Model-Driven Engineering, Services and Interactive Real-Time Applications

1.1 Overview

Model-driven software engineering (MDE) (Kent, 2002) refers to the generation of software systems from high-level abstractions using meta-models and models. A meta-model provides the language abstraction of a system, while models, i.e. instances of the meta-models, allow the specification of an intended application based upon the constraints imposed by the meta-model. Typically, MDE is used in the building of a domain specific language (DSL) (Fowler & Pearson, 2010). A DSL, as opposed to a general purpose low-level language like Java or C++, is a high-level language containing abstractions that are specific to a certain application area or task. For example, the language constructs for a DSL in the automotive domain may refer to concepts relating directly to automotive concepts (e.g. vehicle type, engine capacity, transmission, etc.).

The architecture of such languages typically consists of two key elements: the abstract and the concrete syntax. The abstract syntax is usually defined using a model. As this model is actually a model of other models it is called a meta-model. The meta-model describes the different concepts of the language and the relationships between them. The concrete syntax describes what syntactic elements constitute the language, or how the elements of the abstract syntax are to be presented or specified. One example is that in the Unified Modeling Language (UML) (OMG, 2010c) a Class is represented by a box. A language may have several concrete syntaxes for the same abstract syntax. For example it can have both a graphical notation (diagrams) and a textual notation. The field of language engineering is not new, but in recent years tool support has improved considerably. This eases the creation of both abstract and concrete syntaxes and the connections between them. Examples of such tools are the Eclipse Graphical Modeling Framework (GMF) (Eclipse, 2010b) and MetaEdit from MetaCase (Metacase, 2010). The Object Management Group (OMG) (OMG, 2010a), the standardisation organisation behind the UML, typically when standardising such specific languages requires a meta-model and a UML profile representing the concrete syntax.

In this chapter we describe a number of the state of the art approaches in modeling with respect to language development, services and real-time modeling.

2.1 MOF

The Meta Object Facilities (MOF) (OMG, 2010b) proposed by the OMG provides a meta-metamodel at its top layer. If we consider a meta-model as concepts for describing models, then a meta-metamodel can be considered as the concepts used for describing a given meta-model. MOF is based on the object-oriented paradigm and there are different flavours in existence: Complete MOF (CMOF), Essential MOF (EMOF) and Semantic MOF (SMOF). CMOF is the whole of the MOF specification, whereas the EMOF contains only a subset of the main elements of MOF. SMOF is currently a proposal for adding additional semantics to MOF. MOF is currently utilised by UML and Ecore, i.e. the meta-model of the Eclipse Modeling Framework (Eclipse, 2010a).