Barcelona: A Design and Runtime Environment for Declarative Artifact-Centric BPM

A promising approach to managing business operations is based on business artifacts, a.k.a. business entities (with lifecycles) [8, 6]. These are key conceptual entities that are central to guiding the operations of a business, and whose content changes as they move through those operations. A business artifact type is modeled using (a) an information model, which is intended to hold all business-relevant data about entities of this type, and (b) a lifecycle model, which is intended to hold the possible ways that an entity of this type might progress through the business. In 2010 a declarative style of business artifact lifecycles, called Guard-Stage-Milestone (GSM), was introduced [4, 5]. GSM has since been adopted [7] to form the conceptual basis of the OMG Case Management Model and Notation (CMMN) standard [1]. The Barcelona component of the recently open-sourced [2] ArtiFact system supports both design-time and run-time environments for GSM. Both of these will be illustrated in the proposed demo. The GSM approach will be illustrated in the demo using a simplified OrderToCash scenario. Figure 1 shows a screen shot from Barcelona that provides a view of the design editor for this scenario. The focus is on a single artifact type, called CustomerOrder. The information model, which is essentially a record with scalar and nested relation fields, is not illustrated in the figure, but is accessible from the tree on the left side. The example focuses on the steps of Drafting a (customized) product based on an incoming order; Submitting the draft for approval; and then Processing the order. These activities are captured as top-level stages in the GSM schema for this example, which is illustrated in the right-hand portion of Figure 1. Stages may contain a single task (as is the case with Drafting and Submitting), and may be nested (as is the case with Processing and inside that, with Preparing). Stages may be executed once or repeatedly, and may execute in parallel. Launching of a stage execution is controlled by rules-based guards, designated using blue diamonds on the right edge of the stage. These may be triggered by an external event (in which case a yellow “lightening bolt” is included), or by internal events. Completion of a stage execution is controlled by rules-based milestones, indicated by orange disks on the right-hand boundaries of stages. These, too, may be triggered by external or internal events. The Barcelona engine can support GSM schemas with multiple artifact types, and can support large numbers of artifact instances. In typical applications the instances are