Executable specification is regarded as an important supporting tool for software system design, because it integrates the method of formal analysis, and the more experimental approach of prototyping and testing to analyze and to verify the design of a system at early stage of the software life cycle. However, executable specification is still a virgin area in OO research. The motivation of this research is to bridge this important technological gap in the current OO research. An executable design specification language for OO systems will be studied. The language is called extended G-Nets (eG-Nets), which is based on the theory of Petri nets, and the PI's previous work on the G- Net framework. The design of eG-Nets represents a modular approach for software specifications in the sense that an eG- Net specification not only specifies the behavior of an OO system, but also the structure of the design. EG-Net specifications are directly executable in distributed environment.
