--- jsr166/src/jsr166y/ForkJoinPool.java	2009/07/25 15:50:57	1.23
+++ jsr166/src/jsr166y/ForkJoinPool.java	2009/08/01 21:17:11	1.35
@@ -20,8 +20,8 @@ import java.util.concurrent.atomic.Atomi
 import java.util.concurrent.atomic.AtomicLong;
 
 /**
- * An {@link ExecutorService} for running {@link ForkJoinTask}s.  A
- * ForkJoinPool provides the entry point for submissions from
+ * An {@link ExecutorService} for running {@link ForkJoinTask}s.
+ * A ForkJoinPool provides the entry point for submissions from
  * non-ForkJoinTasks, as well as management and monitoring operations.
  * Normally a single ForkJoinPool is used for a large number of
  * submitted tasks. Otherwise, use would not usually outweigh the
@@ -34,29 +34,29 @@ import java.util.concurrent.atomic.Atomi
  * (eventually blocking if none exist). This makes them efficient when
  * most tasks spawn other subtasks (as do most ForkJoinTasks), as well
  * as the mixed execution of some plain Runnable- or Callable- based
- * activities along with ForkJoinTasks. When setting
- * {@code setAsyncMode}, a ForkJoinPools may also be appropriate for
- * use with fine-grained tasks that are never joined. Otherwise, other
- * ExecutorService implementations are typically more appropriate
- * choices.
+ * activities along with ForkJoinTasks. When setting {@linkplain
+ * #setAsyncMode async mode}, a ForkJoinPool may also be appropriate
+ * for use with fine-grained tasks that are never joined. Otherwise,
+ * other ExecutorService implementations are typically more
+ * appropriate choices.
  *
  * <p>A ForkJoinPool may be constructed with a given parallelism level
  * (target pool size), which it attempts to maintain by dynamically
  * adding, suspending, or resuming threads, even if some tasks are
  * waiting to join others. However, no such adjustments are performed
  * in the face of blocked IO or other unmanaged synchronization. The
- * nested {@code ManagedBlocker} interface enables extension of
+ * nested {@link ManagedBlocker} interface enables extension of
  * the kinds of synchronization accommodated.  The target parallelism
- * level may also be changed dynamically ({@code setParallelism})
+ * level may also be changed dynamically ({@link #setParallelism})
  * and thread construction can be limited using methods
- * {@code setMaximumPoolSize} and/or
- * {@code setMaintainsParallelism}.
+ * {@link #setMaximumPoolSize} and/or
+ * {@link #setMaintainsParallelism}.
  *
  * <p>In addition to execution and lifecycle control methods, this
  * class provides status check methods (for example
- * {@code getStealCount}) that are intended to aid in developing,
+ * {@link #getStealCount}) that are intended to aid in developing,
  * tuning, and monitoring fork/join applications. Also, method
- * {@code toString} returns indications of pool state in a
+ * {@link #toString} returns indications of pool state in a
  * convenient form for informal monitoring.
  *
  * <p><b>Implementation notes</b>: This implementation restricts the
@@ -81,10 +81,10 @@ public class ForkJoinPool extends Abstra
     private static final int MAX_THREADS =  0x7FFF;
 
     /**
-     * Factory for creating new ForkJoinWorkerThreads.  A
-     * ForkJoinWorkerThreadFactory must be defined and used for
-     * ForkJoinWorkerThread subclasses that extend base functionality
-     * or initialize threads with different contexts.
+     * Factory for creating new {@link ForkJoinWorkerThread}s.
+     * A {@code ForkJoinWorkerThreadFactory} must be defined and used
+     * for {@code ForkJoinWorkerThread} subclasses that extend base
+     * functionality or initialize threads with different contexts.
      */
     public static interface ForkJoinWorkerThreadFactory {
         /**
@@ -311,8 +311,8 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if argument represents zero active count and
-     * nonzero runstate, which is the triggering condition for
+     * Returns {@code true} if argument represents zero active count
+     * and nonzero runstate, which is the triggering condition for
      * terminating on shutdown.
      */
     private static boolean canTerminateOnShutdown(int c) {
@@ -586,35 +586,31 @@ public class ForkJoinPool extends Abstra
 
