ConExT-U: A Context-Aware Exception Handling Mechanism for Task-Based Ubiquitous Systems

Context-awareness is a central aspect in the design of ubiquitous systems, characterizing their ability to observe the environment's context changes and adapt its structure and behavior according. Since those systems can be able to make autonomous decisions (i.e., without direct user intervention), dependability becomes an important requirement. The exception handling is a well-known error recovery technique employed to improve the software robustness and contributes to the overall software system's reliability and dependability. However, despite its benefits, exception handling still not widely used in the development of ubiquitous systems. In fact, we argue that is consequence of the lack of a proper exception handling mechanism to support it during the development and execution phases. In order to address this problem, we propose a context-aware exception handling mechanism designed specifically for context-aware ubiquitous systems. The proposed mechanism is implemented as a Java-based framework that provides a task-based model for building robust ubiquitous systems. A prototype of a ubiquitous parking control system is implemented to explore and validate the features of the proposed mechanism.