--- jsr166/src/jsr166y/ForkJoinTask.java 2009/07/22 01:36:51 1.12 +++ jsr166/src/jsr166y/ForkJoinTask.java 2009/07/25 00:34:00 1.17 @@ -5,12 +5,15 @@ */ package jsr166y; -import java.io.Serializable; -import java.util.*; + import java.util.concurrent.*; -import java.util.concurrent.atomic.*; -import sun.misc.Unsafe; -import java.lang.reflect.*; + +import java.io.Serializable; +import java.util.Collection; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.WeakHashMap; /** * Abstract base class for tasks that run within a {@link @@ -81,8 +84,10 @@ import java.lang.reflect.*; * class. While these methods have {@code public} access (to allow * instances of different task subclasses to call each others * methods), some of them may only be called from within other - * ForkJoinTasks. Attempts to invoke them in other contexts result in - * exceptions or errors possibly including ClassCastException. + * ForkJoinTasks (as may be determined using method {@link + * #inForkJoinPool}). Attempts to invoke them in other contexts + * result in exceptions or errors, possibly including + * ClassCastException. * *

Most base support methods are {@code final} because their * implementations are intrinsically tied to the underlying @@ -160,8 +165,8 @@ public abstract class ForkJoinTask im */ static ForkJoinWorkerThread getWorker() { Thread t = Thread.currentThread(); - return ((t instanceof ForkJoinWorkerThread)? - (ForkJoinWorkerThread)t : null); + return ((t instanceof ForkJoinWorkerThread) ? + (ForkJoinWorkerThread) t : null); } final boolean casStatus(int cmp, int val) { @@ -187,12 +192,12 @@ public abstract class ForkJoinTask im ForkJoinPool pool = getPool(); if (pool != null) { int s; // Clear signal bits while setting completion status - do;while ((s = status) >= 0 && !casStatus(s, completion)); + do {} while ((s = status) >= 0 && !casStatus(s, completion)); if ((s & SIGNAL_MASK) != 0) { if ((s &= INTERNAL_SIGNAL_MASK) != 0) pool.updateRunningCount(s); - synchronized(this) { notifyAll(); } + synchronized (this) { notifyAll(); } } } else @@ -205,13 +210,13 @@ public abstract class ForkJoinTask im */ private void externallySetCompletion(int completion) { int s; - do;while ((s = status) >= 0 && - !casStatus(s, (s & SIGNAL_MASK) | completion)); - synchronized(this) { notifyAll(); } + do {} while ((s = status) >= 0 && + !casStatus(s, (s & SIGNAL_MASK) | completion)); + synchronized (this) { notifyAll(); } } /** - * Sets status to indicate normal completion + * Sets status to indicate normal completion. */ final void setNormalCompletion() { // Try typical fast case -- single CAS, no signal, not already done. @@ -223,30 +228,30 @@ public abstract class ForkJoinTask im // internal waiting and notification /** - * Performs the actual monitor wait for awaitDone + * Performs the actual monitor wait for awaitDone. */ private void doAwaitDone() { // Minimize lock bias and in/de-flation effects by maximizing // chances of waiting inside sync try { while (status >= 0) - synchronized(this) { if (status >= 0) wait(); } + synchronized (this) { if (status >= 0) wait(); } } catch (InterruptedException ie) { onInterruptedWait(); } } /** - * Performs the actual monitor wait for awaitDone + * Performs the actual timed monitor wait for awaitDone. */ private void doAwaitDone(long startTime, long nanos) { - synchronized(this) { + synchronized (this) { try { while (status >= 0) { long nt = nanos - System.nanoTime() - startTime; if (nt <= 0) break; - wait(nt / 1000000, (int)(nt % 1000000)); + wait(nt / 1000000, (int) (nt % 1000000)); } } catch (InterruptedException ie) { onInterruptedWait(); @@ -262,11 +267,12 @@ public abstract class ForkJoinTask im * * @return status upon exit */ - private int awaitDone(ForkJoinWorkerThread w, boolean maintainParallelism) { - ForkJoinPool pool = w == null? null : w.pool; + private int