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*/ |
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package jsr166y; |
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import java.io.Serializable; |
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import java.util.*; |
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|
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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import sun.misc.Unsafe; |
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import java.lang.reflect.*; |
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|
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import java.io.Serializable; |
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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</code> |
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* and <code>join</code>, or derivatives such as |
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* <code>invokeAll</code>. 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</code> |
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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</code> |
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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) |
39 |
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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</code> |
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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()</code> 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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* waits for completion and report results using {@code Future} |
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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</code> (available in multiple versions) |
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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, |
95 |
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* established in a constructor, and then defines a <code>compute</code> |
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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</code> access (to allow |
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* instances of different task subclasses to call each others |
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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 other's |
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* methods), some of them may only be called from within other |
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* ForkJoinTasks. Attempts to invoke them in other contexts result in |
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* exceptions or errors possibly including ClassCastException. |
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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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* {@code ClassCastException}. |
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* |
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* <p>Most base support methods are <code>final</code> 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</code> methods |
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* <code>exec</code>, <code>setRawResult</code>, and |
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* <code>getRawResult</code>, 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</code> 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, othewise 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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* parellelism 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>ForkJoinTasks are <code>Serializable</code>, 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>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 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 |
140 |
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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 |
142 |
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* completed, upon which status holds COMPLETED. CANCELLED, or |
143 |
< |
* EXCEPTIONAL, which use the top 3 bits. Tasks undergoing |
144 |
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* blocking waits by other threads have SIGNAL_MASK bits set -- |
145 |
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* bit 15 for external (nonFJ) waits, and the rest a count of |
146 |
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* waiting FJ threads. (This representation relies on |
147 |
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* ForkJoinPool max thread limits). Completion of a stolen task |
148 |
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* with SIGNAL_MASK bits set awakens waiter via notifyAll. Even |
149 |
< |
* though suboptimal for some purposes, we use basic builtin |
150 |
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* wait/notify to take advantage of "monitor inflation" in JVMs |
151 |
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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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volatile int status; // accessed directy 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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> |
/* |
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* See the internal documentation of class ForkJoinPool for a |
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* general implementation overview. ForkJoinTasks are mainly |
141 |
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* responsible for maintaining their "status" field amidst relays |
142 |
> |
* to methods in ForkJoinWorkerThread and ForkJoinPool. The |
143 |
> |
* methods of this class are more-or-less layered into (1) basic |
144 |
> |
* status maintenance (2) execution and awaiting completion (3) |
145 |
> |
* user-level methods that additionally report results. This is |
146 |
> |
* sometimes hard to see because this file orders exported methods |
147 |
> |
* in a way that flows well in javadocs. In particular, most |
148 |
> |
* join mechanics are in method quietlyJoin, below. |
149 |
> |
*/ |
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|
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> |
/* |
152 |
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* The status field holds run control status bits packed into a |
153 |
> |
* single int to minimize footprint and to ensure atomicity (via |
154 |
> |
* CAS). Status is initially zero, and takes on nonnegative |
155 |
> |
* values until completed, upon which status holds value |
156 |
> |
* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking |
157 |
> |
* waits by other threads have the SIGNAL bit set. Completion of |
158 |
> |
* a stolen task with SIGNAL set awakens any waiters via |
159 |
> |
* notifyAll. Even though suboptimal for some purposes, we use |
160 |
> |
* basic builtin wait/notify to take advantage of "monitor |
161 |
> |
