jdk/test/java/util/concurrent/ArrayBlockingQueue/IteratorConsistency.java
changeset 44039 058585425bb7
parent 44038 eb5d68f18d4d
child 44040 3dc7457351f8
--- a/jdk/test/java/util/concurrent/ArrayBlockingQueue/IteratorConsistency.java	Fri Mar 03 10:45:38 2017 -0800
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,755 +0,0 @@
-/*
- * 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 Martin Buchholz 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.lang.ref.WeakReference;
-import java.lang.reflect.Field;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.ArrayDeque;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-import java.util.NoSuchElementException;
-import java.util.Queue;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ThreadLocalRandom;
-
-/*
- * @test
- * @bug 7014263
- * @modules java.base/java.util.concurrent:open
- * @summary White box testing of ArrayBlockingQueue iterators.
- */
-
-/**
- * Tightly coupled to the implementation of ArrayBlockingQueue.
- * Uses reflection to inspect queue and iterator state.
- */
-@SuppressWarnings({"unchecked", "rawtypes"})
-public class IteratorConsistency {
-    final ThreadLocalRandom rnd = ThreadLocalRandom.current();
-    final int CAPACITY = 20;
-    Field itrsField;
-    Field itemsField;
-    Field takeIndexField;
-    Field headField;
-    Field nextField;
-    Field prevTakeIndexField;
-
-    void test(String[] args) throws Throwable {
-        itrsField = ArrayBlockingQueue.class.getDeclaredField("itrs");
-        itemsField = ArrayBlockingQueue.class.getDeclaredField("items");
-        takeIndexField = ArrayBlockingQueue.class.getDeclaredField("takeIndex");
-        headField = Class.forName("java.util.concurrent.ArrayBlockingQueue$Itrs").getDeclaredField("head");
-        nextField = Class.forName("java.util.concurrent.ArrayBlockingQueue$Itrs$Node").getDeclaredField("next");
-        prevTakeIndexField = Class.forName("java.util.concurrent.ArrayBlockingQueue$Itr").getDeclaredField("prevTakeIndex");
-        itrsField.setAccessible(true);
-        itemsField.setAccessible(true);
-        takeIndexField.setAccessible(true);
-        headField.setAccessible(true);
-        nextField.setAccessible(true);
-        prevTakeIndexField.setAccessible(true);
-        test(CAPACITY, true);
-        test(CAPACITY, false);
-    }
-
-    Object itrs(ArrayBlockingQueue q) {
-        try { return itrsField.get(q); }
-        catch (Throwable ex) { throw new AssertionError(ex); }
-    }
-
-    int takeIndex(ArrayBlockingQueue q) {
-        try { return takeIndexField.getInt(q); }
-        catch (Throwable ex) { throw new AssertionError(ex); }
-    }
-
-    List<Iterator> trackedIterators(Object itrs) {
-        try {
-            List<Iterator> its = new ArrayList<>();
-            if (itrs != null)
-                for (Object p = headField.get(itrs); p != null; p = nextField.get(p))
-                    its.add(((WeakReference<Iterator>)(p)).get());
-            Collections.reverse(its);
-            return its;
-        } catch (Throwable ex) { throw new AssertionError(ex); }
-    }
-
-    List<Iterator> trackedIterators(ArrayBlockingQueue q) {
-        return trackedIterators(itrs(q));
-    }
-
-    List<Iterator> attachedIterators(Object itrs) {
-        try {
-            List<Iterator> its = new ArrayList<>();
-            if (itrs != null)
-                for (Object p = headField.get(itrs); p != null; p = nextField.get(p)) {
-                    Iterator it = ((WeakReference<Iterator>)(p)).get();
-                    if (it != null && !isDetached(it))
-                        its.add(it);
-                }
-            Collections.reverse(its);
-            return its;
-        } catch (Throwable ex) { unexpected(ex); return null; }
-    }
-
-    List<Iterator> attachedIterators(ArrayBlockingQueue q) {
-        return attachedIterators(itrs(q));
-    }
-
-    Object[] internalArray(ArrayBlockingQueue q) {
-        try { return (Object[]) itemsField.get(q); }
-        catch (Throwable ex) { throw new AssertionError(ex); }
-    }
-
-    void printInternalArray(ArrayBlockingQueue q) {
-        System.err.println(Arrays.toString(internalArray(q)));
-    }
-
-    void checkExhausted(Iterator it) {
-        if (rnd.nextBoolean()) {
-            check(!it.hasNext());
