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import java.util.Collection; |
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import java.util.Collections; |
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import java.util.List; |
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import java.util.RandomAccess; |
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import java.util.Map; |
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import java.util.WeakHashMap; |
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|
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/** |
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* Abstract base class for tasks that run within a {@link |
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* ForkJoinPool}. A ForkJoinTask is a thread-like entity that is much |
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* Abstract base class for tasks that run within a {@link ForkJoinPool}. |
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* A {@code ForkJoinTask} is a thread-like entity that is much |
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* lighter weight than a normal thread. Huge numbers of tasks and |
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* subtasks may be hosted by a small number of actual threads in a |
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* ForkJoinPool, at the price of some usage limitations. |
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* |
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* <p> A "main" ForkJoinTask begins execution when submitted to a |
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* {@link ForkJoinPool}. Once started, it will usually in turn start |
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* other subtasks. As indicated by the name of this class, many |
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* programs using ForkJoinTasks employ only methods {@code fork} |
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* and {@code join}, or derivatives such as |
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* {@code invokeAll}. However, this class also provides a number |
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* of other methods that can come into play in advanced usages, as |
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* well as extension mechanics that allow support of new forms of |
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* fork/join processing. |
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* <p>A "main" {@code ForkJoinTask} begins execution when submitted |
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* to a {@link ForkJoinPool}. Once started, it will usually in turn |
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* start other subtasks. As indicated by the name of this class, |
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* many programs using {@code ForkJoinTask} employ only methods |
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* {@link #fork} and {@link #join}, or derivatives such as {@link |
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* #invokeAll}. However, this class also provides a number of other |
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* methods that can come into play in advanced usages, as well as |
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* extension mechanics that allow support of new forms of fork/join |
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* processing. |
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* |
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* <p>A ForkJoinTask is a lightweight form of {@link Future}. The |
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* efficiency of ForkJoinTasks stems from a set of restrictions (that |
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* are only partially statically enforceable) reflecting their |
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* intended use as computational tasks calculating pure functions or |
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* operating on purely isolated objects. The primary coordination |
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* mechanisms are {@link #fork}, that arranges asynchronous execution, |
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* and {@link #join}, that doesn't proceed until the task's result has |
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* been computed. Computations should avoid {@code synchronized} |
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* methods or blocks, and should minimize other blocking |
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* synchronization apart from joining other tasks or using |
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* synchronizers such as Phasers that are advertised to cooperate with |
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* fork/join scheduling. Tasks should also not perform blocking IO, |
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* and should ideally access variables that are completely independent |
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* of those accessed by other running tasks. Minor breaches of these |
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* restrictions, for example using shared output streams, may be |
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* tolerable in practice, but frequent use may result in poor |
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* performance, and the potential to indefinitely stall if the number |
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* of threads not waiting for IO or other external synchronization |
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* becomes exhausted. This usage restriction is in part enforced by |
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* not permitting checked exceptions such as {@code IOExceptions} |
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* to be thrown. However, computations may still encounter unchecked |
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* exceptions, that are rethrown to callers attempting join |
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* them. These exceptions may additionally include |
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* RejectedExecutionExceptions stemming from internal resource |
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* exhaustion such as failure to allocate internal task queues. |
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* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}. |
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* The efficiency of {@code ForkJoinTask}s stems from a set of |
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* restrictions (that are only partially statically enforceable) |
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* reflecting their intended use as computational tasks calculating |
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* pure functions or operating on purely isolated objects. The |
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* primary coordination mechanisms are {@link #fork}, that arranges |
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* asynchronous execution, and {@link #join}, that doesn't proceed |
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* until the task's result has been computed. Computations should |
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* avoid {@code synchronized} methods or blocks, and should minimize |
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* other blocking synchronization apart from joining other tasks or |
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* using synchronizers such as Phasers that are advertised to |
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* cooperate with fork/join scheduling. Tasks should also not perform |
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* blocking IO, and should ideally access variables that are |
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* completely independent of those accessed by other running |
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* tasks. Minor breaches of these restrictions, for example using |
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* shared output streams, may be tolerable in practice, but frequent |
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* use may result in poor performance, and the potential to |
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* indefinitely stall if the number of threads not waiting for IO or |
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* other external synchronization becomes exhausted. This usage |
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* restriction is in part enforced by not permitting checked |
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* exceptions such as {@code IOExceptions} to be thrown. However, |
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* computations may still encounter unchecked exceptions, that are |
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* rethrown to callers attempting to join them. These exceptions may |
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* additionally include {@link RejectedExecutionException} stemming |
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* from internal resource exhaustion, such as failure to allocate |
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* internal task queues. |
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* |
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* <p>The primary method for awaiting completion and extracting |
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* results of a task is {@link #join}, but there are several variants: |
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* The {@link Future#get} methods support interruptible and/or timed |
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* waits for completion and report results using {@code Future} |
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* conventions. Method {@link #helpJoin} enables callers to actively |
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* execute other tasks while awaiting joins, which is sometimes more |
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* efficient but only applies when all subtasks are known to be |
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* strictly tree-structured. Method {@link #invoke} is semantically |
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* equivalent to {@code fork(); join()} but always attempts to |
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* begin execution in the current thread. The "<em>quiet</em>" forms |
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* of these methods do not extract results or report exceptions. These |
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* conventions. Method {@link #invoke} is semantically |
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* equivalent to {@code fork(); join()} but always attempts to begin |
