Visual Specification and Parsing of a Statechart Variant using GENGED

In this paper we consider a simple kind of the statechart language which is supported by the CASE tool Rhapsody. This kind of statecharts is already modeled in [4] using graph transformation. In accordance to [4], we allow hierarchical composition (sub-states and super-states) and parallel composition (combination of states by conjunction). A sample statechart is shown by Figure 1. It models the behavior of a blower with High and Low ventilation mode and three different temperature modes. Important is the fact that transitions of the following kinds are not permitted: (1) transitions between states of different statecharts which are not nested inside each other (e.g. a transition from Low to Warm or from Standby to Cool), (2) transitions between a state and one of its super-states (e.g. a transition from Low to its super-state On or from Standby to NotOn), (3) transitions which enter sub-diagrams of parallel states (e.g. a transition from NotOn to High).