Abstract
Within the service-oriented computing domain, Web service composition is an effective realization to satisfy the rapidly changing requirements of business. Therefore, the research into Web service composition has unfolded broadly. Since examining all of the related work in this area becomes a mission next to impossible, the classification of composition approaches can be used to facilitate multiple research tasks. However, the current attempts to classify Web service composition do not have clear objectives. Furthermore, the contexts and technologies of composition approaches are confused in the existing classifications. This paper proposes an effort-oriented classification matrix for Web service composition, which distinguishes between the context and technology dimension. The context dimension is aimed at analyzing the environment influence on the effort of Web service composition, while the technology dimension focuses on the technique influence on the effort. Consequently, besides the traditional classification benefits, this matrix can be used to build the basis of cost estimation for Web service composition in future research. Keywords-service-oriented architecture (SOA); classification matrix; Web service composition; context-oriented; technologyoriented I. INTRODUCTION Web services have been widely accepted as the preferred standards-based way to implement Service-Oriented Architecture (SOA) in practice. Since "only when we reach the level of service composition can we realize all the benefits of SOA" [15], the research into composing Web services has grown significantly along with the increasing necessity of reusing existing resources. In the past decade, lots of work about composing Web services has been reported in the literature. As a result, it is nearly impossible to explore this research area by exhausting all the published composition approaches. However, we can inductively classify the existing Web service composition work, and thereby to facilitate the comprehension of related knowledge. Existing classification work of Web service composition can be found in several survey papers [16, 18]. Nevertheless, these classifications are either inco