REFINEMENT OF OBJECTS AND OPERATIONS IN OBJECT-Z

摘要

In this paper we describe how we can refine both objects and operations in an Object-Z specification. In particular, we will be concerned with changes of granularity of both objects and operations. Objects in that we wish to change the structure of objects in a specification. Operations in that we wish to provide explicit support for action refinement in this language. There are clear advantages in being able to change such levels of granularity when performing a refinement. In this paper we discuss the issues surrounding such refinements and derive general rules to support their use. We illustrate our ideas by looking at a specification of a cash point machine at a bank.