Structural Active-Object Systems Fundamentals

Abstract

Structural active-object system s (SAOSs) are transition-based object-oriented system suitable for rapid development of various concurrent systems. A SAOS is constructed from its component structural active objects (SAOs) by structural and hierarchical composition. The behaviors of SAOs, in turn, are determined by the transition statements provided in their class definitions. Prototype SAOS programs have been developed in such diverse application areas as process and manufacturing control, discrete, analog, and mixed-mode simulation, hardware logic simulation, graphical user interfaces, graphical editors, LAN/WAN protocol simulation, and algorithm animation, with significant reduction in source sizes and program development time. In this paper we examine the fundamental ideas underlying the SAOS approach and emphasize the importance of structural and hierarchical object composition. Key Words and Phrases: Active object, structural composition, hierarchical composition, object composition, rapid prototyping, object-oriented concurrent programming, communicating sequential processes, CCS,LOTOS, ESTELLE, software IC.