| 496 |
|
/** |
| 497 |
|
* Arranges to asynchronously execute this task. While it is not |
| 498 |
|
* necessarily enforced, it is a usage error to fork a task more |
| 499 |
< |
* than once unless it has completed and been reinitialized. This |
| 500 |
< |
* method may be invoked only from within ForkJoinTask |
| 501 |
< |
* computations (as may be determined using method {@link |
| 502 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
| 503 |
< |
* in exceptions or errors, possibly including ClassCastException. |
| 499 |
> |
* than once unless it has completed and been reinitialized. |
| 500 |
|
* |
| 501 |
< |
* @return {@code this}, to simplify usage. |
| 501 |
> |
* <p>This method may be invoked only from within {@code |
| 502 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 503 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 504 |
> |
* result in exceptions or errors, possibly including {@code |
| 505 |
> |
* ClassCastException}. |
| 506 |
> |
* |
| 507 |
> |
* @return {@code this}, to simplify usage |
| 508 |
|
*/ |
| 509 |
|
public final ForkJoinTask<V> fork() { |
| 510 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
| 514 |
|
|
| 515 |
|
/** |
| 516 |
|
* Returns the result of the computation when it is ready. |
| 517 |
< |
* This method differs from {@code get} in that abnormal |
| 518 |
< |
* completion results in RuntimeExceptions or Errors, not |
| 519 |
< |
* ExecutionExceptions. |
| 517 |
> |
* This method differs from {@link #get()} in that |
| 518 |
> |
* abnormal completion results in {@code RuntimeException} or |
| 519 |
> |
* {@code Error}, not {@code ExecutionException}. |
| 520 |
|
* |
| 521 |
|
* @return the computed result |
| 522 |
|
*/ |
| 543 |
|
} |
| 544 |
|
|
| 545 |
|
/** |
| 546 |
< |
* Forks the given tasks, returning when {@code isDone} holds for |
| 547 |
< |
* each task or an exception is encountered. This method may be |
| 548 |
< |
* invoked only from within ForkJoinTask computations (as may be |
| 549 |
< |
* determined using method {@link #inForkJoinPool}). Attempts to |
| 550 |
< |
* invoke in other contexts result in exceptions or errors, |
| 551 |
< |
* possibly including ClassCastException. |
| 546 |
> |
* Forks the given tasks, returning when {@code isDone} holds |
| 547 |
> |
* for each task or an exception is encountered. |
| 548 |
> |
* |
| 549 |
> |
* <p>This method may be invoked only from within {@code |
| 550 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 551 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 552 |
> |
* result in exceptions or errors, possibly including {@code |
| 553 |
> |
* ClassCastException}. |
| 554 |
|
* |
| 555 |
|
* @param t1 the first task |
| 556 |
|
* @param t2 the second task |
| 557 |
|
* @throws NullPointerException if any task is null |
| 558 |
|
* @throws RuntimeException or Error if a task did so |
| 559 |
|
*/ |
| 560 |
< |
public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) { |
| 560 |
> |
public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { |
| 561 |
|
t2.fork(); |
| 562 |
|
t1.invoke(); |
| 563 |
|
t2.join(); |
| 567 |
|
* Forks the given tasks, returning when {@code isDone} holds for |
| 568 |
|
* each task or an exception is encountered. If any task |
| 569 |
|
* encounters an exception, others may be, but are not guaranteed |
| 570 |
< |
* to be, cancelled. This method may be invoked only from within |
| 571 |
< |
* ForkJoinTask computations (as may be determined using method |
| 572 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 573 |
< |
* result in exceptions or errors, possibly including |
| 574 |
< |
* ClassCastException. |
| 570 |
> |
* to be, cancelled. |
| 571 |
> |
* |
| 572 |
> |
* <p>This method may be invoked only from within {@code |
| 573 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 574 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 575 |
> |
* result in exceptions or errors, possibly including {@code |
| 576 |
> |
* ClassCastException}. |
| 577 |
|
* |
| 578 |
< |
* Overloadings of this method exist for the special cases |
