Service Composition at the Presentation Layer using Web Service Annotations

In the eld of Service-Oriented Architectures the implementation of business logic and business processes is well-understood and covered by existing development approaches, but concepts for a lightweight service consumption in order to build interactive service-based applications are still in a preliminary phase. This lack of service-consumerorientation prevents users with limited IT skills to get easy access to services and their o ered functionalities. The paper presents an approach that follows the idea of integration at the presentation layer enhanced by user interface (UI) related service annotations. It describes the relationship of these ideas to already existing mashup approaches and gives an insight into how services can be composed to complex interactive applications in a visual manner without the need to write any code. 1 Motivation and Background Service-Oriented Architectures (SOA) promise to break former monolithic applications into loosely coupled services that can be distributed across several systems. These services are composed to implement business applications and processes. Even though service composition is well-understood and covered by existing approaches for technical developers using languages such as BPEL, tools and methodologies for enabling end-user service composition have been largely ignored [1]. A promising approach for bridging this gap are mashups that focus on a user-centric and lightweight UI integration [2] by combining the philosophy of SOA and approaches of End-User Development [3]. The need for such situational applications to address individual and heterogeneous needs as well as the shift to more exible and dynamic business environments encourage the idea of integrating mashup concepts into the enterprise. Our approach shows a way of overcoming limitations of existing mashup approaches [4] in order to build complex interactive service-based applications. Following our preliminary investigations and description of related work [5], this paper discusses the following contributions: We propose the usage of UI related service annotations to ease service integration and composition. This limits the e ort for the development of ComposableWeb'09