Exception handling in an event-driven system

Exception handling mechanisms were invented in 1970s to support structured programming methods for hierarchically organised software systems. The need to increase reusability and flexibility led to the development of new programming paradigms that do not emphasise hierarchical design. Event-driven systems-in which objects communicate using notifications about changed states-are a prime example. Unfortunately, this style of communication makes exception handling more difficult than in hierarchical systems. We contribute an analysis of the factors which influence exception handling in event-driven systems. The main focus of our discussion lies on the challenge of appropriate exception propagation. We provide results from an empirical case study performed on the source code of the Eclipse IDE that support our analysis.