A Layered Architecture for Flexible Web Service Invocation

Web service composition is emerging as an interesting approach to integrate business applications and
create intra-organizational business processes. Single Web services are combined to create a complex
Web service that will realize the process business logic. Once the process is created, it is executed by an
orchestration engine that invokes individual Web services in the correct order. However, Web services
composing the workflow sometimes become unavailable during the run-time phase, blocking process
execution. This paper describes an architecture that allows the flexible orchestration of business processes.
With this approach, Web services composing the process can be automatically substituted with other
compatible Web services during process execution. A methodology is defined to evaluate Web service
compatibility based on interface matching, in order to select substitutableWeb services