@Override
 public int compareTo(Object r2) {
   if (!(r2 instanceof DynamicType)) {
     return super.compareTo(r2);
   }
   int result = SimpleEntity.timestampCompare(this, (DynamicType) r2);
   if (result != 0) {
     return result;
   } else {
     return super.compareTo(r2);
   }
 }