/*
* 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.
*
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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/
*/
/*
* @test
* @bug 6805775 6815766
* @summary Check weak consistency of concurrent queue iterators
*/
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
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.BlockingQueue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.ThreadLocalRandom;
@SuppressWarnings({"unchecked", "rawtypes"})
public class IteratorWeakConsistency {
final ThreadLocalRandom rnd = ThreadLocalRandom.current();
void test(String[] args) throws Throwable {
test(new LinkedBlockingQueue());
test(new LinkedBlockingQueue(20));
test(new LinkedBlockingDeque());
test(new LinkedBlockingDeque(20));
test(new ConcurrentLinkedDeque());
test(new ConcurrentLinkedQueue());
test(new LinkedTransferQueue());
test(new ArrayBlockingQueue(20));
}
void checkExhausted(Iterator it) {
if (rnd.nextBoolean()) {
check(!it.hasNext());
}
if (rnd.nextBoolean()) {
it.forEachRemaining(e -> { throw new AssertionError(); });
}
if (rnd.nextBoolean())
try { it.next(); fail("should throw"); }
catch (NoSuchElementException success) {}
}
void checkRemoveThrowsISE(Iterator it) {
if (rnd.nextBoolean()) {
try { it.remove(); fail("should throw"); }
catch (IllegalStateException success) {}
}
}
void checkRemoveHasNoEffect(Iterator it, Collection c) {
if (rnd.nextBoolean()) {
int size = c.size();
it.remove(); // no effect
equal(c.size(), size);
checkRemoveThrowsISE(it);
}
}
void test(Queue q) {
//----------------------------------------------------------------
// Check iterators on an empty q
//----------------------------------------------------------------
try {
for (int i = 0; i < 4; i++) {
Iterator it = q.iterator();
if (rnd.nextBoolean()) checkExhausted(it);
checkRemoveThrowsISE(it);
}
} catch (Throwable t) { unexpected(t); }
// TODO: make this more general
try {
for (int i = 0; i < 10; i++)
q.add(i);
Iterator it = q.iterator();
q.poll();
q.poll();
q.poll();
q.remove(7);
List list = new ArrayList();
while (it.hasNext())
list.add(it.next());
equal(list, Arrays.asList(0, 3, 4, 5, 6, 8, 9));
check(! list.contains(null));
System.err.printf("%s: %s%n",
q.getClass().getSimpleName(),
list);
} catch (Throwable t) { unexpected(t); }
try {
q.clear();
q.add(1);
q.add(2);
q.add(3);
q.add(4);
Iterator it = q.iterator();
it.next();
q.remove(2);
q.remove(1);
q.remove(3);
boolean found4 = false;
while (it.hasNext()) {
found4 |= it.next().equals(4);
}
check(found4);
} catch (Throwable t) { unexpected(t); }
try {
q.clear();
Object x = new Object();
for (int i = 0; i < 20; i++)
q.add(x);
equal(20, q.size());
Iterator it1 = q.iterator();
Iterator it2 = q.iterator();
try { it1.remove(); fail(); }
catch (IllegalStateException success) {}
try { it2.remove(); fail(); }
catch (IllegalStateException success) {}
check(it1.next() == x);
check(it2.hasNext());
check(it2.next() == x);
it1.remove();
it2.remove();
equal(19, q.size());
try { it1.remove(); fail(); }
catch (IllegalStateException success) {}
try { it2.remove(); fail(); }
catch (IllegalStateException success) {}
equal(19, q.size());
it1.next();
check(it2.hasNext());
it2.next();
it2.remove();
it1.remove();
equal(18, q.size());
it1.next();
it2.next();
check(q.remove() == x);
equal(17, q.size());
it1.remove();
it2.remove();
equal(17, q.size());
} catch (Throwable t) { unexpected(t); }
//----------------------------------------------------------------
// Check "interior" removal of alternating elements
//----------------------------------------------------------------
try {
q.clear();
final int remainingCapacity = (q instanceof BlockingQueue) ?
((BlockingQueue)q).remainingCapacity() :
Integer.MAX_VALUE;
final int capacity = Math.min(20, remainingCapacity);
List<Iterator> its = new ArrayList<Iterator>();
// Move to "middle"
for (int i = 0; i < capacity/2; i++) {
check(q.add(i));
equal(q.poll(), i);
}
for (int i = 0; i < capacity; i++)
check(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());
}
// 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));
break;
case 1:
for (int i = capacity - 2; i >= 0; i-=2)
check(q.remove(i));
break;
case 2:
Iterator it = q.iterator();
while (it.hasNext()) {
int i = (Integer) it.next();
if ((i & 1) == 0)
it.remove();
}
break;
default: throw new Error();
}
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(!it.hasNext());
} 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(!it.hasNext());
}
}
// q only contains odd elements
for (int i = 0; i < capacity; i++)
check(q.contains(i) ^ ((i & 1) == 0));
} 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 IteratorWeakConsistency().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");}
}