Adding synchronous and asynchronous messages

In sequence diagrams, you can add a synchronous message to a lifeline when you want the system to wait for the operation to complete before it continues with a return message. You add an asynchronous message when the sending participant does not wait for the operation to complete before it continues with the next step.

Note: When you create a synchronous message, a return message is created by default. You can change this default in the Preferences window.
To add a synchronous or an asynchronous message:
  1. Open a sequence diagram that contains multiple lifelines.
  2. In the Palette, click Synchronous Message or Asynchronous Message.
  3. In the interaction frame, click the source lifeline and then drag to the target lifeline.
  4. Complete one of the following steps:
    • If the target lifeline represents a participant of a structured classifier type, such as a class or component, in the Enter Operation Name window, type a name for the operation, and click OK.
    • If the target lifeline represents a participant of a non-structured classifier type, such as an actor, you can rename the selected message.
    Note: If the source lifeline is the same as the target lifeline, you create a self-directed message.

Parent topic: Creating messages in sequence diagrams

Related concepts
Messages

Terms of use | Feedback
(C) Copyright IBM Corporation 2004, 2005. All Rights Reserved.