-            check(isDetached(it));
-        }
-        if (rnd.nextBoolean()) {
-            it.forEachRemaining(e -> { throw new AssertionError(); });
-            checkDetached(it);
-        }
-        if (rnd.nextBoolean())
-            try { it.next(); fail("should throw"); }
-            catch (NoSuchElementException success) {}
-    }
-
-    boolean isDetached(Iterator it) {
-        try {
-            return prevTakeIndexField.getInt(it) < 0;
-        } catch (IllegalAccessException t) { unexpected(t); return false; }
-    }
-
-    void checkDetached(Iterator it) {
-        check(isDetached(it));
-    }
-
-    void removeUsingIterator(ArrayBlockingQueue q, Object element) {
-        Iterator it = q.iterator();
-        while (it.hasNext()) {
-            Object x = it.next();
-            if (element.equals(x))
-                it.remove();
-            checkRemoveThrowsISE(it);
-        }
-    }
-
-    void checkRemoveThrowsISE(Iterator it) {
-        if (rnd.nextBoolean())
-            return;
-        try { it.remove(); fail("should throw"); }
-        catch (IllegalStateException success) {}
-    }
-
-    void checkRemoveHasNoEffect(Iterator it, Collection c) {
-        if (rnd.nextBoolean())
-            return;
-        int size = c.size();
-        it.remove(); // no effect
-        equal(c.size(), size);
-        checkRemoveThrowsISE(it);
-    }
-
-    void checkIterationSanity(Queue q) {
-        if (rnd.nextBoolean())
-            return;
-        int size = q.size();
-        Object[] a = q.toArray();
-        Object[] b = new Object[size+2];
-        Arrays.fill(b, Boolean.TRUE);
-        Object[] c = q.toArray(b);
-        equal(a.length, size);
-        check(b == c);
-        check(b[size] == null);
-        check(b[size+1] == Boolean.TRUE);
-        equal(q.toString(), Arrays.toString(a));
-        Integer[] xx = null, yy = null;
-        if (size > 0) {
-            xx = new Integer[size - 1];
-            Arrays.fill(xx, 42);
-            yy = ((Queue<Integer>)q).toArray(xx);
-            for (Integer zz : xx)
-                equal(42, zz);
-        }
-        Iterator it = q.iterator();
-        for (int i = 0; i < size; i++) {
-            check(it.hasNext());
-            Object x = it.next();
-            check(x == a[i]);
-            check(x == b[i]);
-            if (xx != null) check(x == yy[i]);
-        }
-        check(!it.hasNext());
-    }
-
-    private static void waitForFinalizersToRun() {
-        for (int i = 0; i < 2; i++)
-            tryWaitForFinalizersToRun();
-    }
-
-    private static void tryWaitForFinalizersToRun() {
-        System.gc();
-        final CountDownLatch fin = new CountDownLatch(1);
-        new Object() { protected void finalize() { fin.countDown(); }};
-        System.gc();
-        try { fin.await(); }
-        catch (InterruptedException ie) { throw new Error(ie); }
-    }
-
-    void test(int capacity, boolean fair) {
-        //----------------------------------------------------------------
-        // q.clear will clear out itrs.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                check(q.add(i));
-            check(itrs(q) == null);
-            for (int i = 0; i < capacity; i++) {
-                its.add(q.iterator());
-                equal(trackedIterators(q), its);
-                q.poll();
-                q.add(capacity+i);
-            }
-            q.clear();
-            check(itrs(q) == null);
-            int j = 0;
-            for (Iterator it : its) {
-                if (rnd.nextBoolean())
-                    check(it.hasNext());
-                equal(it.next(), j++);
-                checkExhausted(it);
-            }
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // q emptying will clear out itrs.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            check(itrs(q) == null);
-            for (int i = 0; i < capacity; i++) {
-                its.add(q.iterator());
-                equal(trackedIterators(q), its);
-                q.poll();
-                q.add(capacity+i);
-            }
-            for (int i = 0; i < capacity; i++)
-                q.poll();
-            check(itrs(q) == null);
-            int j = 0;
-            for (Iterator it : its) {
