main() — netty Function Reference

Architecture documentation for the main() function in TcpDnsClient.java from the netty codebase.

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Buffer→ Telemetry→ main() — netty Function Reference

Dependency Diagram

graph TD
  cd1c434a_06e1_fddb_85cd_040fdb61f8c4["main()"]
  b78736d4_8edb_d42a_2963_35bd4229b033["TcpDnsClient"]
  cd1c434a_06e1_fddb_85cd_040fdb61f8c4 -->|defined in| b78736d4_8edb_d42a_2963_35bd4229b033
  42611615_134a_300f_56c1_226f1fc075c0["handleQueryResp()"]
  cd1c434a_06e1_fddb_85cd_040fdb61f8c4 -->|calls| 42611615_134a_300f_56c1_226f1fc075c0
  style cd1c434a_06e1_fddb_85cd_040fdb61f8c4 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

example/src/main/java/io/netty/example/dns/tcp/TcpDnsClient.java lines 72–111

    public static void main(String[] args) throws Exception {
        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) {
                            ChannelPipeline p = ch.pipeline();
                            p.addLast(new TcpDnsQueryEncoder())
                                    .addLast(new TcpDnsResponseDecoder())
                                    .addLast(new SimpleChannelInboundHandler<DefaultDnsResponse>() {
                                        @Override
                                        protected void channelRead0(ChannelHandlerContext ctx, DefaultDnsResponse msg) {
                                            try {
                                                handleQueryResp(msg);
                                            } finally {
                                                ctx.close();
                                            }
                                        }
                                    });
                        }
                    });

            final Channel ch = b.connect(DNS_SERVER_HOST, DNS_SERVER_PORT).sync().channel();

            int randomID = new Random().nextInt(60000 - 1000) + 1000;
            DnsQuery query = new DefaultDnsQuery(randomID, DnsOpCode.QUERY)
                    .setRecord(DnsSection.QUESTION, new DefaultDnsQuestion(QUERY_DOMAIN, DnsRecordType.A));
            ch.writeAndFlush(query).sync();
            boolean success = ch.closeFuture().await(10, TimeUnit.SECONDS);
            if (!success) {
                System.err.println("dns query timeout!");
                ch.close().sync();
            }
        } finally {
            group.shutdownGracefully();
        }
    }