/*

 * Copyright (c) 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/* Test utility classes

 *

 */

import java.io.*;

import java.net.*;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

public class TestServers {

    private TestServers() { }

    /**

     * An abstract server identifies a server which listens on a port on on a

     * given machine.

     */

    static abstract class AbstractServer {

        private AbstractServer() {

        }

        public abstract int getPort();

        public abstract InetAddress getAddress();

    }

    /**

     * A downgraded type of AbstractServer which will refuse connections. Note:

     * use it once and throw it away - this implementation opens an anonymous

     * socket and closes it, returning the address of the closed socket. If

     * other servers are started afterwards, the address/port might get reused

     * and become connectable again - so it's not a good idea to assume that

     * connections using this address/port will always be refused. Connections

     * will be refused as long as the address/port of the refusing server has

     * not been reused.

     */

    static class RefusingServer extends AbstractServer {

        final InetAddress address;

        final int port;

        private RefusingServer(InetAddress address, int port) {

            this.address = address;

            this.port = port;

        }

        @Override

        public int getPort() {

            return port;

        }

        @Override

        public InetAddress getAddress() {

            return address;

        }

        public static RefusingServer startNewServer() throws IOException {

            ServerSocket socket = new ServerSocket(0, 100,

                    InetAddress.getLocalHost());

            RefusingServer server = new RefusingServer(socket.getInetAddress(),

                    socket.getLocalPort());

            socket.close();

            return server;

        }

    }

    /**

     * An abstract class for implementing small TCP servers for the nio tests

     * purposes. Disclaimer: This is a naive implementation that uses the old

     * networking APIs (not those from {@code java.nio.*}) and shamelessly

     * extends/creates Threads instead of using an executor service.

     */

    static abstract class AbstractTcpServer extends AbstractServer

            implements Runnable, Closeable {

        protected final long linger; // #of ms to wait before responding

        private Thread acceptThread; // thread waiting for accept

        // list of opened connections that should be closed on close.

        private List<TcpConnectionThread> connections = new ArrayList<>();

        private ServerSocket serverSocket; // the server socket

        private boolean started = false; // whether the server is started

        Throwable error = null;

        /**

         * Creates a new abstract TCP server.

         *

         * @param linger the amount of time the server should wait before

         * responding to requests.

         */

        protected AbstractTcpServer(long linger) {

            this.linger = linger;

        }

        /**

         * The local port to which the server is bound.

         *

         * @return The local port to which the server is bound.

         * @exception IllegalStateException is thrown if the server is not

         * started.

         */

        @Override

        public final synchronized int getPort() {

            if (!started) {

                throw new IllegalStateException("Not started");

            }

            return serverSocket.getLocalPort();

        }

        /**

         * The local address to which the server is bound.

         *

         * @return The local address to which the server is bound.

         * @exception IllegalStateException is thrown if the server is not

         * started.

         */

        @Override

        public final synchronized InetAddress getAddress() {

            if (!started) {

                throw new IllegalStateException("Not started");

            }

            return serverSocket.getInetAddress();

        }

        /**

         * Tells whether the server is started.

         *

         * @return true if the server is started.

         */

        public final synchronized boolean isStarted() {

            return started;

        }

        /**

         * Creates a new server socket.

         *

         * @param port local port to bind to.

         * @param backlog requested maximum length of the queue of incoming

         * connections.

         * @param address local address to bind to.

         * @return a new bound server socket ready to accept connections.

         * @throws IOException if the socket cannot be created or bound.

         */

        protected ServerSocket newServerSocket(int port, int backlog,

                InetAddress address)

                throws IOException {

            return new ServerSocket(port, backlog, address);

        }

        /**

         * Starts listening for connections.

         *

         * @throws IOException if the server socket cannot be created or bound.

