--- jsr166/src/jsr166y/CountedCompleter.java	2012/10/21 05:28:08	1.5
+++ jsr166/src/jsr166y/CountedCompleter.java	2012/11/18 18:03:10	1.13
@@ -77,7 +77,7 @@ package jsr166y;
  * continuations, other threads need not block waiting to perform
  * them.
  *
- * <p> For example, here is an initial version of a class that uses
+ * <p>For example, here is an initial version of a class that uses
  * divide-by-two recursive decomposition to divide work into single
  * pieces (leaf tasks). Even when work is split into individual calls,
  * tree-based techniques are usually preferable to directly forking
@@ -142,7 +142,7 @@ package jsr166y;
  *
  * As a further improvement, notice that the left task need not even
  * exist.  Instead of creating a new one, we can iterate using the
- * original task, and add a pending count for each fork:
+ * original task, and add a pending count for each fork.
  *
  * <pre> {@code
  * class ForEach<E> ...
@@ -378,6 +378,19 @@ public abstract class CountedCompleter<T
     }
 
     /**
+     * Returns the root of the current computation; i.e., this
+     * task if it has no completer, else its completer's root.
+     *
+     * @return the root of the current computation
+     */
+    public final CountedCompleter<?> getRoot() {
+        CountedCompleter<?> a = this, p;
+        while ((p = a.completer) != null)
+            a = p;
+        return a;
+    }
+
+    /**
      * If the pending count is nonzero, decrements the count;
      * otherwise invokes {@link #onCompletion} and then similarly
      * tries to complete this task's completer, if one exists,
@@ -465,7 +478,6 @@ public abstract class CountedCompleter<T
         }
     }
 
-
     /**
      * Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
      * Replace with a simple call to Unsafe.getUnsafe when integrating
@@ -493,5 +505,4 @@ public abstract class CountedCompleter<T
             }
         }
     }
-
 }