Specifying a trigger

Every transition is associated with a designated message, which is the trigger of the transition. In other words, the trigger of the transition is waiting for its event. A transition cannot be associated with more than one message. Triggers can be events, triggered operations, or timeouts.

About this task

Events are asynchronous; time can pass between the sending of the event and when it actually affects the statechart of the destination. Triggered operations are synchronous; their effect on the statechart of the destination is immediate.

This label is not a valid transition label:

e1 or e2

The trigger part of a transition label cannot use conditional expressions; however, guards can.


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