Activity Output Node

Output Node

An Output Node marks object tokens leaving a structured Activity. It forwards matching tokens from the nested graph to the structured node's outgoing object flows in the parent graph. OutputNode is a Stateflows boundary-routing API, not a UML activity-final node. UML models data crossing such boundaries using pins or activity parameter nodes, depending on the modeled boundary.

flowchart LR
    subgraph nested["Structured Activity"]
        calculate(Calculate total) -->|decimal| output["Output boundary"]
    end
    output -->|decimal| parent(Record total)

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Mermaid approximation: this diagram shows the model's routing, not a complete UML Activity notation. Rounded boxes represent actions; edge labels identify token types or guards. Input/Output boxes name Stateflows boundary APIs, not UML final nodes or a claim that UML uses these box labels. Mermaid does not model pins, activity parameters, or expansion regions natively.

Definition

Connect the inner producer to OutputNode, declare AddOutput() in the nested definition, then connect the containing structured node to a parent consumer:

.AddInitial(initial => initial.AddControlFlow("CalculateTotal"))
.AddStructuredActivity("CalculateTotal", nested => nested
    .AddInitial(initial => initial.AddControlFlow("Calculate"))
    .AddAction(
        "Calculate",
        async c => c.Output(125m),
        node => node.AddFlow<decimal, OutputNode>())
    .AddOutput()
    .AddFlow<decimal>("Record"))
.AddAction("Record", async c =>
    await ledger.RecordAsync(
        c.GetTokensOfType<decimal>().Single(), c.CancellationToken))

The child object-flow type determines the token type exported to the parent. Output Nodes are boundary connectors, not general-purpose nodes needed for flows within one Activity level. Iterative and Parallel Activity Nodes also use their nested Output Node to collect results. See Input Node, Structured Activity Node, and Data Flow.