In communication diagrams, you can create messages to represent
the communication that occurs between participants in interactions.
You can add, delete, reposition, and assign new signatures to messages
in an interaction frame.
Before you begin
Before you can add messages, you must have a communication
diagram open that contains at least two lifelines that are connected
by a message pathway.
About this task
To create a message on a message pathway:
Procedure
- In the Palette, click either Message or Reverse
Message.
- Click the message pathway to which you want to add the
message.
- From the popup window, create a new operation or select
an existing operation to use as the message:
- To create a new operation, click Create New Operation,
type the name of the operation, select the classifier to own the operation,
and click OK.
- To use an existing operation, select it from the list in the
popup or click Select Existing Operation to
search the model for an operation.
Results
As the following figure illustrates, the message is displayed
as an arrow on the message pathway, with an arrowhead that indicates
the direction of the message: forward or reverse. The forward portion
of the message points in the direction that you created the message
pathway. The message label shows the sequence number and the message
name.

What to do next
Note: By default, when you create a message on a message
pathway, both the synchronous call and the return message are added.
To change this, clear the Automatically create return message check
box in the Preferences dialog box.