awaitDone(ForkJoinWorkerThread w, + boolean maintainParallelism) { + ForkJoinPool pool = (w == null) ? null : w.pool; int s; while ((s = status) >= 0) { - if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) { + if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) { if (pool == null || !pool.preJoin(this, maintainParallelism)) doAwaitDone(); if (((s = status) & INTERNAL_SIGNAL_MASK) != 0) @@ -279,13 +285,14 @@ public abstract class ForkJoinTask im /** * Timed version of awaitDone + * * @return status upon exit */ private int awaitDone(ForkJoinWorkerThread w, long nanos) { - ForkJoinPool pool = w == null? null : w.pool; + ForkJoinPool pool = (w == null) ? null : w.pool; int s; while ((s = status) >= 0) { - if (casStatus(s, pool == null? s|EXTERNAL_SIGNAL : s+1)) { + if (casStatus(s, (pool == null) ? s|EXTERNAL_SIGNAL : s+1)) { long startTime = System.nanoTime(); if (pool == null || !pool.preJoin(this, false)) doAwaitDone(startTime, nanos); @@ -307,7 +314,7 @@ public abstract class ForkJoinTask im */ private void adjustPoolCountsOnUnblock(ForkJoinPool pool) { int s; - do;while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK)); + do {} while ((s = status) < 0 && !casStatus(s, s & COMPLETION_MASK)); if (pool != null && (s &= INTERNAL_SIGNAL_MASK) != 0) pool.updateRunningCount(s); } @@ -362,7 +369,7 @@ public abstract class ForkJoinTask im /** * Returns result or throws exception using j.u.c.Future conventions. - * Only call when isDone known to be true. + * Only call when {@code isDone} known to be true. */ private V reportFutureResult() throws ExecutionException, InterruptedException { @@ -428,7 +435,7 @@ public abstract class ForkJoinTask im try { if (!exec()) return; - } catch(Throwable rex) { + } catch (Throwable rex) { setDoneExceptionally(rex); return; } @@ -460,7 +467,7 @@ public abstract class ForkJoinTask im final void cancelIgnoringExceptions() { try { cancel(false); - } catch(Throwable ignore) { + } catch (Throwable ignore) { } } @@ -472,7 +479,7 @@ public abstract class ForkJoinTask im ForkJoinTask t; while ((s = status) >= 0 && (t = w.scanWhileJoining(this)) != null) t.quietlyExec(); - return (s >= 0)? awaitDone(w, false) : s; // block if no work + return (s >= 0) ? awaitDone(w, false) : s; // block if no work } // public methods @@ -482,11 +489,13 @@ public abstract class ForkJoinTask im * necessarily enforced, it is a usage error to fork a task more * than once unless it has completed and been reinitialized. This * method may be invoked only from within ForkJoinTask - * computations. Attempts to invoke in other contexts result in - * exceptions or errors possibly including ClassCastException. + * computations (as may be determined using method {@link + * #inForkJoinPool}). Attempts to invoke in other contexts result + * in exceptions or errors, possibly including ClassCastException. */ public final void fork() { - ((ForkJoinWorkerThread)(Thread.currentThread())).pushTask(this); + ((ForkJoinWorkerThread) Thread.currentThread()) + .pushTask(this); } /** @@ -522,8 +531,9 @@ public abstract class ForkJoinTask im /** * Forks both tasks, returning when {@code isDone} holds for * both of them or an exception is encountered. This method may be - * invoked only from within ForkJoinTask computations. Attempts to - * invoke in other contexts result in exceptions or errors + * invoked only from within ForkJoinTask computations (as may be + * determined using method {@link #inForkJoinPool}). Attempts to + * invoke in other contexts result in exceptions or errors, * possibly including ClassCastException. * * @param t1 one task @@ -541,8 +551,10 @@ public abstract class ForkJoinTask im * Forks the given tasks, returning when {@code isDone} holds * for all of them. If any task encounters an exception, others * may be cancelled. This method may be invoked only from within - * ForkJoinTask