A Cooperative Editor for Hierarchical Diagrams: An Object Petri Net Model

This paper presents a case study on the use of Object Petri Nets. The case study is that of a cooperative editor for hierarchical diagrams. The methodology for deriving the Petri Net model is to follow an object-oriented design methodology: first we prepare the Object Model in the OMT notation of Rumbaugh; then we prepare the Dynamic Model in the form of lifecycles, following the Shlaer-Mellor methodology; and finally we map these models into an Object Petri Net model. This approach has the advantage of guiding the development with well-accepted methodologies, but has the disadvantage of overlooking valid Petri Net solutions to the problem. As a result of this exercise, some loose ends in the Shlaer-Mellor methodology are identified and resolved, and a modification to the semantics of OPN super transitions is proposed. However, one overriding conclusion of this paper is that Object Petri Nets are suitable as a target formalism in such an object-oriented design methodology.