impl dv xs math BigInteger xml datatype DatatypeConstants xml datatype Duration impl dv InvalidDatatypeValueException impl dv ValidationContext yearmonthdurationdv durationdv getactualvalue content validationcontext context invaliddatatypevalueexception parse content durationdv.yearmonthduration_type ex invaliddatatypevalueexception content duration getduration datetimedata date sign date.year date.month sign datatypefactory.newduration sign date.year datatypeconstants.field_undefined biginteger.valueof sign date.year date.month datatypeconstants.field_undefined biginteger.valueof sign date.month