SysML 1.1 RTF Avatar
  1. OMG Issue

SYSML11 — SysML needs instance specs

  • Key: SYSML11-119
  • Legacy Issue Number: 12277
  • Status: closed  
  • Source: Change Vision ( Michael Chonoles)
  • Summary:

    SysML needs instance specs capabilities for several reasons

    1) compatibility with UML and many users' expectations
    2) ability to do animation
    3) ability to show particular values at a time
    4) educational value / illustration value

    No need for a new diagram type, instances can appear on block and sequence diagrams.

  • Reported: SysML 1.0 — Thu, 13 Mar 2008 04:00 GMT
  • Disposition: Resolved — SysML 1.1
  • Disposition Summary:

    No practical substitute has been found for the use of instance specifications to
    specify examples, test cases, and other occurrences of blocks defined in SysML
    user models. Because SysML tool implementations are based on UML
    implementations, diagram support for instance specifications can be simply a
    matter of relaxing any constraints that would disable access to these elements
    from within a strict SysML subset. Instance specifications are already included in
    the SysML metamodel to support other elements of SysML such as the Unit
    stereotype and the initial values compartment.
    Because SysML already defines a taxonomy of its standard diagram types
    (summarized in Annex A and defined in the specification chapters), use of
    instance specifications in SysML must be identify a diagram context where they
    could appear. While they might appear in more than one diagram context, the
    simplest approach for uniformity in user models is to rely on a single context
    where they could be shown. Instead of defining an entirely new diagram context,
    the block definition diagram is a natural place to show either the definitions of
    blocks or instances specifications of these blocks, or any mixture of both. Since all the required metamodel elements for instance specifications are already
    present in SysML, the inclusion of their existing UML-based notation can be
    specified merely by including their diagram elements in the table of graphical
    elements which can be shown on block definition diagrams

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