Together with the states, transitions form the core elements of a state machine.
They describe a transition between two states, regardless of one or more triggers
and a condition. Triggers and a condition can be stated optionally. A transition
without trigger is activated as soon as the source state has completed internal
actions, if any, or as soon as the internal final state of a composite state has been
196 CHAPTER 3 UML??”Unifi ed Modeling Language
reached. If a condition is defined at the transition, then this condition must be met
in order for the transition to be activated.
In Figure 3.60 , the transition from the orthogonal state Climate to the fi nal
state has no trigger. It is activated automatically as soon as the source state has
terminated. In this example, this happens as soon as the fi nal states in both
regions of the state Climate have been reached.
A transition is denoted as an arrow with solid line and a description in the
following syntax:
trigger1, trigger2, ... [condition] / behavior
Triggers can alternatively be denoted using a special symbol, which corresponds
to the symbol for receive signals from activity diagrams ( Figure 3.
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