A message in a UML sequence diagram specifies the kind of communication, and the sender and receiver. Messages can be named freely.
Depending on the type of action the message represents, a message can be of the following sort: synchronous call, asynchronous call, asynchronous signal, or reply. By default, a message is set as a synchronous call. A message can also be a create message or a lost or found message.
The form of the line or arrowhead reflects the sort of message:
On this page:
Setting the message sort
- Click the message line, and then click the
- In the selection window, select the desired message sort, and click OK.
Instead of setting a return message as a reply message after drawing it, hold down Alt when drawing the return message. It automatically turns into a reply message.
Creating a create message
A create message is used to represent the creation of a lifeline. It is drawn to the start of the lifeline. To create a create message, do as follows:
- Draw a message to the target lifeline element. Enterprise Studio Online automatically turns the message into a <<create>> message. The lifeline will be positioned to start at the message.
Creating a delete message
A delete message is sent to terminate another lifeline. The lifeline usually ends. To create a delete message, do as follows:
- Draw a destruction occurrence at the bottom of the lifeline, and then draw a message to the destruction occurrence. Enterprise Studio Online automatically turns the message into a <<delete>> message.
Creating a lost or found message
A lost message is denoted with a black circle at the arrow end of the message. A found message is denoted with a black circle at the starting end of the message. To create a lost message, do as follows:
- Add a lost or found occurrence next to the lifeline, and draw a message from the lifeline to the occurrence.
To create a found message, do as follows:
- Add a lost or found occurrence next to the lifeline, and draw a message from the occurrence to the lifeline.