Add InternetProtocolFamily and use it with NioDatagramChannel

transport/src/main/java/io/netty/channel/socket/InternetProtocolFamily.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel.socket;
+
+/**
+ * Internet Protocol (IP) families
+ */
+public enum InternetProtocolFamily {
+    IPv4,
+    IPv6;
+}

transport/src/main/java/io/netty/channel/socket/nio/NioDatagramChannel.java

@@ -21,6 +21,7 @@ import io.netty.channel.ChannelException;
 import io.netty.channel.ChannelFuture;
 import io.netty.channel.socket.DatagramChannelConfig;
 import io.netty.channel.socket.DatagramPacket;
+import io.netty.channel.socket.InternetProtocolFamily;
 import io.netty.util.internal.DetectionUtil;
 
 import java.io.IOException;
@@ -57,10 +58,30 @@ public final class NioDatagramChannel extends AbstractNioMessageChannel implemen
         }
     }
 
+    private static DatagramChannel newSocket(InternetProtocolFamily ipFamily) {
+        if (ipFamily == null) {
+            return newSocket();
+        }
+
+        if (DetectionUtil.javaVersion() < 7) {
+            throw new UnsupportedOperationException();
+        }
+
+        try {
+            return DatagramChannel.open(ProtocolFamilyConverter.convert(ipFamily));
+        } catch (IOException e) {
+            throw new ChannelException("Failed to open a socket.", e);
+        }
+    }
+
     public NioDatagramChannel() {
         this(newSocket());
     }
 
+    public NioDatagramChannel(InternetProtocolFamily ipFamily) {
+        this(newSocket(ipFamily));
+    }
+
     public NioDatagramChannel(DatagramChannel socket) {
         this(null, socket);
     }

transport/src/main/java/io/netty/channel/socket/nio/ProtocolFamilyConverter.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel.socket.nio;
+
+import io.netty.channel.socket.InternetProtocolFamily;
+
+/**
+ * Helper class which convert the {@link InternetProtocolFamily}.
+ *
+ *
+ */
+final class ProtocolFamilyConverter {
+
+    private ProtocolFamilyConverter() {
+        // Utility class
+    }
+
+    /**
+     * Convert the {@link InternetProtocolFamily}. This MUST only be called on jdk version >= 7.
+     */
+    public static java.net.ProtocolFamily convert(InternetProtocolFamily family) {
+        switch (family) {
+        case IPv4:
+            return java.net.StandardProtocolFamily.INET;
+
+        case IPv6:
+            return java.net.StandardProtocolFamily.INET6;
+        default:
+            throw new IllegalArgumentException();
+        }
+    }
+}