Product Line Annotations with UML-F

The Unified Modeling Language (UML) community has started to define so-called profiles in order to better suit the needs of specific domains or settings. Product lines1 represent a special breed of systems—they are extensible semi-finished pieces of software. Completing the semi-finished software leads to various software pieces, typically specific applications, which share the same core. Though product lines have been developed for a wide range of domains, they apply common construction principles. The intention of the UMLF profile (for framework architectures) is the definition of a UML subset, enriched with a few UML-compliant extensions, which allows the annotation of such artifacts. This paper presents aspects of the profile with a focus on patterns and exemplifies the profile’s usage. 1 What Is a UML Profile? The UML is a large and regrettably complex language. Still, there are many requests to explicitly represent additional features that cannot be described comfortably using the current version of the UML. Therefore, the UML provides mechanisms, in particular stereotypes and tagged values, which allow extensions. These extensions may be defined and grouped in so-called profiles. Thus, a UML profile is defined as an extension of the standard UML with specific elements. A profile provides new notational elements and specializes the semantics of some elements. It may also restrict the use of UML elements. For example, [2] describes in further detail the profiling mechanism and a useful extension of it, called prefaces. A UML profile may target a specific application domain. UML-RT, the real-time profile, is one prominent example. Other profiles may provide tool-specific exten1 We use the terms product line and framework synonymously. Product Line Annotations with UML-F 189 sions. For example, these might shape the UML so that it is better suited for modeling Web-based systems, as the one described in [1]. A Java profile would restrict the UML to single-class inheritance. The UML-F profile, which is described in detail in [4], supports product line annotations. 2 A Selection of Basic UML-F Tags Though the UML version 1.3 already lists 47 stereotypes and 7 tagged values [6] and version 1.4 increased these numbers considerably, only a small number of them are particularly useful for product line annotations. This section picks out some of the tags2 introduced by the UML-F profile for that purpose. 2.1 Product Line and Application Classes Many product lines come together with prefabricated application classes that do not belong to the product line itself. These additional classes can be studied in order to understand the standard usage of a framework by examining and adapting their code, whereas the product line classes themselves are usually not subject to change. «framework» Composite *