Creating lifelines in UML diagrams

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

Before you begin

You must have a sequence or communication diagram open.

About this task

To create a lifeline:

Procedure

  1. In the Palette, click Lifeline.
  2. In the editor, click in an interaction frame where you want to add the new lifeline.
  3. 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.

Results

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.

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