-                if (rnd.nextBoolean())
-                    check(it.hasNext());
-                equal(it.next(), j++);
-                checkExhausted(it);
-            }
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Advancing 2 cycles will remove iterators.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            check(itrs(q) == null);
-            for (int i = capacity; i < 3 * capacity; i++) {
-                its.add(q.iterator());
-                equal(trackedIterators(q), its);
-                q.poll();
-                q.add(i);
-            }
-            for (int i = 3 * capacity; i < 4 * capacity; i++) {
-                equal(trackedIterators(q), its.subList(capacity,2*capacity));
-                q.poll();
-                q.add(i);
-            }
-            check(itrs(q) == null);
-            int j = 0;
-            for (Iterator it : its) {
-                if (rnd.nextBoolean())
-                    check(it.hasNext());
-                equal(it.next(), j++);
-                checkExhausted(it);
-            }
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Interior removal of elements used by an iterator will cause
-        // it to be untracked.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            q.add(0);
-            for (int i = 1; i < 2 * capacity; i++) {
-                q.add(i);
-                Integer[] elts = { -1, -2, -3 };
-                for (Integer elt : elts) q.add(elt);
-                equal(q.remove(), i - 1);
-                Iterator it = q.iterator();
-                equal(it.next(), i);
-                equal(it.next(), elts[0]);
-                Collections.shuffle(Arrays.asList(elts));
-                check(q.remove(elts[0]));
-                check(q.remove(elts[1]));
-                equal(trackedIterators(q), Collections.singletonList(it));
-                check(q.remove(elts[2]));
-                check(itrs(q) == null);
-                equal(it.next(), -2);
-                if (rnd.nextBoolean()) checkExhausted(it);
-                if (rnd.nextBoolean()) checkDetached(it);
-            }
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check iterators on an empty q
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            for (int i = 0; i < 4; i++) {
-                Iterator it = q.iterator();
-                check(itrs(q) == null);
-                if (rnd.nextBoolean()) checkExhausted(it);
-                if (rnd.nextBoolean()) checkDetached(it);
-                checkRemoveThrowsISE(it);
-            }
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check "interior" removal of iterator's last element
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < capacity; i++) {
-                Iterator it = q.iterator();
-                its.add(it);
-                for (int j = 0; j < i; j++)
-                    equal(j, it.next());
-                equal(attachedIterators(q), its);
-            }
-            q.remove(capacity - 1);
-            equal(attachedIterators(q), its);
-            for (int i = 1; i < capacity - 1; i++) {
-                q.remove(capacity - i - 1);
-                Iterator it = its.get(capacity - i);
-                checkDetached(it);
-                equal(attachedIterators(q), its.subList(0, capacity - i));
-                if (rnd.nextBoolean()) check(it.hasNext());
-                equal(it.next(), capacity - i);
-                checkExhausted(it);
-            }
-            equal(attachedIterators(q), its.subList(0, 2));
-            q.remove(0);
-            check(q.isEmpty());
-            check(itrs(q) == null);
-            Iterator it = its.get(0);
-            equal(it.next(), 0);
-            checkRemoveHasNoEffect(it, q);
-            checkExhausted(it);
-            checkDetached(it);
-            checkRemoveHasNoEffect(its.get(1), q);
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check "interior" removal of alternating elements, straddling 2 cycles
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            // Move takeIndex to middle
-            for (int i = 0; i < capacity/2; i++) {
-                check(q.add(i));
-                equal(q.poll(), i);
-            }
-            check(takeIndex(q) == capacity/2);
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < capacity; i++) {
