The semantics are undefined for adding a value that violates the upper multiplicity of the StructuralFeature, and for adding a new value to a StructuralFeature with isReadonly=true after initialization of the object that would have the value. Source Unified Modeling Language 2.5.1
The insertion point is ignored if it is used when isReplaceAll=true. Source Unified Modeling Language 2.5.1
Reinserting an existing value at a new position in an ordered, unique StructuralFeature moves the value to that position (this works because such StructuralFeature values are ordered sets). Source Unified Modeling Language 2.5.1
The semantics are undefined for a value of 0 or an integer greater than the number of existing values Source Unified Modeling Language 2.5.1
A value of unlimited (“*”) for the insertion point means to insert the new value at the end of the sequence. Source Unified Modeling Language 2.5.1
An insertion point that is a positive integer less than or equal to the current number of values means to insert the new value at that position in the sequence of existing values, with the integer 1 meaning the new value will be first in the sequence. Source Unified Modeling Language 2.5.1
If the insertAt InputPin is present, it has type UnlimitedNatural and multiplicity 1..1 Source Unified Modeling Language 2.5.1
NOTE. Values of StructuralFeatures may be ordered even if the upper multiplicity is 1. Source Unified Modeling Language 2.5.1
Adding a value to an ordered StructuralFeature requires an insertion point for the new value given in the insertAt InputPin, which is required for ordered StructuralFeatures when isReplaceAll is false and omitted for unordered StructuralFeatures. Source Unified Modeling Language 2.5.1
If isReplaceAll is false and the StructuralFeature is unordered and unique, then adding a value that is already contained in the StructuralFeature has no effect. Source Unified Modeling Language 2.5.1
If isReplaceAll is true ... The StructuralFeature always has a single value when the Action completes, even if the lower multiplicity of the StructuralFeature is greater than 1. Source Unified Modeling Language 2.5.1
If isReplaceAll is true, then the existing values of the StructuralFeature are removed before the new value is added, except if the StructuralFeature already contains the new value, in which case it is not removed under this option. Source Unified Modeling Language 2.5.1
If the StructuralFeature is an Association end, the semantics are the same as for a CreateLinkAction ..., where the participants in the link are the object being acted on and the new value. Source Unified Modeling Language 2.5.1
The value to be added is given on the value InputPin, which is required. This InputPin has the same type as the StructuralFeature and a multiplicity of 1..1 (that is, a single value is added). Source Unified Modeling Language 2.5.1
16.8.3.3 Add Structural Feature Value Actions: An AddStructuralFeatureValueAction is a StructuralFeatureAction for adding a value to a StructuralFeature of an object. Source Unified Modeling Language 2.5.1