     public void execute(Runnable task) {
         ForkJoinTask<?> job;
-        if (task instanceof AdaptedCallable) // avoid re-wrap
-            job = (AdaptedCallable<?>)task;
-        else if (task instanceof AdaptedRunnable)
-            job = (AdaptedRunnable<?>)task;
+        if (task instanceof ForkJoinTask<?>) // avoid re-wrap
+            job = (ForkJoinTask<?>) task;
         else
-            job = new AdaptedRunnable<Void>(task, null);
+            job = ForkJoinTask.adapt(task, null);
         doSubmit(job);
     }
 
     public <T> ForkJoinTask<T> submit(Callable<T> task) {
-        ForkJoinTask<T> job = new AdaptedCallable<T>(task);
+        ForkJoinTask<T> job = ForkJoinTask.adapt(task);
         doSubmit(job);
         return job;
     }
 
     public <T> ForkJoinTask<T> submit(Runnable task, T result) {
-        ForkJoinTask<T> job = new AdaptedRunnable<T>(task, result);
+        ForkJoinTask<T> job = ForkJoinTask.adapt(task, result);
         doSubmit(job);
         return job;
     }
 
     public ForkJoinTask<?> submit(Runnable task) {
         ForkJoinTask<?> job;
-        if (task instanceof AdaptedCallable) // avoid re-wrap
-            job = (AdaptedCallable<?>)task;
-        else if (task instanceof AdaptedRunnable)
-            job = (AdaptedRunnable<?>)task;
+        if (task instanceof ForkJoinTask<?>) // avoid re-wrap
+            job = (ForkJoinTask<?>) task;
         else
-            job = new AdaptedRunnable<Void>(task, null);
+            job = ForkJoinTask.adapt(task, null);
         doSubmit(job);
         return job;
     }
@@ -633,65 +629,12 @@ public class ForkJoinPool extends Abstra
         return task;
     }
 
-    /**
-     * Adaptor for Runnables. This implements RunnableFuture
-     * to be compliant with AbstractExecutorService constraints.
-     */
-    static final class AdaptedRunnable<T> extends ForkJoinTask<T>
-        implements RunnableFuture<T> {
-        final Runnable runnable;
-        final T resultOnCompletion;
-        T result;
-        AdaptedRunnable(Runnable runnable, T result) {
-            if (runnable == null) throw new NullPointerException();
-            this.runnable = runnable;
-            this.resultOnCompletion = result;
-        }
-        public T getRawResult() { return result; }
-        public void setRawResult(T v) { result = v; }
-        public boolean exec() {
-            runnable.run();
-            result = resultOnCompletion;
-            return true;
-        }
-        public void run() { invoke(); }
-        private static final long serialVersionUID = 5232453952276885070L;
-    }
-
-    /**
-     * Adaptor for Callables
-     */
-    static final class AdaptedCallable<T> extends ForkJoinTask<T>
-        implements RunnableFuture<T> {
-        final Callable<T> callable;
-        T result;
-        AdaptedCallable(Callable<T> callable) {
-            if (callable == null) throw new NullPointerException();
-            this.callable = callable;
-        }
-        public T getRawResult() { return result; }
-        public void setRawResult(T v) { result = v; }
-        public boolean exec() {
-            try {
-                result = callable.call();
-                return true;
-            } catch (Error err) {
-                throw err;
-            } catch (RuntimeException rex) {
-                throw rex;
-            } catch (Exception ex) {
-                throw new RuntimeException(ex);
-            }
-        }
-        public void run() { invoke(); }
-        private static final long serialVersionUID = 2838392045355241008L;
-    }
 
     public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) {
         ArrayList<ForkJoinTask<T>> forkJoinTasks =
             new ArrayList<ForkJoinTask<T>>(tasks.size());
         for (Callable<T> task : tasks)
-            forkJoinTasks.add(new AdaptedCallable<T>(task));
+            forkJoinTasks.add(ForkJoinTask.adapt(task));
         invoke(new InvokeAll<T>(forkJoinTasks));
 
