We propose a design methodology, Service-Oriented Design with Aspects (SODA), for service-oriented systems to address the need to continually upgrade and evolve services while maintaining various versions. Our approach treats aspects as first-class design elements and consistently applies the concept of aspect to all phases of design and evaluation. At the early design stages, crosscutting concerns are first separated out as aspects, and then, services are composed by weaving the different design elements together. The behavior of aspects and services is represented as basic Petri Nets and we present rules for weaving together Petri Nets so as to obtain behavior of the integrated system (with aspects crosscutting services). Even at the evaluation stages, performance and resource data are separated out as aspects to be woven in to the design so as to enable advanced analysis using Petri Net tools. A small order service example is used to illustrate our approach.

Petri net has been widely used for modeling software systems due to its mathematical soundness and support of various tools. In many cases, performance-related analyses of Petri net for a software system need to consider the resource limitations caused by a specific platform. In terms of aspect-oriented approach, the interference of various resources scattered across a software system can be regarded as a specific concern that is only necessary during its performance-related analysis process. To capture the interactions of resources within the Petri net-based software architectural model, we propose an aspect-oriented resource composition model and the XML-based representation language called the resource extension markup language (ReML) for its description. In our approach, one or more resource composition models can be developed and described in ReML separately from the development of base software architectural models. Through the weaving process, a resource composition model can be applied to extend several Petri net-based software architectural models. The resource weaver generates an augmented Petri net used for analyzing performance characteristics of the extended software architectural model with resource interactions. Our aspect-oriented approach facilitates selecting an optimal or superior resource composition model for a software architectural model, and vice versa, which is illustrated using two exemplary server models