Dynamic Composition Techniques Research Articles

SAW-Q: a dynamic composition approach of REST services based on queue model

Service composition is one of the principles of service-oriented architecture; it enables reuse and allows developers to combine existing services in order to create new services that in turn can be part of another composition. Dynamic composition requires that service components are chosen from a set of services with equal or similar functionality at runtime and possibly automatically. The adoption of the REST services in the industry has led to a growing number of services of this type, many with similar functionality. The existing dynamic composition techniques are method-oriented whereas REST is resource-oriented and consider only traditional (WSDL/SOAP) services. We propose SAW-Q, an extension of simple additive weighting (SAW), as a novel dynamic composition technique that follows the principles of the REST style. Additionally, SAW-Q models quality attributes as a function of the actual service demand instead of the traditional constant values. Our model is much more accurate when compared to real implementation, positively improving the quality of dynamic service compositions.

Designing runtime variation points in product line architectures: three cases

Software product lines provide a common architecture, reusable code, and other common assets for a set of related software products. Variation is a central requirement in this context, as the product line components have to be instantiated, composed, and configured in the context of the products. In many approaches either static composition techniques or dynamic composition techniques based on loose relationships, such as association, aggregation, and replacement of entities, are proposed to design the variation points. If the domain of the product requires runtime variation, however, these approaches do not provide any central management facility for the runtime variation points. As a solution to this problem, we propose a pattern language that provides a domain-specific variation language and runtime variation point management facilities as part of the product line. We present three case studies from the areas of interactive digital television and document archiving in which we have applied this pattern language.