| 294 |
|
* @param e the comparison value for checking match |
| 295 |
|
* @param mode mode |
| 296 |
|
* @param nanos timeout value |
| 297 |
< |
* @return matched item, or s if cancelled |
| 297 |
> |
* @return matched item, or null if cancelled |
| 298 |
|
*/ |
| 299 |
|
private E awaitFulfill(Node<E> pred, Node<E> s, E e, |
| 300 |
|
int mode, long nanos) { |
| 360 |
|
for (;;) { |
| 361 |
|
Node<E> h = head.get(); |
| 362 |
|
Node<E> first = h.next; |
| 363 |
< |
if (first != null && first.next == first) { // help advance |
| 363 |
> |
if (first != null && first.get() == first) { // help advance |
| 364 |
|
advanceHead(h, first); |
| 365 |
|
continue; |
| 366 |
|
} |
| 511 |
|
|
| 512 |
|
/** |
| 513 |
|
* Inserts the specified element at the tail of this queue. |
| 514 |
< |
* As the queue is unbounded this method will never throw |
| 514 |
> |
* As the queue is unbounded, this method will never throw |
| 515 |
|
* {@link IllegalStateException} or return {@code false}. |
| 516 |
|
* |
| 517 |
|
* @return {@code true} (as specified by {@link Collection#add}) |
| 522 |
|
} |
| 523 |
|
|
| 524 |
|
/** |
| 525 |
< |
* Transfers the specified element immediately if there exists a |
| 526 |
< |
* consumer already waiting to receive it (in {@link #take} or |
| 527 |
< |
* timed {@link #poll(Object,long,TimeUnit) poll}), otherwise |
| 528 |
< |
* returning {@code false} without enqueuing the element. |
| 525 |
> |
* Transfers the element to a waiting consumer immediately, if possible. |
| 526 |
> |
* |
| 527 |
> |
* <p>More precisely, transfers the specified element immediately |
| 528 |
> |
* if there exists a consumer already waiting to receive it (in |
| 529 |
> |
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}), |
| 530 |
> |
* otherwise returning {@code false} without enqueuing the element. |
| 531 |
|
* |
| 532 |
|
* @throws NullPointerException if the specified element is null |
| 533 |
|
*/ |
| 537 |
|
} |
| 538 |
|
|
| 539 |
|
/** |
| 540 |
< |
* Inserts the specified element at the tail of this queue, |
| 541 |
< |
* waiting if necessary for the element to be received by a |
| 542 |
< |
* consumer invoking {@code take} or {@code poll}. |
| 540 |
> |
* Transfers the element to a consumer, waiting if necessary to do so. |
| 541 |
> |
* |
| 542 |
> |
* <p>More precisely, transfers the specified element immediately |
| 543 |
> |
* if there exists a consumer already waiting to receive it (in |
| 544 |
> |
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}), |
| 545 |
> |
* else inserts the specified element at the tail of this queue |
| 546 |
> |
* and waits until the element is received by a consumer. |
| 547 |
|
* |
| 542 |
– |
* @throws InterruptedException {@inheritDoc} |
| 548 |
|
* @throws NullPointerException if the specified element is null |
| 549 |
|
*/ |
| 550 |
|
public void transfer(E e) throws InterruptedException { |
| 556 |
|
} |
| 557 |
|
|
| 558 |
|
/** |
| 559 |
< |
* Inserts the specified element at the tail of this queue, |
| 560 |
< |
* waiting up to the specified wait time for the element to be |
| 561 |
< |
* received by a consumer invoking {@code take} or {@code poll}. |
| 559 |
> |
* Transfers the element to a consumer if it is possible to do so |
| 560 |
> |
* before the timeout elapses. |
| 561 |
> |
* |
| 562 |
> |
* <p>More precisely, transfers the specified element immediately |
| 563 |
> |
* if there exists a consumer already waiting to receive it (in |
| 564 |
> |
* {@link #take} or timed {@link #poll(long,TimeUnit) poll}), |
| 565 |
> |
* else inserts the specified element at the tail of this queue |
| 566 |
> |
* and waits until the element is received by a consumer, |
| 567 |
> |
* returning {@code false} if the specified wait time elapses |
| 568 |
> |
* before the element can be transferred. |
| 569 |
|
* |
| 558 |
– |
* @throws InterruptedException {@inheritDoc} |
| 570 |
|
* @throws NullPointerException if the specified element is null |
| 571 |
|
*/ |
| 572 |
|
public boolean tryTransfer(E e, long timeout, TimeUnit unit) |
| 587 |
|
throw new InterruptedException(); |
| 588 |
|
} |
| 589 |
|
|
| 579 |
– |
/** |
| 580 |
– |
* @throws InterruptedException {@inheritDoc} |
| 581 |
– |
*/ |
| 590 |
|
public E poll(long timeout, TimeUnit unit) throws InterruptedException { |
| 591 |
|
E e = xfer(null, TIMEOUT, unit.toNanos(timeout)); |
| 592 |
|
if (e != null || !Thread.interrupted()) |
| 762 |
|
} |
| 763 |
|
} |
| 764 |
|
|
| 765 |
+ |
/** |
| 766 |
+ |
* Returns {@code true} if this queue contains no elements. |
| 767 |
+ |
* |
| 768 |
+ |
* @return {@code true} if this queue contains no elements |
| 769 |
+ |
*/ |
| 770 |
|
public boolean isEmpty() { |
| 771 |
|
for (;;) { |
| 772 |
|
Node<E> h = traversalHead(); |
| 848 |
|
} |
| 849 |
|
} |
| 850 |
|
|
| 851 |
+ |
/** |
| 852 |
+ |
* Removes a single instance of the specified element from this queue, |
| 853 |
+ |
* if it is present. More formally, removes an element {@code e} such |
| 854 |
+ |
* that {@code o.equals(e)}, if this queue contains one or more such |
| 855 |
+ |
* elements. |
| 856 |
+ |
* Returns {@code true} if this queue contained the specified element |
| 857 |
+ |
* (or equivalently, if this queue changed as a result of the call). |
| 858 |
+ |
* |
| 859 |
+ |
* @param o element to be removed from this queue, if present |
| 860 |
+ |
* @return {@code true} if this queue changed as a result of the call |
| 861 |
+ |
*/ |
| 862 |
|
public boolean remove(Object o) { |
| 863 |
|
if (o == null) |
| 864 |
|
return false; |
