Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.net;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;

import javax.net.ServerSocketFactory;

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

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.joran.JoranConfigurator;
import ch.qos.logback.core.joran.spi.JoranException;

A simple SocketNode based server. 
     <b>Usage:</b> java ch.qos.logback.classic.net.SimpleSocketServer port configFile

where port is a port number where the server listens and
configFile is an xml configuration file fed to JoranConfigurator. 
Author:
Ceki Gülcü, Sébastien Pennec
Since:
0.8.4/**
 * A simple {@link SocketNode} based server.
 * 
 * <pre>
 *      &lt;b&gt;Usage:&lt;/b&gt; java ch.qos.logback.classic.net.SimpleSocketServer port configFile
 * </pre>
 * 
 * where <em>port</em> is a port number where the server listens and
 * <em>configFile</em> is an xml configuration file fed to
 * {@link JoranConfigurator}.
 * 
 * </pre>
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @author S&eacute;bastien Pennec
 * 
 * @since 0.8.4
 */
public class SimpleSocketServer extends Thread {

    Logger logger = LoggerFactory.getLogger(SimpleSocketServer.class);

    private final int port;
    private final LoggerContext lc;
    private boolean closed = false;
    private ServerSocket serverSocket;
    private List<SocketNode> socketNodeList = new ArrayList<SocketNode>();

    // used for testing purposes
    private CountDownLatch latch;

    public static void main(String argv[]) throws Exception {
        doMain(SimpleSocketServer.class, argv);
    }

    protected static void doMain(Class<? extends SimpleSocketServer> serverClass, String argv[]) throws Exception {
        int port = -1;
        if (argv.length == 2) {
            port = parsePortNumber(argv[0]);
        } else {
            usage("Wrong number of arguments.");
        }

        String configFile = argv[1];
        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
        configureLC(lc, configFile);

        SimpleSocketServer sss = new SimpleSocketServer(lc, port);
        sss.start();
    }

    public SimpleSocketServer(LoggerContext lc, int port) {
        this.lc = lc;
        this.port = port;
    }

    public void run() {

        final String oldThreadName = Thread.currentThread().getName();

        try {

            final String newThreadName = getServerThreadName();
            Thread.currentThread().setName(newThreadName);

            logger.info("Listening on port " + port);
            serverSocket = getServerSocketFactory().createServerSocket(port);
            while (!closed) {
                logger.info("Waiting to accept a new client.");
                signalAlmostReadiness();
                Socket socket = serverSocket.accept();
                logger.info("Connected to client at " + socket.getInetAddress());
                logger.info("Starting new socket node.");
                SocketNode newSocketNode = new SocketNode(this, socket, lc);
                synchronized (socketNodeList) {
                    socketNodeList.add(newSocketNode);
                }
                final String clientThreadName = getClientThreadName(socket);
                new Thread(newSocketNode, clientThreadName).start();
            }
        } catch (Exception e) {
            if (closed) {
                logger.info("Exception in run method for a closed server. This is normal.");
            } else {
                logger.error("Unexpected failure in run method", e);
            }
        }

        finally {
            Thread.currentThread().setName(oldThreadName);
        }
    }

    
Returns the name given to the server thread.
/**
     * Returns the name given to the server thread.
     */
    protected String getServerThreadName() {
        return String.format("Logback %s (port %d)", getClass().getSimpleName(), port);
    }

    
Returns a name to identify each client thread.
/**
     * Returns a name to identify each client thread.
     */
    protected String getClientThreadName(Socket socket) {
        return String.format("Logback SocketNode (client: %s)", socket.getRemoteSocketAddress());
    }

    
Gets the platform default ServerSocketFactory. 

Subclasses may override to provide a custom server socket factory.
/**
     * Gets the platform default {@link ServerSocketFactory}.
     * <p>
     * Subclasses may override to provide a custom server socket factory.
     */
    protected ServerSocketFactory getServerSocketFactory() {
        return ServerSocketFactory.getDefault();
    }

    
Signal another thread that we have established a connection
This is useful for testing purposes.
/**
     * Signal another thread that we have established a connection
     * This is useful for testing purposes.
     */
    void signalAlmostReadiness() {
        if (latch != null && latch.getCount() != 0) {
            // System.out.println("signalAlmostReadiness() with latch "+latch);
            latch.countDown();
        }
    }

    
Used for testing purposes
Params:
latch – /**
     * Used for testing purposes
     * @param latch
     */
    void setLatch(CountDownLatch latch) {
        this.latch = latch;
    }

    
Used for testing purposes
/**
      * Used for testing purposes
      */
    public CountDownLatch getLatch() {
        return latch;
    }

    public boolean isClosed() {
        return closed;
    }

    public void close() {
        closed = true;
        if (serverSocket != null) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                logger.error("Failed to close serverSocket", e);
            } finally {
                serverSocket = null;
            }
        }

        logger.info("closing this server");
        synchronized (socketNodeList) {
            for (SocketNode sn : socketNodeList) {
                sn.close();
            }
        }
        if (socketNodeList.size() != 0) {
            logger.warn("Was expecting a 0-sized socketNodeList after server shutdown");
        }

    }

    public void socketNodeClosing(SocketNode sn) {
        logger.debug("Removing {}", sn);

        // don't allow simultaneous access to the socketNodeList
        // (e.g. removal whole iterating on the list causes
        // java.util.ConcurrentModificationException
        synchronized (socketNodeList) {
            socketNodeList.remove(sn);
        }
    }

    static void usage(String msg) {
        System.err.println(msg);
        System.err.println("Usage: java " + SimpleSocketServer.class.getName() + " port configFile");
        System.exit(1);
    }

    static int parsePortNumber(String portStr) {
        try {
            return Integer.parseInt(portStr);
        } catch (java.lang.NumberFormatException e) {
            e.printStackTrace();
            usage("Could not interpret port number [" + portStr + "].");
            // we won't get here
            return -1;
        }
    }

    static public void configureLC(LoggerContext lc, String configFile) throws JoranException {
        JoranConfigurator configurator = new JoranConfigurator();
        lc.reset();
        configurator.setContext(lc);
        configurator.doConfigure(configFile);
    }
}