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

1. Click the message line, and then click the control on the line end with the arrow head.
   
   
   
   
2. In the selection window, select the desired message sort, and click OK.
   
   

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.