Rearchitecting the UML infrastructure

Abstract

Metamodeling is one of the core foundations of computer-automated multiparadigm modeling. However, there is currently little agreement about what form the required metamodeling approach should take and precisely what role metamodels should play. This article addresses the problem by first describing some fundamental problems in the industry's leading metamodeling technology, the UML framework, and then explaining how this framework could be rearchitected to overcome these problems. Three main issues are identified in the current framework: the dual classification problem arising from the need to capture both the logical and physical classification of model elements, the class/object duality problem arising from the need to capture both the classlike and objectlike facets of some model elements, and the replication of concepts problem arising from the need to define certain concepts multiple times. Three main proposals for rearchitecting the UML framework to overcome these problems are then presented: the separation of logical and physical classification dimensions, the unification of the class and object facets of model elements, and the enhancement of the instantiation mechanism to allow definitions to transcend multiple levels. The article concludes with a discussion of other practical issues involved in rearchitecting the UML modeling framework in the proposed way.

A formalisation of deep metamodelling

“…In this work, we adopt the deep characterisation approach described in [AK02b]. In this approach, each element has a potency.…”

“…In this approach, each element has a potency. In the original proposal of [AK02b], the potency is a natural number which is attached to a model element to describe at how many subsequent metalevels this element can be instantiated. Moreover, the potency decreases in one unit at each instantiation at a deeper metalevel.…”

“…In this approach, a system is specified using models at two metalevels: a metamodel defining allowed types and a model instantiating these types. However, this approach may have limitations [AK02b,AK08,GPHS06], in particular when the metamodel includes the type-object pattern [AK02b,AK08,GPHS06], which requires an explicit modelling of types and their instances at the same metalevel. In this case, deep metamodelling (also called multi-level metamodelling) using more than two metalevels yields simpler models [AK08].…”

“…Deep metamodelling was proposed in the seminal works of Atkinson and Kühne [AK02b], and several researchers and tools have subsequently adopted this approach [ADP09,AM09,dG10,dGCML13]. However, there is still a lack of formalisation of the main concepts of deep metamodelling such as deep characterisation through potency, double linguistic/ontological typing and linguistic extension [dG10].…”

Generic Meta-modelling with Concepts, Templates and Mixin Layers

“…MetaDepth [3] is a new multi-level meta-modelling framework with support for multiple meta-levels at the same time using potency [1]. This approach is very useful to describe what we call deep languages, which are languages that involve two or more meta-levels at the user level.…”