formal MVC: A Pattern for the Integration of ASM Specifications in UI Development

Using architectural patterns is of paramount importance for guaranteeing the correct functionality, maintainability and modularity, especially for complex software systems. The model-view-controller (MVC) pattern is typically used in user interfaces (UIs), since it allows the separation between the internal representation of the information and the way it is shown to users. The main problem of using this approach in a formal setting, where formal models are used to specify the requirements and prove safety properties, is that those models are not directly used within the MVC pattern and, thus, all the activities performed at model-level are somehow lost when implementing the UI. For this reason, in this paper, we present the formal MVC pattern (fMVC), an extension of the classical MVC where the model is a formal specification, written using Abstract State Machines. This pattern is supported by the AsmetaFMVCLib, which allows the user to link the formal model with the view and the controller by using simple Java annotations. We present the application of fMVC on a simple example of a calculator for explanatory purposes, then we apply it to the AMAN case study, which has inspired the definition of fMVC. We discuss the advantages of fMVC and its shortcomings, trying to identify the scenarios where it should be applied and possible alternatives.