Exception Handling Patterns for Process Modeling

Barbara Staudt Lerner
Computer Science Department
Mt. Holyoke College

Stefan Christov, Leon Osterweil, Alexander Wise
Computer Science Department
University of Massachusetts, Amherst

Reda Bendraou
University of Pierre & Marie Curie, Paris, France

Udo Kannengiesser
NICTA, Australia


Process modeling allows for analysis and improvement of processes that coordinate multiple people and tools working together to carry out a task. Process modeling typically focuses on the normative process, that is, how the collaboration transpires when everything goes as desired. Unfortunately, real world processes rarely proceed that smoothly. A more complete analysis of a process requires that the process model also include details about what to do when exceptional situations arise. We have found that in many cases, there are abstract patterns that capture the relationship between exception handling tasks and the normative process. Just as object-oriented design patterns facilitate the development, documentation and maintenance of object-oriented programs, we believe process patterns can facili- tate the development, documentation and maintenance of process models. In this paper, we focus on the exception handling patterns that we have observed over many years of process modeling. We describe these patterns using three process modeling notations: UML 2.0 Activity Diagrams, BPMN and Little-JIL. We present both the abstract structure of the pattern as well as examples of the pattern in use. We also provide some preliminary statistical survey data to support the claim that these patterns are found commonly in actual use and discuss the relative merits of the three notations with respect to their ability to represent these patterns.