UML Interactions represent one of the three UML behaviors. They describe the interwork of parts of a system based on message exchange. UML Interactions can reside on any level of abstraction and they seem sufficiently elaborated for high-level specifications used for sketching the communication among parts of a system. The UML Interactions metamodel, however, reveals some deficiencies for precise specifications of data values and data flows. Even UML 2.5 still does not provide concepts for data flows in UML Interactions. In this paper, we suggest a profile-based extension that integrates data flow concepts with UML Interactions. The extension supports accessing (usage of) values located in data sources and assignment (definition) of values to data sinks in the context of message exchange and invocation of Interactions. The proposed extension improves the expressiveness of UML Interactions in a minimal invasive manner and makes it similar to the capabilities of UML Activities regarding the specification of data flows.
