Application Logic Patterns - Reusable Elements of UserSystem Interaction

Abstract. Patterns of various kind are commonly used to reduce costs and improve quality in software development. This paper introduces the concept of patterns at the level of detailed descriptions of the user-system dialogue. Application Logic Patterns define generalised sequences of in-teractions performed by the system and its users in the context of an ab-stract problem domain. The patterns are organised into a library. They are precisely described by a language which is defined through a strict meta-model. It extends the notation and semantics of the UML activ-ities and use cases. Each of the patterns describing the visible system dynamics is linked to an abstract domain model central to all the pat-domain notions with the notions specific to a given domain. This ease of use and reduction in effort is validated in a controlled experiment using an open-source tool.