Error Handling Techniques for Robust Mission Critical Software

We propose to develop a method and tool that will formalize and streamline error handling already at the very earliest stages of software design. We propose to tackle this problem at the level of object oriented design in a commonly used modeling language, the Unified Modeling Language, UML. Our scheme includes the development of formal error handling notation as an extension to UML (Robust UML) and interpreting error handling models with the use of a Timed Petri Net simulation. The tool we will develop: Robust UML Simulation tool (RUSim) will formalize & streamline the approach to error handling on the one hand, while also improving coverage of exceptional condition identification on the other. The pillars include: 1. Error handling notations: notations will be defined as extensions to UML that will include error condition identification, error handling roles and error coverage. 2. Automated translation of a UML design, including the exception handling aspects, to a Timed Petri Net (TPN) model for full and complete analysis of "unsafe markings" in the net. 3. Online Petri Net Analysis resulting in translation of "unsafe markings" in the net to error conditions that can occur to the software as is implemented in the design model.