/*

 * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

import java.net.*;

import java.io.*;

import java.util.ArrayList;

/**

 * This class implements a simple FTP server that can handle multiple

 * connections concurrently. This is mostly meant as a test environment.

 * You have to provide 2 handlers for it to be effective, one to simulate

 * (or access) a filesystem and one to deal with authentication.

 * See {@link FtpFileSystemHandler} and {@link FtpAuthHandler}.

 *

 * Since it is a subclass of Thread, you have to call <code>start()</code>

 * To get it running.

 *

 * Usage example:<p>

 *

 * <code>

 * FtpServer server = new FtpServer(0);

 * int port = server.getLocalPort();

 * server.setFileSystemHandler(myFSHandler);

 * server.setAuthHandler(myAuthHandler);

 * server.start();

 * </code>

 *

 */

public class FtpServer extends Thread {

    private ServerSocket listener = null;

    private FtpFileSystemHandler fsh = null;

    private FtpAuthHandler auth = null;

    private boolean done = false;

    private ArrayList<FtpCommandHandler> clients = new ArrayList<FtpCommandHandler>();

    /**

     * Creates an instance of an FTP server which will listen for incoming

     * connections on the specified port. If the port is set to 0, it will

     * automatically select an available ephemeral port.

     */

    public FtpServer(int port) throws IOException {

        listener = new ServerSocket(port);

    }

    /**

     * Creates an instance of an FTP server that will listen on the default

     * FTP port, usually 21.

     */

    public FtpServer() throws IOException {

        this(21);

    }

    public void setFileSystemHandler(FtpFileSystemHandler f) {

        fsh = f;

    }

    public void setAuthHandler(FtpAuthHandler a) {

        auth = a;

    }

    public void terminate() {

        done = true;

        interrupt();

    }

    public void killClients() {

        synchronized (clients) {

            int c = clients.size();

            while (c > 0) {

                c--;

                FtpCommandHandler cl = clients.get(c);

                cl.terminate();

                cl.interrupt();

            }

        }

    }

    public int getLocalPort() {

        return listener.getLocalPort();

    }

    void addClient(Socket client) {

        FtpCommandHandler h = new FtpCommandHandler(client, this);

        h.setHandlers(fsh, auth);

        synchronized (clients) {

            clients.add(h);

        }

        h.start();

    }

    void removeClient(FtpCommandHandler cl) {

        synchronized (clients) {

            clients.remove(cl);

        }

    }

    public int activeClientsCount() {

        synchronized (clients) {

            return clients.size();

        }

    }

    public void run() {

        Socket client;

        try {

            while (!done) {

                client = listener.accept();

                addClient(client);

            }

            listener.close();

        } catch (IOException e) {

        }

    }

}