         @SuppressWarnings({"unchecked", "rawtypes"})
@@ -724,7 +667,7 @@ public class ForkJoinPool extends Abstra
      * Returns the handler for internal worker threads that terminate
      * due to unrecoverable errors encountered while executing tasks.
      *
-     * @return the handler, or null if none
+     * @return the handler, or {@code null} if none
      */
     public Thread.UncaughtExceptionHandler getUncaughtExceptionHandler() {
         Thread.UncaughtExceptionHandler h;
@@ -745,7 +688,7 @@ public class ForkJoinPool extends Abstra
      * as handler.
      *
      * @param h the new handler
-     * @return the old handler, or null if none
+     * @return the old handler, or {@code null} if none
      * @throws SecurityException if a security manager exists and
      *         the caller is not permitted to modify threads
      *         because it does not hold {@link
@@ -819,7 +762,7 @@ public class ForkJoinPool extends Abstra
     /**
      * Returns the number of worker threads that have started but not
      * yet terminated.  This result returned by this method may differ
-     * from {@code getParallelism} when threads are created to
+     * from {@link #getParallelism} when threads are created to
      * maintain parallelism when others are cooperatively blocked.
      *
      * @return the number of worker threads
@@ -855,12 +798,11 @@ public class ForkJoinPool extends Abstra
 
 
     /**
-     * Returns true if this pool dynamically maintains its target
-     * parallelism level. If false, new threads are added only to
-     * avoid possible starvation.
-     * This setting is by default true.
+     * Returns {@code true} if this pool dynamically maintains its
+     * target parallelism level. If false, new threads are added only
+     * to avoid possible starvation.  This setting is by default true.
      *
-     * @return true if maintains parallelism
+     * @return {@code true} if maintains parallelism
      */
     public boolean getMaintainsParallelism() {
         return maintainsParallelism;
@@ -871,7 +813,7 @@ public class ForkJoinPool extends Abstra
      * parallelism level. If false, new threads are added only to
      * avoid possible starvation.
      *
-     * @param enable true to maintains parallelism
+     * @param enable {@code true} to maintain parallelism
      */
     public void setMaintainsParallelism(boolean enable) {
         maintainsParallelism = enable;
@@ -882,12 +824,13 @@ public class ForkJoinPool extends Abstra
      * tasks that are never joined. This mode may be more appropriate
      * than default locally stack-based mode in applications in which
      * worker threads only process asynchronous tasks.  This method is
-     * designed to be invoked only when pool is quiescent, and
+     * designed to be invoked only when the pool is quiescent, and
      * typically only before any tasks are submitted. The effects of
      * invocations at other times may be unpredictable.
      *
-     * @param async if true, use locally FIFO scheduling
+     * @param async if {@code true}, use locally FIFO scheduling
      * @return the previous mode
+     * @see #getAsyncMode
      */
     public boolean setAsyncMode(boolean async) {
         boolean oldMode = locallyFifo;
@@ -904,10 +847,11 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if this pool uses local first-in-first-out
+     * Returns {@code true} if this pool uses local first-in-first-out
      * scheduling mode for forked tasks that are never joined.
      *
-     * @return true if this pool uses async mode
+     * @return {@code true} if this pool uses async mode
+     * @see #setAsyncMode
      */
     public boolean getAsyncMode() {
         return locallyFifo;
@@ -948,15 +892,15 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if all worker threads are currently idle. An idle
-     * worker is one that cannot obtain a task to execute because none
-     * are available to steal from other threads, and there are no
-     * pending submissions to the pool. This method is conservative;
-     * it might not return true immediately upon idleness of all
-     * threads, but will eventually become true if threads remain
-     * inactive.
+     * Returns {@code true} if all worker threads are currently idle.
+     * An idle worker is one that cannot obtain a task to execute
+     * because none are available to steal from other threads, and
+     * there are no pending submissions to the pool. This method is
+     * conservative; it might not return {@code true} immediately upon
+     * idleness of all threads, but will eventually become true if
+     * threads remain inactive.
      *
-     * @return true if all threads are currently idle
+     * @return {@code true} if all threads are currently idle
      */
     public boolean isQuiescent() {
         return activeCountOf(runControl) == 0;
@@ -1022,8 +966,8 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if there are any tasks submitted to this pool
-     * that have not yet begun executing.
+     * Returns {@code true} if there are any tasks submitted to this
+     * pool that have not yet begun executing.
      *
      * @return {@code true} if there are any queued submissions
      */
@@ -1036,7 +980,7 @@ public class ForkJoinPool extends Abstra
      * available.  This method may be useful in extensions to this
      * class that re-assign work in systems with multiple pools.
      *
-     * @return the next submission, or null if none
+     * @return the next submission, or {@code null} if none
      */
     protected ForkJoinTask<?> pollSubmission() {
         return submissionQueue.poll();
@@ -1059,7 +1003,7 @@ public class ForkJoinPool extends Abstra
      * @param c the collection to transfer elements into
      * @return the number of elements transferred
      */
-    protected int drainTasksTo(Collection<ForkJoinTask<?>> c) {
+    protected int drainTasksTo(Collection<? super ForkJoinTask<?>> c) {
         int n = submissionQueue.drainTo(c);
         ForkJoinWorkerThread[] ws = workers;
         if (ws != null) {
@@ -1125,8 +1069,22 @@ public class ForkJoinPool extends Abstra
     public void shutdown() {
         checkPermission();
         transitionRunStateTo(SHUTDOWN);
-        if (canTerminateOnShutdown(runControl))
+        if (canTerminateOnShutdown(runControl)) {
+            if (workers == null) { // shutting down before workers created
+                final ReentrantLock lock = this.workerLock;
+                lock.lock();
+                try {
+                    if (workers == null) {
+                        terminate();
+                        transitionRunStateTo(TERMINATED);
+                        termination.signalAll();
+                    }
+                } finally {
+                    lock.unlock();
+                }
+            }
             terminateOnShutdown();
+        }
     }
 
