What is an OCL invariant?
Object Constraint Language (OCL) Invariant. – Constraint that applies to ALL instances of class (or type or interface) – An expression that evaluates to true if the condition is met. – All Invariants must ALWAYS evaluate to true.
What is OCL as adopted in UML class diagram?
UML provides itself a formal language to express constraints, the Object Constraint Language (OCL) [OMG03]. It is a formal language that can be used to specify invariants, pre- and post- conditions as well as describe guards and constraints on operations. OCL expressions do not have side- effects.
Is OCL a formal language?
OCL is a general-purpose (textual) formal language adopted as a standard by the OMG (see the current version of the OCL specification [20]) used to define several kinds of expressions that complement the information of (UML) models.
What are the two categories of OCL expression?
There are five collection types in OCL: Collection – The abstract super type. Set – No duplication, unordered. OrderedSet – No duplication, ordered.
What is the name of OCL?
hypochlorite ion
OCl−, the hypochlorite ion, in chemistry.
What is Eclipse OCL?
Eclipse OCL is an implementation of the Object Constraint Language (OCL) OMG standard for EMF-based models.
Who developed OCL?
This has resulted in the current UML 1.1 proposal. IBM’s primary contribution to UML 1.1 is OCL. OCL was developed by Jos Warmer as a language for business modelling within IBM, derived from the Syntropy method of Steve Cook and John Daniels.
What is OCL in computer science?
The Object Constraint Language (OCL) is a declarative language describing rules applying to Unified Modeling Language (UML) models developed at IBM and is now part of the UML standard. OCL may now be used with any Meta-Object Facility (MOF) Object Management Group (OMG) meta-model, including UML.
Why is OCL used?
Object Constraint Language can be used to specify constraints and other expressions attached to UML models or other models. OCL help to create a precise and unambiguous specification in OO modelling. OCL has its own set of Grammar and rules.
Why do we use OCL?
OCL is part of Unified Modeling Language (UML) and it plays an important role in the analysis phase of the software lifecycle. languages can use OCL to specify constraints and other expressions attached to their models. OCL is the expression language for the Unified Modeling Language (UML).
What is OCL expression?
The Object Constraint Language (OCL) is an expression language that describes constraints on object-oriented languages and other modelling artifacts. A constraint can be seen as a restriction on a model or a system. OCL is the expression language for the Unified Modeling Language (UML).
What is a collection in OCL?
A template type is either a structured collection type or a structured tuple type. In OCL there are four parametrized, concrete collection types, namely Set(T) , Bag(T) , Sequence(T) , and OrderedSet(T) . Both, Set(Integer) and Bag(Integer) , are subtypes of the abstract collection type Collection(Integer) .