/*

 * Copyright (c) 2013, 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

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 */

import org.testng.annotations.Test;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CompletionException;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.CountDownLatch;

import java.util.function.Supplier;

import java.util.stream.IntStream;

import java.util.stream.Stream;

/**

 * @test

 * @bug 8028564

 * @run testng ConcurrentContainsKeyTest

 * @summary Test that entries are always present in the map,

 * when entries are held within one bin that is a tree

 */

@Test

public class ConcurrentContainsKeyTest {

    // The number of entries for each thread to place in a map

    // Should be > ConcurrentHashMap.TREEIFY_THRESHOLD but small

    // enough to allow for enough iteration overlap by multiple threads

    private static final int N = Integer.getInteger("n", 16);

    // The number of rounds each thread performs per entry

    private static final int R = Integer.getInteger("r", 32);

    // The number of iterations of the test

    private static final int I = Integer.getInteger("i", 256);

    // Object to be placed in the concurrent map

    static class X implements Comparable<X> {

        private final int a;

        X(int a) {

            this.a = a;

        }

        public int compareTo(X o) {

            return this.a - o.a;

        }

        public int hashCode() {

            // Return the same hash code to guarantee collisions

            return 0;

        }

    }

    @Test

    public void testContainsKey() {

        X[] content = IntStream.range(0, N).mapToObj(i -> new X(i)).toArray(X[]::new);

        // Create map with an initial size >= ConcurrentHashMap.TREEIFY_THRESHOLD

        // ensuring tree'ification will occur for a small number of entries

        // with the same hash code

        ConcurrentHashMap<Object, Object> m = new ConcurrentHashMap<>(64);

        Stream.of(content).forEach(x -> m.put(x, x));

        test(content, m);

    }

    private static void test(X[] content, ConcurrentHashMap<Object, Object> m) {

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

            testOnce(content, m);

        }

    }

    static class AssociationFailure extends RuntimeException {

        AssociationFailure(String message) {

            super(message);

        }

    }

    private static void testOnce(Object[] content, ConcurrentHashMap<Object, Object> m) {

        CountDownLatch s = new CountDownLatch(1);

        Supplier<Runnable> sr = () -> () -> {

            try {

                s.await();

            }

            catch (InterruptedException e) {

            }

            for (int i = 0; i < R * N; i++) {

                Object o = content[i % content.length];

                if (!m.containsKey(o)) {

                    throw new AssociationFailure("CHM.containsKey failed: entry does not exist");

                }

            }

        };

        int ps = Runtime.getRuntime().availableProcessors();

        Stream<CompletableFuture> runners = IntStream.range(0, ps)

                .mapToObj(i -> sr.get())

                .map(CompletableFuture::runAsync);

        CompletableFuture all = CompletableFuture.allOf(

                runners.toArray(CompletableFuture[]::new));

        // Trigger the runners to start checking key membership

        s.countDown();

        try {

            all.join();

        }

        catch (CompletionException e) {

            Throwable t = e.getCause();

            if (t instanceof AssociationFailure) {

                throw (AssociationFailure) t;

            }

            else {

                throw e;

            }

        }

    }

}