An Object-Z Specification of a Petrol Supply System

Abstract

As modern complex computer systems become increasingly sophisticated and data-intensive, people have long recognized the importance of precisely and unambiguously specifying them with formal methods. This paper advocates the use of Object-Z, a formal specification language, in the description of complex systems. Object-Z is an extension to the Z language to facilitate specification in an object-oriented style. First, we informally describe the syntax and semantics of Object-Z, highlighting those features that facilitate decomposing a large system into a collection of underlying objects and thus separating concerns. Then, we demonstrate the use of Object-Z by presenting a case study of a petrol supply system, illustrating how the system runs by communicating the constituent objects. Finally, we discuss several issues we encountered in this exercise, which may serve as feedback to the development of Object-Z.