Higher-Order Process Modeling: Product-Lining, Variability Modeling and Beyond

Abstract

We present a graphical and dynamic framework for binding and execution of (business) process models. It is tailored to integrate 1) ad hoc processes modeled graphically, 2) third party services discovered in the (Inter)net, and 3) (dynamically) synthesized process chains that solve situationspecific tasks, with the synthesis taking place not only at design time, but also at runtime. Key to our approach is the introduction of type-safe stacked second-order execution contexts that allow for higher-order process modeling. Tamed by our underlying strict service-oriented notion of abstraction, this approach is tailored also to be used by application experts with little technical knowledge: users can select, modify, construct and then pass (component) processes during process execution as if they were data. We illustrate the impact and essence of our framework along a concrete, realistic (business) process modeling scenario: the development of Springer's browser-based Online Conference Service (OCS). The most advanced feature of our new framework allows one to combine online synthesis with the integration of the synthesized process into the running application. This ability leads to a particularly flexible way of implementing self-adaption, and to a particularly concise and powerful way of achieving variability not only at design time, but also at runtime. MotivationBusiness process modeling has evolved from mere collection of requirements artifacts, supported by tools like ARIS [45], to an important element in the whole development process of complex applications. With the introduction of execution semantics for BPMN2 [41,2], business process models have started to be used to integrate the application expert in the overall development process. This inclusive trend is however still young and suffers from complicated mechanisms for integrating user-defined or third party activities/services [8,1,44,3,42]. The only exception is the jABC framework, that was designed from the very beginning for easing the integration process and that even offers systematic formal methods-based product line [26] and variability [11] support. On the other hand, in particular AristaFlow [4] promoted ad hoc process modeling as a particularly convenient way for customization. An ad-hoc approach allows users to adapt processes at runtime for a single use, a heuristics that has also successfully been used in [21] Sec. 3.2.3.What is missing to be fully prepared for future demands is a comprehensive, type-safe framework for flexibility, able to capture variability uniformly both at design time and at runtime in a hierarchical fashion. The usefulness of this ad-hoc and context-aware flexibility is illustrated by the following three increasingly demanding route planning scenarios:Static Route Planning: Planning the route before a trip using e.g. google maps gives a selection of nice choices and the option for a detailed investigation, and one is able to 'personalize' the own trip.

Language-Driven Engineering: From General-Purpose to Purpose-Specific Languages

“…We use here a specialized variant of the process language from the DIME framework [22] which provides fully model-based development of all aspects of a multi-user single-page web application 9 . As the DIME processes are the technological successors of the Service Logic Graphs (SLGs) of the jABC framework [84,100], they comprise building blocks for the inclusion of executable services, and these building blocks are connected according to their flow of control. Included services provide functionality for, e.g., putting emails into (named) baskets and email forwarding, as well as profile-based decision services -the starting points for the vertical decomposition described next.…”

On the Expressiveness of Joining and Splitting

“…This paper explores languages based on process calculi in the style of πcalculus that focus on coordinating workflows and higher-order process modelling [45,44]. The expressiveness of process calculi based upon their choice of communication primitives has been explored before [49,9,16,28,21,23,58].…”

Simple Modeling of Executable Role-Based Workflows: An Application in the Healthcare Domain

“…Its intuitive modeling has been highlighted in depth in (Merten & Steffen, 2013). Its higher-order processing capability (Neubauer & Steffen, 2013a;Neubauer & Steffen, 2013b;Neubauer et al, 2013) leads to a particularly flexible way of implementing self-adaption as well as to a particularly concise and powerful way of achieving variability not only at design time, but also at runtime. Applications of its use span several areas, including policy modeling and enforcement (Windmüller & Steffen, 2013) and modeling of embedded systems' behaviours (Howar et al, 2013).…”