| 578 |
> |
* <p>Overloadings of this method exist for the special cases |
| 579 |
|
* of one to four arguments. |
| 580 |
|
* |
| 581 |
|
* @param tasks the tasks |
| 617 |
|
|
| 618 |
|
/** |
| 619 |
|
* Forks all tasks in the collection, returning when {@code |
| 620 |
< |
* isDone} holds for each task or an exception is encountered. If |
| 621 |
< |
* any task encounters an exception, others may be, but are not |
| 622 |
< |
* guaranteed to be, cancelled. This method may be invoked only |
| 623 |
< |
* from within ForkJoinTask computations (as may be determined |
| 624 |
< |
* using method {@link #inForkJoinPool}). Attempts to invoke in |
| 625 |
< |
* other contexts result in exceptions or errors, possibly |
| 626 |
< |
* including ClassCastException. |
| 620 |
> |
* isDone} holds for each task or an exception is encountered. |
| 621 |
> |
* If any task encounters an exception, others may be, but are |
| 622 |
> |
* not guaranteed to be, cancelled. |
| 623 |
> |
* |
| 624 |
> |
* <p>This method may be invoked only from within {@code |
| 625 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 626 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 627 |
> |
* result in exceptions or errors, possibly including {@code |
| 628 |
> |
* ClassCastException}. |
| 629 |
|
* |
| 630 |
|
* @param tasks the collection of tasks |
| 631 |
|
* @return the tasks argument, to simplify usage |
| 814 |
|
* there are no potential dependencies between continuation of the |
| 815 |
|
* current task and that of any other task that might be executed |
| 816 |
|
* while helping. (This usually holds for pure divide-and-conquer |
| 817 |
< |
* tasks). This method may be invoked only from within |
| 818 |
< |
* ForkJoinTask computations (as may be determined using method |
| 819 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 820 |
< |
* result in exceptions or errors, possibly including |
| 821 |
< |
* ClassCastException. |
| 817 |
> |
* tasks). |
| 818 |
> |
* |
| 819 |
> |
* <p>This method may be invoked only from within {@code |
| 820 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 821 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 822 |
> |
* result in exceptions or errors, possibly including {@code |
| 823 |
> |
* ClassCastException}. |
| 824 |
|
* |
| 825 |
|
* @return the computed result |
| 826 |
|
*/ |
| 832 |
|
} |
| 833 |
|
|
| 834 |
|
/** |
| 835 |
< |
* Possibly executes other tasks until this task is ready. This |
| 836 |
< |
* method may be invoked only from within ForkJoinTask |
| 837 |
< |
* computations (as may be determined using method {@link |
| 838 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
| 839 |
< |
* in exceptions or errors, possibly including ClassCastException. |
| 835 |
> |
* Possibly executes other tasks until this task is ready. |
| 836 |
> |
* |
| 837 |
> |
* <p>This method may be invoked only from within {@code |
| 838 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 839 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 840 |
> |
* result in exceptions or errors, possibly including {@code |
| 841 |
> |
* ClassCastException}. |
| 842 |
|
*/ |
| 843 |
|
public final void quietlyHelpJoin() { |
| 844 |
|
if (status >= 0) { |
| 879 |
|
* Possibly executes tasks until the pool hosting the current task |
| 880 |
|
* {@link ForkJoinPool#isQuiescent}. This method may be of use in |
| 881 |
|
* designs in which many tasks are forked, but none are explicitly |
| 882 |
< |
* joined, instead executing them until all are processed. This |
| 883 |
< |
* method may be invoked only from within ForkJoinTask |
| 884 |
< |
* computations (as may be determined using method {@link |
| 885 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
| 886 |
< |
* in exceptions or errors, possibly including ClassCastException. |
| 882 |
> |
* joined, instead executing them until all are processed. |
| 883 |
> |
* |
| 884 |
> |
* <p>This method may be invoked only from within {@code |
| 885 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 886 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 887 |
