Object behavior composition by transition and state composition

Behavior composition is essential to construct an object-oriented system from interacting objects. We propose a method to compose behaviors of the objects typically found in real-time applications. In our approach, the behaviors of individual objects are first represented by extended state-transition diagrams (ESTDs). Then, in order to obtain the combined behavior of interacting objects, we tentatively combine their ESTDs by merging some of the transitions and states. Finally, we redistribute to individual objects the actions responsible for the interactions among objects. When combined with the structural active-object system (SAGS) approach, the proposed method allows executable code to be produced from specifications. A simple queuing system and a manufacturing control system are used as examples of our presentation