EXECUTABLE OBJECT MODELING WITH STATECHARTS

Most object-oriented methods use a graphical notation, and most also a dopt a state-based formalism to specify behavior. But most also fail t o rigorously define the semantics of the languages they use to describ e behavior. Without rigorous semantics, OO models can never be precise enough to produce fully executable models and enable automatic code s ynthesis. These issues are complicated and go beyond recommending a mo deling approach or methodology-they are language design concerns, requ iring rigorous mathematical underpinnings. Both syntax and semantics m ust be fully worked out: Any possible combination of constructs must b e clearly characterized as syntactically legal or illegal, and each le gal combination must be given a unique and formal meaning. In this art icle, the authors describe their integrated set of diagrammatic langua ges for object modeling built around statecharts and their supporting tool, Rhapsody, which produces a fully executable model and allows aut omatic code synthesis. As a result of the authors' collaboration with the team that defined the Unified Modeling Language, this language set and Rhapsody are consistent with UML.