We present algebraic laws for a language similar to a subset of sequential Java that includes inheritance, recursive classes, dynamic binding, access control, type tests and casts, assignment, but no sharing. These laws are proved sound with respect to a weakest precondition semantics. We also show that they are complete in the sense that they are… (More)
In this paper we present how refactoring of object-oriented programs can be accomplished by using refinement. Our approach is based on algebraic laws of an object-oriented language for refinement similar to Java. We follow a strategy involving data and algorithmic refinement of classes.
Using Morgan's refinement calculus, we can write software in a precise and consistent way. Nevertheless, this may involve long and repetitive developments. Several refinement strategies are useful in different developments, and even in different points of a single development. A lot is gained by identifying these strategies, documenting them as tactics, and… (More)
The cardiac pacemaker has emerged as a case study for evaluating the effectiveness of techniques for the verification and design of embedded systems with complex control requirements. This paper reports on the experiences of using this case study to evaluate the concurrency model of two programming language subsets that target safety-critical systems… (More)