code: public PortletPreferencesType<PortletType<T>> getOrCreatePortletPreferences()
     {
        Node node = childNode.getOrCreate("portlet-preferences");
        PortletPreferencesType<PortletType<T>> portletPreferences = new PortletPreferencesTypeImpl<PortletType<T>>(this, "portlet-preferences", childNode, node);
        return portletPreferences;
     }
docs: If not already created, a new <code>portlet-preferences</code> element with the given value will be created.
  Otherwise, the existing <code>portlet-preferences</code> element will be returned.
  @return  a new or existing instance of <code>PortletPreferencesType<PortletType<T>></code>