A case study on variability in user interfaces

Abstract

Software Product Lines (SPL) enable efficient derivation of products. SPL concepts have been applied successfully in many domains including interactive applications. However, the user interface (UI) part of applications has barely been addressed yet. While standard SPL concepts allow derivation of functionally correct UIs, there are additional nonfunctional requirements, like usability, which have to be considered. This paper presents a case study investigating UI variability found in variants of the commercial web-based information system HIS-GX/QIS. We analyze which aspects of a UI vary and to which degree. The results show that just tweaking the final UI (e.g., using stylesheets) is not sufficient but there is a need for more customization which must be supported by, e.g., UI-specific models.

Model-driven development and evolution of customized user interfaces

“…The study in [19] analyses the UI customizations in detail based on 30 products (running at 30 different universities). It turns out that all products are highly customized.…”

“…Moreover, customizations are spread over most parts of the UI (77.5 % of the UI elements) and over all UI aspects (those listed in Table 1). This includes both, functional customizations like in product derivation (adding and removing UI elements) but also UI-specific customizations (see [19]). This includes complex customizations like changing types of UI elements (e.g., from list box to radio buttons), changing the order of UI elements, merging and splitting screens, or changing the navigation path.…”

“…These aspects are derived from MBUID concepts and shown in the left column of Table 1. In [19] we perform a empirical case study about which of these aspects are customized in practice using the commercial product family of web applications HIS QIS/GX (which we also use for the evaluation in this paper). It shows that customizations for all these UI aspects can be found in practice and, hence, need to be supported by a generic model-driven process.…”

“…For instance, UIs developed by purely automated approaches are not always optimal in terms of quality [2]. In particular, specific users, customers, or target devices can raise unforeseen requirements on the UI that need to be addressed by manual customizations [18,19]. Hence, there is a need to support manual customizations within a model-driven UI development process.…”

“…This is a product family where each product (an individual instance of the software for a particular university) is highly customized according to the individual needs of the university -often by third parties or the university itself. We have performed a detailed analysis of the UI customizations in this UI family [19] showing that customizations are spread all over the UI and cover each aspect of the UI. Our evaluation shows for thirty real-world product instances, that all these individually customized UIs can be developed from a single abstract model using our approach.…”