In sequence diagrams, you can add synchronous and asynchronous
messages to lifelines to represent communication between objects. You can
also specify the signatures of messages.
To create a message:
- In the Palette, click a message type.
- In the interaction frame, click a source lifeline and drag the
cursor to a target lifeline.
- Type a name for the message.
If you create a synchronous message, a return message is created automatically.
Note: You can delay an asynchronous message by dragging the asynchronous
message first horizontally and then vertically across existing messages to
the target lifeline where you want to terminate the message.
Tip: You
can also assign an operation to a message in an existing diagram. In the navigation
view, click an operation and drag it onto a message in the interaction frame.
The operation must belong to the target instance of the object or be visible
to and in scope of the operation in an object.