rmulticast: use DatagramChannel

1 files changed, 19 insertions, 0 deletions

diff --git a/src/main/java/derms/net/Net.java b/src/main/java/derms/net/Net.java
new file mode 100644
index 0000000..f2eb1fd
--- /dev/null
+++ b/src/main/java/derms/net/Net.java
@@ -0,0 +1,19 @@
+package derms.net;
+
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+
+public class Net {
+    /** Return the first non-loopback multicast interface in the system, or throw exception if no such interface exists. */
+    public static NetworkInterface getMulticastInterface() throws SocketException, NoSuchElementException {
+        Enumeration<NetworkInterface> ifss =  NetworkInterface.getNetworkInterfaces();
+        while (ifss.hasMoreElements()) {
+            NetworkInterface ifs = ifss.nextElement();
+            if (ifs.supportsMulticast() && !ifs.isLoopback() && ifs.isUp())
+                return ifs;
+        }
+        throw new NoSuchElementException("no multicast interface available");
+    }
+}