'git mv' rst resources to md

This is mainly intended to keep the git history as neat as possible.
No actual conversion yet, so now both the rst and the paradox docs
are broken, which will be fixed in the next commits.

akka-docs/src/main/paradox/java/code/jdocs/io/JavaUdpMulticastTest.java

@@ -0,0 +1,100 @@
+/**
+ * Copyright (C) 2009-2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+
+package jdocs.io;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.io.Udp;
+import akka.testkit.SocketUtil;
+
+import jdocs.AbstractJavaTest;
+import akka.testkit.javadsl.TestKit;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.*;
+
+
+public class JavaUdpMulticastTest extends AbstractJavaTest {
+
+    static ActorSystem system;
+
+    @BeforeClass
+    public static void setup() {
+        system = ActorSystem.create("JavaUdpMulticastTest");
+    }
+
+    @Test
+    public void testUdpMulticast() throws Exception {
+        new TestKit(system) {{
+            List<NetworkInterface> ipv6Ifaces = new ArrayList<>();
+            for (Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces(); interfaces.hasMoreElements(); ) {
+                NetworkInterface interf = interfaces.nextElement();
+                if (interf.isUp() && interf.supportsMulticast()) {
+                    for (Enumeration<InetAddress> addresses = interf.getInetAddresses(); addresses.hasMoreElements(); ) {
+                        InetAddress address = addresses.nextElement();
+                        if (address instanceof Inet6Address) {
+                            ipv6Ifaces.add(interf);
+                        }
+                    }
+                }
+            }
+            if (ipv6Ifaces.isEmpty()) {
+                system.log().info("JavaUdpMulticastTest skipped since no ipv6 interface supporting multicast could be found");
+            } else {
+                // lots of problems with choosing the wrong interface for this test depending
+                // on the platform (awsdl0 can't be used on OSX, docker[0-9] can't be used in a docker machine etc.)
+                // therefore: try hard to find an interface that _does_ work, and only fail if there was any potentially
+                // working interfaces but all failed
+                for (Iterator<NetworkInterface> interfaceIterator = ipv6Ifaces.iterator(); interfaceIterator.hasNext(); ) {
+                    NetworkInterface ipv6Iface = interfaceIterator.next();
+                    // 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 = SocketUtil.temporaryUdpIpv6Port(ipv6Iface);
+                    final String msg = "ohi";
+                    final ActorRef sink = getRef();
+                    final String iface = ipv6Iface.getName();
+
+                    final ActorRef listener = system.actorOf(Props.create(JavaUdpMulticast.Listener.class, iface, group, port, sink));
+
+                    try {
+                        expectMsgClass(Udp.Bound.class);
+                        final ActorRef sender = system.actorOf(Props.create(JavaUdpMulticast.Sender.class, iface, group, port, msg));
+                        expectMsgEquals(msg);
+                        // success with one interface is enough
+                        break;
+
+                    } catch (AssertionError ex) {
+                        if (!interfaceIterator.hasNext()) throw ex;
+                        else {
+                            system.log().info("Failed to run test on interface {}", ipv6Iface.getDisplayName());
+                        }
+                    } finally {
+                        // unbind
+                        system.stop(listener);
+                    }
+                }
+            }
+        }};
+    }
+
+    @AfterClass
+    public static void tearDown() {
+        TestKit.shutdownActorSystem(system);
+        system = null;
+    }
+}