| 126 |
|
* op.apply(array[lo]); |
| 127 |
|
* tryComplete(); |
| 128 |
|
* } |
| 129 |
< |
* } }</pre> |
| 129 |
> |
* }}</pre> |
| 130 |
|
* |
| 131 |
|
* This design can be improved by noticing that in the recursive case, |
| 132 |
|
* the task has nothing to do after forking its right task, so can |
| 133 |
|
* directly invoke its left task before returning. (This is an analog |
| 134 |
|
* of tail recursion removal.) Also, because the task returns upon |
| 135 |
|
* executing its left task (rather than falling through to invoke |
| 136 |
< |
* tryComplete) the pending count is set to one: |
| 136 |
> |
* {@code tryComplete}) the pending count is set to one: |
| 137 |
|
* |
| 138 |
|
* <pre> {@code |
| 139 |
|
* class ForEach<E> ... |
| 277 |
|
* } |
| 278 |
|
* public void onCompletion(CountedCompleter<?> caller) { |
| 279 |
|
* if (caller != this) { |
| 280 |
< |
* MapReducer<E> child = (MapReducer<E>)caller; |
| 281 |
< |
* MapReducer<E> sib = child.sibling; |
| 282 |
< |
* if (sib == null || sib.result == null) |
| 283 |
< |
* result = child.result; |
| 284 |
< |
* else |
| 285 |
< |
* result = reducer.apply(child.result, sib.result); |
| 280 |
> |
* MapReducer<E> child = (MapReducer<E>)caller; |
| 281 |
> |
* MapReducer<E> sib = child.sibling; |
| 282 |
> |
* if (sib == null || sib.result == null) |
| 283 |
> |
* result = child.result; |
| 284 |
> |
* else |
| 285 |
> |
* result = reducer.apply(child.result, sib.result); |
| 286 |
|
* } |
| 287 |
|
* } |
| 288 |
|
* public E getRawResult() { return result; } |
| 291 |
|
* return new MapReducer<E>(null, array, mapper, reducer, |
| 292 |
|
* 0, array.length).invoke(); |
| 293 |
|
* } |
| 294 |
< |
* } }</pre> |
| 294 |
> |
* }}</pre> |
| 295 |
|
* |
| 296 |
|
* Here, method {@code onCompletion} takes a form common to many |
| 297 |
|
* completion designs that combine results. This callback-style method |
| 303 |
|
* distinguishes cases. Most often, when the caller is {@code this}, |
| 304 |
|
* no action is necessary. Otherwise the caller argument can be used |
| 305 |
|
* (usually via a cast) to supply a value (and/or links to other |
| 306 |
< |
* values) to be combined. Asuuming proper use of pending counts, the |
| 306 |
> |
* values) to be combined. Assuming proper use of pending counts, the |
| 307 |
|
* actions inside {@code onCompletion} occur (once) upon completion of |
| 308 |
|
* a task and its subtasks. No additional synchronization is required |
| 309 |
|
* within this method to ensure thread safety of accesses to fields of |
| 626 |
|
* this task's pending count is non-zero, decrements its pending |
| 627 |
|
* count and returns {@code null}. Otherwise, returns the |
| 628 |
|
* completer. This method can be used as part of a completion |
| 629 |
< |
* traversal loop for homogenous task hierarchies: |
| 629 |
> |
* traversal loop for homogeneous task hierarchies: |
| 630 |
|
* |
| 631 |
|
* <pre> {@code |
| 632 |
< |
* for (CountedCompleter<?> c = firstComplete(); c != null; c = c.nextComplete()) { |
| 632 |
> |
* for (CountedCompleter<?> c = firstComplete(); |
| 633 |
> |
* c != null; |
| 634 |
> |
* c = c.nextComplete()) { |
| 635 |
|
* // ... process c ... |
| 636 |
|
* }}</pre> |
| 637 |
|
* |
| 661 |
|
} |
| 662 |
|
|
| 663 |
|
/** |
| 664 |
< |
* Support for FJT exception propagation |
| 664 |
> |
* Supports ForkJoinTask exception propagation. |
| 665 |
|
*/ |
| 666 |
|
void internalPropagateException(Throwable ex) { |
| 667 |
|
CountedCompleter<?> a = this, s = a; |
| 671 |
|
} |
| 672 |
|
|
| 673 |
|
/** |
| 674 |
< |
* Implements execution conventions for CountedCompleters |
| 674 |
> |
* Implements execution conventions for CountedCompleters. |
| 675 |
|
*/ |
| 676 |
|
protected final boolean exec() { |
| 677 |
|
compute(); |
