Aspect-Oriented Development Method For QoS-Aware Middleware Of Heterogeneous Dynamic Real-Time Systems

With widely applications of real-time systems in various fields, new problems such as real-time communication, heterogeneity are introduced in real-time systems. Dynamic real-time systems nowadays tend to be more and more complex and large in scale, and at the same time are required to be more flexible, autonomous, reliable and adaptive.Meanwhile, QoS requirements of network layer have definitely provided QoS parameters such as capacity, timeliness, service level. QoS requirements of application layer are supported by QoS requirements of operating system layer. In addition non-functional requirements(such as performance, security and reliability) become the new focus of attention, because of fast updating calculation environment and various user requirements. It requires that developer maintains sensitive to QoS, also requests the middleware to provide supports of non-functionality. One of the major challenges is to ensure that the adaptation mechanism of QoS-aware components, which requires middleware configure QoS service according to QoS requirements of client.AOP is a new software development paradigm, which regards the whole system as a combination of different concerns. The Implementation of system is also superposition process of concerns. AOP could attain a higher level of separation of concerns in both functional and non-functional matters by introducing aspect, for the implementation of crosscutting concerns. Different aspects can be designed separately, and woven into system. As the typical crosscutting concerns, research on QoS based AOP is obviously very valuable.There are many implementations of QoS-aware middleware recently, such asQuO, DynamicTAO, COMQUAD, OpenCOM, Quartz, 2K^Q and 2K^Q+. However, research on several mechanism of QoS-aware middleware based AOP is just begun. Therefore, we analyze several mechanisms of QoS-aware middleware with AOP. In succession introduces an example of distributed streaming audio player.In this paper, we focuses on using AOP to analyze QoS-aware middleware's several mechanisms of heterogeneous dynamic real-time systems. Then we express an AOP-based QoS-aware middleware adaptation mechianism.In this mechianism,a layer of indirection can be added using AOP. All components in the service can be wrapped in an aspect.First, this paper researches the real-time systems, middleware and AOSD, outlining the scope of content of this paper; Second, it researches QoS-aware middleware and separation of concerns with AOP in depth and compare with several typical QoS-aware middleware; Third, using AOP to analyze QoS-aware middleware's several mechanisms of heterogeneous dynamic real-time systems; Then, showing the example about AOP-based QoS-aware middleware adaptation mechianism of of heterogeneous dynamic real-time systems. Finally gives some directions of future work.