演员-演员（序列图）

Question

I'm just wondering if it's possible if an actor to actor is allowed in sequence diagram.

and if so can an actor receive true/false statement?

The left one is an actor and the right one is a Class.

Answer 1

Actor-to-actor depiction is used in sequence diagram to shows real-life interaction between the actors, usually at the system level. The goal is to use sequence diagram to identify logic flow and behaviour within the system.

In light of that, it doesn't make sense (and not very helpful) to return a true/false statement to either your aPassenger nor your aCheckInStaff . The message that aCheckInStaff receives should be along the line of " is this ticket valid (does the name match the ID shown, has the ticket expired etc.)? " And that same information will then be passed along to your aPassenger (perhaps together with a boarding pass, if the ticket is valid) to indicate if subsequent flow of actions ie does aPassenger need to fix the error, or can she proceed to gates?

There is a good actor-to-actor interaction example here . Take a look at Figure 1 and follow along its use case description here .