FieldMapComplex fieldMapComplex = new FieldMapComplex();
fieldMapComplex.setDateValue(date);
fieldMapComplex.setDoubleValue(1.0);
fieldMapComplex.setStringValue("stringValue");
FieldMapSimple simple = new FieldMapSimple();
simple.setSimpleStringContent("simpleStringContent");
fieldMapComplex.setContent(simple);
Parser parser =new Parser();
String xml = parser.encode(fieldMapComplex);