ROAD4WS -- Extending Apache Axis2 for Adaptive Service Compositions

Service oriented architecture plays a prominent role in creating and utilizing business services in enterprise computing environments. The service composers produce value by aggregating lower-level re-usable services, scattered across the internet to create application level services. Web service middleware facilitates in defining service compositions in a comprehensive manner. However, in order to ensure the business viability amidst unpredictably changing business requirements, such compositions may need to adapt during the runtime. Such changes might vary from a minor regulation to a major re-structuring of the IT service composition. However, the complexity of the composition shouldn´t increase and the runtime interruptions to the service delivery need to be kept to a minimum. In this paper we introduce ROAD4WS, which is a middleware extension to the popular Apache Axis2 web service engine. The extension brings together the modular adaptive architecture of the Role Oriented Adaptive Design (ROAD) with the web services deployment and consumption capabilities of the Apache Axis2 engine, in order to facilitate deploying adaptive service compositions.