Preventing SLA violations in service compositions using aspect-based fragment substitution

Abstract

In this paper we show how the application of the aspect-oriented programming paradigm to runtime adaptation of service compositions can be used to prevent SLA violations. Adaptations are triggered by predicted violations, and are implemented as substitutions of fragments in the service composition. Fragments are full-fledged standalone compositions, and are linked into the original composition via special activities, which we refer to as virtual activities. Before substitution we evaluate fragments with respect to their expected impact on the performance of the composition, and choose those fragments which are best suited to prevent a predicted violation. We show how our approach can be implemented using Windows Workflow Foundation technology, and discuss our work based on an illustrative case study. © 2010 Springer-Verlag.