PortUsage

Original XMI declaration. §7.12.2–3 Port Definitions and Usages, printed 63 / PDF 95; §8.3.12.6 PortUsage, printed 295 / PDF 327

What to understand

• A port usage can appear as a full node or as a small boundary glyph; its semantic identity is not determined by the drawing size.
• Only port definitions can type a port usage. Conjugated typing uses ~ and reverses in/out while preserving inout.
• The source overview and well-formedness constraints need to be read together: nested-port exceptions prevent an unconditional rule that every nested port value must be non-composite.
• A connection referencing a port does not by itself establish a flow or an executable transfer.

Graphical notation

These are representative, source-checked variants, not an exhaustive notation grammar. The illustrations are original redraws, not official figures.

Full node and boundary port

Context: Structural and interconnection views.

The full node is rounded and labeled port. The compact outline in this older illustration is a geometry primitive only: displayed boundary alternatives include horizontal or vertical direction indicators, plus side-specific labels. Their selection and layout are separate renderer responsibilities.

§8.2.3.12 Ports, printed 210 / PDF 242; §8.2.3.12 Ports, printed 211 / PDF 243; §8.2.3.12 boundary-port alternatives, printed 212 / PDF 244

Restricted reference and proxy variants

Context: Nested ports and part usages within interconnection views.

Dotted-outline reference port productions are restricted to nested ports. The filled-dot proxy option is restricted to a part usage contained within an interconnection view.

§8.2.3.12 restriction notes, printed 214 / PDF 246

Relationships and composition

Feature context: PartDefinition

Port usages can be declared in part definitions.

Condition: Type featuring, declaration ownership and referentiality remain separate questions.

§7.12.2–3, printed 63 / PDF 95

Feature context: PartUsage

Port usages can be nested in part usages.

Condition: Nesting is contextual; a glyph placed on a boundary is not itself evidence of a new ownership rule.

§7.12.2–3, printed 63 / PDF 95

Referenced endpoint: ConnectionUsage

A connection can reference a port feature as an end target.

Condition: Preserve end roles and reference-subsetting relationships; do not infer flow semantics from the line.

§7.13.2, printed 71 / PDF 103

Connected example

hub and mount are port usages typed by Mount. The connection refers to them through axle.mount and wheel.hub. The example uses no directional arrows or transfer behavior.

// Original documentation example. Source-reviewed; not parser-validated.
package AssemblyExample {
    port def Mount;

    part def Wheel {
        port hub : Mount;
    }

    part def Axle {
        port mount : Mount;
    }

    part def Assembly {
        part wheel : Wheel;
        part axle : Axle;
        ref part spare : Wheel[0..1];
        connection link connect axle.mount to wheel.hub;
    }

    part assembly : Assembly;
}

Verification: source-reviewed, not parser-validated or executed. §7.12.2–3, printed 63 / PDF 95; §7.13.2 binary connection shorthand, printed 71 / PDF 103

Properties

The explicit-redefinition view contains 111 active declarations, retaining declaration origins and excluding 4 replaced declarations. It deduplicates diamond paths by identity, excludes private inherited fields, and reports unresolved same-name collisions instead of choosing a winner.

These are metamodel property cardinalities and declared defaults. They do not determine the multiplicity or runtime values of a part, port or connection in a user model. Derived values still require their derivation rules. See property rules.

Replaced declarations

• KerML::Core::Features::Feature::isVariable → SysML::Systems::DefinitionAndUsage::Usage::mayTimeVary
• KerML::Core::Features::Feature::type → SysML::Systems::Ports::PortUsage::portDefinition
• SysML::Systems::DefinitionAndUsage::Usage::definition → SysML::Systems::Ports::PortUsage::portDefinition
• SysML::Systems::Occurrences::OccurrenceUsage::occurrenceDefinition → SysML::Systems::Ports::PortUsage::portDefinition

Reconciliation and limits

Seed reconciliation: SelectedFieldsMatch for direct bases, declared property names/types/bounds/derivation/ordering/subsets/redefinitions, constraint names. This checks selected structural fields only; it does not approve the entire seed or all semantics.

• The pinned XMI overview overgeneralizes referentiality; the profile preserves the nested-port qualification rather than silently applying that overview as an unconditional rule.
• Effective property resolution covers explicit inheritance and redefinition identities; it does not evaluate constraint consistency, OCL derivations or executable behavior.

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