Interaction design in service compositions

This thesis proposes a concept and transformations for designing interactions in a service composition at related abstraction levels. The concept and transformations are aimed at helping designers to bridge the conceptual gap between the business and software domains. In this way, the complexity of an interaction design can be managed adequately. A service composition is specified as one or more interactions between application components. Interaction design is therefore the central activity in the design of a service composition. Interaction design at related abstraction level requires an interaction concept that can model interactions at a higher abstraction level (called abstract interactions) and interactions at a lower abstraction level (called concrete interactions), in order to avoid any conceptual gap between abstraction levels. An interaction is defined as a unit of activity that is performed by multiple entities or participants in cooperation to establish a common result. Different participants can have different views on the established result. The possible results of an interaction are specified using contribution constraints and distribution constraints. Contribution constraints model the responsibility of the participants in the establishment of the interaction result. Distribution constraints model the relation between the participants’ views. An interaction provides synchronisation or time dependency between the participants on each other. This interaction concept can model abstract and concrete interactions. A designer can hence use a single interaction design concept during a design process. Two design transformations are defined, namely interaction refinement and interaction abstraction. Interaction refinement replaces an abstract interaction with a concrete interaction structure. Interaction abstraction replaces a concrete interaction structure with an abstract interaction. A set of conformance requirements and a conformance assessment method are defined to check the conformance between an abstract interaction and concrete interaction structure.