Sequence Diagram

• Resource: http://www.smartdraw.com/resources/centers/uml/uml4.htm
• A sequence diagram describes how objects relate to each other through activation and destruction over time.
• Thus, the sequence diagram is time based.  The further down the diagram you look, the further time progresses.
• Boxes at the top of the diagram represent objects.
• Underneath each box is a line that proceeds to the end of the diagram.
• An arrow from one line will instantiate another object.
• At the point of instantiation, the line turns into a rectangle.  This is called an activation box. When the object ceases to exist because it has finished processing or is killed by another object, the activation box ends and the line begins again.
• This is really hard to explain, so let's look at an example.

Created by:  Brandan Jones December 17, 2001