Explora: a Visualisation Tool for Metric Analysis of Software Corpora

Abstract—When analysing metrics, users find that visualisa-tion tools lack support for (1) defining a threshold to classify whether a value is low, high or common; (2) answering questions that involve many metrics; and (3) enabling analysis of software corpora. In this paper we present Explora, a visualisation tool designed for the simultaneous analysis of multiple metrics of systems in software corpora. Explora incorporates a novel lightweight visualisation technique called PolyGrid that promotes the de-tection of graphical patterns. We present an example where we analyse the relation of subtype polymorphism with inheritance and invocation in corpora of Smalltalk and Java systems and find that (1) subtype polymorphism is more likely to be found in large hierarchies; (2) as class hierarchies grow horizontally, they also do so vertically; and (3) in polymorphic hierarchies the length of the name of the classes is orthogonal to the cardinality of the call sites. I