An object-oriented modeling method for workflow applications

Based on an analysis of workflow applications, the modeling process of such applications is divided into four levels in this paper. They are: the application level, the structure and information level, the execution control level and the implementation level. An object-oriented model corresponding to the four-level modeling process is also given, expressed in UML. An event mechanism is employed in this paper to realize both the control and the distribution mechanism in the logical modeling of workflow applications, illustrated by an event meta-model consisting of four basic event classes. The event definition and notification mechanisms are separated from the event reaction objects, and the definition of functions and the triggering mechanism of the functions are also separated. This may facilitate the dynamic modification of the workflow definitions and may also facilitate the description of the distribution of workflow applications.