Change the Timing Details

It is possible to change the timing details of a Message in a Sequence diagram.

Access     Right-click on the Message | Timing Details

Change Timing



Duration Constraint

Indicate the minimum and maximum limits on how long a message can last.


Duration Constraint Between Messages

Indicate the minimum and maximum interval between sending or receipt of the previous message at the current message's source Lifeline, and sending the current message.


Duration Observation

Capture the duration of a message.


Timing Constraint

Indicate the minimum and maximum time at which the message should arrive at the target.


Timing Observation

Capture the point at which the message was sent.


See the OMG UML specification (UML Superstructure Specification, v2.1.1, p. 511).



In this diagram, on the Open Order Message:

·Duration Constraint has been set to 0...13

On the Get Cart Message:

·Duration Constraint Between Messages has been set to d...d*3
·Duration Observation has been set to d=duration
·Timing Constraint has been set to t...t+3
·Timing Observation has been set to t=now

By typing a value in the Duration Constraint field, you enable the Message angle to be adjusted. After clicking on the OK button on the Timing Details dialog, click on the head of the Message connector and drag the connector up or down to change the angle. You cannot extent the angle beyond the life line of the connecting sequence object or create an angle of less than 5 degrees.

You can also create the Duration Constraint Between Messages line by dragging the General Ordering arrow up to the point at which the previous message joins the source Lifeline for the current message. A dialog displays on which you enter the value for the constraint. Having created the line, you can move it to any point within half way along the current message and half way along the previous message, to avoid overlap with other message timing details. You can edit or delete the value either through the Timing Details dialog or by right-clicking on the line itself and selecting the appropriate context menu option.

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