UML23 — Value of a Property

In several places of §7.3.44 one speaks about the value(s) of a property. However, there is no property on the Property meta-class that map to this value, except the defaultValue property. On the other hand, it is stated that "If a property is derived, then its value or values can be computed from other information " but nothing make mandatory the specification of how this value is computed.

"isDerived", "defaultValue" and the missing "valueSpecification" property of the Property meta-class cannot be totaly independent.

Suggested resolution :

• Add an optional valueSpecification property to the Property meta-class with the type ValueSpecification

• Change defaultValue to be derived according to the following constraint: {OCL}

  defaultValue = if self.isDerived then self.valueSpecification else NULL endif

There is some confusion in the issue. In the UML 2.5 text it is made clear that the phrase “value of a property”
describes the state of instances of the classifier. The property has no value except in the context of an instance.
Disposition: Closed - No Change