SMM11 — Minimum and maximum attributes for the Interval class should be optional

Minimum and maximum attributes for the Interval class should be optional

For nominal or for ordinal the base measure and interval mapping are not needed. To make that more convenient, I propose to make the following changes.

1. The minimum and maximum attributes for the Interval class will be optional

Attributes
maximumOpen:Boolean
True if and only if interval excludes maximum endpoint. Default = false.

minimumOpen:Boolean
True if and only if interval excludes minimum endpoint. Default = false.

maximum:Number[0..1]
Identifies interval’s maximum endpoint.

minimum:Number[0..1]
Identifies interval’s minimum endpoint.

2. We add constraints to Interval indicating that if either minimum or maximum is defined then both are defined.

Constraints
context Interval inv:

if maximum.isOclDefined

then minimum.isOclDefined and maximum = minimum and

(maximumOpen or minimumOpen ? maximum > minimum)

else not minimum.isOclDefined

3. We add constraints to RankingInterval requiring a maximum (and implicitly a minimum).

Constraints
context RankingInterval inv:

maximum.isOclDefined

4. We add constraints to GradeMeasure forbidding the intervals without minimum or maximums if gradeTo is specified.

Constraints
context GradeMeasure inv:

(gradeTo->notEmpty implies

interval->forall(i | not i.minimum.isOclUndefined() and

not i.maximum.isOclUndefined())) and

(interval->exists(i | i.minimum.isOclUndefined() or

i.maximum.isOclUndefined()) implies

gradeTo->isEmpty)

(1) The minimum and maximum attributes for the Interval class will be optional. (2) Add constraints to Interval indicating that if either minimum or maximum is defined then both are defined. (3) Add constraints to RankingInterval requiring a maximum (and implicitly a minimum). (4) Add constraints to GradeMeasure forbidding the intervals without minimum or maximum if gradeTo is specified.