Sequence Diagram
Lifeline
You can create a lifeline by double-clicking on a diagram or choosing how you present it from the tool palette.
※ Online Lifeline is available in Astah System Safety.
Adding BaseClass
You can add a base class to Lifeline by directly typing its Class (Block) name after the Lifeline name.
Or, you can create by clicking [New] button from Lifeline’s property view.
Or, you can drag a Class to Sequence diagram to create a lifeline with the class as its base class.
Show Actor as Lifeline
By dragging an Actor from the tree to diagram, you can represent lifeline in Actor on the Sequence Diagram.
Adjust Lifeline length
After creating a Sequence diagram, you may want to adjust the length of Lifelines to clean up the diagram. Right-click on a diagram and select [Adjust Lifeline Length] and choose from these three options.
| Default | Make all the lifeline to the shortest possible. |
| Align to Minimum | Make all the lifeline to the same length as the shortest one on the diagram.
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| Align to Maximum | Make all the lifeline to the same length as the longest one on the diagram. |
Minimize Execution Specification
To clean up Sequence diagrams, you can minimize the length of Execution Specifications. Right-click on a diagram and select [Adjust ExecutionSpecification Length].
Hide Execution Specification
You can hide the Execution Specification box on the Lifeline.
Currently, this is available in Astah Professional, UML, and System Safety editions only.
1. Click anywhere on a diagram.
2. A property view for the Sequence diagram opens in the left-bottom pane. Tick off the [Execution Specification Visibility].
Message
Found message
To create a found message, select [Synchronous Message] or [Asynchronous Message] from the tool palette and click target Lifeline.
Lost Message
To create a Lost message, select [Synchronous Message] or [Asynchronous Message] from the Tool palette and click Lifeline and then anywhere other than Lifeline.
Gate
To create a gate, select [Synchronous Message] or [Asynchronous Message] from the Tool palette and click on a diagram frame then Lifeline.
Reply Message
There are two ways to create a reply message.
1. Select [Reply Message] from a tool palette and click a lifeline.
2. Or, turn [Reply Message Mode] on a tool palette and create Messages. 
CombinedFragment
Operand
You can create Operand from the CombinedFragment’s Property view or diagram’s pop-up menu.
TIPS: Define loop in the CombinedFragment
You can enter texts and numbers from the CombinedFragment’s Property View.
