UML Diagram: Sequence
(Free Web Tutorials)

by Michael Thomas

On the UML Home page, you can download the whole UML site (all content, tutorials & examples) !!!
(Note: All of the EclipseUML projects used in these tutorials are in .zip files located at: uml\eclipse\viewonly . Just extract them into your workspace.)

Prerequisites

Review the UML Overview tutorial.

Objectives

Get a broad over view of UML "Sequence" diagram.

Definition & Example

Sequence Diagram - is a diagram of the interaction and flow of messages among objects and the relative time ordering of the messages.
Example - (created with EclipseUML - May of 2008) - a very general diagram between an actor (the Customer) and a system (online reservation for a Hotel) to give you a flow of the interactions to make a reservation via the web.
Example - (created with Rational Software Modeler v6.0 - Sept of 2005) - diagram of an online order system.

Goals of the Sequence Diagram

Model the order of the exchange of messages, relative to time, between objects in a system.
Take a use case and expand then internal workings of the objects relative to the order and timing of messages.
Describe the aspects of your system that change over time.
Show classes that exchange message within an interaction arranged in a time sequence.
Horizontally at the top show the objects then vertically show the messages to the objects (from left to right) in order over time (top to bottom).

UML Sequence Diagram Terms (used by EclipseUML for UML2)

Property
Actor
Message
Self Message
Frame
Interaction use
Component
Class
Interface

Future topics

More examples of diagrams...