/*

 * Copyright (c) 2002, 2015, 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

 * @bug 4669040 8130394

 * @summary Test DatagramChannel subsequent receives with no datagram ready

 * @author Mike McCloskey

 */

import java.io.IOException;

import java.io.PrintStream;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.SocketAddress;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.channels.DatagramChannel;

public class Sender {

    static PrintStream log = System.err;

    static volatile SocketAddress clientISA = null;

    public static void main(String[] args) throws Exception {

        test();

    }

    static void test() throws Exception {

        Server server = new Server();

        Client client = new Client(server.port());

        Thread serverThread = new Thread(server);

        serverThread.start();

        Thread clientThread = new Thread(client);

        clientThread.start();

        serverThread.join();

        clientThread.join();

        server.throwException();

        client.throwException();

    }

    public static class Client implements Runnable {

        final int port;

        Exception e = null;

        Client(int port) {

            this.port = port;

        }

        void throwException() throws Exception {

            if (e != null)

                throw e;

        }

        public void run() {

            try {

                DatagramChannel dc = DatagramChannel.open();

                ByteBuffer bb = ByteBuffer.allocateDirect(12);

                bb.order(ByteOrder.BIG_ENDIAN);

                bb.putInt(1).putLong(1);

                bb.flip();

                InetAddress address = InetAddress.getLocalHost();

                InetSocketAddress isa = new InetSocketAddress(address, port);

                dc.connect(isa);

                clientISA = dc.getLocalAddress();

                dc.write(bb);

            } catch (Exception ex) {

                e = ex;

            }

        }

    }

    public static class Server implements Runnable {

        final DatagramChannel dc;

        Exception e = null;

        Server() throws IOException {

            dc = DatagramChannel.open().bind(new InetSocketAddress(0));

        }

        int port() {

            return dc.socket().getLocalPort();

        }

        void throwException() throws Exception {

            if (e != null)

                throw e;

        }

        void showBuffer(String s, ByteBuffer bb) {

            log.println(s);

            bb.rewind();

            for (int i=0; i<bb.limit(); i++) {

                byte element = bb.get();

                log.print(element);

            }

            log.println();

        }

        public void run() {

            SocketAddress sa = null;

            try {

                ByteBuffer bb = ByteBuffer.allocateDirect(12);

                bb.clear();

                // Get the one valid datagram

                dc.configureBlocking(false);

                while (sa == null) {

                    sa = dc.receive(bb);

                    if (sa != null && clientISA != null && !clientISA.equals(sa)) {

                        log.println("Ignore a possible stray diagram from " + sa);

                        sa = null;

                    }

                }

                showBuffer("Received:", bb);

                sa = null;

                for (int i=0; i<100; i++) {

                    bb.clear();

                    sa = dc.receive(bb);

                    if (sa != null)

                        throw new RuntimeException("Test failed");

                }

                dc.close();

            } catch (Exception ex) {

                e = ex;

            }

        }

    }

}