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* execution in the current thread. The "<em>quiet</em>" forms of |
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* these methods do not extract results or report exceptions. These |
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* may be useful when a set of tasks are being executed, and you need |
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* to delay processing of results or exceptions until all complete. |
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* Method {@code invokeAll} (available in multiple versions) |
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* performs the most common form of parallel invocation: forking a set |
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* of tasks and joining them all. |
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* |
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* <p> The ForkJoinTask class is not usually directly subclassed. |
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* <p>The execution status of tasks may be queried at several levels |
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* of detail: {@link #isDone} is true if a task completed in any way |
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* (including the case where a task was cancelled without executing); |
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* {@link #isCompletedNormally} is true if a task completed without |
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* cancellation or encountering an exception; {@link #isCancelled} is |
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* true if the task was cancelled (in which case {@link #getException} |
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* returns a {@link java.util.concurrent.CancellationException}); and |
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* {@link #isCompletedAbnormally} is true if a task was either |
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* cancelled or encountered an exception, in which case {@link |
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* #getException} will return either the encountered exception or |
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* {@link java.util.concurrent.CancellationException}. |
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* |
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* <p>The ForkJoinTask class is not usually directly subclassed. |
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* Instead, you subclass one of the abstract classes that support a |
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* particular style of fork/join processing. Normally, a concrete |
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* particular style of fork/join processing, typically {@link |
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* RecursiveAction} for computations that do not return results, or |
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* {@link RecursiveTask} for those that do. Normally, a concrete |
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* ForkJoinTask subclass declares fields comprising its parameters, |
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* established in a constructor, and then defines a {@code compute} |
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* method that somehow uses the control methods supplied by this base |
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* class. While these methods have {@code public} access (to allow |
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* instances of different task subclasses to call each others |
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* instances of different task subclasses to call each other's |
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* methods), some of them may only be called from within other |
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* ForkJoinTasks (as may be determined using method {@link |
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* #inForkJoinPool}). Attempts to invoke them in other contexts |
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* result in exceptions or errors, possibly including |
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* ClassCastException. |
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* {@code ClassCastException}. |
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* |
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* <p>Most base support methods are {@code final} because their |
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* implementations are intrinsically tied to the underlying |
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* lightweight task scheduling framework, and so cannot be overridden. |
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* Developers creating new basic styles of fork/join processing should |
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* minimally implement {@code protected} methods |
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* {@code exec}, {@code setRawResult}, and |
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* {@code getRawResult}, while also introducing an abstract |
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* computational method that can be implemented in its subclasses, |
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* possibly relying on other {@code protected} methods provided |
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* by this class. |
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* <p>Most base support methods are {@code final}, to prevent |
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* overriding of implementations that are intrinsically tied to the |
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* underlying lightweight task scheduling framework. Developers |
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* creating new basic styles of fork/join processing should minimally |
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* implement {@code protected} methods {@link #exec}, {@link |
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* #setRawResult}, and {@link #getRawResult}, while also introducing |
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* an abstract computational method that can be implemented in its |
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* subclasses, possibly relying on other {@code protected} methods |
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* provided by this class. |
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* |
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* <p>ForkJoinTasks should perform relatively small amounts of |
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* computations, otherwise splitting into smaller tasks. As a very |
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* rough rule of thumb, a task should perform more than 100 and less |
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* than 10000 basic computational steps. If tasks are too big, then |
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* parallelism cannot improve throughput. If too small, then memory |
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* and internal task maintenance overhead may overwhelm processing. |
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* computation. Large tasks should be split into smaller subtasks, |
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* usually via recursive decomposition. As a very rough rule of thumb, |
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* a task should perform more than 100 and less than 10000 basic |
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* computational steps. If tasks are too big, then parallelism cannot |
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* improve throughput. If too small, then memory and internal task |
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* maintenance overhead may overwhelm processing. |
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* |
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* <p>This class provides {@code adapt} methods for {@link Runnable} |
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* and {@link Callable}, that may be of use when mixing execution of |
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* {@code ForkJoinTasks} with other kinds of tasks. When all tasks are |
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* of this form, consider using a pool constructed in <em>asyncMode</em>. |
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* |
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* <p>ForkJoinTasks are {@code Serializable}, which enables them |
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* to be used in extensions such as remote execution frameworks. It is |
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* in general sensible to serialize tasks only before or after, but |
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* not during execution. Serialization is not relied on during |
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* execution itself. |
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* <p>ForkJoinTasks are {@code Serializable}, which enables them to be |
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* used in extensions such as remote execution frameworks. It is |
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* sensible to serialize tasks only before or after, but not during, |
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* execution. Serialization is not relied on during execution itself. |
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* |
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* @since 1.7 |
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* @author Doug Lea |
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*/ |
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public abstract class ForkJoinTask<V> implements Future<V>, Serializable { |
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|
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/** |
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* Run control status bits packed into a single int to minimize |
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* footprint and to ensure atomicity (via CAS). Status is |
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* initially zero, and takes on nonnegative values until |
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* completed, upon which status holds COMPLETED. CANCELLED, or |
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* EXCEPTIONAL, which use the top 3 bits. Tasks undergoing |
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* blocking waits by other threads have SIGNAL_MASK bits set -- |
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* bit 15 for external (nonFJ) waits, and the rest a count of |
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* waiting FJ threads. (This representation relies on |
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* ForkJoinPool max thread limits). Completion of a stolen task |
