Facilitating rich data manipulation in BPEL using E4X

The Business Process Execution Language (BPEL) uses XML to specify the data used within a process and realizes data flow via (globally) shared variables. Additionally, assign activities can be used to copy (parts of) variables to other variables using techniques like XPath or XSLT. Although BPEL’s built-in functionality is sufficient for simple data manipulation tasks, it becomes very cumbersome when dealing with more sophisticated data models, such as arrays. ECMAScript for XML (E4X) extends JavaScript with support for XML-based data manipulation by introducing new XPath-like language features. In this paper we show how E4X can help to significantly ease data manipulation tasks and propose a BPEL extension that allows employing JavaScript/E4X for implementing them. As E4X allows defining custom functions in terms of scripts, reusability with respect to data manipulation is improved. To verify the conceptual framework we present a proof-of-concept implementation based on Apache ODE.

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BPEL for Semantic Web Services (BPEL4SWS)

The Web Services Business Process Execution Language, version 2.0 (WS-BPEL 2.0 or BPEL for brevity) introduces a model for business processes based on Web services. A BPEL process orchestrates interactions among different Web services. The language encompasses features needed to describe complex control flows, including error handling and compensation behavior. BPEL for Semantic Web Services (BPEL4SWS) uses Semantic Web Service Frameworks to define a communication channel between two partner services instead of using the partner link which is based on WSDL 1.1. It enables describing activity implementations in a much more flexible manner based on ontological descriptions of service requesters and providers.

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BPELlight

In this paper we present BPEL light which decouples process logic from interface definitions. By extending BPEL 2.0 with a WSDL-less interaction model, BPEL light allows to specify process models independent of Web service technology. Since its interaction model is based on plain message exchange, it is completely independent of any interface description language. This fosters flexibility and reusability of process models and enables modelling platform and component model independent business processes. The presented approach takes a significant step towards narrowing down the gap between business level and IT level by facilitating a more business-oriented modelling of executable processes.

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