Standards families
UML activity — pins, decisions and interrupts
Actions wired by object and control flow: pins as typed ports on actions, decision/merge diamonds, fork/join bars, interruptible regions.
uml.activity@2New DDN source
Why use it?
The activity diagram is where "the process" becomes checkable: every input must come from somewhere.
When it helps
Detailing an algorithm or business process one level below a use case.
How to read it
- Rounded boxes are actions; small squares on their edges are pins (typed inputs/outputs).
- Diamonds decide or merge; thick bars fork and rejoin concurrent flow.
What you need
- The actions
- What each consumes and produces
- The decision logic
Things to check
- Do not leave a required pin unfed — the validator treats it as the defect it is.
- Merge and decision are different diamonds; do not swap them.
Scope of this diagram
Declared flow with pin and region validation; no execution or simulation is performed.
Work with the converted example
- Open the viewer and select
pins. Inspect the rendered view and its source. - Open the designer. Keep the selected profile and inspect its legal palette and property controls.
- Change one displayed title or an appropriate data value. Apply the edit and check the resulting diagram.
- Run the verifier and review its diagnostics before moving complete content into review.
- Download your edited DDN source to retain the change.
The example uses the indentation-based ddn-next-1 dialect. The language guide explains reusable definitions, dotted data rows and explicit property blocks.