Introducing the Guard-Stage-Milestone Approach for Specifying Business Entity Lifecycles

Business process management, workflow, and case management are critical technologies for managing collections of services, including human activities, to support business operations. One way to manage business operations is based on business entities with lifecycles (BEL’s) (a.k.a. business artifacts), i.e., key conceptual entities that are central to guiding the operations of a business, and whose content changes as they move through those operations. A BEL type includes both an information model that captures, in either materialized or virtual form, all of the business-relevant data about entities of that type, and a lifecycle model, that specifies the possible ways that an entity of this type might progress through the business. Most previous work on BEL’s has been based on the use of lifecycle models based on variants of finite state machines. This paper introduces the Guard-Stage-Milestone (GSM) meta-model for lifecycles, which is an evolution of the previous work on BEL’s. GSM lifecycles are substantially more declarative than the finite state machine variants, and support hierarchy and parallelism within a single entity instance. The GSM operational semantics are based on a form of Event-Condition-Action (ECA) rules. This paper provides an informal, preliminary introduction to the GSM approach, and briefly overviews selected research directions.