Design patterns for developing dynamically adaptive systems

Increasingly, software systems should self-adapt to satisfy new requirements and environmental conditions that may arise after deployment. Due to their high complexity, adaptive programs are difficult to specify, design, verify, and validate. Moreover, the current lack of reusable design expertise that can be leveraged from one adaptive system to another further exacerbates the problem. We studied over thirty adaptation-related research and project implementations available from the literature and open sources to harvest adaptation-oriented design patterns that support the development of adaptive systems. These adaptation-oriented patterns facilitate the separate development of the functional and adaptive logic. In order to support the assurance of adaptive systems, each design pattern includes templates that formally specify invariant properties of adaptive systems. To demonstrate their usefulness, we have applied a subset of our adaptation-oriented patterns to the design and implementation of ZAP.com, an adaptive news web server.