Visualizing OCL Constraint Patterns with VOCL

Abstract

A specification pattern is a generic constraint expression that can be instantiated to solve a class of specification problems. It captures and generalizes frequently used logical expressions in models. Specification patterns have been defined and represented in the Object Constraint Language OCL for UML/OCL modelling. The notation of visual OCL (VOCL) is a visualization of OCL and can be considered as an alternative solution to the textual OCL. This paper provides the visualization of some OCL constraint patterns in VOCL. For this purpose, we introduce constraint pattern templates in VOCL to represent constraint patterns in a diagrammatic form. The benefits of the visualization is that some patterns will be available in a intuitive diagrammatic notation that follows the UML notation.