DatagramPacketEncoder Class — netty Architecture

Source Code

codec-base/src/main/java/io/netty/handler/codec/DatagramPacketEncoder.java lines 45–147

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.sender() == null)
                    && 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);