Exception Handling for Service Component Architectures

The Service Component Architecture (SCA) makes it possible to combine existing and new services based on a variety of technologies with components built using a component-based development approach. However, when asynchronous services compositions are executed, one or more errors can occur, possibly at the same time, affecting the composition's dependability. In many cases, parts of the composition are off-the-shelf components or Web services whose individual dependability cannot be reliably ascertained. In this paper, we propose a novel exception handling model that targets the needs of dependable SCA applications. The model is applicable to service-oriented systems and allows the creation of fault-tolerant asynchronous service compositions. We also present the EH-SCA framework, an instantiation of the proposed model implemented as an extension of the Apache Tuscany SCA infrastructure. Developers can apply this instantiation of the model to both new and existing applications by using a simple and flexible aspect-oriented programming model. Finally, a case study of the EH-SCA framework shows how it can be used to build dependable distributed applications.