Title: IQoS-aware exception resolution for BPEL processes: a middleware-based framework and performance evaluation

Authors: Christos Kareliotis, Costas Vassilakis, Efstathios Rouvas, Panayiotis Georgiadis

Addresses: Department of Informatics and Telecommunications, University of Athens, Panepistimiopolis, 15784, Athens, Greece. ' Department of Computer Science and Technology, University of Peloponnese, Terma Karaiskaki, 22100, Tripoli, Greece. ' Department of Informatics and Telecommunications, University of Athens, Panepistimiopolis, 15784, Athens, Greece. ' Department of Informatics and Telecommunications, University of Athens, Panepistimiopolis, 15784, Athens, Greece

Abstract: Web Services Business Process Execution Language (WS-BPEL) is widely used nowadays for specifying and executing composite business processes. During the execution, however, of such business processes, a number of faults stemming from the nature of SOA may occur. The WS-BPEL scenario designer must therefore use the provisions offered by WS-BPEL to catch these exceptions and resolve them. The system fault handler specification, however, is an additional task for the WS scenario designer, while the presence of such handlers within the scenario necessitates extra maintenance activities. In this paper, we propose a middleware-based framework for system exception resolution, which undertakes the tasks of failure interception, discovery of alternative services and their invocation. The process of selecting the alternative services can be driven by process consumer-specified Quality of Service (QoS) policy. Moreover, the middleware arranges for bridging syntactic differences between the originally invoked services and functionally equivalent replacements to it, by employing XSLT-based transformations. The middleware is deployed and maintained independently of the WS-BPEL scenarios, thus removing the need for specifying and maintaining system fault handlers within the scenarios. We also present performance measures, establishing that the overhead imposed by the addition of the proposed middleware layer is minimal.

Keywords: web services; exception handling; middleware; performance metrics; quality of service; QoS; scalability; BPEL; business processes; exception resolution; performance evaluation; service-oritented architecture; SOA.

DOI: 10.1504/IJWGS.2009.028346

International Journal of Web and Grid Services, 2009 Vol.5 No.3, pp.284 - 320

Published online: 16 Sep 2009 *

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