Triana: a graphical Web service composition and execution toolkit

Service composition refers to the aggregation of services to build complex applications to achieve client requirements. It is an important challenge to make it possible for users to construct complex workflows transparently and thereby insulating them from the complexity of interacting with numerous heterogeneous services. We present an extension to the Triana PSE to facilitate graphical Web service discovery, composition and invocation. Our framework has several novel features which distinguish it from other work in this area. First, users can graphically create complex service compositions. Second, Triana allows the user to share the composite service as a BPELAWS graph or expose it as a service in a one-click manner. Third, Triana allows the user to easily carry out "what-if" analysis by altering existing workflows. Fourth, Triana allows the user to record provenance data for a workflow. Finally, our framework allows the user to execute the composed graph on a Grid or P2P network. Triana is a part of the GridLab and GridOneD projects and is used in the GEO 600 project.