-                Iterator it = q.iterator();
-                its.add(it);
-                for (int j = 0; j < i; j++)
-                    equal(j, it.next());
-                equal(attachedIterators(q), its);
-            }
-            // Remove all even elements, in either direction using
-            // q.remove(), or iterator.remove()
-            switch (rnd.nextInt(3)) {
-            case 0:
-                for (int i = 0; i < capacity; i+=2) {
-                    check(q.remove(i));
-                    equal(attachedIterators(q), its);
-                }
-                break;
-            case 1:
-                for (int i = capacity - 2; i >= 0; i-=2) {
-                    check(q.remove(i));
-                    equal(attachedIterators(q), its);
-                }
-                break;
-            case 2:
-                Iterator it = q.iterator();
-                while (it.hasNext()) {
-                    int i = (Integer) it.next();
-                    if ((i & 1) == 0)
-                        it.remove();
-                }
-                equal(attachedIterators(q), its);
-                break;
-            default: throw new AssertionError();
-            }
-
-            for (int i = 0; i < capacity; i++) {
-                Iterator it = its.get(i);
-                boolean even = ((i & 1) == 0);
-                if (even) {
-                    if (rnd.nextBoolean()) check(it.hasNext());
-                    equal(i, it.next());
-                    for (int j = i+1; j < capacity; j += 2)
-                        equal(j, it.next());
-                    check(!isDetached(it));
-                    check(!it.hasNext());
-                    check(isDetached(it));
-                } else { /* odd */
-                    if (rnd.nextBoolean()) check(it.hasNext());
-                    checkRemoveHasNoEffect(it, q);
-                    equal(i, it.next());
-                    for (int j = i+2; j < capacity; j += 2)
-                        equal(j, it.next());
-                    check(!isDetached(it));
-                    check(!it.hasNext());
-                    check(isDetached(it));
-                }
-            }
-            equal(trackedIterators(q), Collections.emptyList());
-            check(itrs(q) == null);
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check garbage collection of discarded iterators
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < capacity; i++) {
-                its.add(q.iterator());
-                equal(attachedIterators(q), its);
-            }
-            its = null;
-            waitForFinalizersToRun();
-            List<Iterator> trackedIterators = trackedIterators(q);
-            equal(trackedIterators.size(), capacity);
-            for (Iterator x : trackedIterators)
-                check(x == null);
-            Iterator it = q.iterator();
-            equal(trackedIterators(q), Collections.singletonList(it));
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check garbage collection of discarded iterators,
-        // with a randomly retained subset.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            List<Iterator> retained = new ArrayList<>();
-            final int size = 1 + rnd.nextInt(capacity);
-            for (int i = 0; i < size; i++)
-                q.add(i);
-            for (int i = 0; i < size; i++) {
-                Iterator it = q.iterator();
-                its.add(it);
-                equal(attachedIterators(q), its);
-            }
-            // Leave sufficient gaps in retained
-            for (int i = 0; i < size; i+= 2+rnd.nextInt(3))
-                retained.add(its.get(i));
-            its = null;
-            waitForFinalizersToRun();
-            List<Iterator> trackedIterators = trackedIterators(q);
-            equal(trackedIterators.size(), size);
-            for (Iterator it : trackedIterators)
-                check((it == null) ^ retained.contains(it));
-            Iterator it = q.iterator(); // trigger another sweep
-            retained.add(it);
-            equal(trackedIterators(q), retained);
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check incremental sweeping of discarded iterators.
-        // Excessively white box?!
