Event-condition-action rules on RDF metadata in P2P environments

RDF (Resource Description Framework) is one of the technologies proposed to realise the vision of the Semantic Web and it is being increasingly used in distributed Web-based applications. The use of RDF in applications that require timely notification of metadata changes raises the need for mechanisms for monitoring and processing such changes. Event-condition-action (ECA) rules are a natural candidate to fulfill this need. In this paper, we study ECA rules on RDF metadata in P2P environments. We describe a language for defining ECA rules on RDF metadata, including its syntax and execution semantics. We develop conservative tests for determining the termination and confluence of sets of such ECA rules. We describe an architecture supporting such rules in P2P environments, and our current implementation of this architecture. We also discuss techniques for relaxing the isolation and atomicity requirements of transactions.