Extending UML for Real-Time Component Based Architectures

A new style for concurrent object oriented architectures was proposed by the author in his doctoral thesis report [7]. The style can be used in object oriented systems when individual paths of execution are required to be concurrent and multiple processes may be positioned along the path to control the action. Therefore each process controls a segment of the path sequentially. So he called the style PPOOA, ‘Pipelines of Processes in Object Oriented Architectures [8]. PPOOA promotes that architectural decisions related to concurrency in real-time systems should be made at the preliminary design phase. Currently UML [12] is the standard notation for object oriented development. An important issue of UML is its capacity to be extended by using the profiling concept that allows the compatibility with other UML modeling issues. A UML profile is defined as a stereotype of package that groups model elements that have been customized for a specific domain. It allows one to develop variants of the UML suited for such specific domain [3]. The PPOOA profile described in this article is compatible with UML and improves its use in real-time architectures. The UML stereotypes are extended with the elements of the style (periodic and aperiodic processes, controller object, and coordination mechanisms). The modeling of flows of activities with a textual but rigorous notation is also critical for the analysis of the time responsiveness in real-time systems. The PPOOA profile has been implemented in a CASE tool as part of the research work of the CARTS project funded by the European Union, IST initiative.