code: public void setDocumentLocator (@Nullable final Locator aLocator)
    {
      if (m_bTrackPosition)
      {
        m_aLocator = aLocator;
        _updatePosition ("setLocator");
        if (aLocator instanceof Locator2)
        {
          m_sSourceXMLVersion = ((Locator2) aLocator).getXMLVersion ();
          m_sSourceXMLEncoding = ((Locator2) aLocator).getEncoding ();
        }
      }
    }
docs: Called before startDocument (if called)