* inflation" in JVMs that we would otherwise need to emulate to |
162 |
> |
* avoid adding further per-task bookkeeping overhead. We want |
163 |
> |
* these monitors to be "fat", i.e., not use biasing or thin-lock |
164 |
> |
* techniques, so use some odd coding idioms that tend to avoid |
165 |
> |
* them. |
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*/ |
167 |
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|
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/** The run status of this task */ |
169 |
> |
volatile int status; // accessed directly by pool and workers |
170 |
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|
171 |
> |
private static final int NORMAL = -1; |
172 |
> |
private static final int CANCELLED = -2; |
173 |
> |
private static final int EXCEPTIONAL = -3; |
174 |
> |
private static final int SIGNAL = 1; |
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|
176 |
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/** |
177 |
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* Table of exceptions thrown by tasks, to enable reporting by |
178 |
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* callers. Because exceptions are rare, we don't directly keep |
179 |
< |
* them with task objects, but instead us a weak ref table. Note |
179 |
> |
* them with task objects, but instead use a weak ref table. Note |
180 |
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* that cancellation exceptions don't appear in the table, but are |
181 |
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* instead recorded as status values. |
182 |
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* Todo: Use ConcurrentReferenceHashMap |
182 |
> |
* TODO: Use ConcurrentReferenceHashMap |
183 |
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*/ |
184 |
|
static final Map<ForkJoinTask<?>, Throwable> exceptionMap = |
185 |
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Collections.synchronizedMap |
186 |
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(new WeakHashMap<ForkJoinTask<?>, Throwable>()); |
187 |
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|
188 |
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// within-package utilities |
154 |
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|
155 |
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/** |
156 |
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* Get current worker thread, or null if not a worker thread |
157 |
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*/ |
158 |
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static ForkJoinWorkerThread getWorker() { |
159 |
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Thread t = Thread.currentThread(); |
160 |
< |
return ((t instanceof ForkJoinWorkerThread)? |
161 |
< |
(ForkJoinWorkerThread)t : null); |
162 |
< |
} |
163 |
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|
164 |
< |
final boolean casStatus(int cmp, int val) { |
165 |
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return _unsafe.compareAndSwapInt(this, statusOffset, cmp, val); |
166 |
< |
} |
167 |
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|
168 |
< |
/** |
169 |
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* Workaround for not being able to rethrow unchecked exceptions. |
170 |
< |
*/ |
171 |
< |
static void rethrowException(Throwable ex) { |
172 |
< |
if (ex != null) |
173 |
< |
_unsafe.throwException(ex); |
174 |
< |
} |
175 |
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|
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// Setting completion status |
188 |
> |
// Maintaining completion status |
189 |
|
|
190 |
|
/** |
191 |
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* Mark completion and wake up threads waiting to join this task. |
191 |
> |
* Marks completion and wakes up threads waiting to join this task, |
192 |
> |
* also clearing signal request bits. |
193 |
> |
* |
194 |
|
* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL |
195 |
|
*/ |
196 |
< |
final void setCompletion(int completion) { |
197 |
< |
ForkJoinPool pool = getPool(); |
198 |
< |
if (pool != null) { |
199 |
< |
int s; // Clear signal bits while setting completion status |
200 |
< |
do;while ((s = status) >= 0 && !casStatus(s, completion)); |
201 |
< |
|
202 |
< |
if ((s & SIGNAL_MASK) != 0) { |
189 |
< |
if ((s &= INTERNAL_SIGNAL_MASK) != 0) |
190 |
< |
pool.updateRunningCount(s); |
191 |
< |
synchronized(this) { notifyAll(); } |
196 |
> |
private void setCompletion(int completion) { |
197 |
> |
int s; |
198 |
> |
while ((s = status) >= 0) { |
199 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, completion)) { |
200 |
> |
if (s != 0) |
201 |
> |
synchronized (this) { notifyAll(); } |
202 |
> |
break; |
203 |
|
} |
204 |
|
} |
194 |
– |
else |
195 |
– |
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 |
< |
*/ |
202 |
< |
private void externallySetCompletion(int completion) { |
203 |
< |
int s; |
204 |
< |
do;while ((s = status) >= 0 && |
205 |
< |
!casStatus(s, (s & SIGNAL_MASK) | completion)); |
206 |
< |
synchronized(this) { notifyAll(); } |
207 |
< |
} |
208 |
< |
|
209 |
< |
/** |
210 |
< |
* Sets status to indicate normal completion |
211 |
< |
*/ |
212 |
< |
final void setNormalCompletion() { |
213 |
< |
// Try typical fast case -- single CAS, no signal, not already done. |
214 |
< |
// Manually expand casStatus to improve chances of inlining it |
215 |
< |
if (!_unsafe.compareAndSwapInt(this, statusOffset, 0, NORMAL)) |
216 |
< |
setCompletion(NORMAL); |
217 |
< |
} |
218 |
< |
|
219 |
< |
// internal waiting and notification |
220 |
< |
|
221 |
< |
/** |
222 |
< |
* Performs the actual monitor wait for awaitDone |
208 |
> |
* Records exception and sets exceptional completion. |
209 |
> |
* |
210 |
> |
* @return status on exit |
211 |
|
*/ |
212 |
< |
private void doAwaitDone() { |
213 |
< |
// Minimize lock bias and in/de-flation effects by maximizing |
214 |
< |
// chances of waiting inside sync |
227 |
< |
try { |
228 |
< |
while (status >= 0) |
229 |
< |
synchronized(this) { if (status >= 0) wait(); } |
230 |
< |
} catch (InterruptedException ie) { |
231 |
< |
onInterruptedWait(); |
232 |
< |
} |
212 |
> |
private void setExceptionalCompletion(Throwable rex) { |
213 |
> |
exceptionMap.put(this, rex); |
214 |
> |
setCompletion(EXCEPTIONAL); |
215 |
|
} |
216 |
|
|
217 |
|
/** |
218 |
< |
* Performs the actual 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 { |
226 |
< |
while (status >= 0) { |
227 |
< |
long nt = nanos - System.nanoTime() - startTime; |
228 |
< |
if (nt <= 0) |
244 |
< |
break; |
245 |
< |
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(); |
231 |
> |
cancelIfTerminating(); |
232 |
|
} |
233 |
|
} |
234 |
|
} |
235 |
|
|
253 |
– |
// Awaiting completion |
254 |
– |
|
236 |
|
/** |
237 |
< |
* Sets status to indicate there is joiner, then waits for join, |
238 |
< |
* surrounded with pool notifications. |
239 |
< |
* @return status upon exit |
240 |
< |
*/ |
260 |
< |
private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) { |
