- CodeList values shall be expressed as UML enumerations in the Conceptual Model within a UML class given the CodeList stereotype.
- The enumerated CodeList values shall consist of strings which are regular expressions (including explicit fixed values). Note: the use of regular expressions not fully discussed.
- Values appearing in an encoded instance must either match a regular expression appearing in the enumeration or appear in an External Source that replaces that enumeration.
- If an External Source is used, then the values in the External Source shall replace any values present in the UML enumeration.
- Encoded values from an External Source must include the URI for the external source. How this is done is defined by an encoding specification and mst follw rules and conventions of the encoding language. For example, an XML-encoded codelist value might have an element attribute specifying the URI defining the source or codespace for that source.
- Regardless of the method of encding vales from an External Source, the absence of a specification of an External Source implies that the codelist value must be present in the enumeration in the UML specification.
- Any attribute defined with the Codelist stereotype may be replaced by an External Source.
- The standard does not provide a normative list of External Sources.