Class UML 2.3::Extension
Description:
An extension is used to indicate that the properties of a metaclass are extended through a stereotype, and gives the ability to flexibly add (and later remove) stereotypes to classes.Direct Superclasses: AssociationDirect Subclasses: Class Precedence List: Extension, Association, Classifier, TemplateableElement, Type, PackageableElement, ParameterableElement, Namespace, RedefinableElement, NamedElement, Relationship, ElementProperties:
isRequired : Boolean (1 1); -- source Extension Indicates whether an instance of the extending stereotype must be created
when an instance of the extended class is created. The attribute value
is derived from the value of the lower property of the ExtensionEnd referenced
by Extension::ownedEnd; a lower value of 1 means that isRequired is true,
but otherwise it is false. Since the default value of ExtensionEnd::lower
is 0, the default value of isRequired is false.{readonly}
Default value: FALSE
metaclass : Class (1 1); -- source Extension ownedEnd : ExtensionEnd (1 1); -- source Extension endType : Type (1 *); -- source Association isDerived : Boolean (1 1); -- source Association memberEnd : Property (2 *); -- source Association navigableOwnedEnd : Property (0 *); -- source Association attribute : Property (0 *); -- source Classifier collaborationUse : CollaborationUse (0 *); -- source Classifier feature : Feature (0 *); -- source Classifier general : Classifier (0 *); -- source Classifier generalization : Generalization (0 *); -- source Classifier inheritedMember : NamedElement (0 *); -- source Classifier isAbstract : Boolean (1 1); -- source Classifier isFinalSpecialization : Boolean (1 1); -- source Classifier ownedTemplateSignature : RedefinableTemplateSignature (0 1); -- source Classifier ownedUseCase : UseCase (0 *); -- source Classifier powertypeExtent : GeneralizationSet (0 *); -- source Classifier redefinedClassifier : Classifier (0 *); -- source Classifier representation : CollaborationUse (0 1); -- source Classifier substitution : Substitution (0 *); -- source Classifier templateParameter : ClassifierTemplateParameter (0 1); -- source Classifier useCase : UseCase (0 *); -- source Classifier templateBinding : TemplateBinding (0 *); -- source TemplateableElement package : Package (0 1); -- source Type visibility : VisibilityKind (1 1); -- source PackageableElement owningTemplateParameter : TemplateParameter (0 1); -- source ParameterableElement elementImport : ElementImport (0 *); -- source Namespace importedMember : PackageableElement (0 *); -- source Namespace member : NamedElement (0 *); -- source Namespace A collection of NamedElements identifiable within the Namespace, either
by being owned or by being introduced by importing or inheritance.{readonly}
Derived union with sources: (ownedRule, ownedMember, importedMember, ownedUseCase, inheritedMember, feature, attribute, memberEnd, ownedEnd)
ownedMember : NamedElement (0 *); -- source Namespace A collection of NamedElements owned by the Namespace.{composite, readonly}
Derived union with sources: (ownedRule, ownedUseCase, ownedEnd)
Subsets: Element.ownedElement, Namespace.member
Opposite: NamedElement.namespace
ownedRule : Constraint (0 *); -- source Namespace packageImport : PackageImport (0 *); -- source Namespace isLeaf : Boolean (1 1); -- source RedefinableElement redefinedElement : RedefinableElement (0 *); -- source RedefinableElement redefinitionContext : Classifier (0 *); -- source RedefinableElement clientDependency : Dependency (0 *); -- source NamedElement Indicates the dependencies that reference the client.Opposite: Dependency.client
name : String (0 1); -- source NamedElement nameExpression : StringExpression (0 1); -- source NamedElement namespace : Namespace (0 1); -- source NamedElement qualifiedName : String (0 1); -- source NamedElement A name which allows the NamedElement to be identified within a hierarchy
of nested Namespaces. It is constructed from the names of the containing
namespaces starting at the root of the hierarchy and ending with the name
of the NamedElement itself.{readonly, derived}
relatedElement : Element (1 *); -- source Relationship ownedComment : Comment (0 *); -- source Element ownedElement : Element (0 *); -- source Element owner : Element (0 1); -- source ElementConstraints:
Signature: non_owned_end() : Boolean;Description: The non-owned end of an Extension is typed by a Class.
The OCL used here is not normative.
Editor's notes: metaclass, not metaclass(). Classifier, not class
Expression:
metaclass->notEmpty() and metaclass.oclIsKindOf(Classifier)Original:
metaclass()->notEmpty() and metaclass()->oclIsKindOf(Class)Signature: is_binary() : Boolean;Description: An Extension is binary, i.e., it has only two memberEnds.
Expression:
memberEnd->size() = 2Operations:
Signature: metaclassEnd() : Property;Description: The query metaclassEnd() returns the Property that is typed by a metaclass (as opposed to a stereotype).
The OCL used here is not normative.
Editor's notes: Borrowed from UML2.5
Expression:
memberEnd->reject(p | ownedEnd->includes(p.oclAsType(ExtensionEnd)))->any(true)Original:
result = memberEnd->reject(ownedEnd)Signature: metaclass.1() : Class;Description: The query metaclass() returns the metaclass that is being extended (as opposed to the extending stereotype).
Expression:
result = metaclassEnd().typeSignature: isRequired.1() : Boolean;Description: The query isRequired() is true if the owned end has a multiplicity with the lower bound of 1.
Expression:
result = (ownedEnd->lowerBound() = 1)Send questions or comments to [email protected].