Evolutionary development of object behaviors

In object-oriented development methodologies, behavior of the system to be developed is usually specified as a collection of state diagrams for the objects involved in the system. We need to describe them so that each individual object reacts correctly to the events it receives. Also, we have to consider the entire system behaves properly as the result of the collective behavior of each object and this is usually done by the help of interaction or collaboration diagrams. We propose an evolutionary development method which allows to describe the system looking over its entire behavior, while it could be executed and tested at any stage of its development. It is based on the concept of stepwise reification and abstract execution. In this method, the system behavior is constructed by starting from its very abstract initial form and then gradually evolving it until its ultimate form is obtained. The evolution is done by executing and testing its abstract intermediate description and by reifying it to the next step. Execution of the abstract intermediate objects are done symbolically. We firstly formalize behaviors of object systems by the collection of regular expressions which are executed in parallel and by the concept of their collaboration. Next, on the foundation, we formalize the idea of evolutionary development of objects behavior in terms of rewriting behavior identifiers. Finally, we give an example to illustrate our method.