Object Flow Definition for Refined Activity Diagrams

Activity diagrams are a well-known means to model the control flow of system behavior. Their expressiveness can be enhanced by using their object flow notation. In addition, we refine activities by pairs of preand post-conditions formulated by interrelated object diagrams. To define a clear semantics for refined activity diagrams with object flow, we use a graph transformation approach. Control flow is formalized by sets of transformation rule sequences, while object flow is described by partial dependencies between transformation rules. This approach is illustrated by a simple service-based on-line university calendar.