String svalue = fac.convertToString(d, value);
String svalue = helper.convertToString(fac, d, value);
  protected void saveDataTypeElementSingle(EObject o, EStructuralFeature f)  {    String name = helper.getQName(f);    Object value = helper.getValue(o, f);    if (value == null)    {      doc.startElement(name);      doc.addAttribute(XSI_NIL, "true");      doc.endEmptyElement();      declareXSI = true;    }    else    {      EDataType d = (EDataType)f.getEType();      EPackage ePackage = d.getEPackage();      EFactory fac = ePackage.getEFactoryInstance();      doc.startElement(name);      String svalue = fac.convertToString(d, value);      if (escape != null)      {        svalue = escape.convert(svalue);      }      doc.endContentElement(svalue);    }  }