code: private int getSeenMessageCount()
     {
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.entry(this, tc,"getSeenMessageCount");
        
        int seenMsgs = 0;
        for (int x = 0; x < nextIndex; x++)
        {
           if (messages[x] != null) seenMsgs++;
        }
        
        if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled()) SibTr.exit(this, tc,"getSeenMessageCount", ""+seenMsgs);
        return seenMsgs;
     }
docs: Private method to determine how many messages have been seen and not unlocked or deleted. It
  does this by looking at the number of non-null elements before the current item.
  <p>
  Note that if an item was seen but then the cursor was reset it will become unseen again
  until it is viewed with nextLocked().
  
  @return Returns the number of seen items that have not been deleted or unlocked.