On the Classification of UML’s Meta Model Extension Mechanism

Although the UML meta model extension mechanism has been used in many modeling fields in which extension of UML is needed, UML specification has little necessary classification and application guidance on the meta model extension mechanism. This paper defines four levels of UML’s meta model extension mechanism, and discusses the readability, expression capability, use scope and tool support on the basis of precise definitions of each level. The work on the paper reinforces the maneuverability of the UML meta model extension mechanism, and provides a reliable theoretical base for the development of modeling tools that support meta model extension.