Persistent Contextual Values as Inter-Process Layers

Mobile applications today often fail to be context aware when they also need to be customizable and efficient at run-time. Context-oriented programming allows programmers to develop applications that are more context aware. Its central construct, the so-called layer, however, is not customizable. We propose to use novel persistent contextual values for mobile development. Persistent contextual values automatically adapt their value to the context. Furthermore they provide access without overhead. Key-value configuration files contain the specification of contextual values and the persisted contextual values themselves. By modifying the configuration files, the contextual values can easily be customized for every context. From the specification, we generate code to simplify development. Our implementation, called Elektra, permits development in several languages including C++ and Java. In a benchmark we compare layer activations between threads and between applications. In a case study involving a web-server on a mobile embedded device the performance overhead is minimal, even with many context switches.Comment: 8 pages Mobile! 16, October 31, 2016, Amsterdam, Netherland

Introducing Context Awareness in Unmodified, Context-unaware Software

Software tends to be highly configurable, but most applications are hardly context aware. For example, a web browser provides many settings to configure printers and proxies, but nevertheless it is unable to dynamically adapt to a new workplace. In this paper we aim to empirically demonstrate that by dynamic and automatic reconfiguration of unmodified software we can systematically introduce context awareness. In 16 real-world applications comprising 50 million lines of code we empirically investigate which of the 2,683 run-time configuration accesses (1) already take context into account, or (2) can be manipulated at run-time to do so. The results show that context awareness can be exploited far beyond the developers' initial intentions. Our tool Elektra dynamically intercepts the run-time configuration accesses and replaces them with a context aware implementation. Users only need to specify contexts and add context sensors to make use of this potential

Challenges in Validating FLOSS Conguration

Part 3: Licensing, Strategies, and PracticesInternational audienceDevelopers invest much effort into validating configuration during startup of free/libre and open source software (FLOSS) applications. Nevertheless, hardly any tools exist to validate configuration files to detect misconfigurations earlier. This paper aims at understanding the challenges to provide better tools for configuration validation. We use mixed methodology: (1) We analyzed 2,683 run-time configuration accesses in the source-code of 16 applications comprising 50 million lines of code. (2) We conducted a questionnaire survey with 162 FLOSS contributors completing the survey. We report our experiences about building up a FLOSS community that tackles the issues by unifying configuration validation with an external configuration access specification. We discovered that information necessary for validation is often missing in the applications and FLOSS developers dislike dependencies on external packages for such validations

Introducing Context Awareness in Unmodified, Context-unaware Software

International audienceSoftware tends to be highly configurable, but most applications are hardly context aware. For example, a web browser provides many settings to configure printers and proxies, but nevertheless it is unable to dynamically adapt to a new workplace. In this paper we aim to empirically demonstrate that by dynamic and automatic reconfiguration of unmodified software we can systematically introduce context awareness. In 16 real-world applications comprising 50 million lines of code we empirically investigate which of the 2,683 run-time configuration accesses (1) already take context into account, or (2) can be manipulated at run-time to do so. The results show that context awareness can be exploited far beyond the developers' initial intentions. Our tool Elektra dynamically intercepts the run-time configuration accesses and replaces them with a context aware implementation. Users only need to specify contexts and add context sensors to make use of this potential