Pattern 11 (Restriction)

FLASH animation of Restriction pattern


This pattern captures features to restrict the syntax and semantics of a process modeling language, by removing modeling concepts from the language's meta-model or restrict- ing the existing ones. This pattern impacts all process models described by the restricted meta-model.


To improve understandability and maintenance through a simplified process model.


Fig. 10a shows the restriction of the "Home Loan" model in Fig. 6a after removing the concept of Event from the BPMN meta-model.


A smaller number of element types is easier to learn for modeling novices [50], [123]. For this reason, modelers tend to use only a subset of language elements in practice [123].


Different conformance classes have been intro- duced in BPMN 2.0 to restrict the meta-model in a con- trolled way [87]. There are four classes for Process Modeling, Process Execution, BPEL Process Execution, and Choreog- raphy Modeling. Another example of meta-model restriction is the proposal by Silver [106]. It introduces three levels of BPMN usage: Level 1 for business people, Level 2 for analysts, and Level 3 for developers. The more business- oriented levels only contain a subset of the overall BPMN notation. A similar distinction is sometimes also made by software vendors. In Tibco's iProcess Suite, for instance, a process model can be classified according to its purpose, i.e. business analysis, deployment or simulation, where the meta- models for deployment and simulation implement a subset of the BPMN notation. Similarly, the BPEL standard defines a subset for abstract processes [12]. Becker and et. [14] outline an approach for creating process model projections based on the restriction of the process' meta-model. These projections are achieved by applying so-called configuration parameters to meta-model elements in order to simplify the notation for a specific audience. For example, one can hide the resource perspective in the eEPC meta-model so that all the roles and organizational units that are associated with eEPC Functions are removed. This functionality is also implemented in the form of filters by tools such as ARIS [29].