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

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 *

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 * 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.

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import org.testng.annotations.DataProvider;

import org.testng.annotations.Test;

import java.security.SecureRandom;

import java.util.ArrayList;

import java.util.List;

import java.util.Random;

import java.util.Set;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.ExecutionException;

import java.util.concurrent.ThreadLocalRandom;

import java.util.concurrent.TimeUnit;

import java.util.concurrent.TimeoutException;

import java.util.function.Supplier;

import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;

import static java.util.stream.Collectors.toSet;

import static org.testng.Assert.*;

/**

 * @test

 * @run testng RandomStreamTest

 * @summary test stream methods on Random

 * @author Brian Goetz

 */

public class RandomStreamTest {

    private static final int SIZE = 1000;

    @DataProvider(name = "suppliers")

    public Object[][] randomSuppliers() {

        return new Object[][] {

            {new Random(), SIZE},

            {new SecureRandom(), SIZE}

        };

    }

    @Test(dataProvider = "suppliers")

    public void testRandomIntStream(final Random random, final int count) {

        final List<Integer> destination = new ArrayList<>(count);

        random.ints().limit(count).forEach(destination::add);

        assertEquals(destination.size(), count);

    }

    @Test(dataProvider = "suppliers")

    public void testRandomLongStream(final Random random, final int count) {

        final List<Long> destination = new ArrayList<>(count);

        random.longs().limit(count).forEach(destination::add);

        assertEquals(destination.size(), count);

    }

    @Test(dataProvider = "suppliers")

    public void testRandomDoubleStream(final Random random, final int count) {

        final List<Double> destination = new ArrayList<>(count);

        random.doubles().limit(count).forEach(destination::add);

        random.doubles().limit(count).forEach(d -> assertTrue(d >= 0.0 && d < 1.0));

        assertEquals(destination.size(), count);

    }

    @Test

    public void testIntStream() {

        final long seed = System.currentTimeMillis();

        final Random r1 = new Random(seed);

        final int[] a = new int[SIZE];

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

            a[i] = r1.nextInt();

        }

        final Random r2 = new Random(seed); // same seed

        final int[] b = r2.ints().limit(SIZE).toArray();

        assertEquals(a, b);

    }

    @Test

    public void testLongStream() {

        final long seed = System.currentTimeMillis();

        final Random r1 = new Random(seed);

        final long[] a = new long[SIZE];

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

            a[i] = r1.nextLong();

        }

        final Random r2 = new Random(seed); // same seed

        final long[] b = r2.longs().limit(SIZE).toArray();

        assertEquals(a, b);

    }

    @Test

    public void testDoubleStream() {

        final long seed = System.currentTimeMillis();

        final Random r1 = new Random(seed);

        final double[] a = new double[SIZE];

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

            a[i] = r1.nextDouble();

        }

        final Random r2 = new Random(seed); // same seed

        final double[] b = r2.doubles().limit(SIZE).toArray();

        assertEquals(a, b);

    }

    @Test

    public void testThreadLocalIntStream() throws InterruptedException, ExecutionException, TimeoutException {

        ThreadLocalRandom tlr = ThreadLocalRandom.current();

        testRandomResultSupplierConcurrently(() -> tlr.ints().limit(SIZE).boxed().collect(toList()));

    }

    @Test

    public void testThreadLocalLongStream() throws InterruptedException, ExecutionException, TimeoutException {

        ThreadLocalRandom tlr = ThreadLocalRandom.current();

        testRandomResultSupplierConcurrently(() -> tlr.longs().limit(SIZE).boxed().collect(toList()));

    }

    @Test

    public void testThreadLocalDoubleStream() throws InterruptedException, ExecutionException, TimeoutException {

        ThreadLocalRandom tlr = ThreadLocalRandom.current();

        testRandomResultSupplierConcurrently(() -> tlr.doubles().limit(SIZE).boxed().collect(toList()));

    }

    <T> void testRandomResultSupplierConcurrently(Supplier<T> s) throws InterruptedException, ExecutionException, TimeoutException {

        // Produce 10 completable future tasks

        final int tasks = 10;

        List<CompletableFuture<T>> cfs = Stream.generate(() -> CompletableFuture.supplyAsync(s)).

                limit(tasks).collect(toList());

        // Wait for all tasks to complete

        // Timeout is beyond reasonable doubt that completion should

        // have occurred unless there is an issue

        CompletableFuture<Void> all = CompletableFuture.allOf(cfs.stream().toArray(CompletableFuture[]::new));

        all.get(1, TimeUnit.MINUTES);

        // Count the distinct results, which should equal the number of tasks

        long rc = cfs.stream().map(CompletableFuture::join).distinct().count();

        assertEquals(rc, tasks);

    }

}