The ExposesItsArray ModellingRule exposes a special semantic on VariableTypes having a single- or multidimensional array as the data type. It indicates that each value of the array will also be exposed as a Variable in the AddressSpace.
The ExposesItsArray ModellingRule can only be applied on InstanceDeclarations of NodeClass Variable that are part of a VariableType having a single- or multidimensional array as its data type.
The Variable A having this ModellingRule shall be referenced by a forward hierarchical Reference from a VariableType B. B shall have a ValueRank value that is equal to or larger than zero. A should have a data type that reflects at least parts of the data that is managed in the array of B. Each instance of B shall reference one instance of A for each of its array elements. The used Reference shall be of the same type as the hierarchical Reference that connects B with A or a subtype of it. If there are more than one forward hierarchical References between A and B, then all instances based on B shall be referenced with all those References.
Figure 21 gives an example. A is an instance of Type_A having two entries in its value array. Therefore it references two instances of the same type as the InstanceDeclaration ArrayExpose. The BrowseNames of those instances are not defined by the ModellingRule. In general, it is not possible to get a Variable representing a specific entry in the array (e.g. the second). Clients will typically either get the array or access the Variables directly, so there is no need to provide that information.
Figure 21 – Example on using ExposesItsArray
It is allowed to reference A by other InstanceDeclarations as well. Those References have to be reflected on each instance based on A.
Figure 22 gives an example. The Property EUUnit is referenced by ArrayExpose and therefore each instance based on ArrayExpose references the instance based on the InstanceDeclaration EUUnit.