261 |
< |
ForkJoinPool pool = w == null? null : w.pool; |
262 |
< |
int s; |
263 |
< |
while ((s = status) >= 0) { |
264 |
< |
if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) { |
265 |
< |
if (pool == null || !pool.preJoin(this, maintainParallelism)) |
266 |
< |
doAwaitDone(); |
267 |
< |
if (((s = status) & INTERNAL_SIGNAL_MASK) != 0) |
268 |
< |
adjustPoolCountsOnUnblock(pool); |
269 |
< |
break; |
270 |
< |
} |
271 |
< |
} |
272 |
< |
return s; |
273 |
< |
} |
274 |
< |
|
275 |
< |
/** |
276 |
< |
* Timed version of awaitDone |
277 |
< |
* @return status upon exit |
237 |
> |
* Blocks a worker thread until completed or timed out. Called |
238 |
> |
* only by pool. |
239 |
> |
* |
240 |
> |
* @return status on exit |
241 |
|
*/ |
242 |
< |
private int awaitDone(ForkJoinWorkerThread w, long nanos) { |
280 |
< |
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); |
287 |
< |
if ((s = status) >= 0) { |
288 |
< |
adjustPoolCountsOnCancelledWait(pool); |
289 |
< |
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); |
293 |
< |
break; |
250 |
> |
} catch (InterruptedException ie) { |
251 |
> |
cancelIfTerminating(); |
252 |
|
} |
253 |
+ |
s = status; |
254 |
|
} |
255 |
|
return s; |
256 |
|
} |
257 |
|
|
258 |
|
/** |
259 |
< |
* Notify pool that thread is unblocked. Called by signalled |
301 |
< |
* 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 |
< |
* Notify 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)) { |
318 |
< |
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 |
< |
* Handle interruptions during waits. |
284 |
< |
*/ |
285 |
< |
private void onInterruptedWait() { |
329 |
< |
ForkJoinWorkerThread w = getWorker(); |
330 |
< |
if (w == null) |
331 |
< |
Thread.currentThread().interrupt(); // re-interrupt |
332 |
< |
else if (w.isTerminating()) |
333 |
< |
cancelIgnoringExceptions(); |
334 |
< |
// else if FJworker, ignore interrupt |
335 |
< |
} |
336 |
< |
|
337 |
< |
// Recording and reporting exceptions |
338 |
< |
|
339 |
< |
private void setDoneExceptionally(Throwable rex) { |
340 |
< |
exceptionMap.put(this, rex); |
341 |
< |
setCompletion(EXCEPTIONAL); |
342 |
< |
} |
343 |
< |
|
344 |
< |
/** |
345 |
< |
* Throws the exception associated with status s; |
346 |
< |
* @throws the exception |
347 |
< |
*/ |
348 |
< |
private void reportException(int s) { |
349 |
< |
if ((s &= COMPLETION_MASK) < NORMAL) { |
350 |
< |
if (s == CANCELLED) |
351 |
< |
throw new CancellationException(); |
352 |
< |
else |
353 |
< |
rethrowException(exceptionMap.get(this)); |
354 |
< |
} |
355 |
< |
} |
356 |
< |
|
357 |
< |
/** |
358 |
< |
* Returns result or throws exception using j.u.c.Future conventions |
359 |
< |
* Only call when isDone known to be true. |
360 |
< |
*/ |
361 |
< |
private V reportFutureResult() |
362 |
< |
throws ExecutionException, InterruptedException { |
363 |
< |
int s = status & COMPLETION_MASK; |
364 |
< |
if (s < NORMAL) { |
365 |
< |
Throwable ex; |
366 |
< |
if (s == CANCELLED) |
367 |
< |
throw new CancellationException(); |
368 |
< |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
369 |
< |
throw new ExecutionException(ex); |
370 |
< |
if (Thread.interrupted()) |
371 |
< |
throw new InterruptedException(); |
372 |
< |
} |
373 |
< |
return getRawResult(); |
374 |
< |
} |
375 |
< |
|
376 |
< |
/** |
377 |
< |
* Returns result or throws exception using j.u.c.Future conventions |
378 |
< |
* with timeouts |
379 |
< |
*/ |
380 |
< |
private V reportTimedFutureResult() |
381 |
< |
throws InterruptedException, ExecutionException, TimeoutException { |
382 |
< |
Throwable ex; |
383 |
< |
int s = status & COMPLETION_MASK; |
384 |
< |
if (s == NORMAL) |
385 |
< |
return getRawResult(); |
386 |
< |
if (s == CANCELLED) |
387 |
< |
throw new CancellationException(); |
388 |
< |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
389 |
< |
throw new ExecutionException(ex); |
390 |
< |
if (Thread.interrupted()) |
391 |
< |
throw new InterruptedException(); |
392 |
< |
throw new TimeoutException(); |
393 |
< |
} |
394 |
< |
|
395 |
< |
// internal execution methods |
396 |
< |
|
397 |
< |
/** |
398 |
< |
* Calls exec, recording completion, and rethrowing exception if |
399 |
< |
* encountered. Caller should normally check status before calling |
400 |
< |
* @return true if completed normally |
401 |
< |
*/ |
402 |
< |
private boolean tryExec() { |
403 |
< |
try { // try block must contain only call to exec |
404 |
< |
if (!exec()) |
405 |
< |
return false; |
406 |
< |
} catch (Throwable rex) { |
407 |
< |
setDoneExceptionally(rex); |
408 |
< |
rethrowException(rex); |
409 |
< |
return false; // not reached |
410 |
< |
} |
411 |
< |
setNormalCompletion(); |
412 |
< |
return true; |
413 |
< |
} |
414 |
< |
|
415 |
< |
/** |
416 |
< |
* Main execution method used by worker threads. Invokes |
417 |
< |
* 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() { |
420 |
– |
if (status >= 0) { |
421 |
– |
try { |
422 |
– |
if (!exec()) |
423 |
– |
return; |
424 |
– |
} catch(Throwable rex) { |
425 |
– |
setDoneExceptionally(rex); |
426 |
– |
return; |
427 |
– |
} |
428 |
– |
setNormalCompletion(); |
429 |
– |
} |
430 |
– |
} |
431 |
– |
|
432 |
– |
/** |
433 |
– |
* Calls exec, recording but not rethrowing exception |
434 |
– |
* Caller should normally check status before calling |
435 |
– |
* @return true if completed normally |
436 |
– |
*/ |
437 |
– |
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; |
444 |
< |
} |
445 |
< |
setNormalCompletion(); |
446 |
< |
return true; |
447 |
< |
} |
448 |
< |
|
449 |
< |
/** |
450 |
< |
* Cancel, ignoring any exceptions it throws |
451 |
< |
*/ |
452 |
< |
final void cancelIgnoringExceptions() { |
453 |
< |
try { |
454 |
< |
cancel(false); |
455 |
< |
} catch(Throwable ignore) { |
292 |
> |
setExceptionalCompletion(rex); |
293 |
> |
return; |
294 |
|
} |
295 |
< |
} |
458 |
< |
|
459 |
< |
/** |
460 |
< |
* Main implementation of helpJoin |
461 |
< |
*/ |
462 |
< |
private int busyJoin(ForkJoinWorkerThread w) { |
463 |
< |
int s; |
464 |
< |
ForkJoinTask<?> t; |
465 |
< |
while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null) |
466 |
< |
t.quietlyExec(); |
467 |
< |
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. Attempts to invoke in other contexts result in |
306 |
< |
* 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 |
317 |
|
*/ |
318 |
< |
public final void fork() { |
319 |
< |
((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this); |
318 |
> |
public final ForkJoinTask<V> fork() { |
319 |
> |
((ForkJoinWorkerThread) Thread.currentThread()) |
320 |
> |
.pushTask(this); |
321 |
> |
return this; |
322 |
|
} |
323 |
|
|
324 |
|
/** |
325 |
< |
* Returns the result of the computation when it is ready. |
326 |
< |
* This method differs from <code>get</code> 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. |
343 |
< |
* @throws Throwable (a RuntimeException, Error, or unchecked |
344 |
< |
* exception) if the underlying computation did so. |
342 |
> |
* necessary, and returns its result, or throws an (unchecked) |
