/*

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

 *

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

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 *

 * 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     4530538

 * @summary Basic unit test of ThreadMXBean.getAllThreadIds()

 * @author  Alexei Guibadoulline and Mandy Chung

 *

 * @key intermittent

 * @modules java.management

 * @run main/othervm AllThreadIds

 */

import java.lang.management.*;

import java.time.Instant;

import java.util.concurrent.Phaser;

import java.util.function.Supplier;

public class AllThreadIds {

    /**

     * A supplier wrapper for the delayed format printing.

     * The supplied value will have to be formatted as <em>$s</em>

     * @param <T> The wrapped type

     */

    private static final class ArgWrapper<T> {

        private final Supplier<T> val;

        public ArgWrapper(Supplier<T> val) {

            this.val = val;

        }

        @Override

        public String toString() {

            T resolved = val.get();

            return resolved != null ? resolved.toString() : null;

        }

    }

    private static final boolean live[] = new boolean[ALL_THREADS];

    private static final Thread allThreads[] = new Thread[ALL_THREADS];

    private static final ThreadMXBean mbean = ManagementFactory.getThreadMXBean();

    private static boolean testFailed = false;

    private static boolean trace = false;

    private static long prevTotalThreadCount = 0;

    private static int prevLiveThreadCount = 0;

    private static int prevPeakThreadCount = 0;

    private static final Phaser startupCheck = new Phaser(ALL_THREADS + 1);

    private static void printThreadList() {

        long[] list = mbean.getAllThreadIds();

        for (int i = 1; i <= list.length; i++) {

            System.out.println(i + ": Thread id = " + list[i-1]);

        }

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

            Thread t = allThreads[i];

            System.out.println(t.getName() + " Id = " + t.getId() +

                " die = " + live[i] +

                " alive = " + t.isAlive());

        }

    }

    private static void checkInitialState() throws Exception {

        updateCounters();

        checkThreadCount(0, 0);

    }

    private static void checkAllThreadsAlive() throws Exception {

        updateCounters();

        // Start all threads and wait to be sure they all are alive

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

            setLive(i, true);

            allThreads[i] = new MyThread(i);

            allThreads[i].setDaemon(i < DAEMON_THREADS);

            allThreads[i].start();

        }

        // wait until all threads are started.

        startupCheck.arriveAndAwaitAdvance();

        checkThreadCount(ALL_THREADS, 0);

        if (trace) {

            printThreadList();

        }

        // Check mbean now. All threads must appear in getAllThreadIds() list

        long[] list = mbean.getAllThreadIds();

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

            long expectedId = allThreads[i].getId();

            boolean found = false;

            if (trace) {

                System.out.print("Looking for thread with id " + expectedId);

            }

            for (int j = 0; j < list.length; j++) {

                if (expectedId == list[j]) {

                    found = true;

                    break;

                }

            }

            if (!found) {

                testFailed = true;

            }

            if (trace) {

                if (!found) {

                    System.out.print(". TEST FAILED.");

                }

                System.out.println();

            }

        }

        if (trace) {

            System.out.println();

        }

    }

    private static void checkDaemonThreadsDead() throws Exception {

        updateCounters();

        // Stop daemon threads, wait to be sure they all are dead, and check

        // that they disappeared from getAllThreadIds() list

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

            setLive(i, false);

        }

        // make sure the daemon threads are completely dead

        joinDaemonThreads();

        // and check the reported thread count

        checkThreadCount(0, DAEMON_THREADS);

        // Check mbean now

        long[] list = mbean.getAllThreadIds();

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

            long expectedId = allThreads[i].getId();

            boolean found = false;

            boolean alive = (i >= DAEMON_THREADS);

            if (trace) {

                System.out.print("Looking for thread with id " + expectedId +

                    (alive ? " expected alive." : " expected terminated."));

            }

            for (int j = 0; j < list.length; j++) {

                if (expectedId == list[j]) {

                    found = true;

                    break;

                }

            }

            if (alive != found) {

                testFailed = true;

            }

            if (trace) {

                if (alive != found) {

                    System.out.println(" TEST FAILED.");

                } else {

                    System.out.println();

                }

            }

        }

    }

    private static void checkAllThreadsDead() throws Exception {

        updateCounters();

        // Stop all threads and wait to be sure they all are dead

        for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {

            setLive(i, false);

        }

        // make sure the non-daemon threads are completely dead

        joinNonDaemonThreads();

        // and check the thread count

        checkThreadCount(0, ALL_THREADS - DAEMON_THREADS);

    }

    private static void checkThreadCount(int numNewThreads,

                                         int numTerminatedThreads)

        throws Exception {

        checkLiveThreads(numNewThreads, numTerminatedThreads);

        checkPeakThreads(numNewThreads);

        checkTotalThreads(numNewThreads);

        checkThreadIds();

