| 20 |
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import java.util.ConcurrentModificationException; |
| 21 |
|
import java.util.NoSuchElementException; |
| 22 |
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import java.util.concurrent.ConcurrentMap; |
| 23 |
+ |
import java.util.concurrent.ThreadLocalRandom; |
| 24 |
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import java.util.concurrent.locks.LockSupport; |
| 25 |
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import java.io.Serializable; |
| 26 |
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|
| 352 |
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* Encodings for special uses of Node hash fields. See above for |
| 353 |
|
* explanation. |
| 354 |
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*/ |
| 355 |
< |
static final int MOVED = 0x80000000; // hash field for fowarding nodes |
| 355 |
> |
static final int MOVED = 0x80000000; // hash field for forwarding nodes |
| 356 |
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static final int LOCKED = 0x40000000; // set/tested only as a bit |
| 357 |
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static final int WAITING = 0xc0000000; // both bits set/tested together |
| 358 |
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static final int HASH_BITS = 0x3fffffff; // usable bits of normal node hash |
| 436 |
|
*/ |
| 437 |
|
final void tryAwaitLock(Node[] tab, int i) { |
| 438 |
|
if (tab != null && i >= 0 && i < tab.length) { // bounds check |
| 439 |
+ |
int r = ThreadLocalRandom.current().nextInt(); // randomize spins |
| 440 |
|
int spins = MAX_SPINS, h; |
| 441 |
|
while (tabAt(tab, i) == this && ((h = hash) & LOCKED) != 0) { |
| 442 |
|
if (spins >= 0) { |
| 443 |
< |
if (--spins == MAX_SPINS >>> 1) |
| 444 |
< |
Thread.yield(); // heuristically yield mid-way |
| 443 |
> |
r ^= r << 1; r ^= r >>> 3; r ^= r << 10; // xorshift |
| 444 |
> |
if (r >= 0 && --spins == 0) |
| 445 |
> |
Thread.yield(); // yield before block |
| 446 |
|
} |
| 447 |
|
else if (casHash(h, h | WAITING)) { |
| 448 |
|
synchronized (this) { |
| 1294 |
|
* |
| 1295 |
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* At each step, the iterator snapshots the key ("nextKey") and |
| 1296 |
|
* value ("nextVal") of a valid node (i.e., one that, at point of |
| 1297 |
< |
* snapshot, has a nonnull user value). Because val fields can |
| 1297 |
> |
* snapshot, has a non-null user value). Because val fields can |
| 1298 |
|
* change (including to null, indicating deletion), field nextVal |
| 1299 |
|
* might not be accurate at point of use, but still maintains the |
| 1300 |
|
* weak consistency property of holding a value that was once |
| 2240 |
|
} |
| 2241 |
|
|
| 2242 |
|
static final class Values<K,V> extends MapView<K,V> |
| 2243 |
< |
implements Collection<V> { |
| 2243 |
> |
implements Collection<V> { |
| 2244 |
|
Values(ConcurrentHashMapV8<K, V> map) { super(map); } |
| 2245 |
|
public final boolean contains(Object o) { return map.containsValue(o); } |
| 2246 |
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|
