Processing the Evolution of Quality Requirements of Web Service Orchestrations: A Pattern-Based Approach

Currently Web services remain one of the leading technologies for implementing components of distributed service oriented software architectures. One of the most frequent form of compositions of these entities is Web service orchestration. As any other software artifact, such service compositions are subject to an unescapable evolution (Lehman's first law of software evolution). Either for answering new user requirements, for adapting, for correcting or for enhancing the provided functionality or quality, an architect has to conduct some evolutions on the design of these artifacts. In this paper, we present a method which aims at helping software architects of Web service orchestrations in processing an evolution of quality requirements. This method introduces a template for describing quality evolution "intents". It then analyzes these intents and assists the architects in answering them by proposing some patterns. We consider in our work the postulate stating that quality can be implemented through patterns, which are specified with checkable/process able languages. Besides this, the method that we propose simulates the application of these patterns and notifies the architect with its consequences on the other implemented qualities.