| 6 |
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package jsr166e; |
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import java.util.concurrent.TimeUnit; |
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+ |
import java.util.concurrent.TimeoutException; |
| 10 |
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import java.util.concurrent.locks.Lock; |
| 11 |
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import java.util.concurrent.locks.ReentrantLock; |
| 12 |
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import java.util.concurrent.locks.Condition; |
| 23 |
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* the lock is held. When it is even (i.e., ({@code lock.getSequence() |
| 24 |
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* & 1L) == 0L}), the lock is released. Method {@link |
| 25 |
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* #awaitAvailability} can be used to await availability of the lock, |
| 26 |
< |
* returning its current sequence number. Sequence numbers are of type |
| 27 |
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* {@code long} to ensure that they will not wrap around until |
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< |
* hundreds of years of use under current processor rates. A |
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< |
* SequenceLock can be created with a specified number of |
| 30 |
< |
* spins. Attempts to lock or await release retry at least the given |
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< |
* number of times before blocking. If not specified, a default, |
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< |
* possibly platform-specific, value is used. |
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> |
* returning its current sequence number. Sequence numbers (as well as |
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* reentrant hold counts) are of type {@code long} to ensure that they |
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> |
* will not wrap around until hundreds of years of use under current |
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> |
* processor rates. A SequenceLock can be created with a specified |
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* number of spins. Attempts to acquire the lock in method {@link |
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> |
* #lock} will retry at least the given number of times before |
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* blocking. If not specified, a default, possibly platform-specific, |
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* value is used. |
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* |
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* <p>Except for the lack of support for specified fairness policies, |
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< |
* or {@link Condition} objects, a SequenceLock can be used in the same |
| 37 |
< |
* way as {@link ReentrantLock}, and has a nearly identical |
| 38 |
< |
* API. SequenceLocks may be preferable in contexts in which multiple |
| 39 |
< |
* threads invoke read-only methods much more frequently than fully |
| 40 |
< |
* locked methods. |
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> |
* or {@link Condition} objects, a SequenceLock can be used in the |
| 37 |
> |
* same way as {@link ReentrantLock}. It provides similar status and |
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> |
* monitoring methods, such as {@link #isHeldByCurrentThread}. |
| 39 |
> |
