Request for review : 7121314 : Behavior mismatch between AbstractCollection.toArray(T[] ) and its spec
Sean Chou
zhouyx at linux.vnet.ibm.com
Sun Apr 1 09:24:28 UTC 2012
Hi David,
I made the new webrev with your modified testcase:
http://cr.openjdk.java.net/~zhouyx/7121314/webrev.04/ .
The link to the bug:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7121314
The link to the start of the thread:
http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-March/009512.html
On Sun, Apr 1, 2012 at 11:25 AM, David Holmes <david.holmes at oracle.com>wrote:
> Simplified testcase below.
>
> Let's finalise this please.
>
> Thanks,
> David
>
>
> On 1/04/2012 1:08 PM, Sean Chou wrote:
>
>> Hi Ulf,
>>
>> This is a regression testcase, there is no performance issue or
>> future refactoring.
>> Please wait for David's comments.
>>
>> On Sun, Apr 1, 2012 at 7:22 AM, Ulf Zibis <Ulf.Zibis at gmx.de
>> <mailto:Ulf.Zibis at gmx.de>> wrote:
>>
>> Hi Sean,
>>
>> thanks for your effort.
>>
>> Am 31.03.2012 11:43, schrieb Sean Chou:
>>
>> Hi David and Ulf,
>>
>> The new webrev is at:
>> http://cr.openjdk.java.net/~__**zhouyx/7121314/webrev.03/<http://cr.openjdk.java.net/~__zhouyx/7121314/webrev.03/>
>> <http://cr.openjdk.java.net/~**zhouyx/7121314/webrev.03/<http://cr.openjdk.java.net/~zhouyx/7121314/webrev.03/>
>> >
>> <http://cr.openjdk.java.net/%_**_7Ezhouyx/7121314/webrev.03/
>>
>> <http://cr.openjdk.java.net/%**7Ezhouyx/7121314/webrev.03/<http://cr.openjdk.java.net/%7Ezhouyx/7121314/webrev.03/>>>
>> .
>>
>>
>> About the fix, I remained the previous one.
>> About the testcase, I merged the 3 files into one.
>> During merging, there are 2 modifications:
>> 1. I added static modifier to the 3 classes, which are enclosed
>> by class ToArrayTest;
>>
>> You do not need the indirection via main()...run()...test() if you
>> have all in 1 file. This was only necessary to feature a general
>> usability of InfraStructure. You can go back to David's 1 + 1 nested
>> class approach replacing TConcurrentHashMapX by TestCollection and
>> maybe rename realMain() to test().
>> Additionally, loading 4 classes for 1 test would have some
>> performance impact on the test run, which could be avoided.
>>
>>
>> 2. I removed field TestCollection.fixedSize, which is never read
>> after Ulf fixed the bug in testcase.
>>
>> This field would serve to "reset" the TestCollection to fixed
>> default size without the need of new instantiation for later
>> refactoring or testcase addition.
>>
>> As just discussed before, the doc for setSizeSequence() could be
>> little more specific:
>> 71 /*
>> 72 * Sets the values that size() will return on each use.
>> The first
>> 73 * call to size will return sizes[0], then sizes[1]
>> etc. This
>> 74 * allows us to emulate a concurrent change to the
>> contents of
>> 75 * the collection without having to perform concurrent
>> changes.
>> 76 * If sizes[n+1] contains a larger value than on last
>> n-th invocation,
>> 77 * the collection will appear to have shrunk when
>> iterated; if a
>> 78 * smaller value then the collection will appear to
>> have grown.
>> 79 * When the last element of sizes is reached, the
>> collection will
>> 80 * appear size-fixed.
>> 81 */
>>
>>
>> The link to the bug:
>> http://bugs.sun.com/__**bugdatabase/view_bug.do?bug___**id=7121314<http://bugs.sun.com/__bugdatabase/view_bug.do?bug___id=7121314>
>>
>> <http://bugs.sun.com/**bugdatabase/view_bug.do?bug_**id=7121314<http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7121314>
>> >
>> The link to the start of the thread:
>> http://mail.openjdk.java.net/_**_pipermail/core-libs-dev/2012-**
>> __March/009512.html<http://mail.openjdk.java.net/__pipermail/core-libs-dev/2012-__March/009512.html>
>>
>> <http://mail.openjdk.java.net/**pipermail/core-libs-dev/2012-**
>> March/009512.html<http://mail.openjdk.java.net/pipermail/core-libs-dev/2012-March/009512.html>
>> >
>>
>> Good idea, to repeat these links.
>>
>> -Ulf
>>
>>
>>
>>
>> --
>> Best Regards,
>> Sean Chou
>>
>>
>
> /*
> * Copyright (c) 2012, 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
> * or visit www.oracle.com if you need additional information or have any
> * questions.
> */
>
> /*
> * @test
> * @bug 7121314
> * @summary AbstractCollection.toArray(T[]**) doesn't return the given
> array
> * in concurrent modification.
