Programming Live Distributed Objects With Distributed Data Flows

This paper presents a new object-oriented approach to modeling the semantics of distributed multi-party protocols such as leader election, distributed locking, or reliable multicast, and a programming language that supports it. The approach builds on and extends the live distributed objects model by introducing a new concept of a distributed flow, a stream of messages flowing concurrently at multiple locations. The flows correspond to variables, private fields, and method parameters in Java-like languages; they are the means by which the authors store and communicate state. Active protocol instances, which correspond to Java objects, consume and output flows; their internal states are encapsulated as internal flows, and all of their internal logic is represented as operations on flows.