Inducing metaassociations and induced relationships

The definition of the exact meaning of conceptual modeling concepts is considered a relevant issue since it enhances their effective and appropriate use by designers and facilitates the automatic processing of the models where they are included. Three related concepts that permit to improve the definition of an association in UML and which still lack of a formal semantic definition are: association redefinition, association specialization and association subsetting. This paper formalizes their semantics and points out the similarities and differences that exist among them. The formalization we propose is based on the meta-modelling approach and a semantic domain composed of a set of basic UML concepts and OCL expressions, which have a previous formal definition in the literature and which are well-understood. Preprint

Information and Software Technology, 2014

Context -Generalization is a fundamental relationship in object orientation and in the UML (Unified Modeling Language). The generalization relationship is represented in the UML metamodel as a "directed relationship". Objective -Being a directed relationship corresponds to the nature of generalization in the semantic domain of object orientation: a relationship that is directed from the subclass to the superclass. However, we claim that the particular form this relationship adopts in the metamodel is erroneous, which entails a series of inconveniencies for model manipulation tools that try to adhere to the UML specification. Moreover, we think that this error could be due to a misinterpretation of the relationships between metamodeling levels in the UML: represented reality (M0), model (M1) and metamodel (M2). This problem also affects other directed relationships: Dependency and its various subtypes, Include and Extend between use cases, and others. Method -We analyze the features of the generalization relationship in various domains and how it has been metamodeled in UML. We examine the problems, both theoretical and technological, posed by the UML metamodel of generalization. We then compare it with the metamodel of other directed relationships. Results -We arrive at the conclusion that the metamodel of all directed relationships could be improved. Namely, we claim that, at level M2, the metamodel should not contain any one-way meta-associations: all meta-associations should be two-way, both for practical and theoretical reasons. Conclusions -The rationale for our main claim can be summarized as follows: connected graphical symbols do know each other, and the goal of a metamodel is to specify the syntactic properties of a language, ergo meta-associations must be two-way. This, of course, does not preclude at all the use of one-way associations at the user model level (M1).

The use of general purpose modeling languages (GPMLs) in specifying software applications has given way to the use of domain-specific modeling languages (DSMLs). DSMLs offer a vocabulary of terms and concepts that are fundamental to the problem and solution domains, whereas GPMLs constructs are usually too generic to be directly applied in some domains. Many DSMLs are high-level textual programming languages, which offered little support for modeling at the analysis, and design phases of application development. The objective of this work is to develop semiformal graphical DSMLs, which are to be used at the analysis and design stages of application development. The benefits derived from such DSML are reuse of domain artifacts; reduction in delivering completed products; rigorous analysis of domain applications; and more maintainable applications.

1999

The Unified Modelling Language is emerging as a de-facto standard for modelling object-oriented systems. However, the semantics document that a part of the standard definition primarily provides a description of the language's syntax and well-formedness rules. The meaning of the language, which is mainly described in English, is too informal

Seventh International Database Engineering and Applications Symposium, 2003. Proceedings., 2003

In the context of information system engineering, we propose a four-layer metamodeling architecture with a comprehensive set of operations on metamodels. Our architecture enables modelers to use a three-step modeling process: first, giving an informal description of the universe of the discourse (in terms of modeling paradigms); then, defining a corresponding UML dialect (in terms of metamodels); and finally -using the chosen dialect-describing a model of an information system. By using specific properties of our metamodeling architecture, we define formal and semantical operations on metamodels, e.g., integration of metamodels. In this paper we focus on a measure of a semantical distance between metamodels.

2015

The UML standard has adopted a meta-modelling approach to defining the abstract syntax of UML. A meta-modelling approach is taken essentially to aid the construction of automated tools, but the semantics is defined by statements in English. A meta-model that incorporates precise semantics would support the construction of tools that could perform semantically-oriented tasks, such as consistency checking. One approach to defining the formal semantics of a language is denotational: essentially elaborating (in mathematics) the value or instance denoted by an expression of the language in a particular context. However, instances must also be expressed in some language: in UML, instances of the static model are expressed using object diagrams. Thus a meta-model can be constructed which incorporates (a) the modelling language itself, (b) the modelling language of instances, and (c) the mapping of one into the other. The current UML meta-model provides some support for (a) and (b), but not...

Lecture Notes in Computer Science, 2002

UML is a widespread software modeling language. It can be a good candidate for modeling non-software systems, such as enterprise systems. While several proposals have been formulated, they are either incomplete or complex. In this paper we propose a modeling approach that is based on the basic object-orientation concepts. In particular we stress the use of instance models as a key concept.

«UML» 2001—The Unified Modeling Language. …, 2001

Associations between classifiers are among the most fundamental of UML concepts. However, there is considerable room for disagreement concerning what an association is, semantically. These have implications for the modeller because they can result in serious misunderstandings of static structure diagrams; similarly, they have implications for tool developers. In this paper we describe and classify the variants which have implicitly or explicitly been described. We discuss the scope for, and difficulties in, understanding these as specialisations of a more general notion and we address the implications for future versions of UML.

2004

The usage of UML in specific contexts (like real-time systems or process modelling) is specially appealing since it provides a standard modelling notation widely used by the software engineering community. However, such usage usually requires to tailor (extend) the UML metamodel. The standard extension mechanisms suffer from several expressiveness limitations. In this report we identify these limitations and we define a two-tiered methodology to construct standard metamodels as extensions of the UML metamodel. Specifically, we present a methodology to obtain a conservative extension of the UML 1.4 metamodel (as a particular case of any well-defined MOF-model instance) and another to transform an extended UML 1.4 metamodel into a UML profile. As a result, we are able to combine the expressiveness provided by the explicit extension with the standardization coming from the use of profiles, which allows also the usage of existing tools.

Lecture Notes in Computer Science, 2006

In fact, UML2 offers two definitions of associations. One is implicit in several Description and Semantics sections of the Spec and belongs to the UML folklore. It simply says that an association is a set of links. The other-official and formal-definition is explicitly fixed by the UML metamodel and shows that there is much more to associations than just being sets of links. Particularly, association ends can be owned by either component classes or by the very association (with a striking difference between binary and multiary associations), be navigable or not, and have some constraints on combining ownership and navigability. The paper presents a formal framework, based on sets and mappings, where all notions involved in the both definitions can be accurately explained and formally explicated. Our formal definitions allow us to reconcile the two views of associations, unify ownership for binary and multiary associations and, finally, detect a few flaws in the association part of the UML metamodel.