> |
* result in exceptions or errors, possibly including {@code |
| 888 |
> |
* ClassCastException}. |
| 889 |
|
*/ |
| 890 |
|
public static void helpQuiesce() { |
| 891 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
| 938 |
|
* by the current thread, and has not commenced executing in |
| 939 |
|
* another thread. This method may be useful when arranging |
| 940 |
|
* alternative local processing of tasks that could have been, but |
| 941 |
< |
* were not, stolen. This method may be invoked only from within |
| 942 |
< |
* ForkJoinTask computations (as may be determined using method |
| 943 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 944 |
< |
* result in exceptions or errors, possibly including |
| 945 |
< |
* ClassCastException. |
| 941 |
> |
* were not, stolen. |
| 942 |
> |
* |
| 943 |
> |
* <p>This method may be invoked only from within {@code |
| 944 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 945 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 946 |
> |
* result in exceptions or errors, possibly including {@code |
| 947 |
> |
* ClassCastException}. |
| 948 |
|
* |
| 949 |
|
* @return {@code true} if unforked |
| 950 |
|
*/ |
| 957 |
|
* Returns an estimate of the number of tasks that have been |
| 958 |
|
* forked by the current worker thread but not yet executed. This |
| 959 |
|
* value may be useful for heuristic decisions about whether to |
| 960 |
< |
* fork other tasks. This method may be invoked only from within |
| 961 |
< |
* ForkJoinTask computations (as may be determined using method |
| 962 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 963 |
< |
* result in exceptions or errors, possibly including |
| 964 |
< |
* ClassCastException. |
| 960 |
> |
* fork other tasks. |
| 961 |
> |
* |
| 962 |
> |
* <p>This method may be invoked only from within {@code |
| 963 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 964 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 965 |
> |
* result in exceptions or errors, possibly including {@code |
| 966 |
> |
* ClassCastException}. |
| 967 |
> |
* |
| 968 |
|
* @return the number of tasks |
| 969 |
|
*/ |
| 970 |
|
public static int getQueuedTaskCount() { |
| 980 |
|
* usages of ForkJoinTasks, at steady state, each worker should |
| 981 |
|
* aim to maintain a small constant surplus (for example, 3) of |
| 982 |
|
* tasks, and to process computations locally if this threshold is |
| 983 |
< |
* exceeded. This method may be invoked only from within |
| 984 |
< |
* ForkJoinTask computations (as may be determined using method |
| 985 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 986 |
< |
* result in exceptions or errors, possibly including |
| 987 |
< |
* ClassCastException. |
| 983 |
> |
* exceeded. |
| 984 |
> |
* |
| 985 |
> |
* <p>This method may be invoked only from within {@code |
| 986 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 987 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 988 |
> |
* result in exceptions or errors, possibly including {@code |
| 989 |
> |
* ClassCastException}. |
| 990 |
> |
* |
| 991 |
|
* @return the surplus number of tasks, which may be negative |
| 992 |
|
*/ |
| 993 |
|
public static int getSurplusQueuedTaskCount() { |
| 1039 |
|
* null even if a task exists but cannot be accessed without |
| 1040 |
|
* contention with other threads. This method is designed |
| 1041 |
|
* primarily to support extensions, and is unlikely to be useful |
| 1042 |
< |
* otherwise. This method may be invoked only from within |
| 1043 |
< |
* ForkJoinTask computations (as may be determined using method |
| 1044 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 1045 |
< |
* result in exceptions or errors, possibly including |
| 1046 |
< |
* ClassCastException. |
| 1042 |
> |
* otherwise. |
| 1043 |
> |
* |
| 1044 |
> |
* <p>This method may be invoked only from within {@code |
| 1045 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 1046 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 1047 |
> |
