Figure 9-16: Usage example of item flow decomposition

Although the flow direction of each nested Port (not shown) is in the same direction within each parent Port, the flow direction indicators have not been shown on each parent Port in the upper IBD (compare with spec figure), to emphasise this:

SysML-1.6: 'In Figure 9-16, the item flow classifier (EnginePart) is a supertype of the classifiers of the item flows in the decomposition.'

SysML-1.6: 'The flow properties are all in the types of the nested ports, while the composing item flow summarizes the kinds of items flowing by generalization.'

However, indicating a flow direction here on the parent Ports would be permissible, because:

SysML-1.6: 'Ports with types that have flow properties all in the same direction, either all in or all out, can have an arrow inside them indicating the direction of the properties with respect to the owning block.'

SysML-1.6: 'This includes the direction of flow properties on nested ports, and if the port is full and its type is unencapsulated, ports on parts of the port, recursively. The arrows are perpendicular to the boundary lines they overlap.'

Note how (unlike in the spec figure version) the flow properties on the types of the nested ports have been exposed in the lower BDD, and the flow direction indicators have been shown on the Ports in the structure compartment for A1.

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Figure 9-17: Usage example of item flow decomposition

Notes

Snippets (quotes/extracts)

[SysML-1.6] Connectors with item flows can be decomposed by association blocks that have additional item flows. The relationship between an item flow and those in the association block is determined by the modeler.

[SysML-1.6] Figures 9.16 and 9.17 are examples of item flow decomposition that modelers might choose, but they are not the only possible decompositions and are not required.

[SysML-1.6] In Figure 9-16, the item flow classifier (EnginePart) is a supertype of the classifiers of the item flows in the decomposition.

[SysML-1.6] The flow properties are all in the types of the nested ports, while the composing item flow summarizes the kinds of items flowing by generalization.

[SysML-1.6] Ports with types that have flow properties all in the same direction, either all in or all out, can have an arrow inside them indicating the direction of the properties with respect to the owning block.

[SysML-1.6] This includes the direction of flow properties on nested ports, and if the port is full and its type is unencapsulated, ports on parts of the port, recursively. The arrows are perpendicular to the boundary lines they overlap.

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