A Contract Language for Service-Oriented Dynamic Collaborations

Dynamic collaborations are built using contributed resources that have come across the organizational boundaries. These resources include data, application, software, tools as well as infrastructures, and are typically subject to a rich set of access policies. The automated instantiation of a collaboration using such resources including their interoperability is a difficult problem. Existing systems are either built for specific resources, or use manual and ad-hoc approaches. This problem has attracted the Web Services community, where Web Services standards such as WSLA and WS-CDL have been proposed to address similar problems. These approaches are designed to deal with scenarios involving two parties: a service provider and a service consumer. They do not scale well to multiparty nature of dynamic collaborations. This paper proposes a contract language for dynamic multiparty collaborations that captures the contributed resources and negotiated agreements on them, as well as the mechanisms for instantiation and termination of the collaboration. The language itself has been defined using XML Schema and has been implemented in a dynamic collaboration platform to provide a connectivity service.