CS2002 - Week 7 - Activity Diagrams

Question 1

Primary focus of an activity diagram

Answer 1

Modelling procedural processing

Question 2

Node

Answer 2

basic element of activity diagrams, specifys user-defined behaviour (actions, objects, control nodes)

Question 3

Edges

Answer 3

connects activites and nodes (actions)

Question 4

Token in activity diagrams

Answer 4

A virtual mechanism that:
- grants execution permission to actions (control token)
- transports data (object token)

Question 5

Key control nodes

Answer 5

Initial node: Starts activity
Activity final node: Ends all flows
Decision node: Splits paths with guards
Merge node: Combines alternative paths

Question 6

Concurrent paths modeling (Parallelisation vs Synchronisation)

Answer 6

Parallelisation node: Splits into concurrent flows
Synchronisation node: Waits for all flows to complete

Question 7

Object node

Answer 7

Represents data/objects exchanged between actions

Question 8

Central Buffers vs Data Stores

Answer 8

Central Buffer: Transient (deletes tokens after reading)
Data Store: Permanent (copies tokens)

Question 9

Types of event-based actions

Answer 9

Send signal: Triggers an event
Accept event: Waits for an event/time

Question 10

Partition

Answer 10

Groups nodes by responsibility/roles

Question 11

Types of exception handling

Answer 11

Exception handler: Replaces a failed action
Interruptible region: Terminates a group of actions on an event

Question 12

Symbol for call behaviour action

Answer 12

Fork icon

Question 13

Token reaches an activity final node

Answer 13

All flows terminate immediately (even concurrent ones)

Question 14

Guards in activity diagrams

Answer 14

Ensure flows continue only if specific conditions are met
Must be mutually exclusive for decision nodes. (In square brackets: [grade >= 5])

Question 15

Connectors usage

Answer 15

To simplify diagrams when actions are far apart (avoid crossing lines)