Data Flow Switch - modelint/shlaer-mellor-metamodel GitHub Wiki

Consider a downstream Action that takes a single Data Flow input. Now let's assume that there is some conditional logic upstream, say a Switch Action or a Decision. Based on the evaluated logic, one of two different Data Flows may end up feeding the downstream Action's input.

A data flow switch takes a set of two or more input Data Flows each conveying the same Type. In any given execution of the enclosing Activity, only one of these inputs may be enabled. This mutual exclusion must be enforced by a Decision or a Switch Action. The output of the Data Flow Switch will be enabled when a corresponding input is enabled and the input data will be conveyed on the output flow.

All Data Flows in and out of a Data Flow Switch are by necessity of the same Type. Here is an example of a Data Flow Switch shown both in Scrall and as a data flow diagram:

images/flow-subsystem/data-flow-switch-10.png

Identifiers

1. Output flow + Activity + Domain

Attributes

No non-referential attributes.