Activation Bar

An Activation Bar in a UML Sequence Diagram represents the time period during which a participant (Lifeline) is active or performing an operation. In Modeldraw, you can use Activation Bars to show when objects are processing or controlling the flow of the program.

Activation Bars

Understanding Activation Bar

An Activation Bar represents the active period of a Lifeline. Key characteristics include:

• It shows when a participant is executing an operation

• It is drawn as a thin rectangle on top of a Lifeline

• Its length indicates the duration of the activation

• It can be nested to show recursive calls or multiple levels of activation

An Activation Bar is represented in UML by a rectangular box placed on a Lifeline.

Activation Bars are crucial in Sequence Diagrams for:

• Showing the flow of control between participants

• Indicating the relative time and duration of operations

• Representing nested calls and complex interactions

Creating an Activation Bar

To create an Activation Bar in Modeldraw:

1. Select the Activation Bar tool from the toolbox

2. Click on the Lifeline where you want the activation to start