Brief Overview of UML Diagrams with a Simple Example

ECE 417/617:Elements of Software Engineering

Stan BirchfieldClemson University

A Simple Problem

1 5 V

light

switch

1. Use Case Diagram

SimpleCircuit

FlipOn

FlipOff

ViewLight

User

Functionality from user’s point of view

2. Class Diagram

Battery5V

Switch

Resistor Light

Structure of system (objects, attributes, associations, operations)

3. Interaction Diagram: (a) Sequence Diagram

ResistorSwitch Battery Light

Messages between objects

UserFlipOn() HeatUp() Drain()

Shine()

3. Interaction Diagram: (b) Collaboration Diagram

Resistor

More compact, but harder to interpret

User1. FlipOn()

1.1 HeatUp()

1.3 Drain()1.2 Shine()

Battery

Switch

Light

4. Statechart Diagram

Transitions between states of one object(Extension of Finite State Machine (FSM) model)

LightOff

LightOn

flipSwitchOn

flipSwitchOff

4. Statechart Diagram (different objects)

Cold Hot

flipSwitchOn

flipSwitchOff

NotDraining

Draining

flipSwitchOn

flipSwitchOff

(Resistor) (Battery)

5. Activity Diagram

Actions are states

Flip Switch On Flip Switch Off

SummaryWe have looked at five diagrams:

1. Use case diagrams [Functional Model]-- models functionality from user’s point of view

2. Class diagrams [Object Model]-- models structure of system using objects

3. Interaction diagrams [Dynamic Model](sequence and collaboration)-- models messages passed between objects

4. Statechart diagrams [Dynamic Model]-- models transitions between states

5. Activity diagrams [Dynamic Model]-- models flow control as transitions between activities

The actual UML spec has 12 diagrams, but these five will be sufficient for us.