Conjugation in SysML-1.7 is Type-based: InterfaceBlock, ~InterfaceBlock, and DirectedFeature

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Tutorial
TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo
Section
09:03: Port conjugation in SysML is now Type-based
UML keywords
Port
SysML keywords
~InterfaceBlock
~InterfaceBlock::original
InterfaceBlock
conjugation
FlowProperty
FlowProperty::direction
FlowDirectionKind
FlowDirectionKind::in
FlowDirectionKind::inout
FlowDirectionKind::out
FeatureDirectionKind::provided
FeatureDirectionKind::required
FeatureDirectionKind::providedrequired
Slide kind
SysML Block Definition Diagram (BDD)
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The mechanism for conjugated Ports has been changed in SysML 1.6, it now conjugates the Type! If you are using an InterfaceBlock to type a Port you can conjugate that 'original' on another Port by typing it with an ~InterfaceBlock.
SysML-1.6: 'The ~InterfaceBlock stereotype (shall be pronounced: "conjugated interface block") is a specialization of InterfaceBlock that has the same features as its original InterfaceBlock except that its DirectedFeatures and FlowProperties are reversed (conjugated'
SysML-1.6: 'InterfaceBlock ... for example, in flow properties are conjugated as out flow properties and provided features are conjugated as required features. '
SysML-1.6: 'Conjugation is specified by a constraint giving the features of ~InterfaceBlocks according to those of their original InterfaceBlocks ... It is expected that tools conforming to this specification automatically create features of ~InterfaceBlocks.'
Webel: SysML1.7: Port contract matching is Feature-based, not Type-based. There's nothing particularly magical or special about use of an ~InterfaceBlock on a "conjugating" SysML Port, it's just a convenient way of managing one-to-one Feature matching!
You can also use the nice SysMLv1 IBD Compartments to expose the underlying contract:
SysML-1.7: 'SysML permits any property shown on an internal block diagram to also show compartments within the property box. These compartments may be given standard or user-customized labels just as on block definitions.'
Webel Best Practice: In general, the SysML DirectedFeature approach is more powerful and the notation is cleaner than UML provided/required Interfaces. Prefer SysML DirectedFeatures unless you have a really good reason to use Interfaces!
UML Port conjugation is dead (since SysML-1.6); Long live conjugation of the Port's type!
Since SysML-1.6 use of direct UML conjugation of Ports is NOT supported; If you are using InterfaceBlocks use instead a conjugated ~InterfaceBlock type!
Up next
09:04: Ports and contracts
Notes
[POLICY] Since SysML-1.6 use of direct UML conjugation of Ports is NOT supported; If you are using InterfaceBlocks use instead a conjugated ~InterfaceBlock type!
[WARNING] Until tool support for ~InterfaceBlock comes you have to make a decision: (1) Bake your own «~InterfaceBlock» then deal with clashes when tool support comes; (2) stick with the DEPRECATED UML conjugation (not nested-port friendly) and await migration.
[TOOL, WARNING] MagicDraw/Cameo 19SP3 still supports the DEPRECATED UML Port conjugation (but it is recommended here that you DO NOT use it, even though there might be future migration for such directly conjugated Ports).
[TIP, WORKAROUND]{INFORMATIVE} [HISTORICAL] HOWTO easily "hack" the SysML-1.6 ~InterfaceBlock conjugation and «~interfaceBlock» keywords in MagicDraw/Cameo. [NOW SUPPORTED 2024x Golden]
[TIP] Place your SysML-1.6 ~InterfaceBlock conjugation under the 'original' InterfaceBlock (i.e. make the original the containment owner).
[WARNING] The mechanism for conjugated Ports has been changed in SysML 1.6, it now conjugates the Type! If you are using an InterfaceBlock to type a Port you can conjugate that 'original' on another Port by typing it with an ~InterfaceBlock.
[ASSERTION] SysML: Typing a Port by an InterfaceBlock or ~InterfaceBlock does NOT imply that the Port is a ProxyPort (but ProxyPort must be typed by an InterfaceBlock or ~InterfaceBlock)
[CAVEAT, TOOL]{INFORMATIVE} [HISTORICAL] MagicDraw/Cameo 19SP3: Does NOT yet support ~InterfaceBlock [NOW SUPPORTED in 2024x Golden]
[POLICY]{STRONG} Avoid mixing flow properties on the Type of a Port with directed features (operations and values); One distinguishes between "ports with flows" and "contract ports".
[DISPLAY, TIP, TOOL] MagicDraw/Cameo: Stereotypes should be created/managed in UML Profile Diagrams and owned by Profile packages, but Stereotypes and Metaclasses can be displayed on UML Class Diagrams and SysML Block Definition Diagrams
[TIP] MagicDraw/Cameo: You can easily find all elements a Stereotype has been applied to via the Stereotype's specification dialog.
[TIP] If you are using Blocks (not InterfaceBlocks) to Type your Ports just use "manual" feature-by feature direction inversion to achieve type conjugation (and you can even use a ~ tilde prefix)
[ISSUE, WARNING] In SysML the NOW DEPRECATED (since SysML-1.6) direct UML Port conjugation does not work consistently with SysML DirectedFeature and SysML FlowProperty on nested ports!
[ASSERTION, WISHLIST] SysMLv1.6 Provided/required DirectedFeature contracts for ProxyPorts SHOULD be satisfiable Feature-wise (including as subsets of Features) not necessarily just at the level of entire Blocks (types)! [See also the SysMLv1.7 spec changes.]
[TIP]{STRONG} In general, the SysML DirectedFeature approach is more powerful and the notation is cleaner than UML provided/required Interfaces. Prefer SysML DirectedFeatures unless you have a really good reason to use Interfaces!
Snippets (quotes/extracts)
  [SysML-1.6] The ~InterfaceBlock stereotype (shall be pronounced: "conjugated interface block") is a specialization of InterfaceBlock that has the same features as its original InterfaceBlock except that its DirectedFeatures and FlowProperties are reversed (conjugated
  [SysML-1.6] InterfaceBlock ... for example, in flow properties are conjugated as out flow properties and provided features are conjugated as required features.
  [SysML-1.6] Conjugation is specified by a constraint giving the features of ~InterfaceBlocks according to those of their original InterfaceBlocks ... It is expected that tools conforming to this specification automatically create features of ~InterfaceBlocks.
  [SysML-1.6] [SysML1.6: PREFER SysML1.7] A DirectedFeature indicates whether the feature is supported by the owning block (provided), or is to be supported by other blocks for the owning block to use (required), or both ...
  [SysML-1.7] A DirectedFeature indicates whether the feature is supported by the owning block (provided) for other connected blocks to use, or is to be supported by a connected block for the owning block to use (required), or both (providedRequired).
  [SysML-1.7] InterfaceBlock::isconjugated_not_used Any port typed by an InterfaceBlock shall have its isConjugated property set to false.
  [SysML-1.6] SysML permits any property shown on an internal block diagram to also show compartments within the property box. These compartments may be given standard or user-customized labels just as on block definitions.
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Figure 9-1: Port Stereotypes
Figure D.39 - Flow Allocation to Power Subsystem (Power Functional Allocation)
Figure D.19 - Internal Structure of the Power Subsystem (Internal Block Diagram)
Figure D.20 - Blocks Typing Ports in the Power Subsystem (ICE Port Type Definitions)
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