UML extensibility


UML defines three extensibility mechanisms to allow modelers to add extensions without having to modify the underlying modeling language. These three mechanisms are stereotypes, constraints and tagged values. Each project comes with a ‘UML extensibility’ node. UML Stereotypes and UML Constraints are gathered in this node.

UML allows the addition of a pair of string (a tag string and a value string) on every model element. User-defined properties provide the same functionality, however the value can be of any type (string, integer, boolean, and so on). Thus User-defined properties do the same as UML tagged values, but they do it better. See User Properties for more details.