--- jsr166/src/jsr166y/ForkJoinTask.java 2009/08/04 00:36:45 1.33 +++ jsr166/src/jsr166y/ForkJoinTask.java 2009/08/04 13:16:54 1.36 @@ -68,15 +68,29 @@ import java.util.WeakHashMap; * execute other tasks while awaiting joins, which is sometimes more * efficient but only applies when all subtasks are known to be * strictly tree-structured. Method {@link #invoke} is semantically - * equivalent to {@code fork(); join()} but always attempts to - * begin execution in the current thread. The "quiet" forms - * of these methods do not extract results or report exceptions. These + * equivalent to {@code fork(); join()} but always attempts to begin + * execution in the current thread. The "quiet" forms of + * these methods do not extract results or report exceptions. These * may be useful when a set of tasks are being executed, and you need * to delay processing of results or exceptions until all complete. * Method {@code invokeAll} (available in multiple versions) * performs the most common form of parallel invocation: forking a set * of tasks and joining them all. * + *

The execution status of tasks may be queried at several levels + * of detail: {@link #isDone} is true if a task completed in any way + * (including the case where a task was cancelled without executing); + * {@link #isCancelled} is true if completion was due to cancellation; + * {@link #isCompletedNormally} is true if a task completed without + * cancellation or encountering an exception; {@link + * #isCompletedExceptionally} is true if if the task encountered an + * exception (in which case {@link #getException} returns the + * exception); {@link #isCancelled} is true if the task was cancelled + * (in which case {@link #getException} returns a {@link + * java.util.concurrent.CancellationException}); and {@link + * #isCompletedAbnormally} is true if a task was either cancelled or + * encountered an exception. + * *

The ForkJoinTask class is not usually directly subclassed. * Instead, you subclass one of the abstract classes that support a * particular style of fork/join processing, typically {@link @@ -115,7 +129,7 @@ import java.util.WeakHashMap; * java.lang.Runnable} and {@link java.util.concurrent.Callable}, that * may be of use when mixing execution of ForkJoinTasks with other * kinds of tasks. When all tasks are of this form, consider using a - * pool in {@link ForkJoinPool#setAsyncMode}. + * pool in {@link ForkJoinPool#setAsyncMode async mode}. * *

ForkJoinTasks are {@code Serializable}, which enables them to be * used in extensions such as remote execution frameworks. It is @@ -382,6 +396,8 @@ public abstract class ForkJoinTask im */ private V reportFutureResult() throws ExecutionException, InterruptedException { + if (Thread.interrupted()) + throw new InterruptedException(); int s = status & COMPLETION_MASK; if (s < NORMAL) { Throwable ex; @@ -389,8 +405,6 @@ public abstract class ForkJoinTask im throw new CancellationException(); if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) throw new ExecutionException(ex); - if (Thread.interrupted()) - throw new InterruptedException(); } return getRawResult(); } @@ -401,6 +415,8 @@ public abstract class ForkJoinTask im */ private V reportTimedFutureResult() throws InterruptedException, ExecutionException, TimeoutException { + if (Thread.interrupted()) + throw new InterruptedException(); Throwable ex; int s = status & COMPLETION_MASK; if (s == NORMAL) @@ -409,8 +425,6 @@ public abstract class ForkJoinTask im throw new CancellationException(); if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) throw new ExecutionException(ex); - if (Thread.interrupted()) - throw new InterruptedException(); throw new TimeoutException(); } @@ -529,10 +543,9 @@ public abstract class ForkJoinTask im /** * Commences performing this task, awaits its completion if - * necessary, and return its result. + * necessary, and return its result, or throws an (unchecked) + * exception if the underlying computation did so. * - * @throws Throwable (a RuntimeException, Error, or unchecked - * exception) if the underlying computation did so * @return the computed result */ public final V invoke() { @@ -543,8 +556,12 @@ public abstract class ForkJoinTask im } /** - * Forks the given tasks, returning when {@code isDone} holds - * for each task or an exception is encountered. + * Forks the given tasks, returning when {@code isDone} holds for + * each task or an (unchecked) exception is encountered, in which + * case the exception is rethrown. If more than one task + * encounters an exception, then this method throws any one of + * these exceptions. The individual status of each task may be + * checked using {@link #getException()} and related methods. * *

