Declarative techniques for model-driven business process integration
Author: IBM Systems Journal

Model Driven Architecture ** (MDA **) has been proposed by the Object Management Group (OMG) to enhance the efficiency and quality of software development and to reinforce the use of an enterprise architecture strategy. Models can be specified from different views, such as that of a business analyst or an information technology (IT) architect, and can be represented at different levels of abstraction. MDA separates the business or application logic from the underlying platform technology and represents this logic with precise semantic models. In particular, MDA distinguishes between Platform-Independent Models (PIMs) and Platform-Specific Models (PSMs). These models are meant to span the entire life cycle of a software system, facilitate software production and maintenance tasks, and increase software quality.

In order for MDA to succeed as a new and emerging software development paradigm, automatic tools must be available that address two key challenges in particular: the analysis and verification of model-based designs, which allow a human user or an automatic tool to generate new insights into the structural and behavioral features of the modeled system or process; and the mapping and transformation between different models and metamodels with the goal of facilitating conversion to and from PIMs and PSMs. (A metamodel is a precise definition of the constructs and rules needed for creating models.)

Figure 1 shows a set of transformations between a PIM and a PSM. PIMs can be automatically transformed into executable PSMs by compilation techniques. Compilation constitutes the main focus of this paper. We investigate how compilation transforms a PIM (specified by a UML 2.0 ** [Unified Modeling Language ** Version 2] activity diagram (1) that captures the operational requirements of a process at the business level into an executable PSM--namely, a program in the Business Process Execution Language for Web Service (BPEL4WS) (2) that satisfies the operational requirements captured in the PIM. Compilation is a one-way process producing code from a model, where the code and the model may remain linked or evolve independently of each other. In contrast, model reconciliation links models together such that they remain synchronized even if those models change, thus requiring bidirectional transformations. Bidirectional transformations between business process models and IT execution models are of particular importance, because they enable organizations to develop business-level and IT-level models at their own pace, while keeping the models synchronized.