PSSM 1.0 FTF Avatar
  1. OMG Issue

PSSM_ — Example state machine appears to violate UML constraints

  • Key: PSSM_-9
  • Status: closed  
  • Source: AGI ( Daniel Yankowsky)
  • Summary:

    In this state machine, there is a fork pseudostate with two outgoing transitions. One transition targets a state, while the other transition appears to target a junction pseudostate.

    The UML 2.5.1 spec includes the constraint `fork_segment_state` ( Constraints) that requires that any transition originating at a fork must terminate at a state. Such a transition is not allowed to terminate at a pseudostate.

    (Incidentally, that particular constraint doesn't seem particularly useful, as any undesirable case that the constraint is trying to prevent could be instead created via default entry into an orthogonal state. But the constraint exists nonetheless.)

  • Reported: PSSM 1.0b1 — Thu, 13 Sep 2018 17:26 GMT
  • Disposition: Resolved — PSSM 1.0
  • Disposition Summary:

    Resolution of issue PSSM_-9

    Agreed. Transition_023 violates constraint fork_segment_state (see subclause in [UML 2.5.1]). Indeed, transition T4 outgoing the fork pseudostate directly targets a junction pseudostate. This is forbidden since the constraints specifies that a transition outgoing a fork pseudostate shall only have a state as a target.

    Hence, the state machine specifying the test behavior shall be updated as well as the description provided in the subclause of [PSSM 1.0b].

  • Updated: Mon, 1 Apr 2019 18:19 GMT
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