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* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even |
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* though suboptimal for some purposes, we use basic builtin |
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* wait/notify to take advantage of "monitor inflation" in JVMs |
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* that we would otherwise need to emulate to avoid adding further |
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* per-task bookkeeping overhead. Note that bits 16-28 are |
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* currently unused. Also value 0x80000000 is available as spare |
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* completion value. |
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/* |
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* See the internal documentation of class ForkJoinPool for a |
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* general implementation overview. ForkJoinTasks are mainly |
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* responsible for maintaining their "status" field amidst relays |
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* to methods in ForkJoinWorkerThread and ForkJoinPool. The |
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* methods of this class are more-or-less layered into (1) basic |
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* status maintenance (2) execution and awaiting completion (3) |
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* user-level methods that additionally report results. This is |
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* sometimes hard to see because this file orders exported methods |
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* in a way that flows well in javadocs. In particular, most |
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* join mechanics are in method quietlyJoin, below. |
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*/ |
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|
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/* |
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* The status field holds run control status bits packed into a |
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* single int to minimize footprint and to ensure atomicity (via |
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* CAS). Status is initially zero, and takes on nonnegative |
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* values until completed, upon which status holds value |
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* NORMAL. CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking |
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* waits by other threads have the SIGNAL bit set. Completion of |
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* a stolen task with SIGNAL set awakens any waiters via |
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* notifyAll. Even though suboptimal for some purposes, we use |
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* basic builtin wait/notify to take advantage of "monitor |
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* inflation" in JVMs that we would otherwise need to emulate to |
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* avoid adding further per-task bookkeeping overhead. We want |
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* these monitors to be "fat", i.e., not use biasing or thin-lock |
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* techniques, so use some odd coding idioms that tend to avoid |
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* them. |
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*/ |
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|
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/** The run status of this task */ |
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volatile int status; // accessed directly by pool and workers |
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|
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static final int COMPLETION_MASK = 0xe0000000; |
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static final int NORMAL = 0xe0000000; // == mask |
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static final int CANCELLED = 0xc0000000; |
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static final int EXCEPTIONAL = 0xa0000000; |
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static final int SIGNAL_MASK = 0x0000ffff; |
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static final int INTERNAL_SIGNAL_MASK = 0x00007fff; |
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static final int EXTERNAL_SIGNAL = 0x00008000; // top bit of low word |
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private static final int NORMAL = -1; |
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private static final int CANCELLED = -2; |
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private static final int EXCEPTIONAL = -3; |
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private static final int SIGNAL = 1; |
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|
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/** |
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* Table of exceptions thrown by tasks, to enable reporting by |
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Collections.synchronizedMap |
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(new WeakHashMap<ForkJoinTask<?>, Throwable>()); |
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|
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// within-package utilities |
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|
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/** |
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* Gets current worker thread, or null if not a worker thread. |
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*/ |
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static ForkJoinWorkerThread getWorker() { |
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Thread t = Thread.currentThread(); |
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return ((t instanceof ForkJoinWorkerThread) ? |
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(ForkJoinWorkerThread) t : null); |
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} |
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|
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final boolean casStatus(int cmp, int val) { |
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return UNSAFE.compareAndSwapInt(this, statusOffset, cmp, val); |
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} |
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|
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/** |
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* Workaround for not being able to rethrow unchecked exceptions. |
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*/ |
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static void rethrowException(Throwable ex) { |
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if (ex != null) |
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UNSAFE.throwException(ex); |
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} |
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|
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// Setting completion status |
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// Maintaining completion status |
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|
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/** |
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* Marks completion and wakes up threads waiting to join this task. |
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> |
* Marks completion and wakes up threads waiting to join this task, |
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* also clearing signal request bits. |
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* |
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* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL |
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*/ |
196 |
< |
final void setCompletion(int completion) { |
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ForkJoinPool pool = getPool(); |
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< |
if (pool != null) { |
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int s; // Clear signal bits while setting completion status |
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do {} while ((s = status) >= 0 && !casStatus(s, completion)); |
201 |
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|
202 |
< |
if ((s & SIGNAL_MASK) != 0) { |
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< |
if ((s &= INTERNAL_SIGNAL_MASK) != 0) |
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< |
pool.updateRunningCount(s); |
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< |
synchronized (this) { notifyAll(); } |
196 |
> |
private void setCompletion(int completion) { |
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> |
int s; |
198 |
> |
while ((s = status) >= 0) { |
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> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) { |
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> |
if (s != 0) |
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> |
synchronized (this) { notifyAll(); } |
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> |
break; |
203 |
|
} |
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} |
203 |
– |
else |
204 |
– |
externallySetCompletion(completion); |
205 |
– |
} |
206 |
– |
|
207 |
– |
/** |
208 |
– |
* Version of setCompletion for non-FJ threads. Leaves signal |
209 |
– |
* bits for unblocked threads to adjust, and always notifies. |
210 |
– |
*/ |
211 |
– |
private void externallySetCompletion(int completion) { |
212 |
– |
int s; |
213 |
– |
do {} while ((s = status) >= 0 && |
214 |
– |
!casStatus(s, (s & SIGNAL_MASK) | completion)); |
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– |
synchronized (this) { notifyAll(); } |
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} |
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|
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/** |
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* Sets status to indicate normal completion. |
208 |
> |
* Records exception and sets exceptional completion. |
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> |
* |
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> |
* @return status on exit |
211 |
|
*/ |
212 |
< |
final void setNormalCompletion() { |
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< |
// Try typical fast case -- single CAS, no signal, not already done. |
214 |
< |
// Manually expand casStatus to improve chances of inlining it |
224 |
< |
if (!UNSAFE.compareAndSwapInt(this, statusOffset, 0, NORMAL)) |
225 |
< |
setCompletion(NORMAL); |
226 |
< |
} |
227 |
< |
|
228 |
< |
// internal waiting and notification |
229 |
< |
|
230 |
< |
/** |
231 |
< |
* Performs the actual monitor wait for awaitDone. |