343 |
> |
* {@code RuntimeException} or {@code Error} if the underlying |
344 |
> |
* computation did so. |
345 |
> |
* |
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</code> holds for |
358 |
< |
* both of them or an exception is encountered. This method may be |
359 |
< |
* invoked only from within ForkJoinTask computations. Attempts to |
360 |
< |
* invoke in other contexts result in exceptions or errors |
361 |
< |
* possibly including ClassCastException. |
362 |
< |
* @param t1 one task |
363 |
< |
* @param t2 the other task |
364 |
< |
* @throws NullPointerException if t1 or t2 are null |
365 |
< |
* @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</code> 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. Attempts to invoke in other contexts |
390 |
< |
* result in exceptions or errors possibly including ClassCastException. |
391 |
< |
* @param tasks the array of tasks |
392 |
< |
* @throws NullPointerException if tasks or any element are null. |
393 |
< |
* @throws RuntimeException or Error if any task did so. |
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 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</code> 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 |
444 |
< |
* computations. Attempts to invoke in other contexts resul!t in |
445 |
< |
* 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 |
< |
* @throws NullPointerException if tasks or any element are null. |
460 |
< |
* @throws RuntimeException or Error if any task did so. |
459 |
> |
* @return the tasks argument, to simplify usage |
460 |
> |
* @throws NullPointerException if tasks or any element are null |
461 |
|
*/ |
462 |
< |
public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) { |
463 |
< |
if (!(tasks instanceof List)) { |
464 |
< |
invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()])); |
465 |
< |
return; |
462 |
> |
public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) { |
463 |
> |
if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) { |
464 |
> |
invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()])); |
465 |
> |
return tasks; |
466 |
|
} |
467 |
+ |
@SuppressWarnings("unchecked") |
468 |
|
List<? extends ForkJoinTask<?>> ts = |
469 |
< |
(List<? extends ForkJoinTask<?>>)tasks; |
469 |
> |
(List<? extends ForkJoinTask<?>>) tasks; |
470 |
|
Throwable ex = null; |
471 |
|
int last = ts.size() - 1; |
472 |
|
for (int i = last; i >= 0; --i) { |
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); |
500 |
< |
} |
622 |
< |
|
623 |
< |
/** |
624 |
< |
* Returns true if the computation performed by this task has |
625 |
< |
* completed (or has been cancelled). |
626 |
< |
* @return true if this computation has completed |
627 |
< |
*/ |
628 |
< |
public final boolean isDone() { |
629 |
< |
return status < 0; |
630 |
< |
} |
631 |
< |
|
632 |
< |
/** |
633 |
< |
* Returns true if this task was cancelled. |
634 |
< |
* @return true if this task was cancelled |
635 |
< |
*/ |
636 |
< |
public final boolean isCancelled() { |
637 |
< |
return (status & COMPLETION_MASK) == CANCELLED; |
499 |
> |
UNSAFE.throwException(ex); |
500 |
> |
return tasks; |
501 |
|
} |
502 |
|
|
503 |
|
/** |
504 |
< |
* Asserts that the results of this task's computation will not be |
505 |
< |
* used. If a cancellation occurs before atempting to execute this |
506 |
< |
* task, then execution will be suppressed, <code>isCancelled</code> |
507 |
< |
* will report true, and <code>join</code> will result in a |
508 |
< |
* <code>CancellationException</code> being thrown. Otherwise, when |
509 |
< |
* cancellation races with completion, there are no guarantees |
510 |
< |
* about whether <code>isCancelled</code> will report true, whether |
648 |
< |
* <code>join</code> will return normally or via an exception, or |
649 |
< |
* whether these behaviors will remain consistent upon repeated |
650 |
< |
* 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</code>. |
519 |
> |
* invoke {@link #completeExceptionally}. |
520 |
|
* |
521 |
|
* @param mayInterruptIfRunning this value is ignored in the |
522 |
< |
* default implementation because tasks are not in general |
523 |
< |
* cancelled via interruption. |
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 |
> |
* 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 true if this task threw an exception or was cancelled |
570 |
< |
* @return true if this task threw an exception or was cancelled |
569 |
> |
* Returns {@code true} if this task threw an exception or was cancelled. |
570 |
> |
* |
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. |
592 |
< |
* @return the exception, or null if none |
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 {@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) |
691 |
< |
return new CancellationException(); |
692 |
< |
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 |
|
/** |
603 |
|
* Completes this task abnormally, and if not already aborted or |
604 |
|
* cancelled, causes it to throw the given exception upon |
605 |
< |
* <code>join</code> and related operations. This method may be used |
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 |
609 |
< |
* overridable, but overridden versions must invoke <code>super</code> |
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 |
|
/** |
623 |
|
* Completes this task, and if not already aborted or cancelled, |
624 |
< |
* returning a <code>null</code> result upon <code>join</code> and related |
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 |
629 |
< |
* overridable, but overridden versions must invoke <code>super</code> |
630 |
< |
* implementation to maintain guarantees. |
624 |
> |
* returning the given value as the result of subsequent |
625 |
> |
* invocations of {@code join} and related operations. This method |
626 |
> |
* may be used to provide results for asynchronous tasks, or to |
627 |
> |
* provide alternative handling for tasks that would not otherwise |
628 |
> |
* complete normally. Its use in other situations is |
629 |
> |
* discouraged. This method is overridable, but overridden |
630 |
> |
* versions must invoke {@code super} implementation to maintain |
631 |
> |
* guarantees. |
632 |
|
* |
633 |
< |
* @param value the result value for this task. |
633 |
> |
* @param value the result value for this task |
634 |
|
*/ |
635 |
|
public void complete(V value) { |
636 |
|
try { |
637 |
|
setRawResult(value); |
638 |
< |
} catch(Throwable rex) { |
639 |
< |
setDoneExceptionally(rex); |
638 |
> |
} catch (Throwable rex) { |
639 |
> |
setExceptionalCompletion(rex); |
640 |
|
return; |
641 |
|
} |
642 |
< |
setNormalCompletion(); |
642 |
> |
setCompletion(NORMAL); |
643 |
|
} |
644 |
|
|
645 |
|
public final V get() throws InterruptedException, ExecutionException { |
646 |
< |
ForkJoinWorkerThread w = getWorker(); |
647 |
< |
if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke()) |
648 |
< |
awaitDone(w, true); |
649 |
< |
return reportFutureResult(); |
646 |
> |
quietlyJoin(); |
647 |
> |
if (Thread.interrupted()) |
648 |
> |
