Issue 134: Specification of Constraints

1. Issue 134: Specification of Constraints • There is no standard way of specifying constraints • Constraints in MDR metamodel • OCL expressionscan be provided for metaclass and its instance • Target: Data Element Concept and Conceptual Domain, Value Domain and Data Element and so on. • Constraints of registered data elements (user should be defined) • Target: Conceptual Domain or Value Domain • Representation, Dimensionality and Classification are a kind of constraints • User defined matadata should enable to be defined as extension mechanism, such as ebXML Registry and Repository • Constraint should be described using such user defined slots • Need formal description language such as OCL, CL • We should allow OCL or other specification languages to be used by users of the registry

2. Constraints in Data Element Concept • 4.11.1.3 Data Element Concept • (1) A Data Element Concept is a concept that can be represented in the form of a data element, described independently of any particular representation. • (2) A Data Element Concept may have zero or one Object Class and zero or one Property. • (3) The union of a Property and an Object Class provides significance beyond either that of the Property or the Object Class. • (4) A Data Element Concept thus has aDefinition independent from the Definition of the Object Class or the Property. • (5) As an Administered Item, a Data Element Concept carries its own Administration Record information, allowing it to be identified, named,defined and optionally classified within a Classification Scheme. IdentifiedandOptionallyClassified • (6) A Data Element Concept may be associated with other Data Element Concepts, via the Data Element Concept Relationship. • (7) The nature of the relationship is described using the data element concept relationship type description. IsDescribedUsing • (8) A Data Element Concept may be registered as an Administered Item without necessarily being associated with any Data Element, but a Data Element Concept shall be associatedwith exactly oneConceptual Domain, as represented by the "data element concept-conceptual domain relationship" in Figure 8.MustBeRegistered, ShallBeAssociatedWith • (9)TheConceptual Domainspecifies all validValue Meanings of a Data Element Concept. The Conceptual Domainis described in 4.12.1.1.MustBeContained

3. Examples of OCL expression MustBeContainedUnless…. ….AttributesCannotBeChanged ….CannotBeDeleted ….DependenciesCannotBeChanged ….NamesMustNotCollide ….MustNotBeSelf ….MustBeSame ….MustNotCollideWith…. ….RuleMustBeObeyed No….AllowedFor…..

4. Examples of Constraints (form MOF1.4) • [A ModelElement that is not a Package must have a container. [C-1]] • [The attribute values of a ModelElement which is frozen cannot be changed. [C-2]] • [A frozen ModelElement which is in a frozen Namespace can only be deleted, by deleting the Namespace. [C-3]] • [The link sets that express dependencies of a frozen Element on other Elements cannot be explicitly changed. [C-4]] • [The names of the contents of a Namespace must not collide. [C-5]] • [A Generalizable Element cannot be its own direct or indirect supertype. [C-6]] • [A supertypes of a GeneralizableElement must be of the same kind as the GeneralizableElement itself. [C-7]] • [The names of the contents of a GeneralizableElement should not collide with the names of the contents of any direct or indirect supertype. [C-8]] • [Multiple inheritance must obey the “Diamond Rule.” [C-9]] • [If a Generalizable Element is marked as a “root,” it cannot have any supertypes. [C-10]] • [A GeneralizableElement’s immediate supertypes must all be visible to it. [C-11]] • [A GeneralizableElement cannot inherit from a GeneralizableElement defined as a “leaf.” [C-12]]

5. [C-1] MustBeContainedUnlessPackage • format1: MUST_BE_CONTAINED_UNLESS_PACKAGE • format2: must_be_contained_unless_package • evaluation policy: deferred • description: A ModelElement that is not a Package must have a container. context ModelElement inv: not self.oclIsTypeOf(Package) implies self.container -> size = 1

6. [C-2] FrozenAttributesCannotBeChanged • format1: FROZEN_ATTRIBUTES_CANNOT_BE_CHANGED • format2: frozen_attributes_cannot_be_changed • evaluation policy: immediate • description: The attribute values of a ModelElement which is frozen cannot be changed. context ModelElement inv: self.isFrozen() implies let myTypes = self.oclType() -> allSupertypes() -> 　　　　　　　includes(self.oclType()) in let myAttrs : Set(Attribute) = self.RefBaseObject::refMetaObject() ->asOclType(Class) -> 　　　　　findElementsByTypeExtended(Attribute) in 　　myAttrs -> forAll(a |self.RefObject::refValue@pre(a) = self.RefObject::refValue(a))