-        //----------------------------------------------------------------
-        try {
-            final int SHORT_SWEEP_PROBES = 4;
-            final int LONG_SWEEP_PROBES = 16;
-            final int PROBE_HOP = LONG_SWEEP_PROBES + 6 * SHORT_SWEEP_PROBES;
-            final int PROBE_HOP_COUNT = 10;
-            // Expect around 8 sweeps per PROBE_HOP
-            final int SWEEPS_PER_PROBE_HOP = 8;
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < PROBE_HOP_COUNT * PROBE_HOP; i++) {
-                its.add(q.iterator());
-                equal(attachedIterators(q), its);
-            }
-            // make some garbage, separated by PROBE_HOP
-            for (int i = 0; i < its.size(); i += PROBE_HOP)
-                its.set(i, null);
-            waitForFinalizersToRun();
-            int retries;
-            for (retries = 0;
-                 trackedIterators(q).contains(null) && retries < 1000;
-                 retries++)
-                // one round of sweeping
-                its.add(q.iterator());
-            check(retries >= PROBE_HOP_COUNT * (SWEEPS_PER_PROBE_HOP - 2));
-            check(retries <= PROBE_HOP_COUNT * (SWEEPS_PER_PROBE_HOP + 2));
-            Iterator itsit = its.iterator();
-            while (itsit.hasNext())
-                if (itsit.next() == null)
-                    itsit.remove();
-            equal(trackedIterators(q), its);
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check safety of iterator.remove while in detached mode.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity/2; i++) {
-                q.add(i);
-                q.remove();
-            }
-            check(takeIndex(q) == capacity/2);
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < capacity; i++) {
-                Iterator it = q.iterator();
-                its.add(it);
-                for (int j = 0; j < i; j++)
-                    equal(j, it.next());
-                equal(attachedIterators(q), its);
-            }
-            for (int i = capacity - 1; i >= 0; i--) {
-                Iterator it = its.get(i);
-                equal(i, it.next()); // last element
-                check(!isDetached(it));
-                check(!it.hasNext()); // first hasNext failure
-                check(isDetached(it));
-                int size = q.size();
-                check(q.contains(i));
-                switch (rnd.nextInt(3)) {
-                case 0:
-                    it.remove();
-                    check(!q.contains(i));
-                    equal(q.size(), size - 1);
-                    break;
-                case 1:
-                    // replace i with impostor
-                    if (q.remainingCapacity() == 0) {
-                        check(q.remove(i));
-                        check(q.add(-1));
-                    } else {
-                        check(q.add(-1));
-                        check(q.remove(i));
-                    }
-                    it.remove(); // should have no effect
-                    equal(size, q.size());
-                    check(q.contains(-1));
-                    check(q.remove(-1));
-                    break;
-                case 2:
-                    // replace i with true impostor
-                    if (i != 0) {
-                        check(q.remove(i));
-                        check(q.add(i));
-                    }
-                    it.remove();
-                    check(!q.contains(i));
-                    equal(q.size(), size - 1);
-                    break;
-                default: throw new AssertionError();
-                }
-                checkRemoveThrowsISE(it);
-                check(isDetached(it));
-                check(!trackedIterators(q).contains(it));
-            }
-            check(q.isEmpty());
-            check(itrs(q) == null);
-            for (Iterator it : its)
-                checkExhausted(it);
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check dequeues bypassing iterators' current positions.
