What is a pin in UML activity diagrams?

What is a pin in UML activity diagrams?

• A. A specialized object node that attaches to an action to represent an input or output
• B. A boundary marker for timing
• C. A control node that splits flows
• D. A parameter binding

Answer: (A)

A pin in an activity diagram represents the data ports of an action. They are the points where values flow into and out of an action, showing what data the action needs and what it produces. Think of pins as the concrete places on an action that receive inputs from previous steps and hold the results that will be passed on to the next steps. Each pin can have a type and a multiplicity, and edges connect to these pins to carry the data tokens through the workflow. This makes the data flow explicit: you can see which inputs an action consumes and what outputs it produces, separate from the control flow that guides the order of actions. Not timing markers, not control-flow split points, and not a mechanism for binding parameters, since those are different UML concepts.

A pin in an activity diagram represents the data ports of an action. They are the points where values flow into and out of an action, showing what data the action needs and what it produces. Think of pins as the concrete places on an action that receive inputs from previous steps and hold the results that will be passed on to the next steps. Each pin can have a type and a multiplicity, and edges connect to these pins to carry the data tokens through the workflow. This makes the data flow explicit: you can see which inputs an action consumes and what outputs it produces, separate from the control flow that guides the order of actions.

Not timing markers, not control-flow split points, and not a mechanism for binding parameters, since those are different UML concepts.