Michael Wahler

The Role of Visual Modeling and Model Transformations in Business-driven Development

This paper explores the emerging paradigm of business-driven development, which presupposes a methodology for developing IT solutions that directly satisfy business requirements and needs. At the core of business-driven development are business processes, which are usually modeled by combining graphical and textual notations. During the business-driven development process, business-process models are taken down to the IT level, where they describe the so-called choreography of services in a Service-Oriented Architecture. The derivation of a service choreography based on a business-process model is simple and straightforward for toy examples only-for realistic applications, many challenges at the methodological and technical level have to be solved. This paper explores these challenges and describes selected solutions that have been developed by the research team of the IBM Zurich Research Laboratory.

Declarative techniques for model-driven business process integration

Business process integration and automation are among the most significant factors driving the information technology industry today. In addressing the manifold technology challenges of integration and automation, new standardization efforts aim at improving the interoperability of businesses by moving toward a declarative specification of business processes, that is, one which describes what a business process does and not how it is implemented. At the same time, Model Driven Architecture® focuses on improving the software-engineering methods with which business process solutions are implemented by separating the business or application logic from the underlying platform technology and representing this logic with precise semantic models. In this paper, we present an approach to the model-driven generation of programs in the Business Process Execution Language for Web Services (BPEL4WS), which transforms a graphically represented control-flow model into executable code by using techniques that originated in compiler theory. We discuss the underlying algorithms as well as general questions concerning the representation and analysis of model transformations. We study a declarative representation of transformation rules, where preconditions and postconditions are represented in the Object Constraint Language. By adopting a declarative approach, we pave the way for future automatic consistency checking of transformation rules and bidirectional reconciliation of evolving models.

Model-Driven Constraint Engineering

Precise specification of meta-models is an important prerequisite for the successful application of a model-driven engineering (MDE) process. One means of precise specification are textual constraints. However, the task of constraint de- velopment is time-consuming and error-prone if done manually. In this paper, we present both a methodology and a tool for developing constraints in a systematic way that can be integrated into a CASE tool. Thus, we provide a semi-automated means for integrating constraints into the MDE process. Our approach is based on an extensible library of generic constraint patterns. Con- straint patterns can be combined to create complex constraints and easily parame- terized in a CASE tool. Moreover, we show how these parameterized patterns are transformed into platform-independent or platform-specific constraints by a model transformation.

Efficient analysis of pattern-based constraint specifications

Precision and consistency are important prerequisites for class models to conform to their intended domain semantics. Precision can be achieved by augmenting models with design constraints and consistency can be achieved by avoiding contradictory constraints. However, there are different views of what constitutes a contradiction for design constraints. Moreover, state-of-the-art analysis approaches for proving constrained models consistent either scale poorly or require the use of interactive theorem proving. In this paper, we present a heuristic approach for efficiently analyzing constraint specifications built from constraint patterns. This analysis is based on precise notions of consistency for constrained class models and exploits the semantic properties of constraint patterns, thereby enabling syntax-based consistency checking in polynomial-time. We introduce a consistency checker implementing these ideas and we report on case studies in applying our approach to analyze industrial-scale models. These studies show that pattern-based constraint development supports the creation of concise specifications and provides immediate feedback on model consistency.

A model driven XML transformation framework for Business Performance Management model creation

As XML formats have been widely adopted for representing business documents both within and across enterprises, XML to XML translation becomes a common and critical component for business process integration. Due to limitations of popular approaches such as XSLT for XML translations, we designed a model driven development framework for XML to XML translation with the additional benefits of code re-use and strong built-in model validation. We further applied this framework to the domain of Business Performance Management (BPM), converting documents from human-readable XML format to machine-readable XMI format. Experimental evaluation indicated that XML models can have more than 75% size reduction.