/** Reap one sign message */
 private void reapMessage(SignMessageImpl sm) {
   // Make sure the message has not already been
   // reaped by looking it up in the namespace.
   // This is needed because objects are removed
   // asynchronously from the namespace.
   SignMessage m = SignMessageHelper.lookup(sm.getName());
   if ((m == sm) && !isReferenced(m)) sm.notifyRemove();
 }