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Java example source code file (DatagramPacketEncoder.java)

This example Java source code file (DatagramPacketEncoder.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

addressedenvelope, bytebuf, channelhandlercontext, channelpromise, datagrampacketencoder, encoderexception, exception, inetsocketaddress, list, messagetomessageencoder, net, network, object, override, suppresswarnings, throwable, util

The DatagramPacketEncoder.java Java example source code

/*
 * Copyright 2016 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.handler.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.AddressedEnvelope;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.ChannelPromise;
import io.netty.channel.socket.DatagramPacket;
import io.netty.handler.codec.protobuf.ProtobufEncoder;
import io.netty.util.internal.StringUtil;
import static io.netty.util.internal.ObjectUtil.checkNotNull;

import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.util.List;

/**
 * An encoder that encodes the content in {@link AddressedEnvelope} to {@link DatagramPacket} using
 * the specified message encoder. E.g.,
 *
 * <pre>
 * {@link ChannelPipeline} pipeline = ...;
 * pipeline.addLast("udpEncoder", new {@link DatagramPacketEncoder}(new {@link ProtobufEncoder}(...));
 * </code>
* * Note: As UDP packets are out-of-order, you should make sure the encoded message size are not greater than * the max safe packet size in your particular network path which guarantees no packet fragmentation. * * @param <M> the type of message to be encoded */ public class DatagramPacketEncoder<M> extends MessageToMessageEncoder> { private final MessageToMessageEncoder<? super M> encoder; /** * Create an encoder that encodes the content in {@link AddressedEnvelope} to {@link DatagramPacket} using * the specified message encoder. * * @param encoder the specified message encoder */ public DatagramPacketEncoder(MessageToMessageEncoder<? super M> encoder) { this.encoder = checkNotNull(encoder, "encoder"); } @Override public boolean acceptOutboundMessage(Object msg) throws Exception { if (super.acceptOutboundMessage(msg)) { @SuppressWarnings("rawtypes") AddressedEnvelope envelope = (AddressedEnvelope) msg; return encoder.acceptOutboundMessage(envelope.content()) && envelope.sender() instanceof InetSocketAddress && envelope.recipient() instanceof InetSocketAddress; } return false; } @Override protected void encode( ChannelHandlerContext ctx, AddressedEnvelope<M, InetSocketAddress> msg, List out) throws Exception { assert out.isEmpty(); encoder.encode(ctx, msg.content(), out); if (out.size() != 1) { throw new EncoderException( StringUtil.simpleClassName(encoder) + " must produce only one message."); } Object content = out.get(0); if (content instanceof ByteBuf) { // Replace the ByteBuf with a DatagramPacket. out.set(0, new DatagramPacket((ByteBuf) content, msg.recipient(), msg.sender())); } else { throw new EncoderException( StringUtil.simpleClassName(encoder) + " must produce only ByteBuf."); } } @Override public void bind(ChannelHandlerContext ctx, SocketAddress localAddress, ChannelPromise promise) throws Exception { encoder.bind(ctx, localAddress, promise); } @Override public void connect( ChannelHandlerContext ctx, SocketAddress remoteAddress, SocketAddress localAddress, ChannelPromise promise) throws Exception { encoder.connect(ctx, remoteAddress, localAddress, promise); } @Override public void disconnect(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception { encoder.disconnect(ctx, promise); } @Override public void close(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception { encoder.close(ctx, promise); } @Override public void deregister(ChannelHandlerContext ctx, ChannelPromise promise) throws Exception { encoder.deregister(ctx, promise); } @Override public void read(ChannelHandlerContext ctx) throws Exception { encoder.read(ctx); } @Override public void flush(ChannelHandlerContext ctx) throws Exception { encoder.flush(ctx); } @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { encoder.handlerAdded(ctx); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { encoder.handlerRemoved(ctx); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { encoder.exceptionCaught(ctx, cause); } }

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