!act #15626 expose DatagramChannel creation in DatagramChannelCreator

* move channel creation logic to a separate trait
* new Java API: AbstractSocketOption

akka-samples/akka-docs-udp-multicast/src/test/scala/ScalaUdpMulticastSpec.scala

@@ -0,0 +1,52 @@
+/**
+ * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
+ */
+
+package docs.io
+
+import java.net.{Inet6Address, InetSocketAddress, NetworkInterface, StandardProtocolFamily}
+import java.nio.channels.DatagramChannel
+
+import akka.actor.{ActorSystem, Props}
+import akka.testkit.TestKit
+import org.scalatest.{BeforeAndAfter, WordSpecLike}
+
+import scala.collection.JavaConversions.enumerationAsScalaIterator
+
+class ScalaUdpMulticastSpec extends TestKit(ActorSystem("ScalaUdpMulticastSpec")) with WordSpecLike with BeforeAndAfter {
+
+  "listener" should {
+    "send message back to sink" in {
+      val Some(ipv6Iface) = NetworkInterface.getNetworkInterfaces.collectFirst {
+        case iface if iface.getInetAddresses.exists(_.isInstanceOf[Inet6Address]) => iface
+      }
+
+      val port = TestUtils.temporaryUdpIpv6Port(ipv6Iface)
+
+      val (iface, group, msg, sink) = (ipv6Iface.getName, "FF33::1200", "ohi", testActor)
+
+      val listener = system.actorOf(Props(classOf[Listener], iface, group, port, sink))
+      val sender = system.actorOf(Props(classOf[Sender], group, port, msg))
+
+      expectMsg(msg)
+
+      // unbind
+      system.stop(listener)
+    }
+  }
+
+  def afterAll = {
+    TestKit.shutdownActorSystem(system)
+  }
+
+}
+
+object TestUtils {
+  def temporaryUdpIpv6Port(iface: NetworkInterface) = {
+    val serverSocket = DatagramChannel.open(StandardProtocolFamily.INET6).socket()
+    serverSocket.bind(new InetSocketAddress(iface.getInetAddresses.nextElement(), 0))
+    val port = serverSocket.getLocalPort
+    serverSocket.close()
+    port
+  }
+}