Abstract. This paper introduces the ISpec approach to interface specification. ISpec supports the development of interface specifications at various levels of formality and detail in a way compatible with objectoriented modelling techniques (UML). The incremental nature of the levels and the underlying formal framework of ISpec allow informal interface specifications to be made formal in steps. The body of the paper consists of a discussion of the main characteristics of ISpec, which reflect the important decisions taken in the design of ISpec. The idea of component-based specifications and specification plug-ins for constructing heterogeneous specifications is discussed and a small example showing the various levels of specification supported by ISpec is presented.
H. B. M. Jonkers