232 |
< |
*/ |
233 |
< |
private void doAwaitDone() { |
234 |
< |
// Minimize lock bias and in/de-flation effects by maximizing |
235 |
< |
// chances of waiting inside sync |
236 |
< |
try { |
237 |
< |
while (status >= 0) |
238 |
< |
synchronized (this) { if (status >= 0) wait(); } |
239 |
< |
} catch (InterruptedException ie) { |
240 |
< |
onInterruptedWait(); |
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< |
} |
212 |
> |
private void setExceptionalCompletion(Throwable rex) { |
213 |
> |
exceptionMap.put(this, rex); |
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> |
setCompletion(EXCEPTIONAL); |
215 |
|
} |
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|
217 |
|
/** |
218 |
< |
* Performs the actual timed monitor wait for awaitDone. |
218 |
> |
* Blocks a worker thread until completion. Called only by |
219 |
> |
* pool. Currently unused -- pool-based waits use timeout |
220 |
> |
* version below. |
221 |
|
*/ |
222 |
< |
private void doAwaitDone(long startTime, long nanos) { |
223 |
< |
synchronized (this) { |
222 |
> |
final void internalAwaitDone() { |
223 |
> |
int s; // the odd construction reduces lock bias effects |
224 |
> |
while ((s = status) >= 0) { |
225 |
|
try { |
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< |
while (status >= 0) { |
227 |
< |
long nt = nanos - System.nanoTime() - startTime; |
228 |
< |
if (nt <= 0) |
253 |
< |
break; |
254 |
< |
wait(nt / 1000000, (int) (nt % 1000000)); |
226 |
> |
synchronized(this) { |
227 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s,SIGNAL)) |
228 |
> |
wait(); |
229 |
|
} |
230 |
|
} catch (InterruptedException ie) { |
231 |
< |
onInterruptedWait(); |
258 |
< |
} |
259 |
< |
} |
260 |
< |
} |
261 |
< |
|
262 |
< |
// Awaiting completion |
263 |
< |
|
264 |
< |
/** |
265 |
< |
* Sets status to indicate there is joiner, then waits for join, |
266 |
< |
* surrounded with pool notifications. |
267 |
< |
* |
268 |
< |
* @return status upon exit |
269 |
< |
*/ |
270 |
< |
private int awaitDone(ForkJoinWorkerThread w, |
271 |
< |
boolean maintainParallelism) { |
272 |
< |
ForkJoinPool pool = (w == null) ? null : w.pool; |
273 |
< |
int s; |
274 |
< |
while ((s = status) >= 0) { |
275 |
< |
if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) { |
276 |
< |
if (pool == null || !pool.preJoin(this, maintainParallelism)) |
277 |
< |
doAwaitDone(); |
278 |
< |
if (((s = status) & INTERNAL_SIGNAL_MASK) != 0) |
279 |
< |
adjustPoolCountsOnUnblock(pool); |
280 |
< |
break; |
231 |
> |
cancelIfTerminating(); |
232 |
|
} |
233 |
|
} |
283 |
– |
return s; |
234 |
|
} |
235 |
|
|
236 |
|
/** |
237 |
< |
* Timed version of awaitDone |
237 |
> |
* Blocks a worker thread until completed or timed out. Called |
238 |
> |
* only by pool. |
239 |
|
* |
240 |
< |
* @return status upon exit |
240 |
> |
* @return status on exit |
241 |
|
*/ |
242 |
< |
private int awaitDone(ForkJoinWorkerThread w, long nanos) { |
292 |
< |
ForkJoinPool pool = (w == null) ? null : w.pool; |
242 |
> |
final int internalAwaitDone(long millis) { |
243 |
|
int s; |
244 |
< |
while ((s = status) >= 0) { |
245 |
< |
if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) { |
246 |
< |
long startTime = System.nanoTime(); |
247 |
< |
if (pool == null || !pool.preJoin(this, false)) |
248 |
< |
doAwaitDone(startTime, nanos); |
299 |
< |
if ((s = status) >= 0) { |
300 |
< |
adjustPoolCountsOnCancelledWait(pool); |
301 |
< |
s = status; |
244 |
> |
if ((s = status) >= 0) { |
245 |
> |
try { |
246 |
> |
synchronized(this) { |
247 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s,SIGNAL)) |
248 |
> |
wait(millis, 0); |
249 |
|
} |
250 |
< |
if (s < 0 && (s & INTERNAL_SIGNAL_MASK) != 0) |
251 |
< |
adjustPoolCountsOnUnblock(pool); |
305 |
< |
break; |
250 |
> |
} catch (InterruptedException ie) { |
251 |
> |
cancelIfTerminating(); |
252 |
|
} |
253 |
+ |
s = status; |
254 |
|
} |
255 |
|
return s; |
256 |
|
} |
257 |
|
|
258 |
|
/** |
259 |
< |
* Notifies pool that thread is unblocked. Called by signalled |
313 |
< |
* threads when woken by non-FJ threads (which is atypical). |
259 |
> |
* Blocks a non-worker-thread until completion. |
260 |
|
*/ |
261 |
< |
private void adjustPoolCountsOnUnblock(ForkJoinPool pool) { |
261 |
> |
private void externalAwaitDone() { |
262 |
|
int s; |
263 |
< |
do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK)); |
264 |
< |
if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0) |
265 |
< |
pool.updateRunningCount(s); |
266 |
< |
} |
267 |
< |
|
268 |
< |
/** |
269 |
< |
* Notifies pool to adjust counts on cancelled or timed out wait. |
270 |
< |
*/ |
271 |
< |
private void adjustPoolCountsOnCancelledWait(ForkJoinPool pool) { |
272 |
< |
if (pool != null) { |
273 |
< |
int s; |
274 |
< |
while ((s = status) >= 0 && (s & INTERNAL_SIGNAL_MASK) != 0) { |
275 |
< |
if (casStatus(s, s - 1)) { |
330 |
< |
pool.updateRunningCount(1); |
263 |
> |
while ((s = status) >= 0) { |
264 |
> |
synchronized(this) { |
265 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)){ |
266 |
> |
boolean interrupted = false; |
267 |
> |
while (status >= 0) { |
268 |
> |
try { |
269 |
> |
wait(); |
270 |
> |
} catch (InterruptedException ie) { |
271 |
> |
interrupted = true; |
272 |
> |
} |
273 |
> |
} |
274 |
> |
if (interrupted) |
275 |
> |
Thread.currentThread().interrupt(); |
276 |
|
break; |
277 |
|
} |
278 |
|
} |
280 |
|
} |
281 |
|
|
282 |
|
/** |
283 |
< |
* Handles interruptions during waits. |
284 |
< |
*/ |
285 |
< |
private void onInterruptedWait() { |
341 |
< |
ForkJoinWorkerThread w = getWorker(); |
342 |
< |
if (w == null) |
343 |
< |
Thread.currentThread().interrupt(); // re-interrupt |
344 |
< |
else if (w.isTerminating()) |
345 |
< |
cancelIgnoringExceptions(); |
346 |
< |
// else if FJworker, ignore interrupt |
347 |
< |
} |
348 |
< |
|
349 |
< |
// Recording and reporting exceptions |
350 |
< |
|
351 |
< |
private void setDoneExceptionally(Throwable rex) { |
352 |
< |
exceptionMap.put(this, rex); |
353 |
< |
setCompletion(EXCEPTIONAL); |
354 |
< |
} |
355 |
< |
|
356 |
< |
/** |
357 |
< |
* Throws the exception associated with status s. |
358 |
< |
* |
359 |
< |
* @throws the exception |
360 |
< |
*/ |
361 |
< |
private void reportException(int s) { |
362 |
< |
if ((s &= COMPLETION_MASK) < NORMAL) { |
363 |
< |
if (s == CANCELLED) |
364 |
< |
throw new CancellationException(); |
365 |
< |
else |
366 |
< |
rethrowException(exceptionMap.get(this)); |
367 |
< |
} |
368 |
< |
} |
369 |
< |
|
370 |
< |
/** |
371 |
< |
* Returns result or throws exception using j.u.c.Future conventions. |
372 |
< |
* Only call when {@code isDone} known to be true. |
373 |
< |
*/ |
374 |
< |
private V reportFutureResult() |
375 |
< |
throws ExecutionException, InterruptedException { |
376 |
< |
int s = status & COMPLETION_MASK; |
377 |
< |
if (s < NORMAL) { |
378 |
< |
Throwable ex; |
379 |
< |
if (s == CANCELLED) |
380 |
< |
throw new CancellationException(); |
381 |
< |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
382 |
< |
throw new ExecutionException(ex); |
383 |
< |
if (Thread.interrupted()) |
384 |
< |
throw new InterruptedException(); |
385 |
< |
} |
386 |
< |
return getRawResult(); |
387 |
< |
} |
388 |
< |
|
389 |
< |
/** |
390 |
< |
* Returns result or throws exception using j.u.c.Future conventions |
391 |
< |
* with timeouts. |
392 |
< |
*/ |
393 |
< |
private V reportTimedFutureResult() |
394 |
< |
throws InterruptedException, ExecutionException, TimeoutException { |
395 |
< |
Throwable ex; |
396 |
< |
int s = status & COMPLETION_MASK; |
397 |
< |
if (s == NORMAL) |
398 |
< |
return getRawResult(); |
399 |
< |
if (s == CANCELLED) |
400 |
< |
throw new CancellationException(); |
401 |
< |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
402 |
< |
throw new ExecutionException(ex); |
403 |
< |
if (Thread.interrupted()) |
404 |
< |
throw new InterruptedException(); |
405 |
< |
throw new TimeoutException(); |
406 |
< |
} |
407 |
< |
|
408 |
< |
// internal execution methods |
409 |
< |
|
410 |
< |
/** |
411 |
< |
* Calls exec, recording completion, and rethrowing exception if |
412 |
< |
* encountered. Caller should normally check status before calling. |
413 |
< |
* |
414 |
< |
* @return true if completed normally |
415 |
< |
*/ |
416 |
< |
private boolean tryExec() { |
417 |
< |
try { // try block must contain only call to exec |
418 |
< |
if (!exec()) |
419 |
< |
return false; |
420 |
< |
} catch (Throwable rex) { |
421 |
< |
setDoneExceptionally(rex); |
422 |
< |
rethrowException(rex); |
423 |
< |
return false; // not reached |
424 |
< |
} |
425 |
< |
setNormalCompletion(); |
426 |
< |
return true; |
427 |
< |
} |
428 |
< |
|
429 |
< |
/** |
430 |
< |
* Main execution method used by worker threads. Invokes |
431 |
< |
* base computation unless already complete. |
283 |
> |
* Unless done, calls exec and records status if completed, but |
284 |
> |
* doesn't wait for completion otherwise. Primary execution method |
285 |
> |
* for ForkJoinWorkerThread. |
286 |
|
*/ |
287 |
|
final void quietlyExec() { |
434 |
– |
if (status >= 0) { |
435 |
– |
try { |
436 |
– |
if (!exec()) |
437 |
– |
return; |
438 |
– |
} catch (Throwable rex) { |
439 |
– |
setDoneExceptionally(rex); |
440 |
– |
return; |
441 |
– |
} |
442 |
– |
setNormalCompletion(); |
443 |
– |
} |
444 |
– |
} |
445 |
– |
|
446 |
– |
/** |
447 |
– |
* Calls exec(), recording but not rethrowing exception. |
448 |
– |
* Caller should normally check status before calling. |
449 |
– |
* |
450 |
– |
* @return true if completed normally |
451 |
– |
*/ |
452 |
– |
private boolean tryQuietlyInvoke() { |
288 |
|
try { |
289 |
< |
if (!exec()) |
290 |
< |
return false; |
289 |
> |
if (status < 0 || !exec()) |
290 |
> |
return; |
291 |
|
} catch (Throwable rex) { |
292 |
< |
setDoneExceptionally(rex); |
293 |
< |
return false; |
459 |
< |
} |
460 |
< |
setNormalCompletion(); |
461 |
< |
return true; |
462 |
< |
} |
463 |
< |
|
464 |
< |
/** |
465 |
< |
* Cancels, ignoring any exceptions it throws. |
466 |
< |
*/ |
467 |
< |
final void cancelIgnoringExceptions() { |
468 |
< |
try { |
469 |
< |
cancel(false); |
470 |
< |
} catch (Throwable ignore) { |
292 |
> |
setExceptionalCompletion(rex); |
293 |
> |
return; |
294 |
|
} |
295 |
< |
} |
473 |
< |
|
474 |
< |
/** |
475 |
< |
* Main implementation of helpJoin |
476 |
< |
*/ |
477 |
< |
private int busyJoin(ForkJoinWorkerThread w) { |
478 |
< |
int s; |
479 |
< |
ForkJoinTask<?> t; |
480 |
< |
while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null) |
481 |
< |
t.quietlyExec(); |
482 |
< |
return (s >= 0) ? awaitDone(w, false) : s; // block if no work |
295 |
> |
setCompletion(NORMAL); // must be outside try block |
296 |
|
} |
297 |
|
|
298 |
|
// public methods |
300 |
|
/** |
301 |
|
* Arranges to asynchronously execute this task. While it is not |
302 |
|
* necessarily enforced, it is a usage error to fork a task more |
303 |
< |
* than once unless it has completed and been reinitialized. This |
304 |
< |
* method may be invoked only from within ForkJoinTask |
305 |
< |
* computations (as may be determined using method {@link |
306 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
307 |
< |
* in exceptions or errors, possibly including ClassCastException. |
303 |
> |
* than once unless it has completed and been reinitialized. |
