Minor Description
According the schema shows at http://www.schemacentral.com/sc/niem21/t-gmd_PT_FreeText_PropertyType.html a PT_FreeText can contains either a CharacterString or various code lists. However current SIS implementation accepts only a CharacterString. We need to accept code list as-well. We can do that by adding some getCodeList() method in the SIS PT_FreeText class. Only one of getCodeList() and getCharacterString() methods can return a non-null value.