In sequence diagrams, you can create messages to represent the communication that occurs between participants in lifelines. You can add, delete, reposition, and assign new operations to messages in an interaction frame.
Adding synchronous and asynchronous messages
In sequence diagrams, you can add a synchronous message to a lifeline when you want the system to wait for the operation to complete before it continues with a return message. You add an asynchronous message when the sending participant does not wait for the operation to complete before it continues with the next step.Adding create and destroy messages
In sequence diagrams, you can add a create message or a destroy message to a lifeline to represent the creation or the destruction of a participant. You add the create message above any messages and interaction fragments that are covered by the lifeline; you add the destroy message below the messages and interaction fragments.Delaying the receipt of asynchronous messages
In sequence diagrams, you can move the sending point and the receiving point of an asynchronous message between lifelines to manipulate the time delay between the sending event and the receiving event. You can have multiple messages that occur between the sending and receiving lifelines.Moving synchronous messages
In sequence diagrams, you can move all message types on lifelines. However, when you move a synchronous message with a return message, you must move the send message and the return message separately and in a particular order; otherwise, only one part of the message moves on the lifeline.Reordering messages
In sequence diagrams, you can move a message across other messages and interaction fragments on the same lifeline or on another lifeline to reorder the message. After a reorder, the message number automatically indicates the updated position on the lifeline.Deleting messages
You can delete a message from a specific sequence diagram or from all sequence diagrams and models. When you delete a message, you have different results depending on the type of message that you delete.Reconnecting messages
In sequence diagrams, you can change the source lifeline or target lifeline of a message to reconnect the message to the new lifeline.Assigning operations to messages
In sequence diagrams, you can set a message signature by assigning an operation to it. When you create a message, the operation on the target participant is created automatically and you are prompted to name the newly created operation. You can replace an operation in a sequence diagram with another operation existing in the Model Explorer view.
Parent topic: Modeling interactions by using sequence diagrams
Related concepts
Sequence diagrams
Interaction frames
Messages