SysML 2.0b2 FTF Avatar
  1. OMG Issue

SYSML2 — checkFlowConnectionUsageSpecialization is too restrictive about FlowConnections

  • Key: SYSML2-597
  • Status: open  
  • Source: Model Driven Solutions ( Mr. Ed Seidewitz)
  • Summary:

    In FlowConnectionUsage, the constraint checkFlowConnectionUsageSpecialization states that

    If a FlowConnectionUsage has no itemFlowEnds, then it must directly or indirectly specialize the base FlowConnectionUsage Connections::messageConnections from the Systems Library model. Otherwise, it must directly or indirectly specialize the FlowConnectionUsage Connections::flowConnections.

    The property itemFlowEnds is derived as all connectorEnds that are ItemFlowEnds. The (Kernel) metaclass ItemFlowEnd is used when a FlowConnectionUsage is parsed from the special flow notation. However, a FlowConnectionUsage can also be written using regular connection notation, which will not have ItemFlowEnds, e.g.,

    flow {
        end ::>> operator {
            out cmd : Command :>> sourceOutput;
        end ::>> device {
            in cmd  : Command :>> targetInput;

    But, currently, this will implicitly specialize messageConnections, not flowConnections, which seems unexpected, since this is structurally a complete flow declaration.

  • Reported: SysML 2.0b1 — Thu, 14 Dec 2023 21:46 GMT
  • Updated: Mon, 8 Apr 2024 18:21 GMT