* SequenceLocks may be preferable in contexts in which multiple |
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> |
* threads invoke short read-only methods much more frequently than |
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> |
* fully locked methods. |
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* |
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* <p> Methods {@code awaitAvailability} and {@code getSequence} can |
| 44 |
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* be used together to define (partially) optimistic read-only methods |
| 45 |
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* that are usually more efficient than ReadWriteLocks when they |
| 46 |
< |
* apply. These read-only methods typically read multiple field |
| 47 |
< |
* values into local variables when the lock is not held, retrying if |
| 48 |
< |
* the sequence number changed while doing so. Alternatively, because |
| 49 |
< |
* {@code awaitAvailability} accommodates reentrancy, a method can |
| 50 |
< |
* retry a bounded number of times before switching to locking mode. |
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< |
* While conceptually straightforward, expressing these ideas can be |
| 52 |
< |
* verbose. For example: |
| 46 |
> |
* apply. These methods should in general be structured as loops that |
| 47 |
> |
* await lock availability, then read {@code volatile} fields into |
| 48 |
> |
* local variables (and may further read other values derived from |
| 49 |
> |
* these, for example the {@code length} of a {@code volatile} array), |
| 50 |
> |
* and retry if the sequence number changed while doing so. |
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> |
* Alternatively, because {@code awaitAvailability} accommodates |
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> |
* reentrancy, a method can retry a bounded number of times before |
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* switching to locking mode. While conceptually straightforward, |
| 54 |
> |
* expressing these ideas can be verbose. For example: |
| 55 |
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* |
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< |
* <pre> {@code |
| 56 |
> |
* <pre> {@code |
| 57 |
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* class Point { |
| 58 |
< |
* private float x, y; |
| 59 |
< |
* private final SequenceLock sl = new SequenceLock(); |
| 58 |
> |
* private volatile double x, y; |
| 59 |
> |
* private final SequenceLock sl = new SequenceLock(); |
| 60 |
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* |
| 61 |
< |
* void move(float deltaX, float deltaY) { // an excluively locked method |
| 62 |
< |
* sl.lock(); |
| 63 |
< |
* try { |
| 64 |
< |
* x += deltaX; |
| 65 |
< |
* y += deltaY; |
| 66 |
< |
* } finally { |
| 67 |
< |
* sl.unlock(); |
| 68 |
< |
* } |
| 69 |
< |
* } |
| 61 |
> |
* // an exclusively locked method |
| 62 |
> |
* void move(double deltaX, double deltaY) { |
| 63 |
> |
* sl.lock(); |
| 64 |
> |
* try { |
| 65 |
> |
* x += deltaX; |
| 66 |
> |
* y += deltaY; |
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> |
* } finally { |
| 68 |
> |
* sl.unlock(); |
| 69 |
> |
* } |
| 70 |
> |
* } |
| 71 |
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* |
| 72 |
< |
* float distanceFromOriginV1() { // A read-only method |
| 73 |
< |
* float currentX, currentY; |
| 74 |
< |
* long seq; |
| 75 |
< |
* do { |
| 76 |
< |
* seq = sl.awaitAvailability(); |
| 77 |
< |
* currentX = x; |
| 78 |
< |
* currentY = y; |
| 79 |
< |
* } while (sl.getSequence() != seq); // retry if sequence changed |
