Program Comprehension

Live Trace Visualization for System and Program Comprehension in Large Software Landscapes

In many enterprises, the number of deployed applications is constantly increasing. Those applications - often several hundreds - form large software landscapes. The comprehension of such landscapes is frequently impeded due to, for instance, architectural erosion, personnel turnover, or changing requirements. Furthermore, events such as performance anomalies can often only be understood in correlation with the states of the applications. Therefore, an efficient and effective way to comprehend such software landscapes in combination with the details of each application is required. In this thesis, we introduce a live trace visualization approach to support system and program comprehension in large software landscapes. It features two perspectives: a landscape-level perspective using UML elements and an application-level perspective following the 3D software city metaphor. Our main contributions are 1) an approach named ExplorViz for enabling live trace visualization of large software landscapes, 2) a monitoring and analysis approach capable of logging and processing the huge amount of conducted method calls in large software landscapes, and 3) display and interaction concepts for the software city metaphor beyond classical 2D displays and 2D pointing devices. Extensive lab experiments show that our monitoring and analysis approach elastically scales to large software landscapes while imposing only a low overhead on the productive systems. Furthermore, several controlled experiments demonstrate an increased efficiency and effectiveness for solving comprehension tasks when using our visualization. ExplorViz is available as open-source software on www.explorviz.net. Additionally, we provide extensive experimental packages of our evaluations to facilitate the verifiability and reproducibility of our results.

Software Visualization

Software Visualization: From Theory to Practice was initially selected as a special volume for "The Annals of Software Engineering (ANSE) Journal", which has been discontinued. This special edited volume, is the first to discuss software visualization in the perspective of software engineering. It is a collection of 14 chapters on software visualization, covering the topics from theory to practical systems. The chapters are divided into four Parts: Visual Formalisms, Human Factors, Architectural Visualization, and Visualization in Practice. They cover a comprehensive range of software visualization topics, including *Visual programming theory and techniques for rapid software prototyping and graph visualization, including distributed programming; *Visual formalisms such as Flowchart, Event Graph, and Process Communication Graph; *Graph-oriented distributed programming; *Program visualization for software understanding, testing/debugging and maintenance; *Object-oriented re-design based on legacy procedural software; *Cognitive models for designing software exploration tools; *Human comprehensibility of visual modeling diagrams in UML; *UML extended with pattern compositions for software reuse; *Visualization of software architecture and Web architecture for better understanding; *Visual programming and program visualization for music synthesizers; *Drawing diagrams nicely using clustering techniques for software engineering.

Computer Program Comprehension Processes : the Effect of Application Domain Knowledge