304 |
> |
* Subsequent modifications to the state of this task or any data |
305 |
> |
* it operates on are not necessarily consistently observable by |
306 |
> |
* any thread other than the one executing it unless preceded by a |
307 |
> |
* call to {@link #join} or related methods, or a call to {@link |
308 |
> |
* #isDone} returning {@code true}. |
309 |
> |
* |
310 |
> |
* <p>This method may be invoked only from within {@code |
311 |
> |
* ForkJoinTask} computations (as may be determined using method |
312 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
313 |
> |
* result in exceptions or errors, possibly including {@code |
314 |
> |
* ClassCastException}. |
315 |
|
* |
316 |
< |
* @return {@code this}, to simplify usage. |
316 |
> |
* @return {@code this}, to simplify usage |
317 |
|
*/ |
318 |
|
public final ForkJoinTask<V> fork() { |
319 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
322 |
|
} |
323 |
|
|
324 |
|
/** |
325 |
< |
* Returns the result of the computation when it is ready. |
326 |
< |
* This method differs from {@code get} in that abnormal |
327 |
< |
* completion results in RuntimeExceptions or Errors, not |
328 |
< |
* ExecutionExceptions. |
325 |
> |
* Returns the result of the computation when it {@link #isDone is done}. |
326 |
> |
* This method differs from {@link #get()} in that |
327 |
> |
* abnormal completion results in {@code RuntimeException} or |
328 |
> |
* {@code Error}, not {@code ExecutionException}. |
329 |
|
* |
330 |
|
* @return the computed result |
331 |
|
*/ |
332 |
|
public final V join() { |
333 |
< |
ForkJoinWorkerThread w = getWorker(); |
334 |
< |
if (w == null || status < 0 || !w.unpushTask(this) || !tryExec()) |
335 |
< |
reportException(awaitDone(w, true)); |
333 |
> |
quietlyJoin(); |
334 |
> |
Throwable ex; |
335 |
> |
if (status < NORMAL && (ex = getException()) != null) |
336 |
> |
UNSAFE.throwException(ex); |
337 |
|
return getRawResult(); |
338 |
|
} |
339 |
|
|
340 |
|
/** |
341 |
|
* Commences performing this task, awaits its completion if |
342 |
< |
* necessary, and return its result. |
342 |
> |
* necessary, and returns its result, or throws an (unchecked) |
343 |
> |
* {@code RuntimeException} or {@code Error} if the underlying |
344 |
> |
* computation did so. |
345 |
|
* |
523 |
– |
* @throws Throwable (a RuntimeException, Error, or unchecked |
524 |
– |
* exception) if the underlying computation did so |
346 |
|
* @return the computed result |
347 |
|
*/ |
348 |
|
public final V invoke() { |
349 |
< |
if (status >= 0 && tryExec()) |
350 |
< |
return getRawResult(); |
351 |
< |
else |
352 |
< |
return join(); |
349 |
> |
quietlyInvoke(); |
350 |
> |
Throwable ex; |
351 |
> |
if (status < NORMAL && (ex = getException()) != null) |
352 |
> |
UNSAFE.throwException(ex); |
353 |
> |
return getRawResult(); |
354 |
|
} |
355 |
|
|
356 |
|
/** |
357 |
< |
* Forks both tasks, returning when {@code isDone} holds for |
358 |
< |
* both of them or an exception is encountered. This method may be |
359 |
< |
* invoked only from within ForkJoinTask computations (as may be |
360 |
< |
* determined using method {@link #inForkJoinPool}). Attempts to |
361 |
< |
* invoke in other contexts result in exceptions or errors, |
362 |
< |
* possibly including ClassCastException. |
363 |
< |
* |
364 |
< |
* @param t1 one task |
365 |
< |
* @param t2 the other task |
366 |
< |
* @throws NullPointerException if t1 or t2 are null |
367 |
< |
* @throws RuntimeException or Error if either task did so |
357 |
> |
* Forks the given tasks, returning when {@code isDone} holds for |
358 |
> |
* each task or an (unchecked) exception is encountered, in which |
359 |
> |
* case the exception is rethrown. If more than one task |
360 |
> |
* encounters an exception, then this method throws any one of |
361 |
> |
* these exceptions. If any task encounters an exception, the |
362 |
> |
* other may be cancelled. However, the execution status of |
363 |
> |
* individual tasks is not guaranteed upon exceptional return. The |
364 |
> |
* status of each task may be obtained using {@link |
365 |
> |
* #getException()} and related methods to check if they have been |
366 |
> |
* cancelled, completed normally or exceptionally, or left |
367 |
> |
* unprocessed. |
368 |
> |
* |
369 |
> |
* <p>This method may be invoked only from within {@code |
370 |
> |
* ForkJoinTask} computations (as may be determined using method |
371 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
372 |
> |
* result in exceptions or errors, possibly including {@code |
373 |
> |
* ClassCastException}. |
374 |
> |
* |
375 |
> |
* @param t1 the first task |
376 |
> |
* @param t2 the second task |
377 |
> |
* @throws NullPointerException if any task is null |
378 |
|
*/ |
379 |
< |
public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) { |
379 |
> |
public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { |
380 |
|
t2.fork(); |
381 |
|
t1.invoke(); |
382 |
|
t2.join(); |
383 |
|
} |
384 |
|
|
385 |
|
/** |
386 |
< |
* Forks the given tasks, returning when {@code isDone} holds |
387 |
< |
* for all of them. If any task encounters an exception, others |
388 |
< |
* may be cancelled. This method may be invoked only from within |
389 |
< |
* ForkJoinTask computations (as may be determined using method |
390 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
391 |
< |
* result in exceptions or errors, possibly including |
392 |
< |
* ClassCastException. |
386 |
> |
* Forks the given tasks, returning when {@code isDone} holds for |
387 |
> |
* each task or an (unchecked) exception is encountered, in which |
388 |
> |
* case the exception is rethrown. If more than one task |
389 |
> |
* encounters an exception, then this method throws any one of |
390 |
> |
* these exceptions. If any task encounters an exception, others |
391 |
> |
* may be cancelled. However, the execution status of individual |
392 |
> |
* tasks is not guaranteed upon exceptional return. The status of |
393 |
> |
* each task may be obtained using {@link #getException()} and |
394 |
> |
* related methods to check if they have been cancelled, completed |
395 |
> |
* normally or exceptionally, or left unprocessed. |
396 |
> |
* |
397 |
> |
* <p>This method may be invoked only from within {@code |
398 |
> |
* ForkJoinTask} computations (as may be determined using method |
399 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
400 |
> |
* result in exceptions or errors, possibly including {@code |
401 |
> |
* ClassCastException}. |
402 |
|
* |
403 |
< |
* @param tasks the array of tasks |
404 |
< |
* @throws NullPointerException if tasks or any element are null |
564 |
< |
* @throws RuntimeException or Error if any task did so |
403 |
> |
* @param tasks the tasks |
404 |
> |
* @throws NullPointerException if any task is null |
405 |
|
*/ |
406 |
|
public static void invokeAll(ForkJoinTask<?>... tasks) { |
407 |
|
Throwable ex = null; |
416 |
|
t.fork(); |
417 |
|
else { |
418 |
|
t.quietlyInvoke(); |
419 |
< |
if (ex == null) |
419 |
> |
if (ex == null && t.status < NORMAL) |
420 |
|
ex = t.getException(); |
421 |
|
} |
422 |
|
} |
427 |
|
t.cancel(false); |
428 |
|
else { |
429 |
|
t.quietlyJoin(); |
430 |
< |
if (ex == null) |
430 |
> |
if (ex == null && t.status < NORMAL) |
431 |
|
ex = t.getException(); |
432 |
|
} |
433 |
|
} |
434 |
|
} |
435 |
|
if (ex != null) |
436 |
< |
rethrowException(ex); |
436 |
> |
UNSAFE.throwException(ex); |
437 |
|
} |
438 |
|
|
439 |
|
/** |
440 |
< |
* Forks all tasks in the collection, returning when |
441 |
< |
* {@code isDone} holds for all of them. If any task |
442 |
< |
* encounters an exception, others may be cancelled. This method |
443 |
< |
* may be invoked only from within ForkJoinTask computations (as |
444 |
< |
* may be determined using method {@link |
445 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
446 |
< |
* in exceptions or errors, possibly including ClassCastException. |
440 |
> |
* Forks all tasks in the specified collection, returning when |
441 |
> |
* {@code isDone} holds for each task or an (unchecked) exception |
442 |
> |
* is encountered, in which case the exception is rethrown. If |
443 |
> |
* more than one task encounters an exception, then this method |
444 |
> |
* throws any one of these exceptions. If any task encounters an |
445 |
> |
* exception, others may be cancelled. However, the execution |
446 |
> |
* status of individual tasks is not guaranteed upon exceptional |
447 |
> |
* return. The status of each task may be obtained using {@link |
448 |
> |
* #getException()} and related methods to check if they have been |
449 |
> |
* cancelled, completed normally or exceptionally, or left |
450 |
> |
* unprocessed. |
451 |
> |
* |
452 |
> |
* <p>This method may be invoked only from within {@code |
453 |
> |
* ForkJoinTask} computations (as may be determined using method |
454 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
455 |
> |
* result in exceptions or errors, possibly including {@code |
456 |
> |
* ClassCastException}. |
457 |
|
* |
458 |
|
* @param tasks the collection of tasks |
459 |
|
* @return the tasks argument, to simplify usage |
460 |
|
* @throws NullPointerException if tasks or any element are null |
611 |
– |
* @throws RuntimeException or Error if any task did so |
461 |
|
*/ |
462 |
|
public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) { |
463 |
< |
if (!(tasks instanceof List<?>)) { |
463 |
> |
if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) { |
464 |
|
invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()])); |
465 |
|
return tasks; |
466 |
|
} |
479 |
|
t.fork(); |
480 |
|
else { |
481 |
|
t.quietlyInvoke(); |
482 |
< |
if (ex == null) |
482 |
> |
if (ex == null && t.status < NORMAL) |
483 |
|
ex = t.getException(); |
484 |
|
} |
485 |
|
} |
490 |
|
t.cancel(false); |
491 |
|
else { |
492 |
|
t.quietlyJoin(); |
493 |
< |
if (ex == null) |
493 |
> |
if (ex == null && t.status < NORMAL) |
494 |
|
ex = t.getException(); |
495 |
|
} |
496 |
|
} |
497 |
|
} |
498 |
|
if (ex != null) |
499 |
< |
rethrowException(ex); |
499 |
> |
UNSAFE.throwException(ex); |
500 |
|
return tasks; |
501 |
|
} |
502 |
|
|
503 |
|
/** |
504 |
< |
* Returns true if the computation performed by this task has |
505 |
< |
* completed (or has been cancelled). |
506 |
< |
* |
507 |
< |
* @return true if this computation has completed |
508 |
< |
*/ |
509 |
< |
public final boolean isDone() { |
510 |
< |
return status < 0; |
662 |
< |
} |
663 |
< |
|
664 |
< |
/** |
665 |
< |
* Returns true if this task was cancelled. |
666 |
< |
* |
667 |
< |
* @return true if this task was cancelled |
668 |
< |
*/ |
669 |
< |
public final boolean isCancelled() { |
670 |
< |
return (status & COMPLETION_MASK) == CANCELLED; |
671 |
< |
} |
672 |
< |
|
673 |
< |
/** |
674 |
< |
* Asserts that the results of this task's computation will not be |
675 |
< |
* used. If a cancellation occurs before attempting to execute this |
676 |
< |
* task, then execution will be suppressed, {@code isCancelled} |
677 |
< |
* will report true, and {@code join} will result in a |
678 |
< |
* {@code CancellationException} being thrown. Otherwise, when |
679 |
< |
* cancellation races with completion, there are no guarantees |
680 |
< |