| 80 |
< |
* return (float)Math.sqrt(currentX * currentX + currentY * currentY); |
| 81 |
< |
* } |
| 72 |
> |
* // A read-only method |
| 73 |
> |
* double distanceFromOriginV1() { |
| 74 |
> |
* double currentX, currentY; |
| 75 |
> |
* long seq; |
| 76 |
> |
* do { |
| 77 |
> |
* seq = sl.awaitAvailability(); |
| 78 |
> |
* currentX = x; |
| 79 |
> |
* currentY = y; |
| 80 |
> |
* } while (sl.getSequence() != seq); // retry if sequence changed |
| 81 |
> |
* return Math.sqrt(currentX * currentX + currentY * currentY); |
| 82 |
> |
* } |
| 83 |
|
* |
| 84 |
< |
* float distanceFromOriginV2() { // Uses bounded retries before locking |
| 85 |
< |
* float currentX, currentY; |
| 86 |
< |
* long seq; |
| 87 |
< |
* int retries = RETRIES_BEFORE_LOCKING; // for example 8 |
| 88 |
< |
* try { |
| 89 |
< |
* do { |
| 90 |
< |
* if (--retries < 0) |
| 91 |
< |
* sl.lock(); |
| 92 |
< |
* seq = sl.awaitAvailability(); |
| 93 |
< |
* currentX = x; |
| 94 |
< |
* currentY = y; |
| 95 |
< |
* } while (sl.getSequence() != seq); |
| 96 |
< |
* } finally { |
| 97 |
< |
* if (retries < 0) |
| 98 |
< |
* sl.unlock(); |
| 99 |
< |
* } |
| 100 |
< |
* return (float)Math.sqrt(currentX * currentX + currentY * currentY); |
| 101 |
< |
* } |
| 102 |
< |
*}}</pre> |
| 84 |
> |
* // Uses bounded retries before locking |
| 85 |
> |
* double distanceFromOriginV2() { |
| 86 |
> |
* double currentX, currentY; |
| 87 |
> |
* long seq; |
| 88 |
> |
* int retries = RETRIES_BEFORE_LOCKING; // for example 8 |
| 89 |
> |
* try { |
| 90 |
> |
* do { |
| 91 |
> |
* if (--retries < 0) |
| 92 |
> |
* sl.lock(); |
| 93 |
> |
* seq = sl.awaitAvailability(); |
| 94 |
> |
* currentX = x; |
| 95 |
> |
* currentY = y; |
| 96 |
> |
* } while (sl.getSequence() != seq); |
| 97 |
> |
* } finally { |
| 98 |
> |
* if (retries < 0) |
| 99 |
> |
* sl.unlock(); |
| 100 |
> |
* } |
| 101 |
> |
* return Math.sqrt(currentX * currentX + currentY * currentY); |
| 102 |
> |
* } |
| 103 |
> |
* }}</pre> |
| 104 |
|
* |
| 105 |
|
* @since 1.8 |
| 106 |
|
* @author Doug Lea |
| 109 |
|
private static final long serialVersionUID = 7373984872572414699L; |
| 110 |
|
|
| 111 |
|
static final class Sync extends AbstractQueuedLongSynchronizer { |
| 112 |
+ |
static final long serialVersionUID = 2540673546047039555L; |
| 113 |
+ |
|
| 114 |
|
/** |
| 115 |
|
* The number of times to spin in lock() and awaitAvailability(). |
| 116 |
|
*/ |
| 119 |
|
/** |
| 120 |
|
* The number of reentrant holds on this lock. Uses a long for |
| 121 |
|
* compatibility with other AbstractQueuedLongSynchronizer |
| 122 |
< |
* operations. |
| 122 |
> |
* operations. Accessed only by lock holder. |
| 123 |
|
*/ |
| 124 |
|
long holds; |
| 125 |
|
|
| 161 |
|
} |
| 162 |
|
|
| 163 |
|
public final long tryAcquireShared(long unused) { |
| 164 |
< |
return ((getState() & 1L) == 0L || |
| 165 |
< |
getExclusiveOwnerThread() == Thread.currentThread()) ? |
| 166 |
< |
1L : -1L; // must return long |
| 164 |
> |
return (((getState() & 1L) == 0L) ? 1L : |
| 165 |
> |
(getExclusiveOwnerThread() == Thread.currentThread()) ? 0L: |
| 166 |
> |
-1L); |
| 167 |
|
} |
| 168 |
|
|
| 169 |
|
public final boolean tryReleaseShared(long unused) { |
| 170 |
< |
return true; |
| 170 |
> |
return (getState() & 1L) == 0L; |
| 171 |
|
} |
| 172 |
|
|
| 173 |
|
public final Condition newCondition() { |
| 182 |
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|
| 183 |
|
final void lock() { |
| 184 |
|
int k = spins; |
| 185 |
< |
while (!tryAcquire(1)) { |
| 185 |
> |
while (!tryAcquire(1L)) { |
| 186 |
|
if (k == 0) { |
| 187 |
