Package Fingerprints: A visual summary of package interface usage

Abstract

Context: Object-oriented languages such as Java, Smalltalk, and C++ structure their programs using packages. Maintainers of large systems need to understand how packages relate to each other, but this task is complex because packages often have multiple clients and play different roles (class container, code ownership. . . ). Several approaches have been proposed, among which the use of cohesion and coupling metrics. Such metrics help identify candidate packages for restructuring; however, they do not help maintainers actually understand the structure and interrelationships between packages.Objectives: In this paper, we use pre-attentive processing as the basis for package visualization and see to what extent it could be used in package understanding.Method: We present the package fingerprint, a 2D visualization of the references made to and from a package. The proposed visualization offers a semantically rich, but compact and zoomable views centered on packages. We focus on two views (incoming and outgoing references) that help users understand how the package under analysis is used by the system and how it uses the system.Results: We applied these views on four large systems: Squeak, JBoss, Azureus, and ArgoUML. We obtained several interesting results, among which, the identification of a set of recurring visual patterns that help maintainers: (a) more easily identify the role of and the way a package is used within the system (e.g., the package under analysis provides a set of layered services), and, (b) detect either problematic situations (e.g., a single package that groups together a large number of basic services) or opportunities for better package restructuring (e.g., removing cyclic dependencies among packages). The visualization generally scaled well and the detection of different patterns was always possible.Conclusion: The proposed visualizations and patterns proved to be useful in understanding and maintaining the different systems we addressed. To generalize to other contexts and systems, a real user study is required.

Modularization Metrics: Assessing Package Organization in Legacy Large Object-Oriented Software

“…Much of these efforts are focused on package cohesion and coupling from the point of view of maximizing intrapackage dependencies. But although this point of view is important for assessing an aspect of package structure, it is definitely not enough for assessing software modularization [3], [30], [17], [2], [1]. Fortunately, Santonu Sarkar et al [35], [36] have recently proposed a set of metrics that characterize several aspects of the quality of modularization.…”

Effectively Incorporating Expert Knowledge in Automated Software Remodularisation

“…This technique allows architectural problems to be observed. This approach is similar to the Package Fingerprint [47], a technique that allows maintainers to visually inspect their architectures for similar potential defects by presenting the dependencies amongst packages in the system. Unlike Package Blueprints and Fingerprints, SUMO does not attempt to visualise the structure of the system, making it more similar to Distribution Maps in the information it displays.…”

AniMatrix: A Matrix-Based Visualization of Software Evolution

“…Lattix [16] uses a matrix-based representation to visualize and interact with the layered structure of source code, in addition to showing module dependencies. Package Fingerprints [17] similarly allow visualizing incoming and outgoing couplings to encapsulated packages using a matrix-inspired approach. TreeMatrix [18] combines node-link and matrices to depict high level and low level structures of source code, along with their relationships.…”