ViSta: a tool suite for the visualization of behavioral requirements
ViSta is a tool suite designed to support the requirements specification phase of reactive systems. It enables the user to prepare and analyze a diagrammatic description of requirements using the statechart notation. ViSta includes a template wizard, a graphical editor and a statechart visualization tool. The template wizard guides the user through the steps necessary for the extraction of relevant information from a textual description of requirements. This information is stored in a database that is used by the statechart visualization tool to automatically generate statechart layouts. The statechart visualization tool offers a framework that combines hierarchical drawing, labeling, and floorplanning techniques. Hence, the automatically produced drawings enjoy several important aesthetic properties: they emphasize the natural hierarchical decomposition of states into substates; they have a low number of edge crossings; they have a good aspect ratio, and require a small area. These aesthetic features are invaluable since they allow the user to shift focus from organizing the mental or physical structure of the requirements document to its analysis.