No matter which tools, techniques, and methodologies are used for software development, it remains an error-prone process. Nevertheless, changing such important constituents of the software process surely has an effect on the types of faults inherent in the developed software. For instance, some types of faults are typical for structured development, whereas others are typical for object-oriented development. This chapter explores the question of whether component-based software requires new testing techniques, and proposes an integrated testing technique. This technique integrates various tasks during testing component-based software: whiteand black-box testing of the main component (i.e., the top level component controlling the other components), black-box testing of components, black-box testing of the middleware and integration testing of the main component with other components. Benefits of this technique are shown using a real-world example: the technique is automatable and applicable to existing component-based software.

The use of components in development of complex software systems can surely have various benefits. Their testing, however, is still one of the open issues in software engineering. Both the developer of a component and the developer of a system using components often face the problem that information vital for certain development tasks is not available. Such a lack of information has various consequences to both. One of the important consequences is that it might not only obligate the developer of a system to test the components used, it might also complicate these tests. This article gives an overview of component testing approaches that explicitly respect a lack of information in development.

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A common challenge in the development of web applications today lies in the handling of unforeseen navigation steps initiated by the user through the browser’s Back, Forward and Reload buttons. These operations break the synchrony of dialog states on the server and the client, provoking non-intuitive and possibly destructive application behaviour if not properly handled. We therefore present an approach to handling Back and Forward navigation that realizes undo/redo semantics and illustrate its implementation using the example of a web-based conference management system. The presented approach is subsequently discussed with regard to its general applicability and alternative handling semantics.

The domain requirements of software projects often seem so specialized to developers that their original design does not incorporate any commercial-off-the-shelf (COTS) components. However, if major implementation problems are encountered at a later stage in the project, the integration of a COTS component that promises to solve those problems may become a desirable alternative to struggling on with the original implementation. While a number of methods and criteria have already been proposed for requirements engineering, risk assessment and candidate selection of COTS components, they were developed for application in the initial phases of a project and thus do not take into account the much tighter time and design constraints imposedin a later project stage. To spark discussion on necessary adaptations of the established methods, this position paper uses the example of a concrete project to illustrate the characteristics of “switch or struggle” situations and proposes an initial set of risk factors to be considered at that time.

Unter wertebasierter Softwareentwicklung versteht man Methoden, Modelle und Messgrößen, mit denen Manager, Entwickler und Anwender von Software verschiedene Zielkonflikte im Softwareprozess auf wirtschaftlicher Basis bewerten und auflösen können. In diesem Artikel stellen wir einige dieser Ansätze vor und zeigen, in welchen Situationen diese von Nutzen sein können.

We describe a new WWW-based information system called Squirrel which demonstrates an attempt to integrate a relational database system (RDBS) with an information retrieval system (IRS) providing context based access to a SGML document collection. Indexing of the documents is performed on full-text basis whereas search capabilities include ranking of the retrieved documents. A functioning prototype has been implemented and is available on the Internet.

We recently developed and published a scaleable multi-user benchmark called XMach-1 (XML Data Management benchmark) for evaluating the performance of XML data management systems [1]. To our knowledge it is the first such benchmark. It aims at realistically evaluating the performance of individual systems as well as to allow for a performance comparison between different systems and architectures ranging from native XML data management systems to XML-enabled relational DBMS. Specifying and implementing the benchmark revealed a number of problems which are partly due to the lack of a standardized XML query language, the complexity of the XML format and the relative immaturity of current XML database software. After a brief review of XMach-1 we will discuss our experiences made so far.

Die Benutzerfreundlichkeit von Web-Anwendungen leidet häufig unter der fehlenden Unterst¨utzung hierarchischer Dialogsequenzen, an die Benutzer sich während der Arbeit mit fensterbasierten Benutzeroberflächen und ihren hierarchisch strukturierten Dialogfenstern bereits gewöhnt haben. Für Multikanal-Anwendungen liegt eine zusätzliche Herausforderung darin, die geräteunabhängige Geschäftslogik mit den gerätespezifischen Interaktionsmustern zu verbinden, die die unterschiedlichen Ein-/Ausgabefähigkeiten verschiedener Clients erforderlich machen. Um diese Probleme anzusprechen, stellen wir eine grafische Dialogfluss-Notation vor, die die Spezifikation hierarchischer Dialogsequenzen für verschiedene Präsentationskanäle ermöglicht. Nach Übersetzung in eine XML-basierte Dialogbeschreibungssprache eignet sich diese Spezifikation als Eingabe für ein Framework, das die Dialogfl¨usse komplexer Web-Anwendungen steuert.