Chapter 4 - Use-Case diagram

Use Case

Describes basic system functions in terms of what the user can do and how the system responds. Each use case describes exactly one function.

Actor

Someone who uses the system to achieve a particular goal

Primary actor

user who initiates the use of the system - left side

Secondary actor

User who responds or reacts after an action is performed, provides support, or receives output - right side

An include relationship

Represents the inclusion of the functionality of one use case within another, happens every time a Base Use Case is executed

An extend relationship

Represents the extension of the use to include optional behaviour. Happens sometimes when a certain criteria is met

Generalization relationship

AKA inheritance, breaks a general use case into specialized use cases

Activity Diagram

Models how a business operates through business processes. Used to illustrate movement of data between activities

Elements of activity diagram

Activity, Object Node, Control Flow, Control Nodes

Object Node - Activity diagram element

Represents a flow of information from one activity to another

Control flow - Activity diagram element

Models the execution paths

Types Control Nodes - Activity diagram element

-Initial node

-Final activity node

-Decision node

-Merge node

-Fork node

-Join node

Activity

Represents a set of actions

initial Node

The beginning of a set of actions

Final Node

Stops all flows in an activity

Decision Node

Represents a test condition

Merge Node

Used to bring back different decision paths that were created using a decision node

Fork Node

Used to split behaviour into a set of concurrent flows of activities for actions

Join Node

Used to bring back together a set of concurrent flows of activities or actions

Swimlane

A way to break an activity diagram into rows or columns. Assigns activties to specific actors or systems