Evaluating Maintainability with Code Metrics for Model-to-Model Transformations

Abstract

Abstract. Using model-to-model transformations to generate analysis models or code from architecture models is sought to promote compliance and reuse of components. The maintainability of transformations is influenced by various characteristics -as with every programming language artifact. Code metrics are often used to estimate code maintainability. However, most of the established metrics do not apply to declarative transformation languages (such as QVT Relations) since they focus on imperative (e.g. object-oriented) coding styles. One way to characterize the maintainability of programs are code metrics. However, the vast majority of these metrics focus on imperative (e.g., object-oriented) coding styles and thus cannot be reused as-is for transformations written in declarative languages. In this paper we propose an initial set of quality metrics to evaluate transformations written in the declarative QVT Relations language. We apply the presented set of metrics to several reference transformations to demonstrate how to judge transformation maintainability based on our metrics.

Assessing and improving quality of QVTo model transformations

“…As another example, if a new version of the QVTo engine is released, it may be necessary to reevaluate the implementation-dependent properties. The high proportion of transformation-local properties is likely a result of our approach, since existing quality models also have high proportions of properties local to a single module or class (e.g., van Amstel et al 2010;Kapová et al 2010), and the developers interviewed work also most frequently on modifying single transformations. We do not consider the effect of our approach on the properties a threat to validity, however, since our approach was designed to capture the most pertinent concerns in QVTo quality.…”

“…An example of information gathered during this review is that mixing notations (e.g., text, graphical) can reduce understandability. A number of metric sets that have been proposed in model transformation literature (e.g., Kapová et al 2010;Vignaga 2009) were also encountered.…”

“…However, due to the top-down approach, van Amstel's metrics (van Amstel 2012) describe relatively shallow properties compared to the rich data incorporated in our quality properties. Kapová et al (2010) presented a set of maintainability metrics for QVTr. There a combination of ''automated'' and ''manual'' metrics was proposed.…”

A Catalogue of Refactorings for Model-to-Model Transformations.

“…With this purpose, we have surveyed recent work on model transformation metrics [vALvdB09,KGBH10,vAvdB11].…”

“…For that, it is necessary to find an alignment of metrics to quality attributes, i.e., whether a lower/higher value of a metric improves/worsens a given quality attribute. This is still an open issue in the model transformation field due to the lack of large empirical studies [KGBH10]. However, some initial empirical studies have been already conducted [vAvdB11] that will help us to justify the quality improvements of our refactorings (apart from relying on our own experience in the field).…”