code: @SuppressWarnings("unchecked")
      protected Iterator _transform(final Iterator iterator) {
          if (iterator == null) return null;
          if (iterator instanceof BeanIterator) return iterator;
          return new BeanIterator(iterator, this);
      }
docs: <p>_transform.</p>
  
  @param iterator a {@link java.util.Iterator} object.
  @return a {@link java.util.Iterator} object.