Kollaboratives Reengineering und Modularisieren von Softwaresystemen

Software systems evolve over their lifetime. Changing requirements make it inevitable for developers to modify and extend the underlying code base. Specific requirements emerge in the context of open source software where everybody can contribute and requirements can change over time. In particular, research software is often not structured with a maintainable and extensible architecture. Furthermore, often databases are employed for retrieving, storing, and processing application data. Insufficient knowledge of the actual structure and behavior of such software systems and related databases can entail further challenges. Thus, understanding these software systems embodies a crucial task, which needs to be addressed in an appropriate way to face inevitable challenges while performing software changes. Approaches based on alternative display and interaction concepts can support this task by offering a more immersive user experience. In this thesis, we introduce three complementary approaches to support the evolution and particularly understanding of software systems in different aspects. Our main contributions are (i) an approach named CORAL for enabling collaborative reengineering and modularization of software systems, (ii) a gesture-based, collaborative, and multi-user-featuring Virtual Reality approach named ExplorViz VR for the software city metaphor, and (iii) a database behavior live-visualization approach named RACCOON for database comprehension of software systems. An extensive case study shows that our CORAL approach is capable of supporting reengineering and modularization processes. Furthermore, several lab experiments demonstrate the high usability, and efficiency and effectiveness for solving comprehension tasks when using the visualization within our multi-user VR approach ExplorViz VR. All implementations are available as open-source software on www.explorviz.net. Additionally, we provide an extensive experimental package of our latest VR evaluation to facilitate the verifiability and reproducibility of our results

On the Modularization of ExplorViz towards Collaborative Open Source Development

Software systems evolve over their lifetime. Changing conditions such as requirements or customer requests make it inevitable for developers to perform adjustments to the underlying code base. Especially in the context of open source software where everybody can contribute, demands can change over time and new user groups may be addressed. In particular, research software is often not structured with a maintainable and extensible architecture. In combination with obsolescent technologies, this is a challenging task for developers, especially, when students are involved. In this paper, we report on the modularization process and architecture of our open source research project ExplorViz towards a microservice architecture, which facilitates a collaborative development process for both researchers and students. We describe the modularization measures and present how we solved occurring issues and enhanced our development process. Afterwards, we illustrate our modularization approach with our modernized, extensible software system architecture and highlight the improved collaborative development process. Finally, we present a proof-of-concept implementation featuring several developed extensions in terms of architecture and extensibility

Hands-On: Experiencing Software Architecture in Virtual Reality

Recently, virtual reality (VR) and gesture-based interface devices emerged at the consumer market. Both concepts offer new visualization and interaction capabilities, which can improve the user experience when using software. In Software Engineering, exploring and comprehending software systems is often addressed via visualization techniques. In this paper, we present our VR approach to explore software systems by using a head-mounted display and two different gesture-based interaction devices. Hence, we achieve a more immersive user experience and natural interaction, which benefits the comprehension process. Our VR approach is integrated into ExplorViz, our tool for live trace visualization of large software landscapes. In order to emphasize the advantages, we apply our combined approach on a small software system, running within our webbased tool ExplorViz. In this context, we present both, the visualization and the interaction capabilities

Live Trace Visualisierung für System- und Programmverständnis in großen Softwarelandschaften

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.In vielen Unternehmen nimmt die Anzahl der eingesetzten Anwendungen stetig zu. Diese Anwendungen - meist mehrere hunderte - bilden große Softwarelandschaften. Das Verständnis dieser Softwarelandschaften wird häufig erschwert durch, beispielsweise, Erosion der Architektur, personelle Wechsel oder sich ändernde Anforderungen. Des Weiteren können Ereignisse wie Performance-Anomalien häufig nur in Verbindung mit den Anwendungszuständen verstanden werden. Deshalb wird ein möglichst effizienter und effektiver Weg zum Verständnis solcher Softwarelandschaften in Verbindung mit den Details jeder einzelnen Anwendung benötigt. In dieser Arbeit führen wir einen Ansatz zur live Trace Visualisierung zur Unterstützung des System- und Programmverständnisses von großen Softwarelandschaften ein. Dieser verwendet zwei Perspektiven: eine Landschaftsperspektive mit UML Elementen und eine Applikationsperspektive, welche der 3D Softwarestadtmetapher folgt. Unsere Hauptbeiträge sind 1) ein Ansatz, genannt ExplorViz, um live Trace Visualisierung von großen Softwarelandschaften zu ermöglichen, 2) ein Überwachungs- und Analyseansatz, welcher in der Lage ist die große Anzahl an Methodenaufrufen in einer großen Softwarelandschaft aufzuzeichnen und zu verarbeiten und 3) Anzeige- und Interaktionskonzepte für die Softwarestadtmetapher, welche über klassische 2D Anzeige und 2D Eingabegeräten hinausgehen. Umfassende Laborexperimente zeigen, dass unser Überwachungs- und Analyseansatz für große Softwarelandschaften elastisch skaliert und dabei nur einen geringen Overhead auf den Produktivsystemen erzeugt. Des Weiteren demonstrieren mehrere kontrollierte Experimente eine gesteigerte Effizienz und Effektivität beim Lösen von Verständnisaufgaben unter Verwendung unserer Visualisierung. ExplorViz ist als Open Source Anwendung verfügbar unter www.explorviz.net. Zusätzlich stellen wir umfangreiche Pakete für unsere Evaluierungen zur Verfügung um die Nachvollziehbarkeit und Wiederholbarkeit unserer Ergebnisse zu ermöglichen