* result in exceptions or errors, possibly including {@code |
| 1048 |
> |
* ClassCastException}. |
| 1049 |
|
* |
| 1050 |
|
* @return the next task, or {@code null} if none are available |
| 1051 |
|
*/ |
| 1058 |
|
* Unschedules and returns, without executing, the next task |
| 1059 |
|
* queued by the current thread but not yet executed. This method |
| 1060 |
|
* is designed primarily to support extensions, and is unlikely to |
| 1061 |
< |
* be useful otherwise. This method may be invoked only from |
| 1062 |
< |
* within ForkJoinTask computations (as may be determined using |
| 1063 |
< |
* method {@link #inForkJoinPool}). Attempts to invoke in other |
| 1064 |
< |
* contexts result in exceptions or errors, possibly including |
| 1065 |
< |
* ClassCastException. |
| 1061 |
> |
* be useful otherwise. |
| 1062 |
> |
* |
| 1063 |
> |
* <p>This method may be invoked only from within {@code |
| 1064 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 1065 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 1066 |
> |
* result in exceptions or errors, possibly including {@code |
| 1067 |
> |
* ClassCastException}. |
| 1068 |
|
* |
| 1069 |
|
* @return the next task, or {@code null} if none are available |
| 1070 |
|
*/ |
| 1081 |
|
* {@code null} result does not necessarily imply quiescence |
| 1082 |
|
* of the pool this task is operating in. This method is designed |
| 1083 |
|
* primarily to support extensions, and is unlikely to be useful |
| 1084 |
< |
* otherwise. This method may be invoked only from within |
| 1085 |
< |
* ForkJoinTask computations (as may be determined using method |
| 1086 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 1087 |
< |
* result in exceptions or errors, possibly including |
| 1088 |
< |
* ClassCastException. |
| 1084 |
> |
* otherwise. |
| 1085 |
> |
* |
| 1086 |
> |
* <p>This method may be invoked only from within {@code |
| 1087 |
> |
* ForkJoinTask} computations (as may be determined using method |
| 1088 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
| 1089 |
> |
* result in exceptions or errors, possibly including {@code |
| 1090 |
> |
* ClassCastException}. |
| 1091 |
|
* |
| 1092 |
|
* @return a task, or {@code null} if none are available |
| 1093 |
|
*/ |
| 1152 |
|
} |
| 1153 |
|
|
| 1154 |
|
/** |
| 1155 |
< |
* Returns a new ForkJoinTask that performs the {@code run} |
| 1156 |
< |
* method of the given Runnable as its action, and returns a null |
| 1157 |
< |
* result upon {@code join}. |
| 1155 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
| 1156 |
> |
* method of the given {@code Runnable} as its action, and returns |
| 1157 |
> |
* a null result upon {@link #join}. |
| 1158 |
|
* |
| 1159 |
|
* @param runnable the runnable action |
| 1160 |
|
* @return the task |
| 1164 |
|
} |
| 1165 |
|
|
| 1166 |
|
/** |
| 1167 |
< |
* Returns a new ForkJoinTask that performs the {@code run} |
| 1168 |
< |
* method of the given Runnable as its action, and returns the |
| 1169 |
< |
* given result upon {@code join}. |
| 1167 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
| 1168 |
> |
* method of the given {@code Runnable} as its action, and returns |
| 1169 |
> |
* the given result upon {@link #join}. |
| 1170 |
|
* |
| 1171 |
|
* @param runnable the runnable action |
| 1172 |
|
* @param result the result upon completion |
| 1177 |
|
} |
| 1178 |
|
|
| 1179 |
|
/** |
| 1180 |
< |
* Returns a new ForkJoinTask that performs the {@code call} |
| 1181 |
< |
* method of the given Callable as its action, and returns its |
| 1182 |
< |
* result upon {@code join}, translating any checked |
| 1183 |
< |
* exceptions encountered into {@code RuntimeException}. |
| 1180 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code call} |
| 1181 |
> |
* method of the given {@code Callable} as its action, and returns |
| 1182 |
> |
* its result upon {@link #join}, translating any checked exceptions |
| 1183 |
> |
* encountered into {@code RuntimeException}. |
| 1184 |
|
* |
| 1185 |
|
* @param callable the callable action |
| 1186 |
|
* @return the task |
