--- jsr166/src/jsr166y/ForkJoinTask.java 2009/07/21 18:11:44 1.11
+++ jsr166/src/jsr166y/ForkJoinTask.java 2009/07/23 23:07:57 1.14
@@ -81,8 +81,10 @@ 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
@@ -107,6 +109,9 @@ import java.lang.reflect.*;
* in general sensible to serialize tasks only before or after, but
* not during execution. Serialization is not relied on during
* execution itself.
+ *
+ * @since 1.7
+ * @author Doug Lea
*/
public abstract class ForkJoinTask implements Future, Serializable {
@@ -157,8 +162,8 @@ 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) {
@@ -184,12 +189,12 @@ 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
@@ -202,13 +207,13 @@ 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.
@@ -220,30 +225,30 @@ 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();
@@ -259,11 +264,12 @@ 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)
@@ -276,13 +282,14 @@ 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);
@@ -304,7 +311,7 @@ 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);
}
@@ -359,7 +366,7 @@ 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 {
@@ -425,7 +432,7 @@ public abstract class ForkJoinTask im
try {
if (!exec())
return;
- } catch(Throwable rex) {
+ } catch (Throwable rex) {
setDoneExceptionally(rex);
return;
}
@@ -457,7 +464,7 @@ public abstract class ForkJoinTask im
final void cancelIgnoringExceptions() {
try {
cancel(false);
- } catch(Throwable ignore) {
+ } catch (Throwable ignore) {
}
}
@@ -469,7 +476,7 @@ 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
@@ -479,11 +486,13 @@ 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);
}
/**
@@ -519,8 +528,9 @@ 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
@@ -538,8 +548,10 @@ 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
@@ -582,9 +594,10 @@ 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
@@ -592,11 +605,11 @@ public abstract class ForkJoinTask im
*/
public static void invokeAll(Collection extends ForkJoinTask>> tasks) {
if (!(tasks instanceof List)) {
- invokeAll(tasks.toArray(new ForkJoinTask[tasks.size()]));
+ invokeAll(tasks.toArray(new ForkJoinTask>[tasks.size()]));
return;
}
List extends ForkJoinTask>> ts =
- (List extends ForkJoinTask>>)tasks;
+ (List extends ForkJoinTask>>) tasks;
Throwable ex = null;
int last = ts.size() - 1;
for (int i = last; i >= 0; --i) {
@@ -671,7 +684,7 @@ 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
*/
@@ -721,7 +734,7 @@ 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));
}
@@ -740,7 +753,7 @@ public abstract class ForkJoinTask im
public void complete(V value) {
try {
setRawResult(value);
- } catch(Throwable rex) {
+ } catch (Throwable rex) {
setDoneExceptionally(rex);
return;
}
@@ -770,13 +783,15 @@ 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();
@@ -785,13 +800,14 @@ 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);
}
@@ -830,8 +846,8 @@ 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();
}
/**
@@ -852,14 +868,25 @@ 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;
}
/**
@@ -869,13 +896,16 @@ 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);
}
/**
@@ -887,8 +917,8 @@ public abstract class ForkJoinTask im
* @return the number of tasks
*/
public static int getQueuedTaskCount() {
- return ((ForkJoinWorkerThread)(Thread.currentThread())).
- getQueueSize();
+ return ((ForkJoinWorkerThread) Thread.currentThread())
+ .getQueueSize();
}
/**
@@ -904,7 +934,7 @@ 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();
}
@@ -951,13 +981,15 @@ 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();
}
/**
@@ -965,14 +997,16 @@ 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();
}
/**
@@ -984,15 +1018,16 @@ 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
@@ -1024,7 +1059,7 @@ 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