         */

        public final synchronized void start() throws IOException {

            if (started) {

                return;

            }

            final ServerSocket socket =

                    newServerSocket(0, 100, InetAddress.getLocalHost());

            serverSocket = socket;

            acceptThread = new Thread(this);

            acceptThread.setDaemon(true);

            acceptThread.start();

            started = true;

        }

        /**

         * Calls {@code Thread.sleep(linger);}

         */

        protected final void lingerIfRequired() {

            if (linger > 0) {

                try {

                    Thread.sleep(linger);

                } catch (InterruptedException x) {

                    Thread.interrupted();

                    final ServerSocket socket = serverSocket();

                    if (socket != null && !socket.isClosed()) {

                        System.err.println("Thread interrupted...");

                    }

                }

            }

        }

        final synchronized ServerSocket serverSocket() {

            return this.serverSocket;

        }

        /**

         * The main accept loop.

         */

        @Override

        public final void run() {

            final ServerSocket sSocket = serverSocket();

            try {

                Socket s;

                while (isStarted() && !Thread.interrupted()

                        && (s = sSocket.accept()) != null) {

                    lingerIfRequired();

                    listen(s);

                }

            } catch (Exception x) {

                error = x;

            } finally {

                synchronized (this) {

                    if (!sSocket.isClosed()) {

                        try {

                            sSocket.close();

                        } catch (IOException x) {

                            System.err.println("Failed to close server socket");

                        }

                    }

                    if (started && this.serverSocket == sSocket) {

                        started = false;

                        this.serverSocket = null;

                        this.acceptThread = null;

                    }

                }

            }

        }

        /**

         * Represents a connection accepted by the server.

         */

        protected abstract class TcpConnectionThread extends Thread {

            protected final Socket socket;

            protected TcpConnectionThread(Socket socket) {

                this.socket = socket;

                this.setDaemon(true);

            }

            public void close() throws IOException {

                socket.close();

                interrupt();

            }

        }

        /**

         * Creates a new TcpConnnectionThread to handle the connection through

         * an accepted socket.

         *

         * @param s the socket returned by {@code serverSocket.accept()}.

         * @return a new TcpConnnectionThread to handle the connection through

         * an accepted socket.

         */

        protected abstract TcpConnectionThread createConnection(Socket s);

        /**

         * Creates and starts a new TcpConnectionThread to handle the accepted

         * socket.

         *

         * @param s the socket returned by {@code serverSocket.accept()}.

         */

        private synchronized void listen(Socket s) {

            TcpConnectionThread c = createConnection(s);

            c.start();

            addConnection(c);

        }

        /**

         * Add the connection to the list of accepted connections.

         *

         * @param connection an accepted connection.

         */

        protected synchronized void addConnection(

                TcpConnectionThread connection) {

            connections.add(connection);

        }

        /**

         * Remove the connection from the list of accepted connections.

         *

         * @param connection an accepted connection.

         */

        protected synchronized void removeConnection(

                TcpConnectionThread connection) {

            connections.remove(connection);

        }

        /**

         * Close the server socket and all the connections present in the list

         * of accepted connections.

         *

         * @throws IOException

         */

        @Override

        public synchronized void close() throws IOException {

            if (serverSocket != null && !serverSocket.isClosed()) {

                serverSocket.close();

            }

            if (acceptThread != null) {

                acceptThread.interrupt();

            }

            int failed = 0;

            for (TcpConnectionThread c : connections) {

                try {

                    c.close();

                } catch (IOException x) {

                    // no matter - we're closing.

                    failed++;

                }

            }

            connections.clear();

            if (failed > 0) {

                throw new IOException("Failed to close some connections");

            }

        }

    }

    /**

     * A small TCP Server that emulates the echo service for tests purposes. See

     * http://en.wikipedia.org/wiki/Echo_Protocol This server uses an anonymous

     * port - NOT the standard port 7. We don't guarantee that its behavior

     * exactly matches the RFC - the only purpose of this server is to have

     * something that responds to nio tests...