     /**
@@ -1136,7 +1094,7 @@ public class ForkJoinPool extends Abstra
      * method may or may not be rejected. Unlike some other executors,
      * this method cancels rather than collects non-executed tasks
      * upon termination, so always returns an empty list. However, you
-     * can use method {@code drainTasksTo} before invoking this
+     * can use method {@link #drainTasksTo} before invoking this
      * method to transfer unexecuted tasks to another collection.
      *
      * @return an empty list
@@ -1496,7 +1454,7 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if worker waiting on sync can proceed:
+     * Returns {@code true} if worker waiting on sync can proceed:
      *  - on signal (thread == null)
      *  - on event count advance (winning race to notify vs signaller)
      *  - on interrupt
@@ -1504,7 +1462,7 @@ public class ForkJoinPool extends Abstra
      * If node was not signalled and event count not advanced on exit,
      * then we also help advance event count.
      *
-     * @return true if node can be released
+     * @return {@code true} if node can be released
      */
     final boolean syncIsReleasable(WaitQueueNode node) {
         long prev = node.count;
@@ -1523,8 +1481,8 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if a new sync event occurred since last call to
-     * sync or this method, if so, updating caller's count.
+     * Returns {@code true} if a new sync event occurred since last
+     * call to sync or this method, if so, updating caller's count.
      */
     final boolean hasNewSyncEvent(ForkJoinWorkerThread w) {
         long lc = w.lastEventCount;
@@ -1608,8 +1566,8 @@ public class ForkJoinPool extends Abstra
     }
 