< |
acquire(1); |
| 187 |
> |
acquire(1L); |
| 188 |
|
break; |
| 189 |
|
} |
| 190 |
|
--k; |
| 193 |
|
|
| 194 |
|
final long awaitAvailability() { |
| 195 |
|
long s; |
| 186 |
– |
int k = spins; |
| 196 |
|
while (((s = getState()) & 1L) != 0L && |
| 197 |
|
getExclusiveOwnerThread() != Thread.currentThread()) { |
| 198 |
< |
if (k > 0) |
| 199 |
< |
--k; |
| 191 |
< |
else { |
| 192 |
< |
acquireShared(1); |
| 193 |
< |
releaseShared(1); |
| 194 |
< |
} |
| 198 |
> |
acquireShared(1L); |
| 199 |
> |
releaseShared(1L); |
| 200 |
|
} |
| 201 |
|
return s; |
| 202 |
|
} |
| 203 |
|
|
| 204 |
+ |
final long tryAwaitAvailability(long nanos) |
| 205 |
+ |
throws InterruptedException, TimeoutException { |
| 206 |
+ |
Thread current = Thread.currentThread(); |
| 207 |
+ |
for (;;) { |
| 208 |
+ |
long s = getState(); |
| 209 |
+ |
if ((s & 1L) == 0L || getExclusiveOwnerThread() == current) { |
| 210 |
+ |
releaseShared(1L); |
| 211 |
+ |
return s; |
| 212 |
+ |
} |
| 213 |
+ |
if (!tryAcquireSharedNanos(1L, nanos)) |
| 214 |
+ |
throw new TimeoutException(); |
| 215 |
+ |
// since tryAcquireSharedNanos doesn't return seq |
| 216 |
+ |
// retry with minimal wait time. |
| 217 |
+ |
nanos = 1L; |
| 218 |
+ |
} |
| 219 |
+ |
} |
| 220 |
+ |
|
| 221 |
|
final boolean isLocked() { |
| 222 |
|
return (getState() & 1L) != 0L; |
| 223 |
|
} |
| 243 |
|
/** |
| 244 |
|
* The default spin value for constructor. Future versions of this |
| 245 |
|
* class might choose platform-specific values. Currently, except |
| 246 |
< |
* on uniprocessors, it is set to a small value that ovecomes near |
| 246 |
> |
* on uniprocessors, it is set to a small value that overcomes near |
| 247 |
|
* misses between releases and acquires. |
| 248 |
|
*/ |
| 249 |
|
static final int DEFAULT_SPINS = |
| 251 |
|
|
| 252 |
|
/** |
| 253 |
|
* Creates an instance of {@code SequenceLock} with the default |
| 254 |
< |
* number of retry attempts to lock or await release before |
| 233 |
< |
* blocking. |
| 254 |
> |
* number of retry attempts to acquire the lock before blocking. |
| 255 |
|
*/ |
| 256 |
|
public SequenceLock() { sync = new Sync(DEFAULT_SPINS); } |
| 257 |
|
|
| 258 |
|
/** |
| 259 |
< |
* Creates an instance of {@code SequenceLock} that |
| 260 |
< |
* will retry attempts to lock or await release |
| 261 |
< |
* at least the given number times before blocking. |
| 259 |
> |
* Creates an instance of {@code SequenceLock} that will retry |
| 260 |
> |
* attempts to acquire the lock at least the given number times |
| 261 |
> |
* before blocking. |
| 262 |
|
*/ |
| 263 |
|
public SequenceLock(int spins) { sync = new Sync(spins); } |
| 264 |
|
|
| 265 |
|
/** |
| 266 |
|
* Returns the current sequence number of this lock. The sequence |
| 267 |
< |
* number is advanced upon each lock or unlock action. When this |
| 268 |
< |
* value is odd, the lock is held; when even, it is released. |
| 267 |
> |
* number is advanced upon each acquire or release action. When |
| 268 |
> |
* this value is odd, the lock is held; when even, it is released. |
| 269 |
|
* |
| 270 |
|
* @return the current sequence number |
| 271 |
|
*/ |
| 284 |
|
public long awaitAvailability() { return sync.awaitAvailability(); } |
| 285 |
|
|
| 286 |
|
/** |
| 287 |
< |
* Acquires the lock. |
| 287 |
> |
* Returns the current sequence number if the lock is, or |
| 288 |
> |
* becomes, available within the specified waiting time. |
| 289 |
> |
* |
| 290 |
> |
* <p>If the lock is not available, the current thread becomes |
| 291 |
> |
* disabled for thread scheduling purposes and lies dormant until |