     */

    static final class EchoServer extends AbstractTcpServer {

        public EchoServer() {

            this(0L);

        }

        public EchoServer(long linger) {

            super(linger);

        }

        @Override

        protected TcpConnectionThread createConnection(Socket s) {

            return new EchoConnection(s);

        }

        private final class EchoConnection extends TcpConnectionThread {

            public EchoConnection(Socket socket) {

                super(socket);

            }

            @Override

            public void run() {

                try {

                    final InputStream is = socket.getInputStream();

                    final OutputStream out = socket.getOutputStream();

                    byte[] b = new byte[255];

                    int n;

                    while ((n = is.read(b)) > 0) {

                        lingerIfRequired();

                        out.write(b, 0, n);

                    }

                } catch (IOException io) {

                    // fall through to finally

                } finally {

                    if (!socket.isClosed()) {

                        try {

                            socket.close();

                        } catch (IOException x) {

                            System.err.println(

                                    "Failed to close echo connection socket");

                        }

                    }

                    removeConnection(this);

                }

            }

        }

        public static EchoServer startNewServer() throws IOException {

            return startNewServer(0);

        }

        public static EchoServer startNewServer(long linger) throws IOException {

            final EchoServer echoServer = new EchoServer(linger);

            echoServer.start();

            return echoServer;

        }

    }

    /**

     * A small TCP server that emulates the Day & Time service for tests

     * purposes. See http://en.wikipedia.org/wiki/Daytime_Protocol This server

     * uses an anonymous port - NOT the standard port 13. We don't guarantee

     * that its behavior exactly matches the RFC - the only purpose of this

     * server is to have something that responds to nio tests...

     */

    static final class DayTimeServer extends AbstractTcpServer {

        public DayTimeServer() {

            this(0L);

        }

        public DayTimeServer(long linger) {

            super(linger);

        }

        @Override

        protected TcpConnectionThread createConnection(Socket s) {

            return new DayTimeServerConnection(s);

        }

        @Override

        protected void addConnection(TcpConnectionThread connection) {

            // do nothing - the connection just write the date and terminates.

        }

        @Override

        protected void removeConnection(TcpConnectionThread connection) {

            // do nothing - we're not adding connections to the list...

        }

        private final class DayTimeServerConnection extends TcpConnectionThread {

            public DayTimeServerConnection(Socket socket) {

                super(socket);

            }

            @Override

            public void run() {

                try {

                    final OutputStream out = socket.getOutputStream();

                    lingerIfRequired();

                    out.write(new Date(System.currentTimeMillis())

                            .toString().getBytes("US-ASCII"));

                    out.flush();

                } catch (IOException io) {

                    // fall through to finally

                } finally {

                    if (!socket.isClosed()) {

                        try {

                            socket.close();

                        } catch (IOException x) {

                            System.err.println(

                                    "Failed to close echo connection socket");

                        }

                    }

                }

            }

        }

        public static DayTimeServer startNewServer()

                throws IOException {

            return startNewServer(0);

        }

        public static DayTimeServer startNewServer(long linger)

                throws IOException {

            final DayTimeServer daytimeServer = new DayTimeServer(linger);

            daytimeServer.start();

            return daytimeServer;

        }

    }

    /**

     * An abstract class for implementing small UDP Servers for the nio tests

     * purposes. Disclaimer: This is a naive implementation that uses the old

     * networking APIs (not those from {@code java.nio.*}) and shamelessly

     * extends/creates Threads instead of using an executor service.

     */

    static abstract class AbstractUdpServer extends AbstractServer

            implements Runnable, Closeable {

        protected final long linger; // #of ms to wait before responding

        private Thread acceptThread; // thread waiting for packets

        private DatagramSocket serverSocket; // the server socket

        private boolean started = false; // whether the server is started

        Throwable error = null;

        /**

         * Creates a new abstract UDP server.

         *

         * @param linger the amount of time the server should wait before

         * responding to requests.