* about whether {@code isCancelled} will report true, whether |
681 |
< |
* {@code join} will return normally or via an exception, or |
682 |
< |
* whether these behaviors will remain consistent upon repeated |
683 |
< |
* invocation. |
504 |
> |
* Attempts to cancel execution of this task. This attempt will |
505 |
> |
* fail if the task has already completed, has already been |
506 |
> |
* cancelled, or could not be cancelled for some other reason. If |
507 |
> |
* successful, and this task has not started when cancel is |
508 |
> |
* called, execution of this task is suppressed, {@link |
509 |
> |
* #isCancelled} will report true, and {@link #join} will result |
510 |
> |
* in a {@code CancellationException} being thrown. |
511 |
|
* |
512 |
|
* <p>This method may be overridden in subclasses, but if so, must |
513 |
|
* still ensure that these minimal properties hold. In particular, |
514 |
< |
* the cancel method itself must not throw exceptions. |
514 |
> |
* the {@code cancel} method itself must not throw exceptions. |
515 |
|
* |
516 |
< |
* <p> This method is designed to be invoked by <em>other</em> |
516 |
> |
* <p>This method is designed to be invoked by <em>other</em> |
517 |
|
* tasks. To terminate the current task, you can just return or |
518 |
|
* throw an unchecked exception from its computation method, or |
519 |
< |
* invoke {@code completeExceptionally}. |
519 |
> |
* invoke {@link #completeExceptionally}. |
520 |
|
* |
521 |
|
* @param mayInterruptIfRunning this value is ignored in the |
522 |
< |
* default implementation because tasks are not in general |
522 |
> |
* default implementation because tasks are not |
523 |
|
* cancelled via interruption |
524 |
|
* |
525 |
< |
* @return true if this task is now cancelled |
525 |
> |
* @return {@code true} if this task is now cancelled |
526 |
|
*/ |
527 |
|
public boolean cancel(boolean mayInterruptIfRunning) { |
528 |
|
setCompletion(CANCELLED); |
529 |
< |
return (status & COMPLETION_MASK) == CANCELLED; |
529 |
> |
return status == CANCELLED; |
530 |
|
} |
531 |
|
|
532 |
|
/** |
533 |
< |
* Returns true if this task threw an exception or was cancelled. |
533 |
> |
* Cancels, ignoring any exceptions thrown by cancel. Used during |
534 |
> |
* worker and pool shutdown. Cancel is spec'ed not to throw any |
535 |
> |
* exceptions, but if it does anyway, we have no recourse during |
536 |
> |
* shutdown, so guard against this case. |
537 |
> |
*/ |
538 |
> |
final void cancelIgnoringExceptions() { |
539 |
> |
try { |
540 |
> |
cancel(false); |
541 |
> |
} catch (Throwable ignore) { |
542 |
> |
} |
543 |
> |
} |
544 |
> |
|
545 |
> |
/** |
546 |
> |
* Cancels if current thread is a terminating worker thread, |
547 |
> |
* ignoring any exceptions thrown by cancel. |
548 |
> |
*/ |
549 |
> |
final void cancelIfTerminating() { |
550 |
> |
Thread t = Thread.currentThread(); |
551 |
> |
if ((t instanceof ForkJoinWorkerThread) && |
552 |
> |
((ForkJoinWorkerThread) t).isTerminating()) { |
553 |
> |
try { |
554 |
> |
cancel(false); |
555 |
> |
} catch (Throwable ignore) { |
556 |
> |
} |
557 |
> |
} |
558 |
> |
} |
559 |
> |
|
560 |
> |
public final boolean isDone() { |
561 |
> |
return status < 0; |
562 |
> |
} |
563 |
> |
|
564 |
> |
public final boolean isCancelled() { |
565 |
> |
return status == CANCELLED; |
566 |
> |
} |
567 |
> |
|
568 |
> |
/** |
569 |
> |
* Returns {@code true} if this task threw an exception or was cancelled. |
570 |
|
* |
571 |
< |
* @return true if this task threw an exception or was cancelled |
571 |
> |
* @return {@code true} if this task threw an exception or was cancelled |
572 |
|
*/ |
573 |
|
public final boolean isCompletedAbnormally() { |
574 |
< |
return (status & COMPLETION_MASK) < NORMAL; |
574 |
> |
return status < NORMAL; |
575 |
> |
} |
576 |
> |
|
577 |
> |
/** |
578 |
> |
* Returns {@code true} if this task completed without throwing an |
579 |
> |
* exception and was not cancelled. |
580 |
> |
* |
581 |
> |
* @return {@code true} if this task completed without throwing an |
582 |
> |
* exception and was not cancelled |
583 |
> |
*/ |
584 |
> |
public final boolean isCompletedNormally() { |
585 |
> |
return status == NORMAL; |
586 |
|
} |
587 |
|
|
588 |
|
/** |
589 |
|
* Returns the exception thrown by the base computation, or a |
590 |
< |
* CancellationException if cancelled, or null if none or if the |
591 |
< |
* method has not yet completed. |
590 |
> |
* {@code CancellationException} if cancelled, or {@code null} if |
591 |
> |
* none or if the method has not yet completed. |
592 |
|
* |
593 |
< |
* @return the exception, or null if none |
593 |
> |
* @return the exception, or {@code null} if none |
594 |
|
*/ |
595 |
|
public final Throwable getException() { |
596 |
< |
int s = status & COMPLETION_MASK; |
597 |
< |
if (s >= NORMAL) |
598 |
< |
return null; |
599 |
< |
if (s == CANCELLED) |
726 |
< |
return new CancellationException(); |
727 |
< |
return exceptionMap.get(this); |
596 |
> |
int s = status; |
597 |
> |
return ((s >= NORMAL) ? null : |
598 |
> |
(s == CANCELLED) ? new CancellationException() : |
599 |
> |
exceptionMap.get(this)); |
600 |
|
} |
601 |
|
|
602 |
|
/** |
605 |
|
* {@code join} and related operations. This method may be used |
606 |
|
* to induce exceptions in asynchronous tasks, or to force |
607 |
|
* completion of tasks that would not otherwise complete. Its use |
608 |
< |
* in other situations is likely to be wrong. This method is |
608 |
> |
* in other situations is discouraged. This method is |
609 |
|
* overridable, but overridden versions must invoke {@code super} |
610 |
|
* implementation to maintain guarantees. |
611 |
|
* |
612 |
< |
* @param ex the exception to throw. If this exception is |
613 |
< |
* not a RuntimeException or Error, the actual exception thrown |
614 |
< |
* will be a RuntimeException with cause ex. |
612 |
> |
* @param ex the exception to throw. If this exception is not a |
613 |
> |
* {@code RuntimeException} or {@code Error}, the actual exception |
614 |
> |
* thrown will be a {@code RuntimeException} with cause {@code ex}. |
615 |
|
*/ |
616 |
|
public void completeExceptionally(Throwable ex) { |
617 |
< |
setDoneExceptionally((ex instanceof RuntimeException) || |
618 |
< |
(ex instanceof Error) ? ex : |
619 |
< |
new RuntimeException(ex)); |
617 |
> |
setExceptionalCompletion((ex instanceof RuntimeException) || |
618 |
> |
(ex instanceof Error) ? ex : |
619 |
> |
new RuntimeException(ex)); |
620 |
|
} |
621 |
|
|
622 |
|
/** |
625 |
|
* operations. This method may be used to provide results for |
626 |
|
* asynchronous tasks, or to provide alternative handling for |
627 |
|
* tasks that would not otherwise complete normally. Its use in |
628 |
< |
* other situations is likely to be wrong. This method is |
628 |
> |
* other situations is discouraged. This method is |
629 |
|
* overridable, but overridden versions must invoke {@code super} |
630 |
|
* implementation to maintain guarantees. |
631 |
|
* |
635 |
|
try { |
636 |
|
setRawResult(value); |
637 |
|
} catch (Throwable rex) { |
638 |
< |
setDoneExceptionally(rex); |
638 |
> |
setExceptionalCompletion(rex); |
639 |
|
return; |
640 |
|
} |
641 |
< |
setNormalCompletion(); |
641 |
> |
setCompletion(NORMAL); |
642 |
|
} |
643 |
|
|
644 |
|
public final V get() throws InterruptedException, ExecutionException { |
645 |
< |
ForkJoinWorkerThread w = getWorker(); |
646 |
< |
if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke()) |
647 |
< |
awaitDone(w, true); |
648 |
< |
return reportFutureResult(); |
645 |
> |
quietlyJoin(); |
646 |
> |
if (Thread.interrupted()) |
647 |
> |
throw new InterruptedException(); |
648 |
> |
int s = status; |
649 |
> |
if (s < NORMAL) { |
650 |
> |
Throwable ex; |
651 |
> |
if (s == CANCELLED) |
652 |
> |
throw new CancellationException(); |
653 |
> |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
654 |
> |
throw new ExecutionException(ex); |
655 |
> |
} |
656 |
> |
return getRawResult(); |
657 |
|
} |
658 |
|
|
659 |
|
public final V get(long timeout, TimeUnit unit) |
660 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
661 |
< |
ForkJoinWorkerThread w = getWorker(); |
662 |
< |
if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke()) |
663 |
< |
awaitDone(w, unit.toNanos(timeout)); |
664 |
< |
return reportTimedFutureResult(); |
665 |
< |
} |
666 |
< |
|
667 |
< |
/** |
668 |
< |
* Possibly executes other tasks until this task is ready, then |
669 |
< |
* returns the result of the computation. This method may be more |
670 |
< |
* efficient than {@code join}, but is only applicable when |
671 |
< |
* there are no potential dependencies between continuation of the |
672 |
< |
* current task and that of any other task that might be executed |
673 |
< |
* while helping. (This usually holds for pure divide-and-conquer |
674 |
< |
* tasks). This method may be invoked only from within |
675 |
< |
* ForkJoinTask computations (as may be determined using method |
676 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
677 |
< |
* result in exceptions or errors, possibly including |
678 |
< |
* ClassCastException. |
679 |
< |
* |
680 |
< |
* @return the computed result |
681 |
< |
*/ |
682 |
< |
public final V helpJoin() { |
683 |
< |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread(); |
684 |
< |
if (status < 0 || !w.unpushTask(this) || !tryExec()) |
685 |
< |
reportException(busyJoin(w)); |
686 |
< |
return getRawResult(); |
687 |
< |
} |
688 |
< |
|
689 |
< |
/** |
690 |
< |
* Possibly executes other tasks until this task is ready. This |
691 |
< |
* method may be invoked only from within ForkJoinTask |
692 |
< |
* computations (as may be determined using method {@link |
693 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
694 |
< |
* in exceptions or errors, possibly including ClassCastException. |
695 |
< |
*/ |
696 |
< |
public final void quietlyHelpJoin() { |
697 |
< |
if (status >= 0) { |
698 |
< |
ForkJoinWorkerThread w = |
699 |
< |
(ForkJoinWorkerThread) Thread.currentThread(); |
700 |
< |
if (!w.unpushTask(this) || !tryQuietlyInvoke()) |
701 |
< |
busyJoin(w); |
661 |
> |
Thread t = Thread.currentThread(); |
662 |
> |
ForkJoinPool pool; |
663 |
> |
if (t instanceof ForkJoinWorkerThread) { |
664 |
> |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; |
665 |
> |
if (status >= 0 && w.unpushTask(this)) |
666 |
> |
quietlyExec(); |
667 |
> |
pool = w.pool; |
668 |
> |
} |
669 |
> |
else |
670 |
> |
pool = null; |
671 |
> |
/* |
672 |
> |
* Timed wait loop intermixes cases for FJ (pool != null) and |
673 |
> |
* non FJ threads. For FJ, decrement pool count but don't try |
674 |
> |
* for replacement; increment count on completion. For non-FJ, |
675 |
> |
* deal with interrupts. This is messy, but a little less so |
676 |
> |
* than is splitting the FJ and nonFJ cases. |
677 |
> |
*/ |
678 |
> |
boolean interrupted = false; |
679 |
> |
boolean dec = false; // true if pool count decremented |
680 |
> |
long nanos = unit.toNanos(timeout); |
681 |
> |
for (;;) { |
682 |
> |
if (Thread.interrupted() && pool == null) { |
683 |
> |
interrupted = true; |
684 |
> |
break; |
685 |
> |
} |
686 |
> |
int s = status; |
687 |
> |
if (s < 0) |
688 |
> |
break; |
689 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)) { |
690 |
> |
