/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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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*/
/*
* @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");
}
//--------------------- Infrastructure ---------------------------
static volatile int passed = 0, failed = 0;
static void pass() { passed++; }
static void fail() { failed++; Thread.dumpStack(); }
static void fail(String msg) { System.out.println(msg); fail(); }
static void unexpected(Throwable t) { failed++; t.printStackTrace(); }
static void check(boolean cond) { if (cond) pass(); else fail(); }
static void equal(Object x, Object y) {
if (x == null ? y == null : x.equals(y)) pass();
else {System.out.println(x + " not equal to " + y); fail(); }
}
}