computations. Attempts to invoke in other contexts - * result in exceptions or errors possibly including ClassCastException. + * ForkJoinTask computations (as may be determined using method + * {@link #inForkJoinPool}). Attempts to invoke in other contexts + * result in exceptions or errors, possibly including + * ClassCastException. * * @param tasks the array of tasks * @throws NullPointerException if tasks or any element are null @@ -585,21 +597,23 @@ public abstract class ForkJoinTask im * Forks all tasks in the collection, returning when * {@code isDone} holds for all of them. If any task * encounters an exception, others may be cancelled. This method - * may be invoked only from within ForkJoinTask - * computations. Attempts to invoke in other contexts result in - * exceptions or errors possibly including ClassCastException. + * may be invoked only from within ForkJoinTask computations (as + * may be determined using method {@link + * #inForkJoinPool}). Attempts to invoke in other contexts result + * in exceptions or errors, possibly including ClassCastException. * * @param tasks the collection of tasks * @throws NullPointerException if tasks or any element are null * @throws RuntimeException or Error if any task did so */ public static void invokeAll(Collection> tasks) { - if (!(tasks instanceof List)) { - invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()])); + if (!(tasks instanceof List)) { + invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()])); return; } + @SuppressWarnings("unchecked") List> ts = - (List>)tasks; + (List>) tasks; Throwable ex = null; int last = ts.size() - 1; for (int i = last; i >= 0; --i) { @@ -674,7 +688,7 @@ public abstract class ForkJoinTask im * * @param mayInterruptIfRunning this value is ignored in the * default implementation because tasks are not in general - * cancelled via interruption. + * cancelled via interruption * * @return true if this task is now cancelled */ @@ -724,7 +738,7 @@ public abstract class ForkJoinTask im */ public void completeExceptionally(Throwable ex) { setDoneExceptionally((ex instanceof RuntimeException) || - (ex instanceof Error)? ex : + (ex instanceof Error) ? ex : new RuntimeException(ex)); } @@ -743,7 +757,7 @@ public abstract class ForkJoinTask im public void complete(V value) { try { setRawResult(value); - } catch(Throwable rex) { + } catch (Throwable rex) { setDoneExceptionally(rex); return; } @@ -773,13 +787,15 @@ public abstract class ForkJoinTask im * current task and that of any other task that might be executed * while helping. (This usually holds for pure divide-and-conquer * tasks). This method may be invoked only from within - * ForkJoinTask computations. Attempts to invoke in other contexts - * result in exceptions or errors possibly including ClassCastException. + * ForkJoinTask computations (as may be determined using method + * {@link #inForkJoinPool}). Attempts to invoke in other contexts + * result in exceptions or errors, possibly including + * ClassCastException. * * @return the computed result */ public final V helpJoin() { - ForkJoinWorkerThread w = (ForkJoinWorkerThread)(Thread.currentThread()); + ForkJoinWorkerThread w = (ForkJoinWorkerThread) Thread.currentThread(); if (status < 0 || !w.unpushTask(this) || !tryExec()) reportException(busyJoin(w)); return getRawResult(); @@ -788,13 +804,14 @@ public abstract class ForkJoinTask im /** * Possibly executes other tasks until this task is ready. This * method may be invoked only from within ForkJoinTask - * computations. Attempts to invoke in other contexts result in - * exceptions or errors possibly including ClassCastException. + * computations (as may be determined using method {@link + * #inForkJoinPool}). Attempts to invoke in other contexts result + * in exceptions or errors, possibly including ClassCastException. */ public final void quietlyHelpJoin() { if (status >= 0) { ForkJoinWorkerThread w = - (ForkJoinWorkerThread)(Thread.currentThread()); + (ForkJoinWorkerThread) Thread.currentThread(); if (!w.unpushTask(this) || !tryQuietlyInvoke()) busyJoin(w); } @@ -833,8 +850,8 @@ public abstract class ForkJoinTask im * joined, instead executing them until all are processed. */ public static void helpQuiesce() { - ((ForkJoinWorkerThread)(Thread.currentThread())). - helpQuiescePool(); + ((ForkJoinWorkerThread) Thread.currentThread()) + .helpQuiescePool(); } /** @@ -855,14 +872,25 @@ public abstract class ForkJoinTask im /** * Returns the pool hosting the current task execution, or null - * if this task is executing outside of any pool. + * if this task is executing outside of any ForkJoinPool. * * @return the pool, or null if none */ public static ForkJoinPool getPool() { Thread t = Thread.currentThread(); - return ((t instanceof ForkJoinWorkerThread)? - ((ForkJoinWorkerThread)t).pool : null); + return (t instanceof ForkJoinWorkerThread) ? + ((ForkJoinWorkerThread) t).pool : null; + } + + /** + * Returns {@code true} if the current thread is executing as a + * ForkJoinPool computation. + * + * @return {@code true} if the current thread is executing as a + * ForkJoinPool computation, or false otherwise + */ + public static boolean inForkJoinPool() { + return Thread.currentThread() instanceof ForkJoinWorkerThread; } /** @@ -872,13 +900,16 @@ public abstract class ForkJoinTask im * another thread. This method may be useful when arranging * alternative local processing of tasks that could have been, but * were not, stolen. This method may be invoked only from within - * ForkJoinTask computations. Attempts to invoke in other contexts - * result in exceptions or errors possibly including ClassCastException. + * ForkJoinTask computations (as may be determined using method + * {@link #inForkJoinPool}). Attempts to invoke in other contexts + * result in exceptions or errors, possibly including + * ClassCastException. * * @return true if unforked */ public boolean tryUnfork() { - return ((ForkJoinWorkerThread)(Thread.currentThread())).unpushTask(this); + return ((ForkJoinWorkerThread) Thread.currentThread()) + .unpushTask(this); } /** @@ -890,8 +921,8 @@ public abstract class ForkJoinTask im * @return the number of tasks */ public static int getQueuedTaskCount() { - return ((ForkJoinWorkerThread)(Thread.currentThread())). - getQueueSize(); + return ((ForkJoinWorkerThread) Thread.currentThread()) + .getQueueSize(); } /** @@ -907,7 +938,7 @@ public abstract class ForkJoinTask im * @return the surplus number of tasks, which may be negative */ public static int getSurplusQueuedTaskCount() { - return ((ForkJoinWorkerThread)(Thread.currentThread())) + return ((ForkJoinWorkerThread) Thread.currentThread()) .getEstimatedSurplusTaskCount(); } @@ -954,13 +985,15 @@ public abstract class ForkJoinTask im * be polled or executed next. This method is designed primarily * to support extensions, and is unlikely to be useful otherwise. * This method may be invoked only from within ForkJoinTask - * computations. Attempts to invoke in other contexts result in - * exceptions or errors possibly including ClassCastException. + * computations (as may be determined using method {@link + * #inForkJoinPool}). Attempts to invoke in other contexts result + * in exceptions or errors, possibly including ClassCastException. * * @return the next task, or null if none are available */ protected static ForkJoinTask peekNextLocalTask() { - return ((ForkJoinWorkerThread)(Thread.currentThread())).peekTask(); + return ((ForkJoinWorkerThread) Thread.currentThread()) + .peekTask(); } /** @@ -968,14 +1001,16 @@ public abstract class ForkJoinTask im * queued by the current thread but not yet executed. This method * is designed primarily to support extensions, and