long startTime = System.nanoTime(); |
691 |
> |
long nt; // wait time |
692 |
> |
while (status >= 0 && |
693 |
> |
(nt = nanos - (System.nanoTime() - startTime)) > 0) { |
694 |
> |
if (pool != null && !dec) |
695 |
> |
dec = pool.tryDecrementRunningCount(); |
696 |
> |
else { |
697 |
> |
long ms = nt / 1000000; |
698 |
> |
int ns = (int) (nt % 1000000); |
699 |
> |
try { |
700 |
> |
synchronized(this) { |
701 |
> |
if (status >= 0) |
702 |
> |
wait(ms, ns); |
703 |
> |
} |
704 |
> |
} catch (InterruptedException ie) { |
705 |
> |
if (pool != null) |
706 |
> |
cancelIfTerminating(); |
707 |
> |
else { |
708 |
> |
interrupted = true; |
709 |
> |
break; |
710 |
> |
} |
711 |
> |
} |
712 |
> |
} |
713 |
> |
} |
714 |
> |
break; |
715 |
> |
} |
716 |
|
} |
717 |
+ |
if (pool != null && dec) |
718 |
+ |
pool.incrementRunningCount(); |
719 |
+ |
if (interrupted) |
720 |
+ |
throw new InterruptedException(); |
721 |
+ |
int es = status; |
722 |
+ |
if (es != NORMAL) { |
723 |
+ |
Throwable ex; |
724 |
+ |
if (es == CANCELLED) |
725 |
+ |
throw new CancellationException(); |
726 |
+ |
if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
727 |
+ |
throw new ExecutionException(ex); |
728 |
+ |
throw new TimeoutException(); |
729 |
+ |
} |
730 |
+ |
return getRawResult(); |
731 |
|
} |
732 |
|
|
733 |
|
/** |
734 |
< |
* Joins this task, without returning its result or throwing an |
734 |
> |
* Joins this task, without returning its result or throwing its |
735 |
|
* exception. This method may be useful when processing |
736 |
|
* collections of tasks when some have been cancelled or otherwise |
737 |
|
* known to have aborted. |
738 |
|
*/ |
739 |
|
public final void quietlyJoin() { |
740 |
< |
if (status >= 0) { |
741 |
< |
ForkJoinWorkerThread w = getWorker(); |
742 |
< |
if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke()) |
743 |
< |
awaitDone(w, true); |
740 |
> |
Thread t; |
741 |
> |
if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) { |
742 |
> |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; |
743 |
> |
if (status >= 0) { |
744 |
> |
if (w.unpushTask(this)) { |
745 |
> |
boolean completed; |
746 |
> |
try { |
747 |
> |
completed = exec(); |
748 |
> |
} catch (Throwable rex) { |
749 |
> |
setExceptionalCompletion(rex); |
750 |
> |
return; |
751 |
> |
} |
752 |
> |
if (completed) { |
753 |
> |
setCompletion(NORMAL); |
754 |
> |
return; |
755 |
> |
} |
756 |
> |
} |
757 |
> |
w.joinTask(this); |
758 |
> |
} |
759 |
|
} |
760 |
+ |
else |
761 |
+ |
externalAwaitDone(); |
762 |
|
} |
763 |
|
|
764 |
|
/** |
765 |
|
* Commences performing this task and awaits its completion if |
766 |
< |
* necessary, without returning its result or throwing an |
766 |
> |
* necessary, without returning its result or throwing its |
767 |
|
* exception. This method may be useful when processing |
768 |
|
* collections of tasks when some have been cancelled or otherwise |
769 |
|
* known to have aborted. |
770 |
|
*/ |
771 |
|
public final void quietlyInvoke() { |
772 |
< |
if (status >= 0 && !tryQuietlyInvoke()) |
773 |
< |
quietlyJoin(); |
772 |
> |
if (status >= 0) { |
773 |
> |
boolean completed; |
774 |
> |
try { |
775 |
> |
completed = exec(); |
776 |
> |
} catch (Throwable rex) { |
777 |
> |
setExceptionalCompletion(rex); |
778 |
> |
return; |
779 |
> |
} |
780 |
> |
if (completed) |
781 |
> |
setCompletion(NORMAL); |
782 |
> |
else |
783 |
> |
quietlyJoin(); |
784 |
> |
} |
785 |
|
} |
786 |
|
|
787 |
|
/** |
788 |
|
* Possibly executes tasks until the pool hosting the current task |
789 |
< |
* {@link ForkJoinPool#isQuiescent}. This method may be of use in |
790 |
< |
* designs in which many tasks are forked, but none are explicitly |
791 |
< |
* joined, instead executing them until all are processed. |
789 |
> |
* {@link ForkJoinPool#isQuiescent is quiescent}. This method may |
790 |
> |
* be of use in designs in which many tasks are forked, but none |
791 |
> |
* are explicitly joined, instead executing them until all are |
792 |
> |
* processed. |
793 |
> |
* |
794 |
> |
* <p>This method may be invoked only from within {@code |
795 |
> |
* ForkJoinTask} computations (as may be determined using method |
796 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
797 |
> |
* result in exceptions or errors, possibly including {@code |
798 |
> |
* ClassCastException}. |
799 |
|
*/ |
800 |
|
public static void helpQuiesce() { |
801 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
808 |
|
* this task, but only if reuse occurs when this task has either |
809 |
|
* never been forked, or has been forked, then completed and all |
810 |
|
* outstanding joins of this task have also completed. Effects |
811 |
< |
* under any other usage conditions are not guaranteed, and are |
812 |
< |
* almost surely wrong. This method may be useful when executing |
811 |
> |
* under any other usage conditions are not guaranteed. |
812 |
> |
* This method may be useful when executing |
813 |
|
* pre-constructed trees of subtasks in loops. |
814 |
|
*/ |
815 |
|
public void reinitialize() { |
816 |
< |
if ((status & COMPLETION_MASK) == EXCEPTIONAL) |
816 |
> |
if (status == EXCEPTIONAL) |
817 |
|
exceptionMap.remove(this); |
818 |
|
status = 0; |
819 |
|
} |
822 |
|
* Returns the pool hosting the current task execution, or null |
823 |
|
* if this task is executing outside of any ForkJoinPool. |
824 |
|
* |
825 |
< |
* @return the pool, or null if none |
825 |
> |
* @see #inForkJoinPool |
826 |
> |
* @return the pool, or {@code null} if none |
827 |
|
*/ |
828 |
|
public static ForkJoinPool getPool() { |
829 |
|
Thread t = Thread.currentThread(); |
848 |
|
* by the current thread, and has not commenced executing in |
849 |
|
* another thread. This method may be useful when arranging |
850 |
|
* alternative local processing of tasks that could have been, but |
851 |
< |
* were not, stolen. This method may be invoked only from within |
908 |
< |
* ForkJoinTask computations (as may be determined using method |
909 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
910 |
< |
* result in exceptions or errors, possibly including |
911 |
< |
* ClassCastException. |
851 |
> |
* were not, stolen. |
852 |
|
* |
853 |
< |
* @return true if unforked |
853 |
> |
* <p>This method may be invoked only from within {@code |
854 |
> |
* ForkJoinTask} computations (as may be determined using method |
855 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
856 |
> |
* result in exceptions or errors, possibly including {@code |
857 |
> |
* ClassCastException}. |
858 |
> |
* |
859 |
> |
* @return {@code true} if unforked |
860 |
|
*/ |
861 |
|
public boolean tryUnfork() { |
862 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
869 |
|
* value may be useful for heuristic decisions about whether to |
870 |
|
* fork other tasks. |
871 |
|
* |
872 |
+ |
* <p>This method may be invoked only from within {@code |
873 |
+ |
* ForkJoinTask} computations (as may be determined using method |
874 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
875 |
+ |
* result in exceptions or errors, possibly including {@code |
876 |
+ |
* ClassCastException}. |
877 |
+ |
* |
878 |
|
* @return the number of tasks |
879 |
|
*/ |
880 |
|
public static int getQueuedTaskCount() { |
892 |
|
* tasks, and to process computations locally if this threshold is |
893 |
|
* exceeded. |
894 |
|
* |
895 |
+ |
* <p>This method may be invoked only from within {@code |
896 |
+ |
* ForkJoinTask} computations (as may be determined using method |
897 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
898 |
+ |
* result in exceptions or errors, possibly including {@code |
899 |
+ |
* ClassCastException}. |
900 |
+ |
* |
901 |
|
* @return the surplus number of tasks, which may be negative |
902 |
|
*/ |
903 |
|
public static int getSurplusQueuedTaskCount() { |
908 |
|
// Extension methods |
909 |
|
|
910 |
|
/** |
911 |
< |
* Returns the result that would be returned by {@code join}, |
912 |
< |
* even if this task completed abnormally, or null if this task is |
913 |
< |
* not known to have been completed. This method is designed to |
914 |
< |
* aid debugging, as well as to support extensions. Its use in any |
915 |
< |
* other context is discouraged. |
911 |
> |
* Returns the result that would be returned by {@link #join}, even |
912 |
> |
* if this task completed abnormally, or {@code null} if this task |
913 |
> |
* is not known to have been completed. This method is designed |
914 |
> |
* to aid debugging, as well as to support extensions. Its use in |
915 |
> |
* any other context is discouraged. |
916 |
|
* |
917 |
< |
* @return the result, or null if not completed |
917 |
> |
* @return the result, or {@code null} if not completed |
918 |
|
*/ |
919 |
|
public abstract V getRawResult(); |
920 |
|
|
933 |
|
* called otherwise. The return value controls whether this task |
934 |
|
* is considered to be done normally. It may return false in |
935 |
|
* asynchronous actions that require explicit invocations of |
936 |
< |
* {@code complete} to become joinable. It may throw exceptions |
937 |
< |
* to indicate abnormal exit. |
936 |
> |
* {@link #complete} to become joinable. It may also throw an |
937 |
> |
* (unchecked) exception to indicate abnormal exit. |
938 |
|
* |
939 |
< |
* @return true if completed normally |
982 |
< |
* @throws Error or RuntimeException if encountered during computation |
939 |
> |
* @return {@code true} if completed normally |
940 |
|
*/ |
941 |
|
protected abstract boolean exec(); |
942 |
|
|
943 |
|
/** |
944 |
< |
* Returns, but does not unschedule or execute, the task queued by |
945 |
< |
* the current thread but not yet executed, if one is |
944 |
> |
* Returns, but does not unschedule or execute, a task queued by |
945 |
> |
* the current thread but not yet executed, if one is immediately |
946 |
|
* available. There is no guarantee that this task will actually |
947 |
< |
* be polled or executed next. This method is designed primarily |
948 |
< |
* to support extensions, and is unlikely to be useful otherwise. |
949 |
< |
* This method may be invoked only from within ForkJoinTask |
950 |
< |
* computations (as may be determined using method {@link |
951 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
995 |
< |
* in exceptions or errors, possibly including ClassCastException. |
947 |
> |
* be polled or executed next. Conversely, this method may return |
948 |
> |
* null even if a task exists but cannot be accessed without |
949 |
> |
* contention with other threads. This method is designed |
950 |
> |
* primarily to support extensions, and is unlikely to be useful |
951 |
> |
* otherwise. |
952 |
|
* |
953 |
< |
* @return the next task, or null if none are available |
953 |
> |
* <p>This method may be invoked only from within {@code |
954 |
> |
* ForkJoinTask} computations (as may be determined using method |
955 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
956 |
> |
* result in exceptions or errors, possibly including {@code |
957 |
> |
* ClassCastException}. |
958 |
> |
* |
959 |
> |
* @return the next task, or {@code null} if none are available |
960 |
|
*/ |
961 |
|
protected static ForkJoinTask<?> peekNextLocalTask() { |
962 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
967 |
|