7. [C-3] FrozenElementsCannotBeDeleted • format1: FROZEN_ELEMENTS_CANNOT_BE_DELETED • format2: frozen_elements_cannot_be_deleted • evaluation policy: immediate • description: A frozen ModelElement which is in a frozen Namespace can only be deleted, by deleting the Namespace. • context ModelElement • post: • (self.isFrozen@pre() and • self.container@pre -> notEmpty and • self.container.isFrozen@pre()) implies (self.container.Object::non_existent() or not self.Object::non_existent())

8. [C-4] FrozenDependenciesCannotBeChanged • format1: FROZEN_DEPENDENCIES_CANNOT_BE_CHANGED • format2: frozen_dependencies_cannot_be_changed • evaluation policy: immediate • description: The link sets that express dependencies of a frozen Element on other Elements cannot be explicitly changed. • context ModelElement • post: • self.isFrozen() implies • let myClasses = self.oclType() -> allSupertypes() -> includes(self.oclType()) in • let myRefs = Set(Reference) = • self.RefBaseObject::refMetaObject() -> asOclType(Class) -> • findElementsByTypeExtended(Reference) in • let myDepRefs = myRefs -> • select(r | Set{“contents”, “constraints”, “supertypes”, “type”, “referencedEnd”, “exceptions”, “importedNamespace”, “elements”} -> includes(r.name)) in • myDepRefs -> forAll(r |self.RefObject::refValue@pre(r) = • self.RefObject::refValue(r))

9. [C-5] ContentNamesMustNotCollide • format1: CONTENT_NAMES_MUST_NOT_COLLIDE • format2: content_names_must_not_collide • evaluation policy: immediate • description: The names of the contents of a Namespace must not collide. • context Namespace • inv: self.contents.forAll( e1, e2 | e1.name = e2.name implies r1 = r2)

10. [C-6] SupertypeMustNotBeSelf • format1: SUPERTYPE_MUST_NOT_BE_SELF • format2: supertype_must_not_be_self • evaluation policy: immediate • description: A Generalizable Element cannot be its own direct or indirect • supertype. • context GeneralizableElement • inv: self.allSupertypes() -> forAll(s | s <> self)

11. [C-7] SupertypeKindMustBeSame • format1: SUPERTYPE_KIND_MUST_BE_SAME • format2: supertype_kind_must_be_same • evaluation policy: immediate • description: A supertypes of a GeneralizableElement must be of the same kind as the GeneralizableElement itself. • context GeneralizableElement • inv: self.supertypes -> forAll(s | s.oclType() = self.oclType())

12. [C-8] ContentsMustNotCollideWithSupertypes • format1: CONTENTS_MUST_NOT_COLLIDE_WITH_SUPERTYPES • format2: contents_must_not_collide_with_supertypes • evaluation policy: immediate • description: The names of the contents of a GeneralizableElement should not • collide with the names of the contents of any direct or indirect • supertype. • context GeneralizableElement • inv: • let superContents = self.allSupertypes() -> collect(s | s.contents) in • self.contents -> forAll(m1 | superContents -> forAll(m2 | m1.name = m2.name implies m1 = m2))

13. [C-9] DiamondRuleMustBeObeyed • format1: DIAMOND_RULE_MUST_BE_OBEYED • format2: diamond_rule_must_be_obeyed • evaluation policy: immediate • description: Multiple inheritance must obey the “Diamond Rule.” • context GeneralizableElement • inv: • let superNamespaces = • self.supertypes -> collect(s | s.extendedNamespace) in superNamespaces -> asSet -> isUnique(s | s.name)

14. [C-10] NoSupertypesAllowedForRoot • format1: NO_SUPERTYPES_ALLOWED_FOR_ROOT • format2: no_supertypes_allowed_for_root • evaluation policy: immediate • description: If a Generalizable Element is marked as a “root,” it cannot have any supertypes. • context GeneralizableElement • inv: self.isRoot implies self.supertypes -> isEmpty