Spend 5 minutes understanding 4 UML diagrams before it’s too late!

May 15, 2009

Spend 5 minutes understanding 4 UML diagrams before it’s too late!

UML – Unified Modelling Language

Why? To communicate and understand at the same level. Why? To avoid misconceptions!

CLASS DIAGRAMS

- capture static relationships of software;
- capture the physical structure of a system;
- understand what classes reference other classes;
- understand which class ‘owns’ another class;
- a CLASS represents a group that has common states and behaviours
- the RELATIONSHIPS include: dependencies, associations, aggregations, compositions, generalisations, associated classes and associated qualifiers.

class diagram example

USE-CASE DIAGRAMS

- capture and define functional requirements;
- a user story and a use case describe ONE THING ONLY that the software needs to do.

use-case example

ACTIVITY DIAGRAMS

- the “how” does something to something else;
- derived from workflows and flowcharts, because they look very similar;
- defines the behaviour of the model being described.

activity diagram example

SEQUENCE DIAGRAMS

- defines object interaction at runtime to bring software functionality to life in an executed order/sequence;
- used for dynamic modelling.

sequence diagram example

USE-CASE NARRATIVES (non-diagram, text only)

- used to describe the use-case in more narrative terms;
- contains: use case name, iteration, summary, pre-conditions, triggers, course of events; alternate paths; post-condition; business rules; notes; author & date.

Permalink