From WS‐CDL choreography to BPEL process orchestration

Abstract

PurposeThe web service choreography description language (WS‐CDL) is a specification for describing multi‐party collaboration based on web services from a global point‐of‐view. WS‐CDL is designed to be used in conjunction with the web services business process execution language (WS‐BPEL or BPEL). As WS‐CDL is a new choreography language, there has been doubt about the feasibility of a transformation to BPEL. This article aims to show how BPEL process definitions of parties involved in a choreography can be derived from the global WS‐CDL model and what the limitations of such a derivation are.Design/methodology/approachThe authors implemented a prototype of the mappings as a proof of concept.FindingsThe automatic transformation leverages the quality of software components interacting in the choreography as advocated in the model driven architecture (MDA) concept. The mapping reveals that some information has to be added manually to the generated BPEL, in particular, choice conditions and private activities.Research limitations/implicationsA comprehensive evaluation of WS‐CDL with respect to the interaction patterns is still missing. As a resolution to this issue, the authors propose the modelling of choreographies by the help of a more abstract language – in the sense of being more independent of underlying technology – like UML 2.0 Activity Diagrams.Practical implicationsThe automation of the mapping offers substantial speed‐up of the engineering process. Additionally, the automatic generation of BPEL stubs minimizes the risk of inconsistent process implementations by the parties.Originality/valueThe core contribution is to show how BPEL process definitions for parties involved in a choreography can be derived from a global WS‐CDL model.