Abstract
Component-Based Software Architecture is a promising solution for realizing distributed computing systems. To develop high quality software for such systems, an analysis of non-functional aspects of the software properties (also called Quality of Service or QoS) is very important. The UniFrame research project defines a Unified Meta-Component Model Framework (UniFrame) that includes a notion of QoS contracts. A classification of Quality of Service parameters, both static and dynamic, relevant to component-based distributed computing is developed and represented formally using Two-Level Grammar (TLG), an object-oriented formal specification language. TLG may be transformed into both a UML model, augmented with OCL constraints, and executable code in the Java programming language. This may be regarded as standardized code for implementation of the distributed application with dynamic measurement of the Quality of Service aspects incorporated. The approach is consistent with OMG's Model Driven Architecture (MDA) in that QoS properties may be specified at the Platform Independent Model (PIM) level and then carried down to the Platform Specific Model (PSM) level in implementation.