| 292 |
> |
* one of three things happens: |
| 293 |
> |
* |
| 294 |
> |
* <ul> |
| 295 |
|
* |
| 296 |
< |
* <p>Acquires the lock if it is not held by another thread and returns |
| 297 |
< |
* immediately, setting the lock hold count to one. |
| 296 |
> |
* <li>The lock becomes available, in which case the current |
| 297 |
> |
* sequence number is returned. |
| 298 |
|
* |
| 299 |
< |
* <p>If the current thread already holds the lock then the hold |
| 300 |
< |
* count is incremented by one and the method returns immediately. |
| 299 |
> |
* <li>Some other thread {@linkplain Thread#interrupt interrupts} |
| 300 |
> |
* the current thread, in which case this method throws |
| 301 |
> |
* {@link InterruptedException}. |
| 302 |
> |
* |
| 303 |
> |
* <li>The specified waiting time elapses, in which case |
| 304 |
> |
* this method throws {@link TimeoutException}. |
| 305 |
> |
* |
| 306 |
> |
* </ul> |
| 307 |
|
* |
| 308 |
< |
* <p>If the lock is held by another thread then the |
| 309 |
< |
* current thread becomes disabled for thread scheduling |
| 310 |
< |
* purposes and lies dormant until the lock has been acquired, |
| 311 |
< |
* at which time the lock hold count is set to one. |
| 308 |
> |
* @param timeout the time to wait for availability |
| 309 |
> |
* @param unit the time unit of the timeout argument |
| 310 |
> |
* @return the current sequence number if the lock is available |
| 311 |
> |
* upon return from this method |
| 312 |
> |
* @throws InterruptedException if the current thread is interrupted |
| 313 |
> |
* @throws TimeoutException if the lock was not available within |
| 314 |
> |
* the specified waiting time |
| 315 |
> |
* @throws NullPointerException if the time unit is null |
| 316 |
> |
*/ |
| 317 |
> |
public long tryAwaitAvailability(long timeout, TimeUnit unit) |
| 318 |
> |
throws InterruptedException, TimeoutException { |
| 319 |
> |
return sync.tryAwaitAvailability(unit.toNanos(timeout)); |
| 320 |
> |
} |
| 321 |
> |
|
| 322 |
> |
/** |
| 323 |
> |
* Acquires the lock. |
| 324 |
> |
* |
| 325 |
> |
* <p>If the current thread already holds this lock then the hold count |
| 326 |
> |
* is incremented by one and the method returns immediately without |
| 327 |
> |
* incrementing the sequence number. |
| 328 |
> |
* |
| 329 |
> |
* <p>If this lock not held by another thread, this method |
| 330 |
> |
* increments the sequence number (which thus becomes an odd |
| 331 |
> |
* number), sets the lock hold count to one, and returns |
| 332 |
> |
* immediately. |
| 333 |
> |
* |
| 334 |
> |
* <p>If the lock is held by another thread then the current |
| 335 |
> |
* thread may retry acquiring this lock, depending on the {@code |
| 336 |
> |
* spin} count established in constructor. If the lock is still |
| 337 |
> |
* not acquired, the current thread becomes disabled for thread |
| 338 |
> |
* scheduling purposes and lies dormant until enabled by |
| 339 |
> |
* some other thread releasing the lock. |
| 340 |
|
*/ |
| 341 |
|
public void lock() { sync.lock(); } |
| 342 |
|
|
| 344 |
|
* Acquires the lock unless the current thread is |
| 345 |
|
* {@linkplain Thread#interrupt interrupted}. |
| 346 |
|
* |
| 285 |
– |
* <p>Acquires the lock if it is not held by another thread and returns |
| 286 |
– |
* immediately, setting the lock hold count to one. |
| 287 |
– |
* |
| 347 |
|
* <p>If the current thread already holds this lock then the hold count |
| 348 |
< |
* is incremented by one and the method returns immediately. |
| 348 |
> |
* is incremented by one and the method returns immediately without |
| 349 |
> |
