UML - Unified Modeling Language

What is UML ?

UML is an object-oriented, graphic analysis and design standard from the Object Management Group (OMG). It defines nine kinds of diagram.

1. Use Case Diagram: Shows a systems functions from a user's point of view
2. Sequence Diagram: Shows message flow between entities in the system
3. Collaboration Diagram: Shows the structure of relationships between entities
4. Class Diagram: Shows "classes" of system entities. Each class has "attributes" and "operations". Lines between classes are "associations".
5. State Chart: Describes the discrete states which are possible in the system.
6. Component Diagram: Shows software module interaction
7. Deployment Diagram: Shows hardware nodes
8. Activity Diagram: Shows tasks
9. Object Diagram: Shows instantiations of classes (rarely used)

When to Use UML

UML is most useful on large projects particularly those which use Object Oriented Development. It is a relatively "heavy" environment requiring specialized skills and software (see below). It is essential on projects like air traffic control or online banking where "you must get it right first time".

Resources

UML Description from Wikipedia.

UML Specifications version 2.5 as provided by OMG (the standards body responsible for UML).
Download the UML Quick Reference Guide provided by NoMagic.com.

Software Tools

MagicDraw supports the UML 2 Metamodel

Background

In the late 1980's, a proliferation of modeling languages meant that when modeling specialists changed jobs, or even projects, they had to learn a new set of tools. The leading specialists, Grady Booch (Rational Software), James Rumbaugh (Object Modeling Technique), and Ivar Jacobson (Use Cases) among others, agreed on a modified version of a notation originally developed by David Embley and his colleagues. The UML was published by the Object Management Group in 1997..

by Gary Rathwell © reserved

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