/*

 * 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.

 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Written by Doug Lea with assistance from members of JCP JSR-166

 * Expert Group and released to the public domain, as explained at

 * http://creativecommons.org/publicdomain/zero/1.0/

 */

import java.util.concurrent.ThreadLocalRandom;

import java.util.concurrent.atomic.AtomicLong;

import java.util.concurrent.atomic.AtomicReference;

import junit.framework.Test;

import junit.framework.TestSuite;

public class ThreadLocalRandomTest extends JSR166TestCase {

    public static void main(String[] args) {

        main(suite(), args);

    }

    public static Test suite() {

        return new TestSuite(ThreadLocalRandomTest.class);

    }

    /*

     * Testing coverage notes:

     *

     * We don't test randomness properties, but only that repeated

     * calls, up to NCALLS tries, produce at least one different

     * result.  For bounded versions, we sample various intervals

     * across multiples of primes.

     */

    // max numbers of calls to detect getting stuck on one value

    static final int NCALLS = 10000;

    // max sampled int bound

    static final int MAX_INT_BOUND = (1 << 28);

    // max sampled long bound

    static final long MAX_LONG_BOUND = (1L << 42);

    // Number of replications for other checks

    static final int REPS = 20;

    /**

     * setSeed throws UnsupportedOperationException

     */

    public void testSetSeed() {

        try {

            ThreadLocalRandom.current().setSeed(17);

            shouldThrow();

        } catch (UnsupportedOperationException success) {}

    }

    /**

     * Repeated calls to next (only accessible via reflection) produce

     * at least two distinct results, and repeated calls produce all

     * possible values.

     */

    public void testNext() throws ReflectiveOperationException {

        // Inhibit "An illegal reflective access operation has occurred"

        if (!testImplementationDetails) return;

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        final java.lang.reflect.Method m;

        try {

            m = ThreadLocalRandom.class.getDeclaredMethod(

                    "next", new Class[] { int.class });

            m.setAccessible(true);

        } catch (SecurityException acceptable) {

            // Security manager may deny access

            return;

        } catch (Exception ex) {

            // jdk9 module system may deny access

            if (ex.getClass().getSimpleName()

                .equals("InaccessibleObjectException"))

                return;

            throw ex;

        }

        int i;

        {

            int val = new java.util.Random().nextInt(4);

            for (i = 0; i < NCALLS; i++) {

                int q = (int) m.invoke(rnd, new Object[] { 2 });

                if (val == q) break;

            }

            assertTrue(i < NCALLS);

        }

        {

            int r = (int) m.invoke(rnd, new Object[] { 3 });

            for (i = 0; i < NCALLS; i++) {

                int q = (int) m.invoke(rnd, new Object[] { 3 });

                assertTrue(q < (1<<3));

                if (r != q) break;

            }

            assertTrue(i < NCALLS);

        }

    }

    /**

     * Repeated calls to nextInt produce at least two distinct results

     */

    public void testNextInt() {

        int f = ThreadLocalRandom.current().nextInt();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextInt() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextLong produce at least two distinct results

     */

    public void testNextLong() {

        long f = ThreadLocalRandom.current().nextLong();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextLong() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextBoolean produce at least two distinct results

     */

    public void testNextBoolean() {

        boolean f = ThreadLocalRandom.current().nextBoolean();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextBoolean() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextFloat produce at least two distinct results

     */

    public void testNextFloat() {

        float f = ThreadLocalRandom.current().nextFloat();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextFloat() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextDouble produce at least two distinct results

     */

    public void testNextDouble() {

        double f = ThreadLocalRandom.current().nextDouble();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextDouble() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextGaussian produce at least two distinct results

     */

    public void testNextGaussian() {

        double f = ThreadLocalRandom.current().nextGaussian();

        int i = 0;

        while (i < NCALLS && ThreadLocalRandom.current().nextGaussian() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * nextInt(non-positive) throws IllegalArgumentException

     */

    public void testNextIntBoundNonPositive() {

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        for (int bound : new int[] { 0, -17, Integer.MIN_VALUE }) {

            try {

                rnd.nextInt(bound);

                shouldThrow();

            } catch (IllegalArgumentException success) {}

        }

    }

    /**

     * nextInt(least >= bound) throws IllegalArgumentException

     */

    public void testNextIntBadBounds() {

        int[][] badBoundss = {

            { 17, 2 },

            { -42, -42 },

            { Integer.MAX_VALUE, Integer.MIN_VALUE },

        };

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        for (int[] badBounds : badBoundss) {

            try {

                rnd.nextInt(badBounds[0], badBounds[1]);

                shouldThrow();

            } catch (IllegalArgumentException success) {}

        }

    }

    /**

     * nextInt(bound) returns 0 <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextIntBounded() {

