Initial pseudostate

An initial pseudostate is an element of a state machine. It is automatically processed when the state that contains the initial pseudostate is entered (and thus all of its regions are).

An initial pseudostate belongs to a region.

Symbol

An initial pseudostate is shown as a small solid filled circle.

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Symbol in context

images/download/attachments/2785301/initial_pseudostate_symbol_context_1.png

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When a state machine is started, initial pseudostates are searched in all regions of the root state. This search then recursively continues in each state that is a target of a transition whose source is one of the previously found initial pseudostates.

Characteristics

  • It has exactly one outgoing transition.

  • It has no incoming transitions.

  • The outgoing transition can have a behavior, but it cannot have triggers or guards.

  • Each region can contain at most one initial pseudostate.

  • The target of the outgoing transition of the initial pseudostate is always a state.

Interpretation of and deviation from the UML specification

There is no interpretation of and deviation from the UML specification for a state machine's initial pseudostate.