Software architects view systems under
construction from multiple viewpoints such as the 4+1 logical,
development, physical, process, and scenario viewpoints. Their methods
and tools typically center on these structural viewpoints. The capturing
of architectural decision rationale, however, is another essential
viewpoint, which only recently has become a software architecture
research topic. Unfortunately, most of the emerging architectural
decision modeling tools only support the retrospective capturing of
decisions made; they do not support a proactive modeling of decisions
required (issues) and available solutions (alternatives). This limits
the opportunities for reuse.
In this lecture, we first present two large-scale industry projects to motivate the benefits of proactive architectural decision modeling. Next, we introduce a meta model which separates decisions required from decisions made to support reuse. As meta model instances, we present excerpts from a 500-node Service-Oriented Architecture (SOA) decision model harvested from full lifecycle projects since 2001: We investigate selected SOA design decisions such as the selection of integration style and message exchange patterns, transaction management, and service granularity. We also demonstrate how to capture decisions required and their alternatives in Architectural Decision Knowledge Wiki, a Web 2.0 collaboration system and application wiki supporting decision maker collaboration over the Web. Meta model, reusable SOA decision model and application wiki jointly support real-world usage scenarios such as project team education, architecture design method support, facilitation of technical quality assurance reviews, and IT governance.
Dr. Olaf Zimmermann is a Research Staff Member in the IBM Zurich Research Lab. Olaf recently received his Ph. D. (Dr. rer. nat) from Suttgart University, Germany (Prof. Frank Leymann); in his Ph. D. dissertation, he created an architectural decision modeling framework for Service-Oriented Architetcure (SOA) design. Olaf also is an Open Group Master Certified and IBM senior certified Executive IT Architect; he has 20 years of IT industry experience.
Previously, Olaf was a solution architect, helping IBM clients designing enterprise-scale SOA/Web services and Java Enterprise Edition (JEE) solutions on numerous professional services projects. He also educated practitioners around the world on emerging middleware technologies. In the beginning of his career, Olaf worked as a scientific consultant in the IBM European Networking Center (ENC) in Heidelberg, Germany, focusing on industry-specific middleware frameworks for systems and network management.
Olaf is a regular conference speaker and an author of the Springer text book „Perspectives on Web Services“. He contributed to several IBM Redbooks such as „Web Services Wizardry with WebSphere Studio Application Developer“.