R1275 - modelint/shlaer-mellor-metamodel GitHub Wiki

R1275 / Generalization

External Service is an External Event or External Operation

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In other words, a dynamic interaction with another Domain is either asynchronous or synchronous.

When an External Event is dispatched by some Activity in the calling Domain, that Activity continues processing without waiting for any response.

When an External Operation is invoked, on the other hand, the calling Activity must wait until the target Domain returns control.