In sequence diagrams, you can add synchronous and asynchronous
messages to lifelines to represent the communication between interaction instances.
You can also specify the operations, or methods, of messages. You add an asynchronous
message when the sending instance does not wait for the operation to complete
before it continues with the next step
You must have a sequence diagram with multiple lifelines open in the
diagram editor.
Note: When you create a synchronous message, a
return message is created automatically.
To create a synchronous or asynchronous message:
- In the Palette, click Synchronous
Message or Asynchronous Message.
- In the interaction frame, click a source lifeline and drag it to
a target lifeline.
- Complete one of the following steps:
- If the target lifeline represents an instance of a structured classifier
type, such as a class or component, click inside the interaction frame; in
the Enter Operation Name window, type a name for the
operation, and click OK.
- If the target lifeline represents an instance 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.