        // sample bound space across prime number increments

        for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {

            int f = ThreadLocalRandom.current().nextInt(bound);

            assertTrue(0 <= f && f < bound);

            int i = 0;

            int j;

            while (i < NCALLS &&

                   (j = ThreadLocalRandom.current().nextInt(bound)) == f) {

                assertTrue(0 <= j && j < bound);

                ++i;

            }

            assertTrue(i < NCALLS);

        }

    }

    /**

     * nextInt(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextIntBounded2() {

        for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {

            for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {

                int f = ThreadLocalRandom.current().nextInt(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                int j;

                while (i < NCALLS &&

                       (j = ThreadLocalRandom.current().nextInt(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * nextLong(non-positive) throws IllegalArgumentException

     */

    public void testNextLongBoundNonPositive() {

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        for (long bound : new long[] { 0L, -17L, Long.MIN_VALUE }) {

            try {

                rnd.nextLong(bound);

                shouldThrow();

            } catch (IllegalArgumentException success) {}

        }

    }

    /**

     * nextLong(least >= bound) throws IllegalArgumentException

     */

    public void testNextLongBadBounds() {

        long[][] badBoundss = {

            { 17L, 2L },

            { -42L, -42L },

            { Long.MAX_VALUE, Long.MIN_VALUE },

        };

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        for (long[] badBounds : badBoundss) {

            try {

                rnd.nextLong(badBounds[0], badBounds[1]);

                shouldThrow();

            } catch (IllegalArgumentException success) {}

        }

    }

    /**

     * nextLong(bound) returns 0 <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextLongBounded() {

        for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {

            long f = ThreadLocalRandom.current().nextLong(bound);

            assertTrue(0 <= f && f < bound);

            int i = 0;

            long j;

            while (i < NCALLS &&

                   (j = ThreadLocalRandom.current().nextLong(bound)) == f) {

                assertTrue(0 <= j && j < bound);

                ++i;

            }

            assertTrue(i < NCALLS);

        }

    }

    /**

     * nextLong(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextLongBounded2() {

        for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {

            for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {

                long f = ThreadLocalRandom.current().nextLong(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                long j;

                while (i < NCALLS &&

                       (j = ThreadLocalRandom.current().nextLong(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * nextDouble(non-positive) throws IllegalArgumentException

     */

    public void testNextDoubleBoundNonPositive() {

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        double[] badBounds = {

            0.0d,

            -17.0d,

            -Double.MIN_VALUE,

            Double.NEGATIVE_INFINITY,

            Double.NaN,

        };

        for (double bound : badBounds) {

            try {

                rnd.nextDouble(bound);

                shouldThrow();

            } catch (IllegalArgumentException success) {}

        }

    }

    /**

     * nextDouble(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextDoubleBounded2() {

        for (double least = 0.0001; least < 1.0e20; least *= 8) {

            for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {

                double f = ThreadLocalRandom.current().nextDouble(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                double j;

                while (i < NCALLS &&

                       (j = ThreadLocalRandom.current().nextDouble(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * Different threads produce different pseudo-random sequences

     */

    public void testDifferentSequences() {

        // Don't use main thread's ThreadLocalRandom - it is likely to

        // be polluted by previous tests.

        final AtomicReference<ThreadLocalRandom> threadLocalRandom =

        final AtomicLong rand = new AtomicLong();

        long firstRand = 0;

        ThreadLocalRandom firstThreadLocalRandom = null;

        Runnable getRandomState = new CheckedRunnable() {

            public void realRun() {

                ThreadLocalRandom current = ThreadLocalRandom.current();

                assertSame(current, ThreadLocalRandom.current());

                // test bug: the following is not guaranteed and not true in JDK8

                //                assertNotSame(current, threadLocalRandom.get());

                rand.set(current.nextLong());

                threadLocalRandom.set(current);

            }};

        Thread first = newStartedThread(getRandomState);

        awaitTermination(first);

        firstRand = rand.get();

        firstThreadLocalRandom = threadLocalRandom.get();

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

            Thread t = newStartedThread(getRandomState);

            awaitTermination(t);

            if (firstRand != rand.get())

                return;

        }

        fail("all threads generate the same pseudo-random sequence");

    }

    /**

     * Repeated calls to nextBytes produce at least values of different signs for every byte

     */

    public void testNextBytes() {

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        int n = rnd.nextInt(1, 20);

        byte[] bytes = new byte[n];

        outer:

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

            for (int tries = NCALLS; tries-->0; ) {

                byte before = bytes[i];

                rnd.nextBytes(bytes);

                byte after = bytes[i];

                if (after * before < 0)

                    continue outer;

            }

            fail("not enough variation in random bytes");

        }

    }

    /**

     * Filling an empty array with random bytes succeeds without effect.

     */

    public void testNextBytes_emptyArray() {

        ThreadLocalRandom.current().nextBytes(new byte[0]);

    }

    public void testNextBytes_nullArray() {

        try {

            ThreadLocalRandom.current().nextBytes(null);

            shouldThrow();

        } catch (NullPointerException success) {}

    }

}