| description |
Web service orchestrations -- expressed in the Web Service Business
Process Execution Language (WS-BPEL or BPEL for short) -- are a
manifestation of the two-level-programming paradigm where services,
i.e. the business functions used by the composite application, are
composed through BPEL's control flow constructs. BPEL processes
Web service orchestrations, business functions therefore can be
transparently accessed remotely, allowing to build composite
applications that integrate business functions provided by different
partners on different locations. As of today, execution of BPEL
processes, i.e. the evaluation of the processes' control flow,
is performed by a central workflow engine. In certain scenarios,
such as complex collaborative cross-partner interactions, this
approach of centralized workflow enactment leads to
un-natural'' process models; process models that are not
driven by the processes' original business goal but by
infrastructural or organizational reasons. In this paper, we propose
an alternative approach to enacting BPEL process control flow in a
distributed, decentralized manner. We present the overall process
lifecycle and give a detailed description of the underlying process
model.
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