BlockingSocketServer.java

package io.datakernel.net;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ThreadFactory;

public final class BlockingSocketServer {
	public interface AcceptHandler {
		void onAccept(Socket socket) throws IOException;
	}

	private static final Logger logger = LoggerFactory.getLogger(BlockingSocketServer.class);
	private ThreadFactory acceptThreadFactory;
	private final ExecutorService executor;
	private final AcceptHandler acceptHandler;
	private ServerSocketSettings serverSocketSettings;
	private SocketSettings socketSettings;
	private final List<InetSocketAddress> listenAddresses = new ArrayList<>();

	private final List<ServerSocket> serverSockets = new ArrayList<>();
	private final Map<ServerSocket, Thread> acceptThreads = new HashMap<>();

	private BlockingSocketServer(ExecutorService executor, AcceptHandler acceptHandler) {
		this.executor = executor;
		this.acceptHandler = acceptHandler;
	}

	public BlockingSocketServer withAcceptThreadFactory(ThreadFactory acceptThreadFactory) {
		this.acceptThreadFactory = acceptThreadFactory;
		return this;
	}

	public BlockingSocketServer withListenAddresses(List<InetSocketAddress> listenAddresses) {
		this.listenAddresses.addAll(listenAddresses);
		return this;
	}

	public BlockingSocketServer withListenAddresses(InetSocketAddress... listenAddresses) {
		return withListenAddresses(Arrays.asList(listenAddresses));
	}

	public BlockingSocketServer withListenAddress(InetSocketAddress listenAddress) {
		this.listenAddresses.add(listenAddress);
		return this;
	}

	public BlockingSocketServer withListenPort(int port) {
		return withListenAddress(new InetSocketAddress(port));
	}

	public BlockingSocketServer withServerSocketSettings(ServerSocketSettings socketSettings) {
		this.serverSocketSettings = socketSettings;
		return this;
	}

	public BlockingSocketServer withSocketSettings(SocketSettings socketSettings) {
		this.socketSettings = socketSettings;
		return this;
	}

	private void serveClient(final Socket socket) throws IOException {
		socketSettings.applySettings(socket.getChannel());
		executor.execute(new Runnable() {
			@Override
			public void run() {
				try {
					acceptHandler.onAccept(socket);
				} catch (Exception e) {
					logger.error("Failed to serve socket " + socket, e);
				}
			}
		});
	}

	public void start() throws Exception {
		for (final InetSocketAddress address : listenAddresses) {
			final ServerSocket serverSocket = new ServerSocket(address.getPort(), serverSocketSettings.getBacklog(), address.getAddress());
			serverSocketSettings.applySettings(serverSocket.getChannel());
			serverSockets.add(serverSocket);
			Runnable runnable = new Runnable() {
				@Override
				public void run() {
					while (!Thread.interrupted()) {
						try {
							serveClient(serverSocket.accept());
						} catch (Exception e) {
							if (Thread.currentThread().isInterrupted())
								break;
							logger.error("Socket error for " + serverSocket, e);
						}
					}
				}
			};
			Thread acceptThread = acceptThreadFactory == null ?
					new Thread(runnable) :
					acceptThreadFactory.newThread(runnable);
			acceptThread.setDaemon(true);
			acceptThreads.put(serverSocket, acceptThread);
			acceptThread.start();
		}
	}

	public void stop() throws Exception {
		for (ServerSocket serverSocket : serverSockets) {
			Thread acceptThread = acceptThreads.get(serverSocket);
			acceptThread.interrupt();
			serverSocket.close();
		}
		for (Thread acceptThread : acceptThreads.values()) {
			acceptThread.join();
		}
		serverSockets.clear();
	}
}