throw new InterruptedException(); |
649 |
> |
int s = status; |
650 |
> |
if (s < NORMAL) { |
651 |
> |
Throwable ex; |
652 |
> |
if (s == CANCELLED) |
653 |
> |
throw new CancellationException(); |
654 |
> |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
655 |
> |
throw new ExecutionException(ex); |
656 |
> |
} |
657 |
> |
return getRawResult(); |
658 |
|
} |
659 |
|
|
660 |
|
public final V get(long timeout, TimeUnit unit) |
661 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
662 |
< |
ForkJoinWorkerThread w = getWorker(); |
663 |
< |
if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke()) |
664 |
< |
awaitDone(w, unit.toNanos(timeout)); |
665 |
< |
return reportTimedFutureResult(); |
666 |
< |
} |
667 |
< |
|
668 |
< |
/** |
669 |
< |
* Possibly executes other tasks until this task is ready, then |
670 |
< |
* returns the result of the computation. This method may be more |
671 |
< |
* efficient than <code>join</code>, but is only applicable when |
672 |
< |
* there are no potemtial dependencies between continuation of the |
673 |
< |
* current task and that of any other task that might be executed |
674 |
< |
* while helping. (This usually holds for pure divide-and-conquer |
675 |
< |
* tasks). This method may be invoked only from within |
676 |
< |
* ForkJoinTask computations. Attempts to invoke in other contexts |
677 |
< |
* resul!t in exceptions or errors possibly including ClassCastException. |
678 |
< |
* @return the computed result |
679 |
< |
*/ |
680 |
< |
public final V helpJoin() { |
681 |
< |
ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread()); |
682 |
< |
if (status < 0 || !w.unpushTask(this) || !tryExec()) |
683 |
< |
reportException(busyJoin(w)); |
684 |
< |
return getRawResult(); |
685 |
< |
} |
686 |
< |
|
687 |
< |
/** |
688 |
< |
* Possibly executes other tasks until this task is ready. This |
689 |
< |
* method may be invoked only from within ForkJoinTask |
690 |
< |
* computations. Attempts to invoke in other contexts resul!t in |
691 |
< |
* exceptions or errors possibly including ClassCastException. |
692 |
< |
*/ |
693 |
< |
public final void quietlyHelpJoin() { |
694 |
< |
if (status >= 0) { |
695 |
< |
ForkJoinWorkerThread w = |
696 |
< |
(ForkJoinWorkerThread)(Thread.currentThread()); |
697 |
< |
if (!w.unpushTask(this) || !tryQuietlyInvoke()) |
698 |
< |
busyJoin(w); |
662 |
> |
Thread t = Thread.currentThread(); |
663 |
> |
ForkJoinPool pool; |
664 |
> |
if (t instanceof ForkJoinWorkerThread) { |
665 |
> |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; |
666 |
> |
if (status >= 0 && w.unpushTask(this)) |
667 |
> |
quietlyExec(); |
668 |
> |
pool = w.pool; |
669 |
> |
} |
670 |
> |
else |
671 |
> |
pool = null; |
672 |
> |
/* |
673 |
> |
* Timed wait loop intermixes cases for FJ (pool != null) and |
674 |
> |
* non FJ threads. For FJ, decrement pool count but don't try |
675 |
> |
* for replacement; increment count on completion. For non-FJ, |
676 |
> |
* deal with interrupts. This is messy, but a little less so |
677 |
> |
* than is splitting the FJ and nonFJ cases. |
678 |
> |
*/ |
679 |
> |
boolean interrupted = false; |
680 |
> |
boolean dec = false; // true if pool count decremented |
681 |
> |
long nanos = unit.toNanos(timeout); |
682 |
> |
for (;;) { |
683 |
> |
if (pool == null && Thread.interrupted()) { |
684 |
> |
interrupted = true; |
685 |
> |
break; |
686 |
> |
} |
687 |
> |
int s = status; |
688 |
> |
if (s < 0) |
689 |
> |
break; |
690 |
> |
if (UNSAFE.compareAndSwapInt(this, statusOffset, s, SIGNAL)) { |
691 |
> |
long startTime = System.nanoTime(); |
692 |
> |
long nt; // wait time |
693 |
> |
while (status >= 0 && |
694 |
> |
(nt = nanos - (System.nanoTime() - startTime)) > 0) { |
695 |
> |
if (pool != null && !dec) |
696 |
> |
dec = pool.tryDecrementRunningCount(); |
697 |
> |
else { |
698 |
> |
long ms = nt / 1000000; |
699 |
> |
int ns = (int) (nt % 1000000); |
700 |
> |
try { |
701 |
> |
synchronized(this) { |
702 |
> |
if (status >= 0) |
703 |
> |
wait(ms, ns); |
704 |
> |
} |
705 |
> |
} catch (InterruptedException ie) { |
706 |
> |
if (pool != null) |
707 |
> |
cancelIfTerminating(); |
708 |
> |
else { |
709 |
> |
interrupted = true; |
710 |
> |
break; |
711 |
> |
} |
712 |
> |
} |
713 |
> |
} |
714 |
> |
} |
715 |
> |
break; |
716 |
> |
} |
717 |
|
} |
718 |
+ |
if (pool != null && dec) |
719 |
+ |
pool.incrementRunningCount(); |
720 |
+ |
if (interrupted) |
721 |
+ |
throw new InterruptedException(); |
722 |
+ |
int es = status; |
723 |
+ |
if (es != NORMAL) { |
724 |
+ |
Throwable ex; |
725 |
+ |
if (es == CANCELLED) |
726 |
+ |
throw new CancellationException(); |
727 |
+ |
if (es == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
728 |
+ |
throw new ExecutionException(ex); |
729 |
+ |
throw new TimeoutException(); |
730 |
+ |
} |
731 |
+ |
return getRawResult(); |
732 |
|
} |
733 |
|
|
734 |
|
/** |
735 |
< |
* Joins this task, without returning its result or throwing an |
735 |
> |
* Joins this task, without returning its result or throwing its |
736 |
|
* exception. This method may be useful when processing |
737 |
|
* collections of tasks when some have been cancelled or otherwise |
738 |
|
* known to have aborted. |
739 |
|
*/ |
740 |
|
public final void quietlyJoin() { |
741 |
< |
if (status >= 0) { |
742 |
< |
ForkJoinWorkerThread w = getWorker(); |
743 |
< |
if (w == null || !w.unpushTask(this) || !tryQuietlyInvoke()) |
744 |
< |
awaitDone(w, true); |
741 |
> |
Thread t; |
742 |
> |
if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread) { |
743 |
> |
ForkJoinWorkerThread w = (ForkJoinWorkerThread) t; |
744 |
> |
if (status >= 0) { |
745 |
> |
if (w.unpushTask(this)) { |
746 |
> |
boolean completed; |
747 |
> |
try { |
748 |
> |
completed = exec(); |
749 |
> |
} catch (Throwable rex) { |
750 |
> |
setExceptionalCompletion(rex); |
751 |
> |
return; |
752 |
> |
} |
753 |
> |
if (completed) { |
754 |
> |
setCompletion(NORMAL); |
755 |
> |
return; |
756 |
> |
} |
757 |
> |
} |
758 |
> |
w.joinTask(this); |
759 |
> |
} |
760 |
|
} |
761 |
+ |
else |
762 |
+ |
externalAwaitDone(); |
763 |
|
} |
764 |
|
|
765 |
|
/** |
766 |
|
* Commences performing this task and awaits its completion if |
767 |
< |
* necessary, without returning its result or throwing an |
768 |
< |
* exception. This method may be useful when processing |
804 |
< |
* collections of tasks when some have been cancelled or otherwise |
805 |
< |
* known to have aborted. |
767 |
> |
* necessary, without returning its result or throwing its |
768 |
> |
* exception. |
769 |
|
*/ |
770 |
|
public final void quietlyInvoke() { |
771 |
< |
if (status >= 0 && !tryQuietlyInvoke()) |
772 |
< |
quietlyJoin(); |
771 |
> |
if (status >= 0) { |
772 |
> |
boolean completed; |
773 |
> |
try { |
774 |
> |
completed = exec(); |
775 |
> |
} catch (Throwable rex) { |
776 |
> |
setExceptionalCompletion(rex); |
777 |
> |
return; |
778 |
> |
} |
779 |
> |
if (completed) |
780 |
> |
setCompletion(NORMAL); |
781 |
> |
else |
782 |
> |
quietlyJoin(); |
783 |
> |
} |
784 |
|
} |
785 |
|
|
786 |
|
/** |
