RelComp anti-pattern

Full name

Relation Composition

Type

Logical

Feature

Association

Description
Consider two associations, no matter their stereotypes:

A, that connects ASource and ATarget; and B, that connects BSource and BTarget.

For this anti-pattern to occur, one of the possible statements needs to be true:

BSource equals or is a subtype of ATarget and BTarget equals or is a subtype of ATarget. BSource equals or is a subtype of ASource and BTarget equals or is a subtype of ASource.

Justification

The instantiation of the two relations identified in this anti-pattern may restrict one another.

Contraints

  1. A and B are different associations.

  2. The association A must have a minimum cardinality greater than 0 and a maximum greater than 1 in the association end connected to ATarget.

  3. One of the following sentences must evaluate to true:

    \[\begin{split}(ATarget = BSource \ \lor \ ancestorOf(ATarget,BSource)) \land \\ (ATarget = BTarget \ \lor \ ancestorOf(ATarget, BTarget))\end{split}\]
    \[\begin{split}(ASource = BSource \ \lor \ ancestorOf(ASource,BSource)) \land \\ (ASource = BTarget \ \lor \ ancestorOf(ASource, BTarget))\end{split}\]
Examples

Examples

Refactoring Plans

  1. [OCL] Set Existential Composition: add an OCL invariant to enforce that type B has an existential composition to type A:

    context BSource
    inv: self.bTarget->asSet()->forAll( y |
    ASource.allInstances()->exists( z |
    z.aTarget->asSet()->contains(self) and
    z.aTarget->asSet()->contains(y))

  2. [OCL] Set Right universal Composition: add an OCL invariant to enforce that type B has a right universal composition to type A:

    context BSource
    inv: self.bTarget->asSet()->forAll( y |
    ASource.allInstances()->forAll( z |
    z.aTarget->asSet()->contains(self) implies
    z.aTarget->asSet()->contains(y))

  3. [OCL] Set Left Universal Composition: add an OCL invariant to enforce that type B has a left universal composition to type A:

    context BSource
    inv: self.bTarget->asSet()->forAll( y |
    ASource.allInstances()->forAll( z |
    z.aTarget->asSet()->contains(y) implies
    z.aTarget->asSet()->contains(self))

  4. [OCL] Set Forbidden Composition: add an OCL invariant to enforce that type B has a forbidden composition to type A:

    context BSource
    inv: self.bTarget->asSet()->forAll( y |
    ASource.allInstances()->forAll( z |
    not(z.aTarget->asSet()->contains(y) and
    z.aTarget->asSet()->contains(self)))

  5. [OCL] Set Custom Existential Composition: add an OCL invariant to enforce that type B has a custom existential composition to type A:

    context BSource
    inv: self.bTarget->asSet()->forAll( y |
    ASource.allInstances()->select( z |
    z.aTarget->asSet()->contains(y) and
    z.aTarget->asSet()->contains(self))->size()[>|<|=]n)

References:

Prince Sales, Tiago. (2014). Ontology Validation for Managers.