NioServerSocketChannel Class — netty Architecture

Source Code

transport/src/main/java/io/netty/channel/socket/nio/NioServerSocketChannel.java lines 47–251

public class NioServerSocketChannel extends AbstractNioMessageChannel
                             implements io.netty.channel.socket.ServerSocketChannel {

    private static final ChannelMetadata METADATA = new ChannelMetadata(false, 16);
    private static final SelectorProvider DEFAULT_SELECTOR_PROVIDER = SelectorProvider.provider();

    private static final InternalLogger logger = InternalLoggerFactory.getInstance(NioServerSocketChannel.class);

    private static final Method OPEN_SERVER_SOCKET_CHANNEL_WITH_FAMILY =
            SelectorProviderUtil.findOpenMethod("openServerSocketChannel");

    private static ServerSocketChannel newChannel(SelectorProvider provider, SocketProtocolFamily family) {
        try {
            ServerSocketChannel channel =
                    SelectorProviderUtil.newChannel(OPEN_SERVER_SOCKET_CHANNEL_WITH_FAMILY, provider, family);
            return channel == null ? provider.openServerSocketChannel() : channel;
        } catch (IOException e) {
            throw new ChannelException("Failed to open a socket.", e);
        }
    }

    private final ServerSocketChannelConfig config;

    /**
     * Create a new instance
     */
    public NioServerSocketChannel() {
        this(DEFAULT_SELECTOR_PROVIDER);
    }

    /**
     * Create a new instance using the given {@link SelectorProvider}.
     */
    public NioServerSocketChannel(SelectorProvider provider) {
        this(provider, (SocketProtocolFamily) null);
    }

    /**
     * Create a new instance using the given {@link SelectorProvider} and protocol family (supported only since JDK 15).
     *
     * @deprecated use {@link NioServerSocketChannel#NioServerSocketChannel(SelectorProvider, SocketProtocolFamily)}
     */
    @Deprecated
    public NioServerSocketChannel(SelectorProvider provider, InternetProtocolFamily family) {
        this(provider, family == null ? null : family.toSocketProtocolFamily());
    }

    /**
     * Create a new instance using the given {@link SelectorProvider} and protocol family (supported only since JDK 15).
     */
    public NioServerSocketChannel(SelectorProvider provider, SocketProtocolFamily family) {
        this(newChannel(provider, family));
    }

    /**
     * Create a new instance using the given {@link ServerSocketChannel}.
     */
    public NioServerSocketChannel(ServerSocketChannel channel) {
        super(null, channel, SelectionKey.OP_ACCEPT);
        config = new NioServerSocketChannelConfig(this, javaChannel().socket());
    }

    @Override
    public InetSocketAddress localAddress() {
        return (InetSocketAddress) super.localAddress();
    }

    @Override
    public ChannelMetadata metadata() {
        return METADATA;
    }

    @Override
    public ServerSocketChannelConfig config() {
        return config;
    }

    @Override
    public boolean isActive() {
        // As java.nio.ServerSocketChannel.isBound() will continue to return true even after the channel was closed
        // we will also need to check if it is open.