Web Service Composition: From UML to Optimization

Web services are popular in terms of distributed technology that can successfully solve integration problems between heterogeneous systems. However, web service composition workflows are modeled using BPEL, BPEL4WS, and other programming languages which are difficult and very complex to use. To overcome this problem, a well known and simple modeling language such as Unified Modeling Language (UML) should be studied and used to design the web service composition workflow. Furthermore, with the increasing number of service providers, web services should be composed according to functional and nonfunctional requirements which raise the importance of optimizing web service composition according to QoS attributes. In this paper, a model driven approach will be proposed. The approach allows developers to design the composition workflow using UML sequence diagrams. After parsing the UML workflow, web services will be discovered, composed and optimized. In this paper, a tree-based optimization algorithm will be used. The algorithm will be able to find the optimal composition solution according to multiple QoS attributes. To demonstrate the efficiency and effectiveness of the proposed algorithm, we provided experimental results for a supply chain management system case study with multi QoS attributes.