Transformational interactions for P2P e-commerce

Both peer services and web services offer a perspective of services in the role of resources that can be combined to enable new capabilities greater than the sum of the parts. However, current service composition solutions seem to support either highly dynamic discovery or else very loosely coupled service development, but not both. We propose a facilitator service mechanism that can leverage "reflected" XML-based specifications (borrowed from the web service domain) to direct and enable coordinated sequences of message exchanges (conversations) between services. We extend the specification of a message exchange with the ability to specify transformations to be applied to both inbound and outbound documents. We call these extended message exchanges transformational interactions. The facilitator service can use these transformational interactions to allow service developers to decouple internal and external interfaces. This means that services can be developed and treated as pools of methods that can be composed dynamically.