Activity Diagrams Flashcards
(20 cards)
What is an activity diagram?
A flowchart showing step-by-step actions in a process, with decisions and parallel paths.
What are the two main components of activity diagrams?
Nodes (actions/decisions) and edges (arrows showing flow).
What is an ‘action’ in activity diagrams?
A single task (e.g., ‘Submit Assignment’) shown as a rounded rectangle.
What is a ‘control flow’ edge?
An arrow showing the order of actions (no data passed).
What is an ‘object flow’ edge?
An arrow passing data/objects between actions (e.g., ‘Assignment → Grade’).
What is a ‘token’?
A virtual ‘permission slip’ that allows actions to run when received.
What starts an activity?
Initial node (solid black circle ●).
What ends ALL flows in an activity?
Activity final node (bullseye ⭘).
What ends ONE flow path without stopping others?
Flow final node (X inside circle ⓧ).
How are decisions shown?
Diamond (◇) with guards like ‘[grade > 50]’ on outgoing edges.
What does a ‘merge node’ do?
Combines alternate paths back into one (also a diamond ◇).
How is parallelism shown?
Fork (solid bar ━) splits paths; join (solid bar ━) syncs them.
What is an ‘object node’?
A box holding data between steps (e.g., ‘Task: String’).
What’s the difference between central buffer and data store?
Central buffer deletes data after reading; data store keeps copies.
What does ‘weight=3’ on an edge mean?
3 tokens needed to trigger the next action (default is 1).
What is a ‘partition’ (swimlane)?
Columns/lanes grouping actions by role (e.g., ‘Student’ vs ‘Professor’).
How are exceptions handled?
With ‘exception handler’ nodes that replace failed actions.
What is an ‘interruptible region’?
A dashed area where an event (e.g., ‘Withdraw’) cancels all actions inside.
What’s a ‘call behavior action’?
An action (Ⓐ) that references another activity (reusable).
How are time-based events shown?
Hourglass symbol (⏳) for waits (e.g., ‘Semester ends’).
