OclVoid

OclVoid

The type OclVoid is a type that conforms to all other types except OclInvalid. It has one single instance, identified as null, that corresponds with the UML LiteralNull value specification. Any property call applied on null results in invalid, except for the oclIsUndefined(), oclIsInvalid(), =(OclAny) and <>(OclAny) operations. However, by virtue of the implicit conversion to a collection literal, an expression evaluating to null can be used as source of collection operations (such as ‘isEmpty’). If the source is the null literal, it is implicitly converted to Bag{}.

OclVoid is itself an instance of the metatype VoidType.

conformsTo OclAny

Operations

allInstances() : Set(OclSelf)

Returns Set{null}.

=(object2 : OclSelf) : Boolean precedence: EQUALITY

Redefines the OclAny operation, returning true if object is null, invalid if object is invalid, false otherwise.

<>(object2 : OclSelf) : Boolean precedence: EQUALITY

and(b : Boolean[?]) : Boolean[?] precedence: AND

implies(b : Boolean[?]) : Boolean[?] precedence: IMPLIES

or(b : Boolean[?]) : Boolean[?] precedence: OR

oclIsInvalid() : Boolean validating

oclIsUndefined() : Boolean validating

toString() : String

Returns null.