Source code
package io.netty.example.sctp;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.MultiThreadIoEventLoopGroup;
import io.netty.channel.nio.NioIoHandler;
import io.netty.channel.sctp.SctpChannel;
import io.netty.channel.sctp.nio.NioSctpServerChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
public final class SctpEchoServer {
static final int PORT = Integer.parseInt(System.getProperty("port", "8007"));
public static void main(String[] args) throws Exception {
EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());
final SctpEchoServerHandler serverHandler = new SctpEchoServerHandler();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(group)
.channel(NioSctpServerChannel.class)
.option(ChannelOption.SO_BACKLOG, 100)
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ChannelInitializer<SctpChannel>() {
@Override
public void initChannel(SctpChannel ch) throws Exception {
ch.pipeline().addLast(
serverHandler);
}
});
ChannelFuture f = b.bind(PORT).sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully();
}
}
}
Run 1
The code demonstrates clear structure and follows Netty conventions well. The main method is logically organized with a try-finally block ensuring resource cleanup. Nesting is minimal, limited to the anonymous ChannelInitializer class, which is a standard pattern. Intent is clear - setting up an SCTP echo server with proper bootstrap configuration. Code length is appropriate and concise without unnecessary verbosity. Action granularity is good, with each line performing a single meaningful operation. Reading flow is natural, progressing from setup to binding to shutdown. Minor deductions: several blank lines with comments appear to have stray spaces or are empty, and the anonymous inner class could be replaced with a lambda for slightly better readability in newer Java versions. The static PORT initialization via System.getProperty is a common pattern but could be documented. Overall, highly readable code that follows established patterns.
Run 2
The code is highly readable with a clear, logical structure: imports are organized, the main method flows naturally, and the try-finally block ensures proper resource cleanup. Nesting is minimal, with only one inner class for channel initialization. Intent is evident — setting up an SCTP echo server — and the code is concise without unnecessary verbosity. Each action is on its own line, and the chained builder pattern improves clarity. Minor issues include a few blank lines and a stray comment placeholder that slightly disrupt the reading flow, but overall it is well-structured and easy to understand.
Run 3
The code is generally readable: it has a clear top-level structure, straightforward naming, and a single responsibility. Imports are grouped, and the flow follows a standard Netty bootstrap pattern. The fluent builder chain is reasonably flat and uses indentation well. However, readability is reduced by empty comments (`// ...`) that hint at missing documentation, a variable named `b` that could be more descriptive (e.g., `bootstrap`), and an anonymous inner `ChannelInitializer` that adds one more nesting level without necessity. Some blank lines are inconsistent. The logging and child handler setup is fine, but the static `PORT` initialization from system property is slightly dense. Overall, the code is easy to follow for a developer familiar with Netty but could benefit from clearer variable names and consistent comments or removal of placeholder comments.
Run 1
Code Structure: Logically organizes server configuration, binding, waiting, and cleanup, with resource shutdown in a finally block. Nesting: Mostly shallow, though the anonymous ChannelInitializer introduces moderate nesting. Clarity of intent: Class and API names clearly convey an SCTP echo server, but abbreviated variables b and f reduce clarity. Code length: Concise overall, although excessive blank lines and the unnecessarily split addLast call add visual clutter. Action granularity: Statements generally perform one action each; the fluent configuration chain separates options onto individual lines. Reading flow: Execution follows a natural setup-to-shutdown sequence, but inconsistent whitespace and indentation interrupt scanning.
Run 2
Code Structure: Logically organized into configuration, server startup, waiting, and cleanup, with resource shutdown clearly placed in finally. Nesting: Mostly shallow; the anonymous ChannelInitializer adds moderate indentation but remains manageable. Clarity of intent: The class name and Netty API calls clearly convey an SCTP echo server, although abbreviated variables b and f are less descriptive. Code length: Concise overall, but excessive blank lines and the unnecessarily split addLast call add visual clutter. Action granularity: Statements generally perform one action, and bootstrap configuration places each chained operation on its own line. Reading flow: Execution proceeds naturally from initialization through shutdown, but inconsistent whitespace interrupts the flow.
Run 3
Code Structure: Logically separates initialization, server configuration, binding, waiting, and cleanup, with resource shutdown in finally. Nesting: Mostly shallow; the anonymous ChannelInitializer adds modest nesting. Clarity of intent: The class name and Netty API calls clearly indicate an SCTP echo server, although variable names b and f are vague. Code length: Concise overall, but excessive blank lines and the unnecessarily split addLast call add visual clutter. Action granularity: Statements generally perform one action each, and the fluent configuration chain places each setting on its own line. Reading flow: Execution proceeds naturally from setup through shutdown, though inconsistent spacing and indentation interrupt the flow.