/*
* 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();
}
}