is unlikely to * be useful otherwise. This method may be invoked only from - * within ForkJoinTask computations. Attempts to invoke in other - * contexts result in exceptions or errors possibly including + * within ForkJoinTask computations (as may be determined using + * method {@link #inForkJoinPool}). Attempts to invoke in other + * contexts result in exceptions or errors, possibly including * ClassCastException. * * @return the next task, or null if none are available */ protected static ForkJoinTask pollNextLocalTask() { - return ((ForkJoinWorkerThread)(Thread.currentThread())).pollLocalTask(); + return ((ForkJoinWorkerThread) Thread.currentThread()) + .pollLocalTask(); } /** @@ -987,15 +1022,16 @@ public abstract class ForkJoinTask im * of the pool this task is operating in. This method is designed * primarily to support extensions, and is unlikely to be useful * otherwise. This method may be invoked only from within - * ForkJoinTask computations. Attempts to invoke in other contexts - * result in exceptions or errors possibly including + * ForkJoinTask computations (as may be determined using method + * {@link #inForkJoinPool}). Attempts to invoke in other contexts + * result in exceptions or errors, possibly including * ClassCastException. * * @return a task, or null if none are available */ protected static ForkJoinTask pollTask() { - return ((ForkJoinWorkerThread)(Thread.currentThread())). - pollTask(); + return ((ForkJoinWorkerThread) Thread.currentThread()) + .pollTask(); } // Serialization support @@ -1027,49 +1063,48 @@ public abstract class ForkJoinTask im status |= EXTERNAL_SIGNAL; // conservatively set external signal Object ex = s.readObject(); if (ex != null) - setDoneExceptionally((Throwable)ex); + setDoneExceptionally((Throwable) ex); } - // Temporary Unsafe mechanics for preliminary release - private static Unsafe getUnsafe() throws Throwable { + // Unsafe mechanics for jsr166y 3rd party package. + private static sun.misc.Unsafe getUnsafe() { try { - return Unsafe.getUnsafe(); + return sun.misc.Unsafe.getUnsafe(); } catch (SecurityException se) { try { return java.security.AccessController.doPrivileged - (new java.security.PrivilegedExceptionAction() { - public Unsafe run() throws Exception { - return getUnsafePrivileged(); + (new java.security.PrivilegedExceptionAction() { + public sun.misc.Unsafe run() throws Exception { + return getUnsafeByReflection(); }}); } catch (java.security.PrivilegedActionException e) { - throw e.getCause(); + throw new RuntimeException("Could not initialize intrinsics", + e.getCause()); } } } - private static Unsafe getUnsafePrivileged() + private static sun.misc.Unsafe getUnsafeByReflection() throws NoSuchFieldException, IllegalAccessException { - Field f = Unsafe.class.getDeclaredField("theUnsafe"); + java.lang.reflect.Field f = + sun.misc.Unsafe.class.getDeclaredField("theUnsafe"); f.setAccessible(true); - return (Unsafe) f.get(null); + return (sun.misc.Unsafe) f.get(null); } - private static long fieldOffset(String fieldName) - throws NoSuchFieldException { - return UNSAFE.objectFieldOffset - (ForkJoinTask.class.getDeclaredField(fieldName)); - } - - static final Unsafe UNSAFE; - static final long statusOffset; - - static { + private static long fieldOffset(String fieldName, Class klazz) { try { - UNSAFE = getUnsafe(); - statusOffset = fieldOffset("status"); - } catch (Throwable e) { - throw new RuntimeException("Could not initialize intrinsics", e); + return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName)); + } catch (NoSuchFieldException e) { + // Convert Exception to Error + NoSuchFieldError error = new NoSuchFieldError(fieldName); + error.initCause(e); + throw error; } } + private static final sun.misc.Unsafe UNSAFE = getUnsafe(); + static final long statusOffset = + fieldOffset("status", ForkJoinTask.class); + }