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R811 / M:Mc-1
Switched Data Flow feeds zero, one or many Data Flow Switch
Data Flow Switch switches among one or many Switched Data Flow]
A Data Flow Switch actually requires at least two input Data Flows to be of any use. Otherwise, there isn't any input to switch, just use a single Data Flow instead. The switch will then act as a conduit for the one enabled input during an Activity invocation.
A given Data Flow may or may not provide input through a Data Flow Switch and, its even possible for the same Data Flow to fork out to feed more than one.
Constraint
Each input flow as well as the output flow in a Data Flow Switch must be of the same Type.