Fortune Nets for Fortunettes: Formal, Petri Nets-Based, Engineering of Feedforward for GUI Widgets.

Feedback and feedforward are two fundamental mechanisms that supports users’ activities while interacting with computing devices. While feedback can be easily solved by providing information to the users following the triggering of an action, feedforward is much more complex as it must provide information before an action is performed. Fortunettes is a generic mechanism providing a systematic way of designing feedforward addressing both action and presentation problems. Including a feedforward mechanism significantly increases the complexity of the interactive application hardening developers’ tasks to detect and correct defects. This paper proposes the use of an existing formal notation for describing the behavior of interactive applications and how to exploit that formal model to extend the behavior to offer feedforward. We use a small login example to demonstrate the process and the results.