/** Find all reapable sign messages */
 private void findReapableMessages() {
   Iterator<SignMessage> it = SignMessageHelper.iterator();
   while (it.hasNext()) {
     SignMessage sm = it.next();
     if (sm instanceof SignMessageImpl) reapable.add((SignMessageImpl) sm);
   }
 }
 /** 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();
 }