Expressing Property Specification Patterns with OCL

The textual Object Constraint Language (OCL) is an of- ficial part of the Unified Modeling Language (UML). OCL is primarily used to formulate restrictions over UML mod- els, in particular, invariants and operation pre- and post- conditions in the context of class diagrams. However, OCL is missing means to specify constraints over the dynamic behavior of a UML model. We have therefore developed a temporal extension of OCL that enables modelers to specify behavioral state-oriented constraints. That work provides an alternative to the rather cryptic temporal logic formulae that are commonly used to specify behavioral system prop- erties. This article now illustrates that our OCL extension al- lows for specifying all kinds of properties that are regarded as relevant in practice. We present according temporal OCL expressions for property specification patterns that have been identified in the area of formal specification.