/*

 * 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

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 */

/*

 * 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.Arrays;

import java.util.BitSet;

import java.util.Collection;

import java.util.Comparator;

import java.util.Iterator;

import java.util.NavigableSet;

import java.util.NoSuchElementException;

import java.util.Random;

import java.util.Set;

import java.util.SortedSet;

import java.util.concurrent.ConcurrentSkipListSet;

import junit.framework.Test;

import junit.framework.TestSuite;

public class ConcurrentSkipListSetTest extends JSR166TestCase {

    public static void main(String[] args) {

        main(suite(), args);

    }

    public static Test suite() {

        return new TestSuite(ConcurrentSkipListSetTest.class);

    }

    static class MyReverseComparator implements Comparator {

        public int compare(Object x, Object y) {

            return ((Comparable)y).compareTo(x);

        }

    }

    /**

     * Returns a new set of given size containing consecutive

     * Integers 0 ... n - 1.

     */

    private static ConcurrentSkipListSet<Integer> populatedSet(int n) {

        assertTrue(q.isEmpty());

        for (int i = n - 1; i >= 0; i -= 2)

            assertTrue(q.add(new Integer(i)));

        for (int i = (n & 1); i < n; i += 2)

            assertTrue(q.add(new Integer(i)));

        assertFalse(q.isEmpty());

        assertEquals(n, q.size());

        return q;

    }

    /**

     * Returns a new set of first 5 ints.

     */

    private static ConcurrentSkipListSet set5() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        assertTrue(q.isEmpty());

        q.add(one);

        q.add(two);

        q.add(three);

        q.add(four);

        q.add(five);

        assertEquals(5, q.size());

        return q;

    }

    /**

     * A new set has unbounded capacity

     */

    public void testConstructor1() {

        assertEquals(0, new ConcurrentSkipListSet().size());

    }

    /**

     * Initializing from null Collection throws NPE

     */

    public void testConstructor3() {

        try {

            new ConcurrentSkipListSet((Collection)null);

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * Initializing from Collection of null elements throws NPE

     */

    public void testConstructor4() {

        try {

            new ConcurrentSkipListSet(Arrays.asList(new Integer[SIZE]));

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * Initializing from Collection with some null elements throws NPE

     */

    public void testConstructor5() {

        Integer[] ints = new Integer[SIZE];

        for (int i = 0; i < SIZE - 1; ++i)

            ints[i] = new Integer(i);

        try {

            new ConcurrentSkipListSet(Arrays.asList(ints));

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * Set contains all elements of collection used to initialize

     */

    public void testConstructor6() {

        Integer[] ints = new Integer[SIZE];

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

            ints[i] = new Integer(i);

        ConcurrentSkipListSet q = new ConcurrentSkipListSet(Arrays.asList(ints));

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

            assertEquals(ints[i], q.pollFirst());

    }

    /**

     * The comparator used in constructor is used

     */

    public void testConstructor7() {

        MyReverseComparator cmp = new MyReverseComparator();

        ConcurrentSkipListSet q = new ConcurrentSkipListSet(cmp);

        assertEquals(cmp, q.comparator());

        Integer[] ints = new Integer[SIZE];

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

            ints[i] = new Integer(i);

        q.addAll(Arrays.asList(ints));

        for (int i = SIZE - 1; i >= 0; --i)

            assertEquals(ints[i], q.pollFirst());

    }

    /**

     * isEmpty is true before add, false after

     */

    public void testEmpty() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        assertTrue(q.isEmpty());

        q.add(new Integer(1));

        assertFalse(q.isEmpty());

        q.add(new Integer(2));

        q.pollFirst();

        q.pollFirst();

        assertTrue(q.isEmpty());

    }

    /**

     * size changes when elements added and removed

     */

    public void testSize() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

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

            assertEquals(SIZE - i, q.size());

            q.pollFirst();

        }

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

            assertEquals(i, q.size());

            q.add(new Integer(i));

