QoS Aspect Languages and Their Runtime Integration

Citation: Loyall JP, Bakken DE, Schantz RE, Zinky JA, Karr DA, Vanegas R, Anderson KR. QoS Aspect Languages and Their Runtime Integration. Lecture Notes in Computer Science, Vol. 1511, Springer-Verlag. Proceedings of the Fourth Workshop on Languages, Compilers, and Run-time Systems for Scalable Computers (LCR98), 28-30 May 1998, Pittsburgh, Pennsylvania.

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Abstract Distributed object middleware, such as CORBA, hides system- and network-specific characteristics of objects behind functional interface specifications. This simplifies development and maintenance of distributed objects, contributing to their growing acceptance. Critical applications have Quality of Service (QoS) requirements, however, such as real-time performance, dependability, or security, that are hidden by middleware. Because of this, application developers often bypass distributed object systems, thus gaining little or no advantage from the middleware. We have developed Quality Objects (QuO), a framework for developing distributed applications with QoS requirements. QuO provides a set of aspect languages, called Quality Description Languages (QDL), for specifying possible QoS states, the system resources and mechanisms for measuring and controlling QoS, and behavior for adapting to changing levels of available QoS at runtime.

This paper describes QDL in terms of aspect-oriented programming and introduces the syntax and semantics of the Structure Description Language (SDL), the component of QDL for describing adaptive characteristics of delegates and objects.