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            Queue<Iterator> its0 = new ArrayDeque<>();
-            Queue<Iterator> itsMid = new ArrayDeque<>();
-            List<Iterator> its = new ArrayList<>();
-            for (int i = 0; i < capacity; i++)
-                q.add(i);
-            for (int i = 0; i < 2 * capacity + 1; i++) {
-                Iterator it = q.iterator();
-                its.add(it);
-                its0.add(it);
-            }
-            for (int i = 0; i < 2 * capacity + 1; i++) {
-                Iterator it = q.iterator();
-                for (int j = 0; j < capacity/2; j++)
-                    equal(j, it.next());
-                its.add(it);
-                itsMid.add(it);
-            }
-            for (int i = capacity; i < 3 * capacity; i++) {
-                Iterator it;
-
-                it = its0.remove();
-                checkRemoveThrowsISE(it);
-                if (rnd.nextBoolean()) check(it.hasNext());
-                equal(0, it.next());
-                int victim = i - capacity;
-                for (int j = victim + (victim == 0 ? 1 : 0); j < i; j++) {
-                    if (rnd.nextBoolean()) check(it.hasNext());
-                    equal(j, it.next());
-                }
-                checkExhausted(it);
-
-                it = itsMid.remove();
-                if (victim >= capacity/2)
-                    checkRemoveHasNoEffect(it, q);
-                equal(capacity/2, it.next());
-                if (victim > capacity/2)
-                    checkRemoveHasNoEffect(it, q);
-                for (int j = Math.max(victim, capacity/2 + 1); j < i; j++) {
-                    if (rnd.nextBoolean()) check(it.hasNext());
-                    equal(j, it.next());
-                }
-                checkExhausted(it);
-
-                if (rnd.nextBoolean()) {
-                    equal(victim, q.remove());
-                } else {
-                    ArrayList list = new ArrayList(1);
-                    q.drainTo(list, 1);
-                    equal(list.size(), 1);
-                    equal(victim, list.get(0));
-                }
-                check(q.add(i));
-            }
-            // takeIndex has wrapped twice.
-            Iterator it0 = its0.remove();
-            Iterator itMid = itsMid.remove();
-            check(isDetached(it0));
-            check(isDetached(itMid));
-            if (rnd.nextBoolean()) check(it0.hasNext());
-            if (rnd.nextBoolean()) check(itMid.hasNext());
-            checkRemoveThrowsISE(it0);
-            checkRemoveHasNoEffect(itMid, q);
-            if (rnd.nextBoolean()) equal(0, it0.next());
-            if (rnd.nextBoolean()) equal(capacity/2, itMid.next());
-            check(isDetached(it0));
-            check(isDetached(itMid));
-            equal(capacity, q.size());
-            equal(0, q.remainingCapacity());
-        } catch (Throwable t) { unexpected(t); }
-
-        //----------------------------------------------------------------
-        // Check collective sanity of iteration, toArray() and toString()
-        //----------------------------------------------------------------
-        try {
-            ArrayBlockingQueue q = new ArrayBlockingQueue(capacity, fair);
-            for (int i = 0; i < capacity; i++) {
-                checkIterationSanity(q);
-                equal(capacity, q.size() + q.remainingCapacity());
-                q.add(i);
-            }
-            for (int i = 0; i < (capacity + (capacity >> 1)); i++) {
-                checkIterationSanity(q);
-                equal(capacity, q.size() + q.remainingCapacity());
-                equal(i, q.peek());
-                equal(i, q.poll());
-                checkIterationSanity(q);
-                equal(capacity, q.size() + q.remainingCapacity());
-                q.add(capacity + i);
-            }
-            for (int i = 0; i < capacity; i++) {
-                checkIterationSanity(q);
-                equal(capacity, q.size() + q.remainingCapacity());
-                int expected = i + capacity + (capacity >> 1);
-                equal(expected, q.peek());
-                equal(expected, q.poll());
-            }
-            checkIterationSanity(q);
-        } catch (Throwable t) { unexpected(t); }
-
-    }
-
-    //--------------------- Infrastructure ---------------------------
-    volatile int passed = 0, failed = 0;
-    void pass() {passed++;}
-    void fail() {failed++; Thread.dumpStack();}
-    void fail(String msg) {System.err.println(msg); fail();}
-    void unexpected(Throwable t) {failed++; t.printStackTrace();}
-    void check(boolean cond) {if (cond) pass(); else fail();}
-    void equal(Object x, Object y) {
-        if (x == null ? y == null : x.equals(y)) pass();
-        else fail(x + " not equal to " + y);}
-    public static void main(String[] args) throws Throwable {
-        new IteratorConsistency().instanceMain(args);}
-    public void instanceMain(String[] args) throws Throwable {
-        try {test(args);} catch (Throwable t) {unexpected(t);}
-        System.err.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
-        if (failed > 0) throw new AssertionError("Some tests failed");}
-}