--- jsr166/src/jsr166y/LinkedTransferQueue.java	2009/11/15 01:53:11	1.68
+++ jsr166/src/jsr166y/LinkedTransferQueue.java	2010/04/05 15:50:51	1.72
@@ -343,7 +343,7 @@ public class LinkedTransferQueue<E> exte
      * When these cases arise, rather than always retraversing the
      * entire list to find an actual predecessor to unlink (which
      * won't help for case (1) anyway), we record a conservative
-     * estimate of possible unsplice failures (in "sweepVotes).  We
+     * estimate of possible unsplice failures (in "sweepVotes").  We
      * trigger a full sweep when the estimate exceeds a threshold
      * indicating the maximum number of estimated removal failures to
      * tolerate before sweeping through, unlinking cancelled nodes
@@ -876,17 +876,18 @@ public class LinkedTransferQueue<E> exte
     }
 
     /**
-     * Unlink matched nodes encountered in a traversal from head
+     * Unlinks matched nodes encountered in a traversal from head.
      */
     private void sweep() {
-        Node p = head, s, n;
-        while (p != null && (s = p.next) != null && (n = s.next) != null) {
-            if (p == s || s == n)
-                p = head; // stale
-            else if (s.isMatched())
-                p.casNext(s, n);
-            else
+        for (Node p = head, s, n; p != null && (s = p.next) != null; ) {
+            if (p == s)                    // stale
+                p = head;
+            else if (!s.isMatched())
                 p = s;
+            else if ((n = s.next) == null) // trailing node is pinned
+                break;
+            else
+                p.casNext(s, n);
         }
     }
 
@@ -1124,7 +1125,11 @@ public class LinkedTransferQueue<E> exte
      * @return {@code true} if this queue contains no elements
      */
     public boolean isEmpty() {
-        return firstOfMode(true) == null;
+        for (Node p = head; p != null; p = succ(p)) {
+            if (!p.isMatched())
+                return !p.isData;
+        }
+        return true;
     }
 
     public boolean hasWaitingConsumer() {