Declarative Choreographies with Time and Data

Abstract

Choreographic models express coordination between business roles, in contrast to standard process models that merge local control flow and communication between parties. A choreography is realizable, also known as endpoint projectable, if the independent behaviour of each role in composition with other roles, only behaves exactly in the same way as described in the choreography. We introduce a novel choreographic language expressing safety and liveness properties, incorporating multiperspective constraints in communication flows, data, and time. This language builds upon recent developments in declarative choreographies using the Dynamic Condition Response (DCR) graph formalism and extends it to accommodate data and time. The interaction between multiple dimensions can render models unrealizable, so we determine the conditions required for realizability through causal relationships within multi-perspective declarative choreographies. This way, realizable choreographies are guaranteed freedom of conflicts in the message exchanges that otherwise can lead to deadlocks.