     /**
-     * Returns true if a spare thread appears to be needed.  If
-     * maintaining parallelism, returns true when the deficit in
+     * Returns {@code true} if a spare thread appears to be needed.
+     * If maintaining parallelism, returns true when the deficit in
      * running threads is more than the surplus of total threads, and
      * there is apparently some work to do.  This self-limiting rule
      * means that the more threads that have already been added, the
@@ -1777,11 +1735,13 @@ public class ForkJoinPool extends Abstra
 
     /**
      * Interface for extending managed parallelism for tasks running
-     * in ForkJoinPools. A ManagedBlocker provides two methods.
-     * Method {@code isReleasable} must return true if blocking is not
-     * necessary. Method {@code block} blocks the current thread if
-     * necessary (perhaps internally invoking {@code isReleasable}
-     * before actually blocking.).
+     * in {@link ForkJoinPool}s.
+     *
+     * <p>A {@code ManagedBlocker} provides two methods.
+     * Method {@code isReleasable} must return {@code true} if
+     * blocking is not necessary. Method {@code block} blocks the
+     * current thread if necessary (perhaps internally invoking
+     * {@code isReleasable} before actually blocking.).
      *
      * <p>For example, here is a ManagedBlocker based on a
      * ReentrantLock:
@@ -1805,15 +1765,15 @@ public class ForkJoinPool extends Abstra
          * Possibly blocks the current thread, for example waiting for
          * a lock or condition.
          *
-         * @return true if no additional blocking is necessary (i.e.,
-         * if isReleasable would return true)
+         * @return {@code true} if no additional blocking is necessary
+         * (i.e., if isReleasable would return true)
          * @throws InterruptedException if interrupted while waiting
          * (the method is not required to do so, but is allowed to)
          */
         boolean block() throws InterruptedException;
 
         /**
-         * Returns true if blocking is unnecessary.
+         * Returns {@code true} if blocking is unnecessary.
          */
         boolean isReleasable();
     }
@@ -1823,7 +1783,7 @@ public class ForkJoinPool extends Abstra
      * is a ForkJoinWorkerThread, this method possibly arranges for a
      * spare thread to be activated if necessary to ensure parallelism
      * while the current thread is blocked.  If
-     * {@code maintainParallelism} is true and the pool supports
+     * {@code maintainParallelism} is {@code true} and the pool supports
      * it ({@link #getMaintainsParallelism}), this method attempts to
      * maintain the pool's nominal parallelism. Otherwise it activates
      * a thread only if necessary to avoid complete starvation. This
@@ -1841,10 +1801,10 @@ public class ForkJoinPool extends Abstra
      * be expanded to ensure parallelism, and later adjusted.
      *
      * @param blocker the blocker
-     * @param maintainParallelism if true and supported by this pool,
-     * attempt to maintain the pool's nominal parallelism; otherwise
-     * activate a thread only if necessary to avoid complete
-     * starvation.
+     * @param maintainParallelism if {@code true} and supported by
+     * this pool, attempt to maintain the pool's nominal parallelism;
+     * otherwise activate a thread only if necessary to avoid
+     * complete starvation.
      * @throws InterruptedException if blocker.block did so
      */
     public static void managedBlock(ManagedBlocker blocker,
@@ -1870,65 +1830,31 @@ public class ForkJoinPool extends Abstra
         do {} while (!blocker.isReleasable() && !blocker.block());
     }
 
-    // AbstractExecutorService overrides
+    // AbstractExecutorService overrides.  These rely on undocumented
+    // fact that ForkJoinTask.adapt returns ForkJoinTasks that also
+    // implement RunnableFuture.
 
     protected <T> RunnableFuture<T> newTaskFor(Runnable runnable, T value) {
-        return new AdaptedRunnable<T>(runnable, value);
+        return (RunnableFuture<T>) ForkJoinTask.adapt(runnable, value);
     }
 
     protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
-        return new AdaptedCallable<T>(callable);
-    }
-
-
-    // Unsafe mechanics for jsr166y 3rd party package.
-    private static sun.misc.Unsafe getUnsafe() {
-        try {
-            return sun.misc.Unsafe.getUnsafe();
-        } catch (SecurityException se) {
-            try {
-                return java.security.AccessController.doPrivileged
-                    (new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
-                        public sun.misc.Unsafe run() throws Exception {
-                            return getUnsafeByReflection();
-                        }});
-            } catch (java.security.PrivilegedActionException e) {
-                throw new RuntimeException("Could not initialize intrinsics",
-                                           e.getCause());
-            }
-        }
+        return (RunnableFuture<T>) ForkJoinTask.adapt(callable);
     }
 