787 |
|
* Possibly executes tasks until the pool hosting the current task |
788 |
< |
* {@link ForkJoinPool#isQuiescent}. This method may be of use in |
789 |
< |
* designs in which many tasks are forked, but none are explicitly |
790 |
< |
* joined, instead executing them until all are processed. |
788 |
> |
* {@link ForkJoinPool#isQuiescent is quiescent}. This method may |
789 |
> |
* be of use in designs in which many tasks are forked, but none |
790 |
> |
* are explicitly joined, instead executing them until all are |
791 |
> |
* processed. |
792 |
> |
* |
793 |
> |
* <p>This method may be invoked only from within {@code |
794 |
> |
* ForkJoinTask} computations (as may be determined using method |
795 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
796 |
> |
* result in exceptions or errors, possibly including {@code |
797 |
> |
* ClassCastException}. |
798 |
|
*/ |
799 |
|
public static void helpQuiesce() { |
800 |
< |
((ForkJoinWorkerThread)(Thread.currentThread())). |
801 |
< |
helpQuiescePool(); |
800 |
> |
((ForkJoinWorkerThread) Thread.currentThread()) |
801 |
> |
.helpQuiescePool(); |
802 |
|
} |
803 |
|
|
804 |
|
/** |
805 |
|
* Resets the internal bookkeeping state of this task, allowing a |
806 |
< |
* subsequent <code>fork</code>. This method allows repeated reuse of |
806 |
> |
* subsequent {@code fork}. This method allows repeated reuse of |
807 |
|
* this task, but only if reuse occurs when this task has either |
808 |
|
* never been forked, or has been forked, then completed and all |
809 |
|
* outstanding joins of this task have also completed. Effects |
810 |
< |
* under any other usage conditions are not guaranteed, and are |
811 |
< |
* almost surely wrong. This method may be useful when executing |
810 |
> |
* under any other usage conditions are not guaranteed. |
811 |
> |
* This method may be useful when executing |
812 |
|
* pre-constructed trees of subtasks in loops. |
813 |
|
*/ |
814 |
|
public void reinitialize() { |
815 |
< |
if ((status & COMPLETION_MASK) == EXCEPTIONAL) |
815 |
> |
if (status == EXCEPTIONAL) |
816 |
|
exceptionMap.remove(this); |
817 |
|
status = 0; |
818 |
|
} |
819 |
|
|
820 |
|
/** |
821 |
|
* Returns the pool hosting the current task execution, or null |
822 |
< |
* if this task is executing outside of any pool. |
823 |
< |
* @return the pool, or null if none. |
822 |
> |
* if this task is executing outside of any ForkJoinPool. |
823 |
> |
* |
824 |
> |
* @see #inForkJoinPool |
825 |
> |
* @return the pool, or {@code null} if none |
826 |
|
*/ |
827 |
|
public static ForkJoinPool getPool() { |
828 |
|
Thread t = Thread.currentThread(); |
829 |
< |
return ((t instanceof ForkJoinWorkerThread)? |
830 |
< |
((ForkJoinWorkerThread)t).pool : null); |
829 |
> |
return (t instanceof ForkJoinWorkerThread) ? |
830 |
> |
((ForkJoinWorkerThread) t).pool : null; |
831 |
> |
} |
832 |
> |
|
833 |
> |
/** |
834 |
> |
* Returns {@code true} if the current thread is executing as a |
835 |
> |
* ForkJoinPool computation. |
836 |
> |
* |
837 |
> |
* @return {@code true} if the current thread is executing as a |
838 |
> |
* ForkJoinPool computation, or false otherwise |
839 |
> |
*/ |
840 |
> |
public static boolean inForkJoinPool() { |
841 |
> |
return Thread.currentThread() instanceof ForkJoinWorkerThread; |
842 |
|
} |
843 |
|
|
844 |
|
/** |
847 |
|
* by the current thread, and has not commenced executing in |
848 |
|
* another thread. This method may be useful when arranging |
849 |
|
* alternative local processing of tasks that could have been, but |
850 |
< |
* were not, stolen. This method may be invoked only from within |
851 |
< |
* ForkJoinTask computations. Attempts to invoke in other contexts |
852 |
< |
* result in exceptions or errors possibly including ClassCastException. |
853 |
< |
* @return true if unforked |
850 |
> |
* were not, stolen. |
851 |
> |
* |
852 |
> |
* <p>This method may be invoked only from within {@code |
853 |
> |
* ForkJoinTask} computations (as may be determined using method |
854 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
855 |
> |
* result in exceptions or errors, possibly including {@code |
856 |
> |
* ClassCastException}. |
857 |
> |
* |
858 |
> |
* @return {@code true} if unforked |
859 |
|
*/ |
860 |
|
public boolean tryUnfork() { |
861 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this); |
861 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
862 |
> |
.unpushTask(this); |
863 |
|
} |
864 |
|
|
865 |
|
/** |
867 |
|
* forked by the current worker thread but not yet executed. This |
868 |
|
* value may be useful for heuristic decisions about whether to |
869 |
|
* fork other tasks. |
870 |
+ |
* |
871 |
+ |
* <p>This method may be invoked only from within {@code |
872 |
+ |
* ForkJoinTask} computations (as may be determined using method |
873 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
874 |
+ |
* result in exceptions or errors, possibly including {@code |
875 |
+ |
* ClassCastException}. |
876 |
+ |
* |
877 |
|
* @return the number of tasks |
878 |
|
*/ |
879 |
|
public static int getQueuedTaskCount() { |
880 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())). |
881 |
< |
getQueueSize(); |
880 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
881 |
> |
.getQueueSize(); |
882 |
|
} |
883 |
|
|
884 |
|
/** |
885 |
< |
* Returns a estimate of how many more locally queued tasks are |
885 |
> |
* Returns an estimate of how many more locally queued tasks are |
886 |
|
* held by the current worker thread than there are other worker |
887 |
|
* threads that might steal them. This value may be useful for |
888 |
|
* heuristic decisions about whether to fork other tasks. In many |
890 |
|
* aim to maintain a small constant surplus (for example, 3) of |
891 |
|
* tasks, and to process computations locally if this threshold is |
892 |
|
* exceeded. |
893 |
+ |
* |
894 |
+ |
* <p>This method may be invoked only from within {@code |
895 |
+ |
* ForkJoinTask} computations (as may be determined using method |
896 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
897 |
+ |
* result in exceptions or errors, possibly including {@code |
898 |
+ |
* ClassCastException}. |
899 |
+ |
* |
900 |
|
* @return the surplus number of tasks, which may be negative |
901 |
|
*/ |
902 |
|
public static int getSurplusQueuedTaskCount() { |
903 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())) |
903 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
904 |
|
.getEstimatedSurplusTaskCount(); |
905 |
|
} |
906 |
|
|
907 |
|
// Extension methods |
908 |
|
|
909 |
|
/** |
910 |
< |
* Returns the result that would be returned by <code>join</code>, |
911 |
< |
* even if this task completed abnormally, or null if this task is |
912 |
< |
* not known to have been completed. This method is designed to |
913 |
< |
* aid debugging, as well as to support extensions. Its use in any |
914 |
< |
* other context is discouraged. |
910 |
> |
* Returns the result that would be returned by {@link #join}, even |
911 |
> |
* if this task completed abnormally, or {@code null} if this task |
