Graphical animation of object-oriented software designs (abstract)

Abstract

We have built an extension to a prototype CASE tool called ESPEX, that makes it possible to execute graphically Wassermans Object-Oriented Structured Design (OOSD) notation. The tool itself is implemented in the Smalltalk 80 programming environment. The tool contains a window-based menu-driven graph editor and an integrated graph simulator with animation support. Animation means that the movements of data items and messages between objects are visualized on a workstation display. We have implemented simulation for object instances. We are using moving tokens with data values attached on top of them. Tokens flow from objects to other objects, carrying the essential data with them. The moving tokens indicate clearly the active parts of the model, while the data values also make it possible to visualize the actual computations that take place in the objects. Another advantage of moving tokens is that it is possible to attach time stamps to tokens. With the help of the time stamps it is possible to simulate experimenting with animation techniques for dynamic creation and deletion of objects. We model objects hierarchically, so that an object can be composed of other lower level objects. At the lowest level objects are described with predicate/transition Petri nets, and the computations with IPTBS Meta-IV, Smalltalk-80, or C. The work presented demonstrates that it is possible and feasible to animate object-oriented design notation using a token moving approach. However, there is still much work to be done on the animation of dynamic instantiations and deletion of objects. We believe that graphical animation tools are the enabling technology for teamwork and for conceptual communication in the future concurrent engineering working environments. The work presented in this demo was carried out in the IPTES project. IPTBS is partially funded by the European Communities under the ESPRIT programme.