* incrementing the sequence number. |
| 350 |
|
* |
| 351 |
< |
* <p>If the lock is held by another thread then the |
| 352 |
< |
* current thread becomes disabled for thread scheduling |
| 353 |
< |
* purposes and lies dormant until one of two things happens: |
| 351 |
> |
* <p>If this lock not held by another thread, this method |
| 352 |
> |
* increments the sequence number (which thus becomes an odd |
| 353 |
> |
* number), sets the lock hold count to one, and returns |
| 354 |
> |
* immediately. |
| 355 |
> |
* |
| 356 |
> |
* <p>If the lock is held by another thread then the current |
| 357 |
> |
* thread may retry acquiring this lock, depending on the {@code |
| 358 |
> |
* spin} count established in constructor. If the lock is still |
| 359 |
> |
* not acquired, the current thread becomes disabled for thread |
| 360 |
> |
* scheduling purposes and lies dormant until one of two things |
| 361 |
> |
* happens: |
| 362 |
|
* |
| 363 |
|
* <ul> |
| 364 |
|
* |
| 370 |
|
* </ul> |
| 371 |
|
* |
| 372 |
|
* <p>If the lock is acquired by the current thread then the lock hold |
| 373 |
< |
* count is set to one. |
| 373 |
> |
* count is set to one and the sequence number is incremented. |
| 374 |
|
* |
| 375 |
|
* <p>If the current thread: |
| 376 |
|
* |
| 393 |
|
* @throws InterruptedException if the current thread is interrupted |
| 394 |
|
*/ |
| 395 |
|
public void lockInterruptibly() throws InterruptedException { |
| 396 |
< |
sync.acquireInterruptibly(1); |
| 396 |
> |
sync.acquireInterruptibly(1L); |
| 397 |
|
} |
| 398 |
|
|
| 399 |
|
/** |
| 400 |
|
* Acquires the lock only if it is not held by another thread at the time |
| 401 |
|
* of invocation. |
| 402 |
|
* |
| 403 |
< |
* <p>Acquires the lock if it is not held by another thread and |
| 404 |
< |
* returns immediately with the value {@code true}, setting the |
| 405 |
< |
* lock hold count to one. |
| 403 |
> |
* <p>If the current thread already holds this lock then the hold |
| 404 |
> |
* count is incremented by one and the method returns {@code true} |
| 405 |
> |
* without incrementing the sequence number. |
| 406 |
> |
* |
| 407 |
> |
* <p>If this lock not held by another thread, this method |
| 408 |
> |
* increments the sequence number (which thus becomes an odd |
| 409 |
> |
* number), sets the lock hold count to one, and returns {@code |
| 410 |
> |
* true}. |
| 411 |
|
* |
| 412 |
< |
* <p> If the current thread already holds this lock then the hold |
| 413 |
< |
* count is incremented by one and the method returns {@code true}. |
| 341 |
< |
* |
| 342 |
< |
* <p>If the lock is held by another thread then this method will return |
| 343 |
< |
* immediately with the value {@code false}. |
| 412 |
> |
* <p>If the lock is held by another thread then this method |
| 413 |
> |
* returns {@code false}. |
| 414 |
|
* |
| 415 |
|
* @return {@code true} if the lock was free and was acquired by the |
| 416 |
|
* current thread, or the lock was already held by the current |
| 417 |
|
* thread; and {@code false} otherwise |
| 418 |
|
*/ |
| 419 |
< |
public boolean tryLock() { return sync.tryAcquire(1); } |
| 419 |
> |
public boolean tryLock() { return sync.tryAcquire(1L); } |
| 420 |
|
|
| 421 |
|
/** |
| 422 |
|
* Acquires the lock if it is not held by another thread within the given |
| 423 |
|
* waiting time and the current thread has not been |
| 424 |
|
* {@linkplain Thread#interrupt interrupted}. |
| 425 |
|
* |
| 426 |
< |
* <p>Acquires the lock if it is not held by another thread and returns |
| 427 |
< |
* immediately with the value {@code true}, setting the lock hold count |
