Architectural styles for runtime software adaptation

Runtime software adaptability - the ability to change an application´s behavior during runtime - is an increasingly important capability for systems, both to support continuous operation and to support a good user experience. Achieving such adaptability may be very hard or easy; the degree of difficulty will largely reflect choices made in a system´s architecture. Some architectural styles are much more supportive of dynamic change than others. This paper examines a range of styles and assesses them with respect to a four-element evaluation framework, called BASE. The framework considers how a style supports changes to behavior, state, its execution context, and supports asynchrony of change. Styles considered include REST, event-based, service-oriented, and peer-to-peer.