Exception specification and handling in workflow systems

Abstract

Various unexpected events frequently happen in workflow system. Thus workflow system should be equipped with handlers to cope with the unexpected events. But practically we cannot expect for a workflow system to prepare all the handlers for the potentially occurring events. It is more reasonable to let process designers specify exceptional situations and define corresponding exception handlers at process build time. In there when exceptional events occur, the workflow system detects the exceptions and invokes corresponding exception handlers. To support this mechanism, a workflow system should provide a means to specify exceptions and facilities to detect exception and invoke corresponding exception handlers. In this thesis, we devise an exception specification method using event-transition approach and its handling mechanism using design pattern. Detecting exceptions and mechanism for invoking exception handling routines are developed and embedded into our research workflow system (ICU/COWS).