Unified Modeling Language Reference Manual, The, Second Edition

expansion region

A structured activity node that executes once for each element within an input collection.

Semantics

An expansion region is a mechanism to apply a computation repeatedly to each of the elements within a collection of values. It is a “for all” construct. Outside the region, inputs and outputs are modeled as tokens whose values are collections, such as sets, bags, and lists. Inside the region, the collections are expanded into individual elements, and the region is executed once for each group of elements chosen, one from each input and output collection. All the input collections must have the same size and must be of the same kind (set, bag, list, and so on). The output collections are constructed as part of the execution of ...