Java tutorial
/* * Copyright 2015 Sebastian Schmidl * * Licensed 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 sas.systems.imflux.network.udp; import io.netty.buffer.ByteBuf; import io.netty.channel.AddressedEnvelope; import io.netty.channel.ChannelHandler.Sharable; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelPipeline; import io.netty.channel.DefaultAddressedEnvelope; import io.netty.channel.socket.DatagramPacket; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.MessageToMessageDecoder; import sas.systems.imflux.logging.Logger; import sas.systems.imflux.packet.DataPacket; import java.net.SocketAddress; import java.util.List; /** * Decodes a {@link DatagramPacket} to a {@link DataPacket} wrapped into an {@link AddressedEnvelope} to allow * mulitcast on the used {@link SocketChannel}. You can access the {@link SocketAddress} from this packets source with * {@link AddressedEnvelope#sender()}. This class extends {@link MessageToMessageDecoder} and can therefore be used in multiple * {@link ChannelPipeline}s. * * @author <a href="https://github.com/CodeLionX">CodeLionX</a> */ @Sharable public class UdpDataPacketDecoder extends MessageToMessageDecoder<DatagramPacket> { // constants ------------------------------------------------------------------------------------------------------ protected static final Logger LOG = Logger.getLogger(UdpDataPacketDecoder.class); // constructor ---------------------------------------------------------------------------------------------------- private UdpDataPacketDecoder() { } // public static methods ------------------------------------------------------------------------------------------ /** * * @return instance of UdpControlPacketDecoder */ public static UdpDataPacketDecoder getInstance() { return InstanceHolder.INSTANCE; } // MessageToMessageDecoder ------------------------------------------------------------------------------------------------ /** * Decodes a {@link DatagramPacket} to a {@link DataPacket} wrapped into an {@link AddressedEnvelope} to allow multicast on * the used {@link SocketChannel}. * * @param ctx The context of the ChannelHandler * @param message the message which should be encoded * @param out a list where all messages are written to */ @Override protected void decode(ChannelHandlerContext ctx, DatagramPacket msg, List<Object> out) throws Exception { final ByteBuf content = msg.content(); final SocketAddress sender = msg.sender(); final SocketAddress recipient = msg.recipient(); try { final DataPacket dataPacket = DataPacket.decode(content); final AddressedEnvelope<DataPacket, SocketAddress> newMsg = new DefaultAddressedEnvelope<DataPacket, SocketAddress>( dataPacket, recipient, sender); out.add(newMsg); } catch (Exception e) { LOG.debug("Failed to decode RTP packet.", e); } } // private classes ------------------------------------------------------------------------------------------------ /** * Factory class for the {@link UdpDataPacketDecoder}. * * @author <a href="https://github.com/CodeLionX">CodeLionX</a> */ private static final class InstanceHolder { /** * Private constructor for hiding the implicit default one. */ private InstanceHolder() { }; private static final UdpDataPacketDecoder INSTANCE = new UdpDataPacketDecoder(); } }