Creating lifelines in UML diagrams

In UML diagrams, such as sequence and communication diagrams, you can create lifelines to represent objects in a system.

You must have a sequence or communication diagram open.

To create a lifeline:

In the Palette, click Lifeline.
In the editor, click in an interaction frame where you want to add the new lifeline.

In the dialog box, click a type of lifeline:

Lifeline	Details
Unspecified	This option creates a lifeline without a specified type.
Create Class	This option creates a lifeline that represents a class. You type a name for the new lifeline and then for the object.
Create Actor	This option creates a lifeline that represents an actor. You type a name for the new lifeline and then for the object.
Create Component	This option creates a lifeline that represents a component. You type a name for the new lifeline and then for the object.
Select Existing Element	This option enables you to select an existing element in the model.

When you create a lifeline in a sequence diagram, the lifeline is aligned vertically with other lifelines in the interaction, and extends downward. You can resize a lifeline by clicking it and dragging the anchors vertically or horizontally.

Tip: You can also assign an existing element type to a lifeline: In the navigation view, click a class, interface, or data type and drag it onto a lifeline in the interaction frame.