Am 09.03.2012 09:16, schrieb Sean Chou:
Hi all,
AbstractCollection.toArray(T[] ) might return a new array even if the given array has enough
room for the returned elements when it is concurrently modified. This behavior violates the spec
documented in java.util.Collection .
This patch checks the size of returned array and copies the elements to return to the given
array if it is large enough.
The webrev is at :
http://cr.openjdk.java.net/~zhouyx/7121314/webrev.00/
<http://cr.openjdk.java.net/%7Ezhouyx/7121314/webrev.00/>
More compact and marginally faster:
182 if (!it.hasNext()) { // fewer elements than expected
183 if (a == r) {
184 a[i] = null; // null-terminate
185 } else if (a.length < i) {
186 return Arrays.copyOf(r, i);
187 } else {
188 System.arraycopy(r, 0, a, 0, Math.min(++i, a.length()); // ensure
null-termination
189 }
190 return a;
191 }
There is a test case in the previous discussion. It is not included in the webrev, because the
testcase is heavily implementation dependent. I will add it if it is requested.
I think, we should have a testcase for all 3 cases: fewer / equal / less
elements than expected.
Additionally I think, the correct null-termination should be tested.
Thread[] threads = new Thread[2];
threads[0] = new Thread(new ToArrayThread());
threads[1] = new Thread(new RemoveThread());
Why so complicated?
IMHO better:
Thread toArrayThread = new Thread(new ToArrayThread());
Thread removeThread = new Thread(new RemoveThread());
- Ulf
