Towards a WPSL : a critical analysis of the 20 classical workflow control-flow patterns

Abstract

Abstract. In 2000, after a comprehensive survey of tools and techniques for work\now management, 20 control-\now patterns were identied [5] and made these available through www.work\nowpatterns.com. Since then, many commercial and academic work\now management systems have been evaluated using these patterns. Moreover, standards such as BPEL and XPDL have been evaluated and these evaluations have triggered improve-ments in them. Although the 20 work\now patterns have proven to be useful, the selection of these patterns was done in an ad-hoc manner and the description of the patterns in natural language has been rather am-biguous. Therefore, we propose a more analytical approach using a new Work ow Pattern Specication Language (WPSL). WPSL is independent of any implementation language utilized by contemporary work\now man-agement systems. In this paper, we analyze the 20 original work\now pat-terns using WPSL, discuss the dierent variants of the patterns, and use WPSL to capture the detailed semantics of existing work\now management systems. 1