith("akka.remote.EndpointManager"),
+        FilterAnyProblemStartingWith("akka.remote.Remoting"),
+        FilterAnyProblemStartingWith("akka.remote.RemoteTransport"),
+        FilterAnyProblemStartingWith("akka.remote.InboundMessageDispatcher"),
+        FilterAnyProblemStartingWith("akka.remote.DefaultMessageDispatcher"),
+        FilterAnyProblemStartingWith("akka.remote.transport"),
+          
         // internal api
         FilterAnyProblemStartingWith("akka.stream.impl"),