Performance Analysis of Legacy Perl Software via Batch and Interactive Trace Visualization

Performing an analysis of established software usually is challenging. Based on reverse engineering through dynamic analysis, it is possible to perform a software performance analysis, in order to detect performance bottlenecks or issues. This process is often divided into two consecutive tasks. The first task concerns the monitoring of the legacy software, and the second task covers analysing and visualizing the results. Dynamic analysis is usually addressed via trace visualization, but finding an appropriate representation for a specific issue still remains a great challenge. In this paper we report on our performance analysis of the Perl-based open repository software EPrints, which has now been continuously developed for more than fifteen years. We analyse and evaluate the software using the Kieker monitoring framework, and apply and combine two types of visualization tools, namely Graphviz and Gephi. More precisely, we employ Kieker to reconstruct architectural models from recorded monitoring data, based on dynamic analysis, and Graphviz respectively Gephi for further analysis and visualization of our monitoring results. We acquired knowledge of the software through our instrumentation and analysis via Kieker and the combined visualization of the two aforementioned tools. This allowed us, in collaboration with the EPrints development team, to reverse engineer their software EPrints, to give new and unexpected insights, and to detect potential bottlenecks

Live Visualization of Database Behavior for Large Software Landscapes: The RACCOON Approach

Databases are essential components within large software landscapes, since they are employed in almost every information system. Based on the growing complexity of software systems and a steadily increasing amount of data which is collected, processed, and stored in databases, it is difficult to obtain a live overview of these software landscapes. This often leads to an insufficient knowledge of the actual internal structure and behavior of employed databases. Furthermore, databases are often involved in performance issues within information systems. A solution to these problems is employing live visualizations of databases and related communication from applications within the software landscape. These visualizations allow operators to understand their databases in detail and to analyze database queries performed by applications. Based on established visualization concepts like the entity relationship diagrams and the 3D city metaphor, operators can be supported in the task of database comprehension. Established monitoring techniques, like dynamic and static analysis, can be used to capture necessary information from applications and databases. In this paper, we present our live visualization approach of databases and associated communication for large software landscapes. Our visualization offers two different views – a landscape-level and a database-level perspective. The landscape-level perspective provides an overview of monitored applications and related databases. The database-level perspective reveals database schemas within a database, shows contained tables and relationships, and allows for the inspection of executed queries based on the monitoring information collected at runtime

PerfVis: Pervasive Visualization in Immersive AugmentedReality for Performance Awareness

Developers are usually unaware of the impact of code changes to the performance of software systems. Although developers can analyze the performance of a system by executing, for instance, a performance test to compare the performance of two consecutive versions of the system, changing from a programming task to a testing task would disrupt the development flow. In this paper, we propose the use of a city visualization that dynamically provides developers with a pervasive view of the continuous performance of a system. We use an immersive augmented reality device (Microsoft HoloLens) to display our visualization and extend the integrated development environment on a computer screen to use the physical space. We report on technical details of the design and implementation of our visualization tool, and discuss early feedback that we collected of its usability. Our investigation explores a new visual metaphor to support the exploration and analysis of possibly very large and multidimensional performance data. Our initial result indicates that the city metaphor can be adequate to analyze dynamic performance data on a large and non-trivial software system.Comment: ICPE'19 vision, 4 pages, 2 figure, conferenc