This method may be invoked only from within {@code * ForkJoinTask} computations (as may be determined using method @@ -555,7 +572,6 @@ public abstract class ForkJoinTask im * @param t1 the first task * @param t2 the second task * @throws NullPointerException if any task is null - * @throws RuntimeException or Error if a task did so */ public static void invokeAll(ForkJoinTask t1, ForkJoinTask t2) { t2.fork(); @@ -565,9 +581,13 @@ public abstract class ForkJoinTask im /** * Forks the given tasks, returning when {@code isDone} holds for - * each task or an exception is encountered. If any task - * encounters an exception, others may be, but are not guaranteed - * to be, cancelled. + * each task or an (unchecked) exception is encountered, in which + * case the exception is rethrown. If any task encounters an + * exception, others may be, but are not guaranteed to be, + * cancelled. If more than one task encounters an exception, then + * this method throws any one of these exceptions. The individual + * status of each task may be checked using {@link #getException()} + * and related methods. * *

This method may be invoked only from within {@code * ForkJoinTask} computations (as may be determined using method @@ -576,8 +596,7 @@ public abstract class ForkJoinTask im * ClassCastException}. * * @param tasks the tasks - * @throws NullPointerException if tasks or any element are null - * @throws RuntimeException or Error if any task did so + * @throws NullPointerException if any task is null */ public static void invokeAll(ForkJoinTask... tasks) { Throwable ex = null; @@ -614,11 +633,15 @@ public abstract class ForkJoinTask im /** * Forks all tasks in the specified collection, returning when - * {@code isDone} holds for each task or an exception is - * encountered. If any task encounters an exception, others may - * be, but are not guaranteed to be, cancelled. The behavior of - * this operation is undefined if the specified collection is - * modified while the operation is in progress. + * {@code isDone} holds for each task or an (unchecked) exception + * is encountered. If any task encounters an exception, others + * may be, but are not guaranteed to be, cancelled. If more than + * one task encounters an exception, then this method throws any + * one of these exceptions. The individual status of each task + * may be checked using {@link #getException()} and related + * methods. The behavior of this operation is undefined if the + * specified collection is modified while the operation is in + * progress. * *

This method may be invoked only from within {@code * ForkJoinTask} computations (as may be determined using method @@ -629,7 +652,6 @@ public abstract class ForkJoinTask im * @param tasks the collection of tasks * @return the tasks argument, to simplify usage * @throws NullPointerException if tasks or any element are null - * @throws RuntimeException or Error if any task did so */ public static > Collection invokeAll(Collection tasks) { if (!(tasks instanceof RandomAccess) || !(tasks instanceof List)) { @@ -673,25 +695,6 @@ public abstract class ForkJoinTask im } /** - * Returns {@code true} if the computation performed by this task - * has completed (or has been cancelled). - * - * @return {@code true} if this computation has completed - */ - public final boolean isDone() { - return status < 0; - } - - /** - * Returns {@code true} if this task was cancelled. - * - * @return {@code true} if this task was cancelled - */ - public final boolean isCancelled() { - return (status & COMPLETION_MASK) == CANCELLED; - } - - /** * Attempts to cancel execution of this task. This attempt will * fail if the task has already completed, has already been * cancelled, or could not be cancelled for some other reason. If @@ -721,6 +724,25 @@ public abstract class ForkJoinTask im } /** + * Returns {@code true} if the computation performed by this task + * has completed (or has been cancelled). + * + * @return {@code true} if this computation has completed + */ + public final boolean isDone() { + return status < 0; + } + + /** + * Returns {@code true} if this task was cancelled. + * + * @return {@code true} if this task was cancelled + */ + public final boolean isCancelled() { + return (status & COMPLETION_MASK) == CANCELLED; + } + + /** * Returns {@code true} if this task threw an exception or was cancelled. * * @return {@code true} if this task threw an exception or was cancelled @@ -730,6 +752,26 @@ public abstract class ForkJoinTask im } /** + * Returns {@code true} if this task completed without throwing an + * exception and was not cancelled. + * + * @return {@code true} if this task completed without throwing an + * exception and was not cancelled + */ + public final boolean isCompletedNormally() { + return (status & COMPLETION_MASK) == NORMAL; + } + + /** + * Returns {@code true} if this task threw an exception. + * + * @return {@code true} if this task threw an exception + */ + public final boolean isCompletedExceptionally() { + return (status & COMPLETION_MASK) == EXCEPTIONAL; + } + + /** * Returns the exception thrown by the base computation, or a * {@code CancellationException} if cancelled, or {@code null} if * none or if the method has not yet completed. @@ -1022,11 +1064,10 @@ public abstract class ForkJoinTask im * called otherwise. The return value controls whether this task * is considered to be done normally. It may return false in * asynchronous actions that require explicit invocations of - * {@link #complete} to become joinable. It may throw exceptions - * to indicate abnormal exit. + * {@link #complete} to become joinable. It may also throw an + * (unchecked) exception to indicate abnormal exit. * * @return {@code true} if completed normally - * @throws Error or RuntimeException if encountered during computation */ protected abstract boolean exec();