> * @author Ulf Zibis, David Holmes
> */
>
> import java.util.AbstractCollection;
> import java.util.Arrays;
> import java.util.Iterator;
>
> public class ToArrayTest {
>
> static class TestCollection<E> extends AbstractCollection<E> {
>
> private final E[] elements;
>
>
> private int[] sizes;
> private int nextSize;
>
> public TestCollection(E[] elements) {
> this.elements = elements;
> setSizeSequence(new int[]{elements.length});
> }
>
> /*
> * Sets the values that size() will return on each use. The next
>
> * call to size will return sizes[0], then sizes[1] etc. This
> * allows us to emulate a concurrent change to the contents of
> * the collection without having to perform concurrent changes.
> * If sizes[n+1] contains a larger value, the collection will
> appear to
> * have shrunk when iterated; if a smaller value then the
> * collection will appear to have grown when iterated
>
> */
> void setSizeSequence(int... sizes) {
> this.sizes = sizes;
> nextSize = 0;
> }
>
> /* can change collection's size after each invocation */
>
> @Override
> public int size() {
> return sizes[nextSize == sizes.length-1 ? nextSize :
> nextSize++];
> }
>
> @Override
> public Iterator<E> iterator() {
> return new Iterator<E>() {
>
> int pos = 0;
> public boolean hasNext() {
> return pos < sizes[nextSize];
> }
> public E next() {
> return elements[pos++];
> }
> public void remove() {
> throw new UnsupportedOperationException(**"Not
> supported yet.");
> }
> };
> }
> }
>
> static final Object[] OBJECTS = { new Object(), new Object(), new
> Object() };
> static final TestCollection<?> CANDIDATE = new TestCollection<Object>(**
> OBJECTS);
> static final int CAP = OBJECTS.length; // capacity of the CANDIDATE
> static final int LAST = CAP - 1; // last possible array index
> Object[] a;
> Object[] res;
>
> int last() { return a.length - 1; }
>
> protected void test() throws Throwable {
> // Check array type conversion
> res = new TestCollection<>(new Object[]{"1", "2"}).toArray(new
> String[0]);
> check(res instanceof String[]);
> check(res.length == 2);
> check(res[1] == "2");
>
> // Check incompatible type of target array
> try {
> res = CANDIDATE.toArray(new String[CAP]);
> check(false);
> } catch (Throwable t) {
> check(t instanceof ArrayStoreException);
> }
>
> // Check more elements than a.length
> a = new Object[CAP-1]; // appears too small
> res = CANDIDATE.toArray(a);
> check(res != a);
> check(res[LAST] != null);
>
> // Check equal elements as a.length
> a = new Object[CAP]; // appears to match
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] != null);
>
> // Check equal elements as a.length
> a = new Object[CAP+1]; // appears too big
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] == null);
>
> // Check less elements than expected, but more than a.length
> a = new Object[CAP-2]; // appears too small
> CANDIDATE.setSizeSequence(CAP, CAP-1);
> res = CANDIDATE.toArray(a);
> check(res != a);
> check(res.length == CAP-1);
> check(res[LAST-1] != null);
>
> // Check less elements than expected, but equal as a.length
> a = Arrays.copyOf(OBJECTS, CAP); // appears to match
> CANDIDATE.setSizeSequence(CAP, CAP-1);
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] == null);
>
> // Check more elements than expected and more than a.length
> a = new Object[CAP-1]; // appears to match
> CANDIDATE.setSizeSequence(CAP-**1, CAP);
> res = CANDIDATE.toArray(a);
> check(res != a);
> check(res[LAST] != null);
>
> // Check more elements than expected, but equal as a.length
> a = new Object[CAP-1]; // appears to match
> CANDIDATE.setSizeSequence(CAP-**2, CAP-1);
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] != null);
>
> // Check more elements than expected, but less than a.length
> a = Arrays.copyOf(OBJECTS, CAP); // appears to match
> CANDIDATE.setSizeSequence(CAP-**2, CAP-1);
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] == null);
>
> test_7121314();
> }
>
> /*
> * Major target of this testcase, bug 7121314.
> */
> protected void test_7121314() throws Throwable {
> // Check equal elements as a.length, but less than expected
> a = new Object[CAP-1]; // appears too small
> CANDIDATE.setSizeSequence(CAP, CAP-1);
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] != null);
>
> // Check less elements than a.length and less than expected
> a = Arrays.copyOf(OBJECTS, CAP-1); // appears too small
> CANDIDATE.setSizeSequence(CAP, CAP-2);
> res = CANDIDATE.toArray(a);
> check(res == a);
> check(res[last()] == null);
>
> }
>
>
> public static void main(String[] args) throws Throwable {
> ToArrayTest testcase = new ToArrayTest();
> try { testcase.test(); } catch (Throwable t) { unexpected(t); }
>
> System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
> if (failed > 0) throw new Exception("Some tests failed");
> }
>
> private static volatile int passed = 0, failed = 0;
> private static void pass() { passed++; }
> private static void fail() { failed++; Thread.dumpStack(); }
> private static void fail(String msg) { System.out.println(msg); fail(); }
> private static void unexpected(Throwable t) { failed++;
> t.printStackTrace(); }
>
> static void check(boolean cond) { if (cond) pass(); else fail(); }
> static void equals(Object x, Object y) {
>
> if (x == null ? y == null : x.equals(y)) pass();
> else {System.out.println(x + " not equal to " + y); fail(); }}
>
> }
>
>
>
--
Best Regards,
Sean Chou
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