912 |
> |
* is not known to have been completed. This method is designed |
913 |
> |
* to aid debugging, as well as to support extensions. Its use in |
914 |
> |
* any other context is discouraged. |
915 |
|
* |
916 |
< |
* @return the result, or null if not completed. |
916 |
> |
* @return the result, or {@code null} if not completed |
917 |
|
*/ |
918 |
|
public abstract V getRawResult(); |
919 |
|
|
932 |
|
* called otherwise. The return value controls whether this task |
933 |
|
* is considered to be done normally. It may return false in |
934 |
|
* asynchronous actions that require explicit invocations of |
935 |
< |
* <code>complete</code> to become joinable. It may throw exceptions |
936 |
< |
* to indicate abnormal exit. |
937 |
< |
* @return true if completed normally |
938 |
< |
* @throws Error or RuntimeException if encountered during computation |
935 |
> |
* {@link #complete} to become joinable. It may also throw an |
936 |
> |
* (unchecked) exception to indicate abnormal exit. |
937 |
> |
* |
938 |
> |
* @return {@code true} if completed normally |
939 |
|
*/ |
940 |
|
protected abstract boolean exec(); |
941 |
|
|
942 |
|
/** |
943 |
< |
* Returns, but does not unschedule or execute, the task most |
944 |
< |
* recently forked by the current thread but not yet executed, if |
945 |
< |
* one is available. There is no guarantee that this task will |
946 |
< |
* actually be polled or executed next. |
947 |
< |
* This method is designed primarily to support extensions, |
948 |
< |
* and is unlikely to be useful otherwise. |
949 |
< |
* This method may be invoked only from within |
950 |
< |
* ForkJoinTask computations. Attempts to invoke in other contexts |
937 |
< |
* result in exceptions or errors possibly including ClassCastException. |
943 |
> |
* Returns, but does not unschedule or execute, a task queued by |
944 |
> |
* the current thread but not yet executed, if one is immediately |
945 |
> |
* available. There is no guarantee that this task will actually |
946 |
> |
* be polled or executed next. Conversely, this method may return |
947 |
> |
* null even if a task exists but cannot be accessed without |
948 |
> |
* contention with other threads. This method is designed |
949 |
> |
* primarily to support extensions, and is unlikely to be useful |
950 |
> |
* otherwise. |
951 |
|
* |
952 |
< |
* @return the next task, or null if none are available |
952 |
> |
* <p>This method may be invoked only from within {@code |
953 |
> |
* ForkJoinTask} computations (as may be determined using method |
954 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
955 |
> |
* result in exceptions or errors, possibly including {@code |
956 |
> |
* ClassCastException}. |
957 |
> |
* |
958 |
> |
* @return the next task, or {@code null} if none are available |
959 |
|
*/ |
960 |
|
protected static ForkJoinTask<?> peekNextLocalTask() { |
961 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask(); |
961 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
962 |
> |
.peekTask(); |
963 |
|
} |
964 |
|
|
965 |
|
/** |
966 |
< |
* Unschedules and returns, without executing, the task most |
967 |
< |
* recently forked by the current thread but not yet executed. |
968 |
< |
* This method is designed primarily to support extensions, |
969 |
< |
* and is unlikely to be useful otherwise. |
970 |
< |
* This method may be invoked only from within |
971 |
< |
* ForkJoinTask computations. Attempts to invoke in other contexts |
972 |
< |
* result in exceptions or errors possibly including ClassCastException. |
966 |
> |
* Unschedules and returns, without executing, the next task |
967 |
> |
* queued by the current thread but not yet executed. This method |
968 |
> |
* is designed primarily to support extensions, and is unlikely to |
969 |
> |
* be useful otherwise. |
970 |
> |
* |
971 |
> |
* <p>This method may be invoked only from within {@code |
972 |
> |
* ForkJoinTask} computations (as may be determined using method |
973 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
974 |
> |
* result in exceptions or errors, possibly including {@code |
975 |
> |
* ClassCastException}. |
976 |
|
* |
977 |
< |
* @return the next task, or null if none are available |
977 |
> |
* @return the next task, or {@code null} if none are available |
978 |
|
*/ |
979 |
|
protected static ForkJoinTask<?> pollNextLocalTask() { |
980 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())).popTask(); |
980 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
981 |
> |
.pollLocalTask(); |
982 |
|
} |
983 |
|
|
984 |
|
/** |
985 |
< |
* Unschedules and returns, without executing, the task most |
986 |
< |
* recently forked by the current thread but not yet executed, if |
987 |
< |
* one is available, or if not available, a task that was forked |
988 |
< |
* by some other thread, if available. Availability may be |
989 |
< |
* transient, so a <code>null</code> result does not necessarily |
990 |
< |
* imply quiecence of the pool this task is operating in. |
991 |
< |
* This method is designed primarily to support extensions, |
992 |
< |
* and is unlikely to be useful otherwise. |
969 |
< |
* This method may be invoked only from within |
970 |
< |
* ForkJoinTask computations. Attempts to invoke in other contexts |
971 |
< |
* result in exceptions or errors possibly including ClassCastException. |
985 |
> |
* Unschedules and returns, without executing, the next task |
986 |
> |
* queued by the current thread but not yet executed, if one is |
987 |
> |
* available, or if not available, a task that was forked by some |
988 |
> |
* other thread, if available. Availability may be transient, so a |
989 |
> |
* {@code null} result does not necessarily imply quiescence |
990 |
> |
* of the pool this task is operating in. This method is designed |
991 |
> |
* primarily to support extensions, and is unlikely to be useful |
992 |
> |
* otherwise. |
993 |
|
* |
994 |
< |
* @return a task, or null if none are available |
994 |
> |
* <p>This method may be invoked only from within {@code |
995 |
> |
* ForkJoinTask} computations (as may be determined using method |
996 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
997 |
> |
* result in exceptions or errors, possibly including {@code |
998 |
> |
* ClassCastException}. |
999 |
> |
* |
1000 |
> |
* @return a task, or {@code null} if none are available |
1001 |
|
*/ |
1002 |
|
protected static ForkJoinTask<?> pollTask() { |
1003 |
< |
return ((ForkJoinWorkerThread)(Thread.currentThread())). |
1004 |
< |
pollTask(); |
1003 |
> |
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1004 |
> |
.pollTask(); |
1005 |
> |
} |
1006 |
> |
|
1007 |
> |
/** |
1008 |
> |
* Adaptor for Runnables. This implements RunnableFuture |
1009 |
> |
* to be compliant with AbstractExecutorService constraints |
1010 |
> |
* when used in ForkJoinPool. |
1011 |
> |
*/ |
1012 |
> |
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
1013 |
> |
implements RunnableFuture<T> { |
1014 |
> |
final Runnable runnable; |
1015 |
> |
