Strengthening the Modeling Foundation of the MDA

The Model Driven Architecture (MDA) represents a positive step toward a general model-based approach to software engineering. The conceptualization of the MDA is not yet mature; it is still being formed. Elements of a modeling foundation are described in this paper, including an architecture of software engineering and a multi-dimensional modeling space that provides separation of concerns and a systematic and uniform approach to models that is self-similar at all levels of each dimension. The position of the paper is that a modeling approach is the right way forward, but the MDA can be strengthened and made more complete by incorporation of some of the concepts in the proposed modeling foundation. 1. Purpose and content OMG has introduced the Model Driven Architecture (MDA) as its next generation architecture and general approach to technology integration. Much of the work the OMG has previously done can readily be incorporated into a model-oriented approach. Furthermore, the concept of a model driven architecture is more generally applicable to the larger software engineering community, and not limited to OMG technologies. Therefore, the position of this paper is strongly in support of the general thrust of the MDA toward a broader modeling approach. However, a key supposition of this paper is that further strengthening of the modeling foundation for the MDA would be beneficial in realizing MDA goals and the larger goals of software model engineering. The purpose of the paper is to describe a modeling foundation for software engineering, and to indicate how this foundation can strengthen the MDA. The paper proposes a general modeling space as a key element of this approach. The paper has two parts. The first part, in Section 2, provides an introduction to the modeling foundation, with more details in the areas related to the MDA. The second part, in Section 3, raises certain issues in the current MDA, and shows how they are addressed by the modeling foundation. 2. Introduction to modeling foundation The artifacts of software engineering have traditional names such as requirements specification, architecture description, design description, source code, and executable code. In this foundation, all these artifacts are regarded as models. Based on this orientation, the foundation consists of a context described as the architecture of software engineering, followed by an introduction to a general modeling space, which is the key focus of the architecture. Copyright (C) 2002. The MITRE Corporation. All Rights Reserved. Hybertson 2 2.1 Architecture of software engineering The architecture of software engineering consists of three interacting components: a problem space, a modeling space, and an execution space that includes computers. The full architecture includes multiple relations among these three components, but for the purposes of this paper, we focus on three specific relations, as illustrated in Figure 1. The problem space is the “real world” that comes up with problems that can be solved by computers. The problems exhibit great variation, but they are organized into more homogeneous sets of problems called problem domains. The modeling space is an organized collection of all software and system models. Most of this paper is focused on the structure and contents of the modeling space. The execution space is where certain models, called executable models, are used to govern the behavior of the computer and other related run-time resources, which interact with users and other systems in the problem space to solve problems in a given problem domain. The models bridge the gap between specific problem domains in the problem space and specific computer processor architectures in the execution space. Problem space Models Modeling space Execution space 1