A Configuration Management System for Software Product Lines

Software product line engineering (SPLE) is a methodology for developing a family of software products in a particular domain by systematic reuse of shared code in order to improve product quality and reduce development time and cost. Currently, there are no software configuration management (SCM) tools that support software product line evolution. Conventional SCM tools are designed to support single product development. The use of conventional SCM tools forces developers to treat a software product line as a single software project by introducing new programming language constructs or using conditional compilation. We propose a research conguration management prototype called Molhado SPL that is designed specifically to support the evolution of software product lines. Molhado SPL addresses the evolution problem at the configuration level instead of at the code level. We studied the type of operations needed to support the evolution of software product lines and proposed a versioning model and eight cases of change propagation. Molhado SPL supports independent evolution of core assets and products, the sharing of code and the tracking relationships between products and shared code, and the eight cases of change propagation. The Molhado SPL consists of four layers with each layer providing a different type of service. At the heart of Molhado SPL are the versioning model, component object, shared component object, and project objects that allow for independent evolution of products and shared artifacts, for sharing, and for supporting change propagation. Furthermore,they allow product specific changes to shared code without interfering with the core asset that is shared. Products can also introduce product specific assets that only exist in that product. In order to for Molhado SPL to support product line, we implemented XML merging, feature model editing and debugging, and version-aware XML documents. To support merging of XML documents, we implemented a 3-way XML document merging algorithm that uses versioned data structures, change detection, and node identity. To support software product line derivation or modeling of software product line, we implemented support for feature model including editing and debugging. Finally, we created the version-aware XML document framework to support collaborative editing of XML documents without requiring a version repository. The version history is embedded in the documents using XML namespaces, so that the documents remain valid under the XML specification. The version-aware XML framework can also be used to support the exporting of documents from Molhado SPL repository to be edit outside and import back the change history made to the document. We evaluated Molhado SPL with two product lines: a document product line and a the graph data structures product line. This evaluation showed that Molhado SPL supports independently evolution of products and core assets and the eight change propagation cases. We did not evaluate MolhadoSPL in terms of scalability or usability. The main contributions of this dissertation research are: 1) Molhado SPL that supports the evolution of product lines, 2) a fast 3-way XML merge algorithm, 3) a version-aware XML document framework, and 4) a feature model editor and debugger

Towards a holistic framework for software artefact consistency management

A software system is represented by different software artefacts ranging from requirements specifications to source code. As the system evolves, artefacts are often modified at different rates and times resulting in inconsistencies, which in turn can hinder effective communication between stakeholders, and the understanding and maintenance of systems. The problem of the differential evolution of heterogeneous software artefacts has not been sufficiently addressed to date as current solutions focus on specific sets of artefacts and aspects of consistency management and are not fully automated. This thesis presents the concept of holistic artefact consistency management and a proof-of-concept framework, ACM, which aim to support the consistent evolution of heterogeneous software artefacts while minimising the impact on user choices and practices and maximising automation. The ACM framework incorporates traceability, change impact analysis, change detection, consistency checking and change propagation mechanisms and is designed to be extensible. The thesis describes the design, implementation and evaluation of the framework, and an approach to automate trace link creation using machine learning techniques. The framework evaluation uses six open source systems and suggests that managing the consistency of heterogeneous artefacts may be feasible in practical scenarios

Support for Location and Comprehension of User History in Collaborative Work

Users are being embraced as partners in developing computer services in many current computer supported cooperative work systems. Many web-based applications, including collaborative authoring tools like wikis, place users into collaborations with unknown and distant partners. Individual participants in such environments need to identify and understand others' contributions for collaboration to succeed and be efficient. One approach to supporting such understanding is to record user activity for later access. Issues with this approach include difficulties in locating activity of interest in large tasks and the history is often recorded at a system-activity level instead of at a human-activity level. To address these issues, this dissertation introduces CoActIVE, an application-independent history mechanism that clusters records of user activity and extracts keywords in an attempt to provide a human-level representation of history. CoActIVE is integrated in three different software applications to show its applicability and validity. Multiple visualization techniques based on this processing are compared in their ability to improve users' location and comprehension of the activity of others. The results show that filmstrip visualization and visual summarization of user activity show significant improvement over traditional list view interfaces. CoActIVE generates an interpretation of large-scale interaction history and provides the interpretation thorough a variety of visualizations that allow users to navigate the evolution of collaborative work. It supports branching history, with the understanding that asynchronous authoring and design tasks often involve the parallel development of alternatives. Additionally, CoActIVE has the potential to be integrated into a variety of applications with little adjustment for compatibility. Especially, the comparison of visualizations for locating and comprehending the work of others is unique

Ansatz einer entwicklungsprojektweiten Abhängigkeits-Konsistenz des Quellcodemodells zur Qualitätsverbesserung von Software-Entwicklungsprojekten

Heutige Softwareentwicklungsprojekte müssen oft eine Vielzahl von Anforderungen mit hoher Komplexität in kurzen Release-Zyklen umsetzen. Daraus ergeben sich besondere Herausforderungen an Arbeitsteilung, Dokumentation, Prozesssicherheit und Qualität. Entwicklungsarbeiten müssen parallelisiert werden und Softwareentwickler müssen sich immer wieder in den Quellcode einarbeiten. Die Entwickler brauchen schnelle und präzise Rückmeldung über die Qualität ihrer durchgeführten Änderungen am Quellcode. Über feingranulare Traceability Links in den Quellcode werden eine verbesserte Dokumentation und größere Prozesssicherheit ermöglicht. Dazu wird ein Metamodell für den Quellcode definiert und in ein Metamodell mit Anforderungsmanagement, Änderungsmanagement, Testdatenmanagement und Dokumentation eingebunden. Das gesamte Modell wird in einem Software Configuration Management (SCM) Repository abgespeichert, um die Versionierung aller Artefakte und Links zu ermöglichen. In einem Quellcode Editor können die Traceability Links erstellt und genutzt werden. Die Historie einzelner Quellcode Artefakte kann einschließlich der Traceability Links im Editor zur Anzeige gebracht werden. Durch das Vorliegen des Quellcodes als Modell wird auch ein feingranulares pessimistisches Sperren einzelner Modell Artefakte ermöglicht. Damit ist das parallele Bearbeiten einer Klasse oder einer Methode möglich, ohne dass der Quellcode verschmolzen werden muss. Es werden durch die Sperren auch Syntaxfehler im SCM Repository verhindert. Im Quellcode Editor werden die Sperren anderer Entwickler angezeigt. Continuous Integration wird dahingehend erweitert, dass durch Abspeichern von Class-Dateien im Repository ein schneller Produkt-Build und damit auch schnelleres Feedback für den Entwickler ermöglicht wird. Durch Testauswahlstrategien werden nur für den geänderten Quellcode relevante Tests ausgeführt. Eine Testauswahlstrategie verwendet dabei die Traceability Informationen zwischen geänderten Quellcode, Anforderung, Testspezifikation und dem Test-Quellcode. In großen Projekten entstehen auf Grund des Quellcodes sehr große Modelle, die eine Herausforderung bezüglich Speicherbedarfes und Performance darstellen. Es wurden Untersuchungen an Hand eines Projekts mit 6,5 Millionen Quellcode-Zeilen durchgeführt. Für diese Konzepte wurde ein Prototyp auf Basis der Eclipse Entwicklungsumgebung und für Java entwickelt