On Softening OCL Invariants

Abstract

Invariants play a crucial role in system development. This contribution focuses on invariants in systems with so-called occurrence uncertainty, where we are interested in deciding whether a certain pop- ulation (a set of instances from a class model) of the system satisfies an invariant or not, but we are unsure about the actual occurrence of the elements of that population, and also about the degree of satisfaction that is actually required for the invariant to be fulfilled. Invariants are soft in the sense that they are required to hold only for a particular, and a priori uncertain, percentage of the population. The contribution proposes a systematic approach to occurrence uncertainty and a prototypical im- plementation for models with uncertainty and soft invariants allowing to build system states and to make experiments with them.

Keywords

UML model; Integrity constraint; OCL invariant; Uncertainty.

Cite as:

Martin Gogolla, Antonio Vallecillo, “On Softening OCL Invariants”, Journal of Object Technology, Volume 18, no. 2 (July 2019), pp. 6:1-22, doi:10.5381/jot.2019.18.2.a6.