-    private static sun.misc.Unsafe getUnsafeByReflection()
-            throws NoSuchFieldException, IllegalAccessException {
-        java.lang.reflect.Field f =
-            sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
-        f.setAccessible(true);
-        return (sun.misc.Unsafe) f.get(null);
-    }
-
-    private static long fieldOffset(String fieldName, Class<?> klazz) {
-        try {
-            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(fieldName));
-        } catch (NoSuchFieldException e) {
-            // Convert Exception to Error
-            NoSuchFieldError error = new NoSuchFieldError(fieldName);
-            error.initCause(e);
-            throw error;
-        }
-    }
+    // Unsafe mechanics
 
     private static final sun.misc.Unsafe UNSAFE = getUnsafe();
-    static final long eventCountOffset =
-        fieldOffset("eventCount", ForkJoinPool.class);
-    static final long workerCountsOffset =
-        fieldOffset("workerCounts", ForkJoinPool.class);
-    static final long runControlOffset =
-        fieldOffset("runControl", ForkJoinPool.class);
-    static final long syncStackOffset =
-        fieldOffset("syncStack",ForkJoinPool.class);
-    static final long spareStackOffset =
-        fieldOffset("spareStack", ForkJoinPool.class);
+    private static final long eventCountOffset =
+        objectFieldOffset("eventCount", ForkJoinPool.class);
+    private static final long workerCountsOffset =
+        objectFieldOffset("workerCounts", ForkJoinPool.class);
+    private static final long runControlOffset =
+        objectFieldOffset("runControl", ForkJoinPool.class);
+    private static final long syncStackOffset =
+        objectFieldOffset("syncStack",ForkJoinPool.class);
+    private static final long spareStackOffset =
+        objectFieldOffset("spareStack", ForkJoinPool.class);
 
     private boolean casEventCount(long cmp, long val) {
         return UNSAFE.compareAndSwapLong(this, eventCountOffset, cmp, val);
@@ -1945,4 +1871,43 @@ public class ForkJoinPool extends Abstra
     private boolean casBarrierStack(WaitQueueNode cmp, WaitQueueNode val) {
         return UNSAFE.compareAndSwapObject(this, syncStackOffset, cmp, val);
     }
+
+    private static long objectFieldOffset(String field, Class<?> klazz) {
+        try {
+            return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field));
+        } catch (NoSuchFieldException e) {
+            // Convert Exception to corresponding Error
+            NoSuchFieldError error = new NoSuchFieldError(field);
+            error.initCause(e);
+            throw error;
+        }
+    }
+
+    /**
+     * Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
+     * Replace with a simple call to Unsafe.getUnsafe when integrating
+     * into a jdk.
+     *
+     * @return a sun.misc.Unsafe
+     */
+    private static sun.misc.Unsafe getUnsafe() {
+        try {
+            return sun.misc.Unsafe.getUnsafe();
+        } catch (SecurityException se) {
+            try {
+                return java.security.AccessController.doPrivileged
+                    (new java.security
+                     .PrivilegedExceptionAction<sun.misc.Unsafe>() {
+                        public sun.misc.Unsafe run() throws Exception {
+                            java.lang.reflect.Field f = sun.misc
+                                .Unsafe.class.getDeclaredField("theUnsafe");
+                            f.setAccessible(true);
+                            return (sun.misc.Unsafe) f.get(null);
+                        }});
+            } catch (java.security.PrivilegedActionException e) {
+                throw new RuntimeException("Could not initialize intrinsics",
+                                           e.getCause());
+            }
+        }
+    }
 }