* @throws XMLStreamException An exception processing the underlying {@link XMLStreamReader}.
*/
private static void readData(final XMLStreamReader reader, final Configuration configuration, final Datamodel dm)
throws XMLStreamException, ModelException {
Data datum = new Data();
datum.setId(readRequiredAV(reader, ELEM_DATA, ATTR_ID));
datum.setExpr(readAV(reader, ATTR_EXPR));
readNamespaces(configuration, datum);
datum.setNode(readNode(reader, configuration, XMLNS_SCXML, ELEM_DATA, new String[] {"id"}));
dm.addData(datum);
}