        }

    }

    /**

     * add(null) throws NPE

     */

    public void testAddNull() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        try {

            q.add(null);

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * Add of comparable element succeeds

     */

    public void testAdd() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        assertTrue(q.add(zero));

        assertTrue(q.add(one));

    }

    /**

     * Add of duplicate element fails

     */

    public void testAddDup() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        assertTrue(q.add(zero));

        assertFalse(q.add(zero));

    }

    /**

     * Add of non-Comparable throws CCE

     */

    public void testAddNonComparable() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        try {

            q.add(new Object());

            q.add(new Object());

            shouldThrow();

        } catch (ClassCastException success) {

            assertTrue(q.size() < 2);

            for (int i = 0, size = q.size(); i < size; i++)

                assertSame(Object.class, q.pollFirst().getClass());

            assertNull(q.pollFirst());

            assertTrue(q.isEmpty());

            assertEquals(0, q.size());

        }

    }

    /**

     * addAll(null) throws NPE

     */

    public void testAddAll1() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        try {

            q.addAll(null);

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * addAll of a collection with null elements throws NPE

     */

    public void testAddAll2() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        Integer[] ints = new Integer[SIZE];

        try {

            q.addAll(Arrays.asList(ints));

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * addAll of a collection with any null elements throws NPE after

     * possibly adding some elements

     */

    public void testAddAll3() {

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        Integer[] ints = new Integer[SIZE];

        for (int i = 0; i < SIZE - 1; ++i)

            ints[i] = new Integer(i);

        try {

            q.addAll(Arrays.asList(ints));

            shouldThrow();

        } catch (NullPointerException success) {}

    }

    /**

     * Set contains all elements of successful addAll

     */

    public void testAddAll5() {

        Integer[] empty = new Integer[0];

        Integer[] ints = new Integer[SIZE];

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

            ints[i] = new Integer(SIZE - 1 - i);

        ConcurrentSkipListSet q = new ConcurrentSkipListSet();

        assertFalse(q.addAll(Arrays.asList(empty)));

        assertTrue(q.addAll(Arrays.asList(ints)));

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

            assertEquals(i, q.pollFirst());

    }

    /**

     * pollFirst succeeds unless empty

     */

    public void testPollFirst() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

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

            assertEquals(i, q.pollFirst());

        }

        assertNull(q.pollFirst());

    }

    /**

     * pollLast succeeds unless empty

     */

    public void testPollLast() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        for (int i = SIZE - 1; i >= 0; --i) {

            assertEquals(i, q.pollLast());

        }

        assertNull(q.pollFirst());

    }

    /**

     * remove(x) removes x and returns true if present

     */

    public void testRemoveElement() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        for (int i = 1; i < SIZE; i += 2) {

            assertTrue(q.contains(i));

            assertTrue(q.remove(i));

            assertFalse(q.contains(i));

            assertTrue(q.contains(i - 1));

        }

        for (int i = 0; i < SIZE; i += 2) {

            assertTrue(q.contains(i));

            assertTrue(q.remove(i));

            assertFalse(q.contains(i));

            assertFalse(q.remove(i + 1));

            assertFalse(q.contains(i + 1));

        }

        assertTrue(q.isEmpty());

    }

    /**

     * contains(x) reports true when elements added but not yet removed

     */

    public void testContains() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

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

            assertTrue(q.contains(new Integer(i)));

            q.pollFirst();

            assertFalse(q.contains(new Integer(i)));

        }

    }

    /**

     * clear removes all elements

     */

    public void testClear() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        q.clear();

        assertTrue(q.isEmpty());

        assertEquals(0, q.size());

        q.add(new Integer(1));

        assertFalse(q.isEmpty());

        q.clear();

        assertTrue(q.isEmpty());

    }

    /**

     * containsAll(c) is true when c contains a subset of elements

     */

    public void testContainsAll() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        ConcurrentSkipListSet p = new ConcurrentSkipListSet();