| 428 |
< |
* to one. If this lock has been set to use a fair ordering policy then |
| 429 |
< |
* an available lock <em>will not</em> be acquired if any other threads |
| 430 |
< |
* are waiting for the lock. This is in contrast to the {@link #tryLock()} |
| 431 |
< |
* method. If you want a timed {@code tryLock} that does permit barging on |
| 432 |
< |
* a fair lock then combine the timed and un-timed forms together: |
| 433 |
< |
* |
| 434 |
< |
* <pre> {@code |
| 435 |
< |
* if (lock.tryLock() || |
| 436 |
< |
* lock.tryLock(timeout, unit)) { |
| 437 |
< |
* ... |
| 438 |
< |
* }}</pre> |
| 439 |
< |
* |
| 440 |
< |
* <p>If the current thread |
| 371 |
< |
* already holds this lock then the hold count is incremented by one and |
| 372 |
< |
* the method returns {@code true}. |
| 373 |
< |
* |
| 374 |
< |
* <p>If the lock is held by another thread then the |
| 375 |
< |
* current thread becomes disabled for thread scheduling |
| 376 |
< |
* purposes and lies dormant until one of three things happens: |
| 426 |
> |
* <p>If the current thread already holds this lock then the hold count |
| 427 |
> |
* is incremented by one and the method returns immediately without |
| 428 |
> |
* incrementing the sequence number. |
| 429 |
> |
* |
| 430 |
> |
* <p>If this lock not held by another thread, this method |
| 431 |
> |
* increments the sequence number (which thus becomes an odd |
| 432 |
> |
* number), sets the lock hold count to one, and returns |
| 433 |
> |
* immediately. |
| 434 |
> |
* |
| 435 |
> |
* <p>If the lock is held by another thread then the current |
| 436 |
> |
* thread may retry acquiring this lock, depending on the {@code |
| 437 |
> |
* spin} count established in constructor. If the lock is still |
| 438 |
> |
* not acquired, the current thread becomes disabled for thread |
| 439 |
> |
* scheduling purposes and lies dormant until one of three things |
| 440 |
> |
* happens: |
| 441 |
|
* |
| 442 |
|
* <ul> |
| 443 |
|
* |
| 487 |
|
*/ |
| 488 |
|
public boolean tryLock(long timeout, TimeUnit unit) |
| 489 |
|
throws InterruptedException { |
| 490 |
< |
return sync.tryAcquireNanos(1, unit.toNanos(timeout)); |
| 490 |
> |
return sync.tryAcquireNanos(1L, unit.toNanos(timeout)); |
| 491 |
|
} |
| 492 |
|
|
| 493 |
|
/** |
| 494 |
|
* Attempts to release this lock. |
| 495 |
|
* |
| 496 |
< |
* <p>If the current thread is the holder of this lock then the hold |
| 497 |
< |
* count is decremented. If the hold count is now zero then the lock |
| 498 |
< |
* is released. If the current thread is not the holder of this |
| 499 |
< |
* lock then {@link IllegalMonitorStateException} is thrown. |
| 496 |
> |
* <p>If the current thread is the holder of this lock then the |
| 497 |
> |
* hold count is decremented. If the hold count is now zero then |
| 498 |
> |
* the sequence number is incremented (thus becoming an even |
| 499 |
> |
* number) and the lock is released. If the current thread is not |
| 500 |
> |
* the holder of this lock then {@link |
| 501 |
> |
* IllegalMonitorStateException} is thrown. |
| 502 |
|
* |
| 503 |
|
* @throws IllegalMonitorStateException if the current thread does not |
| 504 |
|
* hold this lock |
| 527 |
|
* @return the number of holds on this lock by the current thread, |
| 528 |
|
* or zero if this lock is not held by the current thread |
| 529 |
|
*/ |
| 530 |
< |
public long getHoldCount() { return sync.getHoldCount(); } |
| 530 |
> |
public long getHoldCount() { return sync.getHoldCount(); } |
| 531 |
|
|
| 532 |
|
/** |
| 533 |
|
* Queries if this lock is held by the current thread. |