* Unschedules and returns, without executing, the next task |
968 |
|
* queued by the current thread but not yet executed. This method |
969 |
|
* is designed primarily to support extensions, and is unlikely to |
970 |
< |
* be useful otherwise. This method may be invoked only from |
971 |
< |
* within ForkJoinTask computations (as may be determined using |
972 |
< |
* method {@link #inForkJoinPool}). Attempts to invoke in other |
973 |
< |
* contexts result in exceptions or errors, possibly including |
974 |
< |
* ClassCastException. |
970 |
> |
* be useful otherwise. |
971 |
> |
* |
972 |
> |
* <p>This method may be invoked only from within {@code |
973 |
> |
* ForkJoinTask} computations (as may be determined using method |
974 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
975 |
> |
* result in exceptions or errors, possibly including {@code |
976 |
> |
* ClassCastException}. |
977 |
|
* |
978 |
< |
* @return the next task, or null if none are available |
978 |
> |
* @return the next task, or {@code null} if none are available |
979 |
|
*/ |
980 |
|
protected static ForkJoinTask<?> pollNextLocalTask() { |
981 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
990 |
|
* {@code null} result does not necessarily imply quiescence |
991 |
|
* of the pool this task is operating in. This method is designed |
992 |
|
* primarily to support extensions, and is unlikely to be useful |
993 |
< |
* otherwise. This method may be invoked only from within |
1030 |
< |
* ForkJoinTask computations (as may be determined using method |
1031 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1032 |
< |
* result in exceptions or errors, possibly including |
1033 |
< |
* ClassCastException. |
993 |
> |
* otherwise. |
994 |
|
* |
995 |
< |
* @return a task, or null if none are available |
995 |
> |
* <p>This method may be invoked only from within {@code |
996 |
> |
* ForkJoinTask} computations (as may be determined using method |
997 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
998 |
> |
* result in exceptions or errors, possibly including {@code |
999 |
> |
* ClassCastException}. |
1000 |
> |
* |
1001 |
> |
* @return a task, or {@code null} if none are available |
1002 |
|
*/ |
1003 |
|
protected static ForkJoinTask<?> pollTask() { |
1004 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1005 |
|
.pollTask(); |
1006 |
|
} |
1007 |
|
|
1008 |
< |
// adaptors |
1008 |
> |
/** |
1009 |
> |
* Adaptor for Runnables. This implements RunnableFuture |
1010 |
> |
* to be compliant with AbstractExecutorService constraints |
1011 |
> |
* when used in ForkJoinPool. |
1012 |
> |
*/ |
1013 |
> |
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
1014 |
> |
implements RunnableFuture<T> { |
1015 |
> |
final Runnable runnable; |
1016 |
> |
final T resultOnCompletion; |
1017 |
> |
T result; |
1018 |
> |
AdaptedRunnable(Runnable runnable, T result) { |
1019 |
> |
if (runnable == null) throw new NullPointerException(); |
1020 |
> |
this.runnable = runnable; |
1021 |
> |
this.resultOnCompletion = result; |
1022 |
> |
} |
1023 |
> |
public T getRawResult() { return result; } |
1024 |
> |
public void setRawResult(T v) { result = v; } |
1025 |
> |
public boolean exec() { |
1026 |
> |
runnable.run(); |
1027 |
> |
result = resultOnCompletion; |
1028 |
> |
return true; |
1029 |
> |
} |
1030 |
> |
public void run() { invoke(); } |
1031 |
> |
private static final long serialVersionUID = 5232453952276885070L; |
1032 |
> |
} |
1033 |
|
|
1034 |
|
/** |
1035 |
< |
* Returns a new ForkJoinTask that performs the {@code run} |
1036 |
< |
* method of the given Runnable as its action, and returns a null |
1037 |
< |
* result upon {@code join}. |
1035 |
> |
* Adaptor for Callables |
1036 |
> |
*/ |
1037 |
> |
static final class AdaptedCallable<T> extends ForkJoinTask<T> |
1038 |
> |
implements RunnableFuture<T> { |
1039 |
> |
final Callable<? extends T> callable; |
1040 |
> |
T result; |
1041 |
> |
AdaptedCallable(Callable<? extends T> callable) { |
1042 |
> |
if (callable == null) throw new NullPointerException(); |
1043 |
> |
this.callable = callable; |
1044 |
> |
} |
1045 |
> |
public T getRawResult() { return result; } |
1046 |
> |
public void setRawResult(T v) { result = v; } |
1047 |
> |
public boolean exec() { |
1048 |
> |
try { |
1049 |
> |
result = callable.call(); |
1050 |
> |
return true; |
1051 |
> |
} catch (Error err) { |
1052 |
> |
throw err; |
1053 |
> |
} catch (RuntimeException rex) { |
1054 |
> |
throw rex; |
1055 |
> |
} catch (Exception ex) { |
1056 |
> |
throw new RuntimeException(ex); |
1057 |
> |
} |
1058 |
> |
} |
1059 |
> |
public void run() { invoke(); } |
1060 |
> |
private static final long serialVersionUID = 2838392045355241008L; |
1061 |
> |
} |
1062 |
> |
|
1063 |
> |
/** |
1064 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1065 |
> |
* method of the given {@code Runnable} as its action, and returns |
1066 |
> |
* a null result upon {@link #join}. |
1067 |
|
* |
1068 |
|
* @param runnable the runnable action |
1069 |
|
* @return the task |
1070 |
|
*/ |
1071 |
< |
public static ForkJoinTask<Void> adapt(Runnable runnable) { |
1072 |
< |
return new ForkJoinPool.AdaptedRunnable<Void>(runnable, null); |
1071 |
> |
public static ForkJoinTask<?> adapt(Runnable runnable) { |
1072 |
> |
return new AdaptedRunnable<Void>(runnable, null); |
1073 |
|
} |
1074 |
|
|
1075 |
|
/** |
1076 |
< |
* Returns a new ForkJoinTask that performs the {@code run} |
1077 |
< |
* method of the given Runnable as its action, and returns the |
1078 |
< |
* given result upon {@code join}. |
1076 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1077 |
> |
* method of the given {@code Runnable} as its action, and returns |
1078 |
> |
* the given result upon {@link #join}. |
1079 |
|
* |
1080 |
|
* @param runnable the runnable action |
1081 |
|
* @param result the result upon completion |
1082 |
|
* @return the task |
1083 |
|
*/ |
1084 |
|
public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) { |
1085 |
< |
return new ForkJoinPool.AdaptedRunnable<T>(runnable, result); |
1085 |
> |
return new AdaptedRunnable<T>(runnable, result); |
1086 |
|
} |
1087 |
|
|
1088 |
|
/** |
1089 |
< |
* Returns a new ForkJoinTask that performs the {@code call} |
1090 |
< |
* method of the given Callable as its action, and returns its |
1091 |
< |
* result upon {@code join}, translating any checked |
1092 |
< |
* exceptions encountered into {@code RuntimeException}. |
1089 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code call} |
1090 |
> |
* method of the given {@code Callable} as its action, and returns |
1091 |
> |
* its result upon {@link #join}, translating any checked exceptions |
1092 |
> |
* encountered into {@code RuntimeException}. |
1093 |
|
* |
1094 |
|
* @param callable the callable action |
1095 |
|
* @return the task |
1096 |
|
*/ |
1097 |
< |
public static <T> ForkJoinTask<T> adapt(Callable<T> callable) { |
1098 |
< |
return new ForkJoinPool.AdaptedCallable<T>(callable); |
1097 |
> |
public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) { |
1098 |
> |
return new AdaptedCallable<T>(callable); |
1099 |
|
} |
1100 |
|
|
1101 |
|
// Serialization support |
1103 |
|
private static final long serialVersionUID = -7721805057305804111L; |
1104 |
|
|
1105 |
|
/** |
1106 |
< |
* Save the state to a stream. |
1106 |
> |
* Saves the state to a stream (that is, serializes it). |
1107 |
|
* |
1108 |
|
* @serialData the current run status and the exception thrown |
1109 |
< |
* during execution, or null if none |
1109 |
> |
* during execution, or {@code null} if none |
1110 |
|
* @param s the stream |
1111 |
|
*/ |
1112 |
|
private void writeObject(java.io.ObjectOutputStream s) |
1116 |
|
} |
1117 |
|
|
1118 |
|
/** |
1119 |
< |
* Reconstitute the instance from a stream. |
1119 |
> |
* Reconstitutes the instance from a stream (that is, deserializes it). |
1120 |
|
* |
1121 |
|
* @param s the stream |
1122 |
|
*/ |
1123 |
|
private void readObject(java.io.ObjectInputStream s) |
1124 |
|
throws java.io.IOException, ClassNotFoundException { |
1125 |
|
s.defaultReadObject(); |
1107 |
– |
status &= ~INTERNAL_SIGNAL_MASK; // clear internal signal counts |
1108 |
– |
status |= EXTERNAL_SIGNAL; // conservatively set external signal |
1126 |
|
Object ex = s.readObject(); |
1127 |
|
if (ex != null) |
1128 |
< |
setDoneExceptionally((Throwable) ex); |
1128 |
> |
setExceptionalCompletion((Throwable) ex); |
1129 |
> |
} |
1130 |
> |
|
1131 |
> |
// Unsafe mechanics |
1132 |
> |
|
1133 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1134 |
> |
private static final long statusOffset = |
1135 |
> |
objectFieldOffset("status", ForkJoinTask.class); |
1136 |
> |
|
1137 |
> |
private static long objectFieldOffset(String field, Class<?> klazz) { |
1138 |
> |
try { |
1139 |
> |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
1140 |
> |
} catch (NoSuchFieldException e) { |
1141 |
> |
// Convert Exception to corresponding Error |
1142 |
> |
NoSuchFieldError error = new NoSuchFieldError(field); |
1143 |
> |
error.initCause(e); |
1144 |
> |
throw error; |
1145 |
> |
} |
1146 |
|
} |
1147 |
|
|
1148 |
< |
// Unsafe mechanics for jsr166y 3rd party package. |
1148 |
> |
/** |
1149 |
> |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
1150 |
> |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
1151 |
> |
* into a jdk. |
1152 |
> |
* |
1153 |
> |
* @return a sun.misc.Unsafe |
1154 |
> |
*/ |
1155 |
|
private static sun.misc.Unsafe getUnsafe() { |
1156 |
|
try { |
1157 |
|
return sun.misc.Unsafe.getUnsafe(); |
1158 |
|
} catch (SecurityException se) { |
1159 |
|
try { |
1160 |
|
return java.security.AccessController.doPrivileged |
1161 |
< |
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1161 |
> |
(new java.security |
1162 |
> |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1163 |
|
public sun.misc.Unsafe run() throws Exception { |
1164 |
< |
return getUnsafeByReflection(); |
1164 |
> |
java.lang.reflect.Field f = sun.misc |
1165 |
> |
.Unsafe.class.getDeclaredField("theUnsafe"); |
1166 |
> |
f.setAccessible(true); |
1167 |
> |
return (sun.misc.Unsafe) f.get(null); |
1168 |
|
}}); |
1169 |
|
} catch (java.security.PrivilegedActionException e) { |
1170 |
|
throw new RuntimeException("Could not initialize intrinsics", |
1172 |
|
} |
1173 |
|
} |
1174 |
|
} |
1131 |
– |
|
1132 |
– |
private static sun.misc.Unsafe getUnsafeByReflection() |
1133 |
– |
throws NoSuchFieldException, IllegalAccessException { |
1134 |
– |
java.lang.reflect.Field f = |
1135 |
– |
sun.misc.Unsafe.class.getDeclaredField("theUnsafe"); |
1136 |
– |
f.setAccessible(true); |
1137 |
– |
return (sun.misc.Unsafe) f.get(null); |
1138 |
– |
} |
1139 |
– |
|
1140 |
– |
private static long fieldOffset(String fieldName, Class<?> klazz) { |
1141 |
– |
try { |
1142 |
– |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName)); |
1143 |
– |
} catch (NoSuchFieldException e) { |
1144 |
– |
// Convert Exception to Error |
1145 |
– |
NoSuchFieldError error = new NoSuchFieldError(fieldName); |
1146 |
– |
error.initCause(e); |
1147 |
– |
throw error; |
1148 |
– |
} |
1149 |
– |
} |
1150 |
– |
|
1151 |
– |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1152 |
– |
private static final long statusOffset = |
1153 |
– |
fieldOffset("status", ForkJoinTask.class); |
1154 |
– |
|
1175 |
|
} |