/** remove an entry from the pipe... (marks it evicted to be skipped later) */
 public boolean unlinkEntry(LRUClockNode entry) {
   if (logger.isTraceEnabled(LogMarker.LRU_CLOCK)) {
     logger.trace(
         LogMarker.LRU_CLOCK,
         LocalizedMessage.create(LocalizedStrings.NewLRUClockHand_UNLINKENTRY_CALLED, entry));
   }
   entry.setEvicted();
   stats().incDestroys();
   synchronized (lock) {
     LRUClockNode next = entry.nextLRUNode();
     LRUClockNode prev = entry.prevLRUNode();
     if (next == null || prev == null) {
       // not in the list anymore.
       return false;
     }
     next.setPrevLRUNode(prev);
     prev.setNextLRUNode(next);
     entry.setNextLRUNode(null);
     entry.setPrevLRUNode(null);
   }
   return true;
 }