Reflexion Models for State Machine Extraction and Verification

High-level design models are often used for describing the behavior or structure of a software system. It is generally much easier and more adequate to understand a software system on this level than on the level of individual code lines. Such models are also created by developers as they gain an understanding of the software. Unfortunately, these models often do not correspond to what is really in the code. Murphy et al. introduced the idea of reflexion models in 1995 to overcome this problem. Their approach is today widely used for architecture conformance checking and reconstruction. In this paper, we introduce reflexion models for state machines. Our approach allows to check the correspondence of a hypothetical state machine model with the code. It returns information about convergence, partial convergence, divergence, or absence of the specified states and transitions. Similar to the original reflexion model, the approach can be used for conformance checking as well as interactive reverse engineering of state machine models. We concentrate on the latter and show the potential of the approach in several case studies.