/*

 * Copyright (c) 2001, 2008, 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 6405995

 * @summary Unit test for selector wakeup and interruption

 * @library ..

 */

import java.io.*;

import java.net.*;

import java.nio.*;

import java.nio.channels.*;

import java.util.Random;

public class Wakeup {

    static void sleep(int millis) {

        try {

            Thread.sleep(millis);

        } catch (InterruptedException x) {

            x.printStackTrace();

        }

    }

    static class Sleeper extends TestThread {

        volatile boolean started = false;

        volatile int entries = 0;

        volatile int wakeups = 0;

        volatile boolean wantInterrupt = false;

        volatile boolean gotInterrupt = false;

        volatile Exception exception = null;

        volatile boolean closed = false;

        Object gate = new Object();

        Selector sel;

        Sleeper(Selector sel) {

            super("Sleeper", System.err);

            this.sel = sel;

        }

        public void go() throws Exception {

            started = true;

            for (;;) {

                synchronized (gate) { }

                entries++;

                try {

                    sel.select();

                } catch (ClosedSelectorException x) {

                    closed = true;

                }

                boolean intr = Thread.currentThread().isInterrupted();

                wakeups++;

                System.err.println("Wakeup " + wakeups

                                   + (closed ? " (closed)" : "")

                                   + (intr ? " (intr)" : ""));

                if (wakeups > 1000)

                    throw new Exception("Too many wakeups");

                if (closed)

                    return;

                if (wantInterrupt) {

                    while (!Thread.interrupted())

                        Thread.yield();

                    gotInterrupt = true;

                    wantInterrupt = false;

                }

            }

        }

    }

    private static int checkedWakeups = 0;

    private static void check(Sleeper sleeper, boolean intr)

        throws Exception

    {

        checkedWakeups++;

        if (sleeper.wakeups > checkedWakeups) {

            sleeper.finish(100);

            throw new Exception("Sleeper has run ahead");

        }

        int n = 0;

        while (sleeper.wakeups < checkedWakeups) {

            sleep(50);

            if ((n += 50) > 1000) {

                sleeper.finish(100);

                throw new Exception("Sleeper appears to be dead ("

                                    + checkedWakeups + ")");

            }

        }

        if (sleeper.wakeups > checkedWakeups) {

            sleeper.finish(100);

            throw new Exception("Too many wakeups: Expected "

                                + checkedWakeups

                                + ", got " + sleeper.wakeups);

        }

        if (intr) {

            n = 0;

            // Interrupts can sometimes be delayed, so wait

            while (!sleeper.gotInterrupt) {

                sleep(50);

                if ((n += 50) > 1000) {

                    sleeper.finish(100);

                    throw new Exception("Interrupt never delivered");

                }

            }

            sleeper.gotInterrupt = false;

        }

        System.err.println("Check " + checkedWakeups

                           + (intr ? " (intr " + n + ")" : ""));

    }

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

        Selector sel = Selector.open();

        // Wakeup before select

        sel.wakeup();

        Sleeper sleeper = new Sleeper(sel);

        sleeper.start();

        while (!sleeper.started)

            sleep(50);

        check(sleeper, false);          // 1

        for (int i = 2; i < 5; i++) {

            // Wakeup during select

            sel.wakeup();

            check(sleeper, false);      // 2 .. 4

        }

        // Double wakeup

        synchronized (sleeper.gate) {

            sel.wakeup();

            check(sleeper, false);      // 5

            sel.wakeup();

            sel.wakeup();

        }

        check(sleeper, false);          // 6

        // Interrupt

        synchronized (sleeper.gate) {

            sleeper.wantInterrupt = true;

            sleeper.interrupt();

            check(sleeper, true);       // 7

        }

        // Interrupt before select

        while (sleeper.entries < 8)

            Thread.yield();

        synchronized (sleeper.gate) {

            sel.wakeup();

            check(sleeper, false);      // 8

            sleeper.wantInterrupt = true;

            sleeper.interrupt();

            sleep(50);

        }

        check(sleeper, true);           // 9

        // Close during select

        while (sleeper.entries < 10)

            Thread.yield();

        synchronized (sleeper.gate) {

            sel.close();

            check(sleeper, false);      // 10

        }

        if (sleeper.finish(200) == 0)

            throw new Exception("Test failed");

        if (!sleeper.closed)

            throw new Exception("Selector not closed");

    }

}