UML 1.4 MAILINGLIST Avatar
  1. OMG Issue

UML14 — Activity Diagrams: Relax Traverse-to-Completion semantics

  • Key: UML14-528
  • Legacy Issue Number: 7221
  • Status: closed  
  • Source: Anonymous
  • Summary:

    In my interpretation of the current semantics description of UML
    activity diagrams (Superstructure, Final Adopted Spec, ptc/03-08-02) I
    have identified some rather unpleasant properties of the current
    traverse-to-completion semantics. The full discussion together with
    examples can be found in the attached .pdf, the short of it is:

    *) the current semantics does not prevent deadlocks (as it is
    supposed to do)

    *) it rather induces deadlocks even in simple examples (e.g. examples
    in the UML spec are wrong)

    *) it makes for a very complex evaluation and introduces unnecessary
    synchronization in the (basically asynchronous) notation of Activiy
    Diagrams.

    I therefore propose to relax the semantics of token flow by dropping
    the constraint that every Action has to accept all tokens for all its
    input pins at once. MergeNodes should als be able to buffer tokens
    until their conditions are satisfied. This is a more natural way of
    interpreting ADs.

  • Reported: XMI 2.0 — Mon, 5 Apr 2004 04:00 GMT
  • Disposition: Resolved — UML 1.4.2
  • Disposition Summary:

    see above

  • Updated: Fri, 6 Mar 2015 20:58 GMT