/*
* 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><code>
* {@link ChannelPipeline} pipeline = ...;
* pipeline.addLast("udpEncoder", new {@link DatagramPacketEncoder}(new {@link ProtobufEncoder}(...));
* </code></pre>
*
* 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<AddressedEnvelope<M, InetSocketAddress>> {
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<Object> 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);
}
@Override
public boolean isSharable() {
return encoder.isSharable();
}
}