=doc #15772 Make IPv6 multicast tests work on OS X

* Fixed a small race by waiting for the listenert to be bound
* Changed the Java test to test the Java code (imported the wrong class)
* Changed to a known link local multicas address (the old one just gave me a nop route to host)

akka-samples/akka-docs-udp-multicast/src/main/java/docs/io/JavaUdpMulticast.java

@@ -80,10 +80,13 @@ public class JavaUdpMulticast {
         public void onReceive(Object msg) {
             if (msg instanceof Udp.Bound) {
                 final Udp.Bound b = (Udp.Bound) msg;
-                log.info("Bound to " + b.localAddress());
+                log.info("Bound to {}", b.localAddress());
+                sink.tell(b, getSelf());
             } else if (msg instanceof Udp.Received) {
                 final Udp.Received r = (Udp.Received) msg;
-                log.info("Received '" + r.data().decodeString("utf-8") + "' from '" + r.sender() + "'");
+                final String txt = r.data().decodeString("utf-8");
+                log.info("Received '{}' from {}", txt, r.sender());
+                sink.tell(txt, getSelf());
             } else unhandled(msg);
         }
     }
@@ -91,11 +94,13 @@ public class JavaUdpMulticast {
     public static class Sender extends UntypedActor {
         LoggingAdapter log = Logging.getLogger(getContext().system(), this);
 
+        String iface;
         String group;
         Integer port;
         String message;
 
-        public Sender(String group, Integer port, String msg) {
+        public Sender(String iface, String group, Integer port, String msg) {
+            this.iface = iface;
             this.group = group;
             this.port = port;
             this.message = msg;
@@ -110,7 +115,7 @@ public class JavaUdpMulticast {
         @Override
         public void onReceive(Object msg) {
             if (msg instanceof Udp.SimpleSenderReady) {
-                InetSocketAddress remote = new InetSocketAddress(group, port);
+                InetSocketAddress remote = new InetSocketAddress(group + "%" + iface, port);
                 log.info("Sending message to " + remote);
                 getSender().tell(UdpMessage.send(ByteString.fromString(message), remote), getSelf());
             } else unhandled(msg);

akka-samples/akka-docs-udp-multicast/src/main/scala/ScalaUdpMulticast.scala

@@ -37,22 +37,24 @@ class Listener(iface: String, group: String, port: Int, sink: ActorRef) extends
   //#bind
 
   def receive = {
-    case Udp.Bound(to) => log.info(s"Bound to $to")
+    case b @ Udp.Bound(to) =>
+      log.info("Bound to {}", to)
+      sink ! (b)
     case Udp.Received(data, remote) =>
       val msg = data.decodeString("utf-8")
-      log.info(s"Received '$msg' from '$remote'")
+      log.info("Received '{}' from {}", msg, remote)
       sink ! msg
   }
 }
 
-class Sender(group: String, port: Int, msg: String) extends Actor with ActorLogging {
+class Sender(iface: String, group: String, port: Int, msg: String) extends Actor with ActorLogging {
   import context.system
   IO(Udp) ! Udp.SimpleSender(List(Inet6ProtocolFamily()))
 
   def receive = {
     case Udp.SimpleSenderReady => {
-      val remote = new InetSocketAddress(group, port)
-      log.info(s"Sending message to $remote")
+      val remote = new InetSocketAddress(s"$group%$iface", port)
+      log.info("Sending message to {}", remote)
       sender() ! Udp.Send(ByteString(msg), remote)
     }
   }

akka-samples/akka-docs-udp-multicast/src/test/java/docs/io/JavaUdpMulticastTest.java

@@ -7,6 +7,7 @@ package docs.io;
 import akka.actor.ActorRef;
 import akka.actor.ActorSystem;
 import akka.actor.Props;
+import akka.io.Udp;
 import akka.testkit.JavaTestKit;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -16,6 +17,7 @@ import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.NetworkInterface;
 import java.util.Enumeration;
+import java.util.Random;
 
 public class JavaUdpMulticastTest {
 
@@ -40,14 +42,23 @@ public class JavaUdpMulticastTest {
                 }
             }
 
-            final String group = "FF33::1200";
+            // host assigned link local multicast address http://tools.ietf.org/html/rfc3307#section-4.3.2
+            // generate a random 32 bit multicast address with the high order bit set
+            final String randomAddress = Long.toHexString(((long) Math.abs(new Random().nextInt())) | (1L << 31)).toUpperCase();
+            final StringBuilder groupBuilder = new StringBuilder("FF02:");
+            for (int i = 0; i < 2; i += 1) {
+                groupBuilder.append(":");
+                groupBuilder.append(randomAddress.subSequence(i * 4, i * 4 + 4));
+            }
+            final String group = groupBuilder.toString();
             final Integer port = TestUtils.temporaryUdpIpv6Port(ipv6Iface);
             final String msg = "ohi";
             final ActorRef sink = getRef();
+            final String iface = ipv6Iface.getName();
 
-            final ActorRef listener = system.actorOf(Props.create(Listener.class, ipv6Iface.getName(), group, port, sink));
-            final ActorRef sender = system.actorOf(Props.create(Sender.class, group, port, msg));
-
+            final ActorRef listener = system.actorOf(Props.create(JavaUdpMulticast.Listener.class, iface, group, port, sink));
+            expectMsgClass(Udp.Bound.class);
+            final ActorRef sender = system.actorOf(Props.create(JavaUdpMulticast.Sender.class, iface, group, port, msg));
             expectMsgEquals(msg);
 
             // unbind

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

@@ -6,8 +6,10 @@ package docs.io
 
 import java.net.{Inet6Address, InetSocketAddress, NetworkInterface, StandardProtocolFamily}
 import java.nio.channels.DatagramChannel
+import scala.util.Random
 
 import akka.actor.{ActorSystem, Props}
+import akka.io.Udp
 import akka.testkit.TestKit
 import org.scalatest.{BeforeAndAfter, WordSpecLike}
 
@@ -21,13 +23,18 @@ class ScalaUdpMulticastSpec extends TestKit(ActorSystem("ScalaUdpMulticastSpec")
         case iface if iface.getInetAddresses.exists(_.isInstanceOf[Inet6Address]) => iface
       }
 
+      // host assigned link local multicast address http://tools.ietf.org/html/rfc3307#section-4.3.2
+      // generate a random 32 bit multicast address with the high order bit set
+      val randomAddress: String = (Random.nextInt().abs.toLong | (1L << 31)).toHexString.toUpperCase
+      val group = randomAddress.grouped(4).mkString("FF02::", ":", "")
       val port = TestUtils.temporaryUdpIpv6Port(ipv6Iface)
-
-      val (iface, group, msg, sink) = (ipv6Iface.getName, "FF33::1200", "ohi", testActor)
+      val msg = "ohi"
+      val sink = testActor
+      val iface = ipv6Iface.getName
 
       val listener = system.actorOf(Props(classOf[Listener], iface, group, port, sink))
-      val sender = system.actorOf(Props(classOf[Sender], group, port, msg))
-
+      expectMsgType[Udp.Bound]
+      val sender = system.actorOf(Props(classOf[Sender], iface, group, port, msg))
       expectMsg(msg)
 
       // unbind