Sequence Diagram
Definition
A Sequence Diagram is a type of Interaction Diagram that focuses on Message interchanges between entities. In the UML modelling context it is a type of behavior diagram that enables defining Behavior in some detail.
A sequence diagram interactions by depicting sequences of Message exchanges. In OOP design a sequence diagram describes the interactions between objects to fulfill a specific task. The focus is on the chronological order of the messages exchanged between the interactiong objects.
A sequence diagram typically shows, as parallel vertical or horizontal lines (also called lifelines), different processes or objects that "live" simultaneously, and, as horizontal or vertical arrows, the messages exchanged between them. The spatial arrangement indicates the temporal order in which messages happen.