    }

    private static void checkLiveThreads(int numNewThreads,

                                         int numTerminatedThreads)

        throws InterruptedException {

        int diff = numNewThreads - numTerminatedThreads;

        waitTillEquals(

            diff + prevLiveThreadCount,

            ()->(long)mbean.getThreadCount(),

            "Unexpected number of live threads: " +

                " Prev live = %1$d Current live = ${provided} Threads added = %2$d" +

                " Threads terminated = %3$d",

            ()->prevLiveThreadCount,

            ()->numNewThreads,

            ()->numTerminatedThreads

        );

    }

    private static void checkPeakThreads(int numNewThreads)

        throws InterruptedException {

        waitTillEquals(numNewThreads + prevPeakThreadCount,

            ()->(long)mbean.getPeakThreadCount(),

            "Unexpected number of peak threads: " +

                " Prev peak = %1$d Current peak = ${provided} Threads added = %2$d",

            ()->prevPeakThreadCount,

            ()->numNewThreads

        );

    }

    private static void checkTotalThreads(int numNewThreads)

        throws InterruptedException {

        waitTillEquals(numNewThreads + prevTotalThreadCount,

            ()->mbean.getTotalStartedThreadCount(),

            "Unexpected number of total threads: " +

                " Prev Total = %1$d Current Total = ${provided} Threads added = %2$d",

            ()->prevTotalThreadCount,

            ()->numNewThreads

        );

    }

    private static void checkThreadIds() throws InterruptedException {

        long[] list = mbean.getAllThreadIds();

        waitTillEquals(

            list.length,

            ()->(long)mbean.getThreadCount(),

            "Array length returned by " +

                "getAllThreadIds() = %1$d not matched count = ${provided}",

            ()->list.length

        );

    }

    /**

     * Waits till the <em>expectedVal</em> equals to the <em>retrievedVal</em>.

     * It will report a status message on the first occasion of the value mismatch

     * and then, subsequently, when the <em>retrievedVal</em> value changes.

     * @param expectedVal The value to wait for

     * @param retrievedVal The supplier of the value to check against the <em>expectedVal</em>

     * @param msgFormat The formatted message to be printed in case of mismatch

     * @param msgArgs The parameters to the formatted message

     * @throws InterruptedException

     */

    private static void waitTillEquals(long expectedVal, Supplier<Long> retrievedVal,

                                        String msgFormat, Supplier<Object> ... msgArgs)

        throws InterruptedException {

        Object[] args = null;

        long countPrev = -1;

        while (true) {

            Long count = retrievedVal.get();

            if (count == expectedVal) break;

            if (countPrev == -1 || countPrev != count) {

                if (args == null) {

                    args = new Object[msgArgs.length];

                    for(int i=0; i < msgArgs.length; i++) {

                        args[i] = new ArgWrapper<>((Supplier<Object>)msgArgs[i]);

                    }

                }

                System.err.format("TS: %s\n", Instant.now());

                System.err.format(

                    msgFormat

                        .replace("${provided}", String.valueOf(count))

                        .replace("$d", "$s"),

                    args

                ).flush();

                printThreadList();

                System.err.println("\nRetrying ...\n");

            }

            countPrev = count;

            Thread.sleep(1);

        }

    }

    private static void updateCounters() {

        prevTotalThreadCount = mbean.getTotalStartedThreadCount();

        prevLiveThreadCount = mbean.getThreadCount();

        prevPeakThreadCount = mbean.getPeakThreadCount();

    }

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

        if (args.length > 0 && args[0].equals("trace")) {

            trace = true;

        }

        checkInitialState();

        checkAllThreadsAlive();

        checkDaemonThreadsDead();

        checkAllThreadsDead();

        if (testFailed)

            throw new RuntimeException("TEST FAILED.");

        System.out.println("Test passed.");

    }

    private static void joinDaemonThreads() throws InterruptedException {

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

            allThreads[i].join();

        }

    }

    private static void joinNonDaemonThreads() throws InterruptedException {

        for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {

            allThreads[i].join();

        }

    }

    private static void setLive(int i, boolean val) {

        synchronized(live) {

            live[i] = val;

        }

    }

    private static boolean isLive(int i) {

        synchronized(live) {

            return live[i];

        }

    }

    // The MyThread thread lives as long as correspondent live[i] value is true

    private static class MyThread extends Thread {

        int id;

        MyThread(int id) {

            this.id = id;

        }

        public void run() {

            // signal started

            startupCheck.arrive();

            while (isLive(id)) {

                try {

                    sleep(100);

                } catch (InterruptedException e) {

                    System.out.println("Unexpected exception is thrown.");

                    e.printStackTrace(System.out);

                    testFailed = true;

                }

            }

        }

    }

}