A Sequence diagram depicts the interaction between collaborating groups of objects in a system. These diagrams consist of vertical lines called lifelines, each of which represents the life of a given object. Lifelines are connected by horizontal lines denoting messages passed from one object to the next in the use case. You can also assign self-referential messages to lifelines.
When you click the Diagram window of a Sequence diagram, the IDE displays a specific selection of icons in the Modeling Palette. These icons are not displayed when you click a Diagram window displaying a Class diagram. When you delete a Sequence diagram operation, the IDE deletes all corresponding messages with that name and matching parameters. Naming a message in the Sequence diagram checks the target class' operations for existence and possible addition of the new message to the list of operations.
Typically, a Sequence diagram depicts a single use case in a system, but new UML 2.0 functionality greatly expands upon the basics of Sequence diagram use and functionality. The specifications for UML 2.0 offer the following functionality:
Each instance of the component types listed above appears as a unique lifeline in your Sequence Diagram. |