UML Sequence Diagrams

A sequence diagram is a Unified Modeling Language (UML) diagram that provides a view of the chronological sequence of messages between instances (objects or classifier roles) that work together in an interaction or interaction instance. A sequence diagram consists of a group of instances (represented by lifelines) and the messages that they exchange during the interaction. You line up instances participating in the interaction in any order from left to right, and then you position the messages that they exchange in sequential order from top to bottom. Activations sometimes appear on the lifelines.

A sequence diagram belongs to an interaction in a collaboration or an interaction instance in a collaboration instance.

Related Topics

Model Elements and Relationships in Sequence DiagramsAbout the UML/SD Viewer