BEST: A Unified Business Process Enactment via Streams and Tables for Service Computing
Ahmed Awad, Feras Awaysheh, Hugo A. López
TL;DR
The paper tackles the challenge of executing diverse process modeling notations by proposing BEST, a unified, event-driven execution framework based on streams, tables, and the continuous query language ($CQL$). By mapping both procedural (BPMN) and declarative (DCR) models to $CQL$-driven rules, the approach enables cross-paradigm orchestration and hybrid models within a microservice-friendly architecture implemented on Esper. The authors demonstrate feasibility through a case study on case management, including BPMN, DCR, and a hybrid model, and compare results with Camunda and DCRGraphs.net to validate practical viability. The work offers flexible model evolution and migration, addressing running-instance consistency and future extensions to additional notations, with implications for soundness and compositionality in hybrid process environments.
Abstract
Business process models are essential for the representation, analysis, and execution of organizational processes, serving as orchestration blueprints while relying on (web) services to implement individual tasks. At the representation level, there are two dominant paradigms: procedural (imperative) notations that specify the sequential flows within a process and declarative notations that capture the process as a set of constraints. Although each notation offers distinct advantages in representational clarity and cognitive effectiveness, they are seldom integrated, leading to compatibility challenges. In this paper, we set aside the imperative-declarative dichotomy to focus on orchestrating services that execute the underlying tasks. We propose an execution semantics based on the Continuous Query Language (CQL), where CQL statements respond dynamically to streams of events. As events unfold, these CQL statements update the execution state (tables) and can generate new events, effectively triggering (web) services that implement specific process tasks. By defining all executions around a unified event model, we achieve cross-language and cross-paradigm process enactment. We showcase how industrial process modeling languages, such as BPMN and DCR graphs, can be enacted through CQL queries, allowing seamless orchestration and execution of services across diverse modeling paradigms.