Diploma Thesis DIP-2586

BibliographyPaluszek, Michael: Coordinating Distributed Loops and Fault Handling, Transactional Scopes using WS- Coordination protocols layered on WS-BPEL services.
University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Diploma Thesis No. 2586 (2007).
155 pages, english.
CR-SchemaH.4.1 (Office Automation)
D.2.12 (Software Engineering Interoperability)
D.3.2 (Programming Language Classifications)
C.2.2 (Network Protocols)
C.2.4 (Distributed Systems)
D.1.0 (Programming Techniques General)
Abstract

The aim of the diploma thesis is to enable coordination of intra-process loops and scopes using WS-BPEL business processes and WS-Coordination protocols. In such a scenario a business process is split into several process fragments distributing its loops and scopes. These process fragments have to produce the same behavior as the original process. One of the difficulties in this approach is to achieve a common outcome of distributed loops and scopes and this work concerns this problem especially. In particular, the starting and finishing of fragments of a distributed loop or scope have to be synchronized. As do iterations of a loop. Furthermore, fault handling as well as compensation handling of a distributed scope has to be executed in a manner such that the behavior is propagated into all fragments of the scope.

A system is designed and implemented to enable a concrete realization the protocols, defined as part of the WS-Coordination framework, for coordinating split loops and scopes defined in [15]. To do so, this thesis define the protocols’ WSDL definitions (incl. XML Schemas), BPEL element extensions to identify activity fragments, and the concrete, required extensions to WS-Coordination’s registration so fragments can be joined to the correct instance. Also, it provides the architecture of a coordination system that can react to and affect behavior deep in a BPEL process instance. The system consists of an execution environment for fragmented BPEL processes, using a controller interacting with a modified open source BPEL engine and a coordinator implementation according to the WS-Coordination specification. The fragmented BPEL execution environment may exist multiple times in a network each running an arbitrary amount of BPEL fragments however, the coordinator is a single entity. The thesis shows the modifications and extensions necessary for instrumenting a BPEL engine to support running a scope or loops as a fragment. The results of this work are presented by executing diverse scenarios, coordinated using the designed system and protocols. The scenarios include scopes with fault and compensation handlers, multiple loops, and loops nested in faulting split scopes, all split among several process fragments.

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Department(s)University of Stuttgart, Institute of Architecture of Application Systems
Superviser(s)Khalaf, Rania; Karastoyanova, Dimka
Entry dateMay 25, 2007
   Publ. Computer Science