Four Mechanisms for Adaptable Systems: A Meta-level Approach to Building a Software Product Line

Meta-level architectures combined with domain-specific languages serve as a powerful tool to build and maintain a software product line: Meta-level architectures lead to adaptable software systems. Executable descriptions capture expert knowledge. We have developed a meta-level architecture for a software product line of legal expert systems. Four meta-level mechanisms support both variability and evolution of the product line. Domain analysis had shown that separation of expert knowledge from technical code was essential. Descriptions written in domain-specific languages reside in the meta level, and serve as specification, code, and documentation. Technical code finds its place in interpreting machines in the base level. We discuss how meta-level architectures influence the qualities of software product lines and how properties and patterns of the problem space can guide the design of domain-specific languages. Copyright  2005 John Wiley & Sons, Ltd.