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

            assertTrue(q.containsAll(p));

            assertFalse(p.containsAll(q));

            p.add(new Integer(i));

        }

        assertTrue(p.containsAll(q));

    }

    /**

     * retainAll(c) retains only those elements of c and reports true if changed

     */

    public void testRetainAll() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        ConcurrentSkipListSet p = populatedSet(SIZE);

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

            boolean changed = q.retainAll(p);

            if (i == 0)

                assertFalse(changed);

            else

                assertTrue(changed);

            assertTrue(q.containsAll(p));

            assertEquals(SIZE - i, q.size());

            p.pollFirst();

        }

    }

    /**

     * removeAll(c) removes only those elements of c and reports true if changed

     */

    public void testRemoveAll() {

        for (int i = 1; i < SIZE; ++i) {

            ConcurrentSkipListSet q = populatedSet(SIZE);

            ConcurrentSkipListSet p = populatedSet(i);

            assertTrue(q.removeAll(p));

            assertEquals(SIZE - i, q.size());

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

                Integer x = (Integer)(p.pollFirst());

                assertFalse(q.contains(x));

            }

        }

    }

    /**

     * lower returns preceding element

     */

    public void testLower() {

        ConcurrentSkipListSet q = set5();

        Object e1 = q.lower(three);

        assertEquals(two, e1);

        Object e2 = q.lower(six);

        assertEquals(five, e2);

        Object e3 = q.lower(one);

        assertNull(e3);

        Object e4 = q.lower(zero);

        assertNull(e4);

    }

    /**

     * higher returns next element

     */

    public void testHigher() {

        ConcurrentSkipListSet q = set5();

        Object e1 = q.higher(three);

        assertEquals(four, e1);

        Object e2 = q.higher(zero);

        assertEquals(one, e2);

        Object e3 = q.higher(five);

        assertNull(e3);

        Object e4 = q.higher(six);

        assertNull(e4);

    }

    /**

     * floor returns preceding element

     */

    public void testFloor() {

        ConcurrentSkipListSet q = set5();

        Object e1 = q.floor(three);

        assertEquals(three, e1);

        Object e2 = q.floor(six);

        assertEquals(five, e2);

        Object e3 = q.floor(one);

        assertEquals(one, e3);

        Object e4 = q.floor(zero);

        assertNull(e4);

    }

    /**

     * ceiling returns next element

     */

    public void testCeiling() {

        ConcurrentSkipListSet q = set5();

        Object e1 = q.ceiling(three);

        assertEquals(three, e1);

        Object e2 = q.ceiling(zero);

        assertEquals(one, e2);

        Object e3 = q.ceiling(five);

        assertEquals(five, e3);

        Object e4 = q.ceiling(six);

        assertNull(e4);

    }

    /**

     * toArray contains all elements in sorted order

     */

    public void testToArray() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        Object[] o = q.toArray();

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

            assertSame(o[i], q.pollFirst());

    }

    /**

     * toArray(a) contains all elements in sorted order

     */

    public void testToArray2() {

        ConcurrentSkipListSet<Integer> q = populatedSet(SIZE);

        Integer[] ints = new Integer[SIZE];

        assertSame(ints, q.toArray(ints));

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

            assertSame(ints[i], q.pollFirst());

    }

    /**

     * iterator iterates through all elements

     */

    public void testIterator() {

        ConcurrentSkipListSet q = populatedSet(SIZE);

        Iterator it = q.iterator();

        int i;

        for (i = 0; it.hasNext(); i++)

            assertTrue(q.contains(it.next()));

        assertEquals(i, SIZE);

        assertIteratorExhausted(it);

    }

    /**

     * iterator of empty set has no elements

     */

    public void testEmptyIterator() {

        NavigableSet s = new ConcurrentSkipListSet();

        assertIteratorExhausted(s.iterator());

        assertIteratorExhausted(s.descendingSet().iterator());

    }

    /**

     * iterator.remove removes current element

     */

    public void testIteratorRemove() {