final T resultOnCompletion; |
1016 |
> |
T result; |
1017 |
> |
AdaptedRunnable(Runnable runnable, T result) { |
1018 |
> |
if (runnable == null) throw new NullPointerException(); |
1019 |
> |
this.runnable = runnable; |
1020 |
> |
this.resultOnCompletion = result; |
1021 |
> |
} |
1022 |
> |
public T getRawResult() { return result; } |
1023 |
> |
public void setRawResult(T v) { result = v; } |
1024 |
> |
public boolean exec() { |
1025 |
> |
runnable.run(); |
1026 |
> |
result = resultOnCompletion; |
1027 |
> |
return true; |
1028 |
> |
} |
1029 |
> |
public void run() { invoke(); } |
1030 |
> |
private static final long serialVersionUID = 5232453952276885070L; |
1031 |
> |
} |
1032 |
> |
|
1033 |
> |
/** |
1034 |
> |
* Adaptor for Callables |
1035 |
> |
*/ |
1036 |
> |
static final class AdaptedCallable<T> extends ForkJoinTask<T> |
1037 |
> |
implements RunnableFuture<T> { |
1038 |
> |
final Callable<? extends T> callable; |
1039 |
> |
T result; |
1040 |
> |
AdaptedCallable(Callable<? extends T> callable) { |
1041 |
> |
if (callable == null) throw new NullPointerException(); |
1042 |
> |
this.callable = callable; |
1043 |
> |
} |
1044 |
> |
public T getRawResult() { return result; } |
1045 |
> |
public void setRawResult(T v) { result = v; } |
1046 |
> |
public boolean exec() { |
1047 |
> |
try { |
1048 |
> |
result = callable.call(); |
1049 |
> |
return true; |
1050 |
> |
} catch (Error err) { |
1051 |
> |
throw err; |
1052 |
> |
} catch (RuntimeException rex) { |
1053 |
> |
throw rex; |
1054 |
> |
} catch (Exception ex) { |
1055 |
> |
throw new RuntimeException(ex); |
1056 |
> |
} |
1057 |
> |
} |
1058 |
> |
public void run() { invoke(); } |
1059 |
> |
private static final long serialVersionUID = 2838392045355241008L; |
1060 |
> |
} |
1061 |
> |
|
1062 |
> |
/** |
1063 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1064 |
> |
* method of the given {@code Runnable} as its action, and returns |
1065 |
> |
* a null result upon {@link #join}. |
1066 |
> |
* |
1067 |
> |
* @param runnable the runnable action |
1068 |
> |
* @return the task |
1069 |
> |
*/ |
1070 |
> |
public static ForkJoinTask<?> adapt(Runnable runnable) { |
1071 |
> |
return new AdaptedRunnable<Void>(runnable, null); |
1072 |
> |
} |
1073 |
> |
|
1074 |
> |
/** |
1075 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1076 |
> |
* method of the given {@code Runnable} as its action, and returns |
1077 |
> |
* the given result upon {@link #join}. |
1078 |
> |
* |
1079 |
> |
* @param runnable the runnable action |
1080 |
> |
* @param result the result upon completion |
1081 |
> |
* @return the task |
1082 |
> |
*/ |
1083 |
> |
public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) { |
1084 |
> |
return new AdaptedRunnable<T>(runnable, result); |
1085 |
> |
} |
1086 |
> |
|
1087 |
> |
/** |
1088 |
> |
* Returns a new {@code ForkJoinTask} that performs the {@code call} |
1089 |
> |
* method of the given {@code Callable} as its action, and returns |
1090 |
> |
* its result upon {@link #join}, translating any checked exceptions |
1091 |
> |
* encountered into {@code RuntimeException}. |
1092 |
> |
* |
1093 |
> |
* @param callable the callable action |
1094 |
> |
* @return the task |
1095 |
> |
*/ |
1096 |
> |
public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) { |
1097 |
> |
return new AdaptedCallable<T>(callable); |
1098 |
|
} |
1099 |
|
|
1100 |
|
// Serialization support |
1102 |
|
private static final long serialVersionUID = -7721805057305804111L; |
1103 |
|
|
1104 |
|
/** |
1105 |
< |
* Save the state to a stream. |
1105 |
> |
* Saves the state to a stream (that is, serializes it). |
1106 |
|
* |
1107 |
|
* @serialData the current run status and the exception thrown |
1108 |
< |
* during execution, or null if none. |
1108 |
> |
* during execution, or {@code null} if none |
1109 |
|
* @param s the stream |
1110 |
|
*/ |
1111 |
|
private void writeObject(java.io.ObjectOutputStream s) |
1115 |
|
} |
1116 |
|
|
1117 |
|
/** |
1118 |
< |
* Reconstitute the instance from a stream. |
1118 |
> |
* Reconstitutes the instance from a stream (that is, deserializes it). |
1119 |
> |
* |
1120 |
|
* @param s the stream |
1121 |
|
*/ |
1122 |
|
private void readObject(java.io.ObjectInputStream s) |
1123 |
|
throws java.io.IOException, ClassNotFoundException { |
1124 |
|
s.defaultReadObject(); |
1004 |
– |
status &= ~INTERNAL_SIGNAL_MASK; // clear internal signal counts |
1005 |
– |
status |= EXTERNAL_SIGNAL; // conservatively set external signal |
1125 |
|
Object ex = s.readObject(); |
1126 |
|
if (ex != null) |
1127 |
< |
setDoneExceptionally((Throwable)ex); |
1127 |
> |
setExceptionalCompletion((Throwable) ex); |
1128 |
|
} |
1129 |
|
|
1130 |
< |
// Temporary Unsafe mechanics for preliminary release |
1130 |
> |
// Unsafe mechanics |
1131 |
|
|
1132 |
< |
static final Unsafe _unsafe; |
1133 |
< |
static final long statusOffset; |
1132 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1133 |
> |
private static final long statusOffset = |
1134 |
> |
objectFieldOffset("status", ForkJoinTask.class); |
1135 |
|
|
1136 |
< |
static { |
1136 |
> |
private static long objectFieldOffset(String field, Class<?> klazz) { |
1137 |
|
try { |
1138 |
< |
if (ForkJoinTask.class.getClassLoader() != null) { |
1139 |
< |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
1140 |
< |
f.setAccessible(true); |
1141 |
< |
_unsafe = (Unsafe)f.get(null); |
1142 |
< |
} |
1143 |
< |
else |
1144 |
< |
_unsafe = Unsafe.getUnsafe(); |
1025 |
< |
statusOffset = _unsafe.objectFieldOffset |
1026 |
< |
(ForkJoinTask.class.getDeclaredField("status")); |
1027 |
< |
} catch (Exception ex) { throw new Error(ex); } |
1138 |
> |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
1139 |
> |
} catch (NoSuchFieldException e) { |
1140 |
> |
// Convert Exception to corresponding Error |
1141 |
> |
NoSuchFieldError error = new NoSuchFieldError(field); |
1142 |
> |
error.initCause(e); |
1143 |
> |
throw error; |
1144 |
> |
} |
1145 |
|
} |
1146 |
|
|
1147 |
+ |
/** |
1148 |
+ |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
1149 |
+ |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
1150 |
+ |
* into a jdk. |
1151 |
+ |
* |
1152 |
+ |
* @return a sun.misc.Unsafe |
1153 |
+ |
*/ |
1154 |
+ |
private static sun.misc.Unsafe getUnsafe() { |
1155 |
+ |
try { |
1156 |
+ |
return sun.misc.Unsafe.getUnsafe(); |
1157 |
+ |
} catch (SecurityException se) { |
1158 |
+ |
try { |
1159 |
+ |
return java.security.AccessController.doPrivileged |
1160 |
+ |
(new java.security |
1161 |
+ |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1162 |
+ |
public sun.misc.Unsafe run() throws Exception { |
1163 |
+ |
java.lang.reflect.Field f = sun.misc |
1164 |
+ |
.Unsafe.class.getDeclaredField("theUnsafe"); |
1165 |
+ |
f.setAccessible(true); |
1166 |
+ |
return (sun.misc.Unsafe) f.get(null); |
1167 |
+ |
}}); |
1168 |
+ |
} catch (java.security.PrivilegedActionException e) { |
1169 |
+ |
throw new RuntimeException("Could not initialize intrinsics", |
1170 |
+ |
e.getCause()); |
1171 |
+ |
} |
1172 |
+ |
} |
1173 |
+ |
} |
1174 |
|
} |