What is a UML Sequence Diagram?
Sequence diagrams describe interactions among classes in terms of an exchange of messages over time.
Basic Sequence Diagram Symbols and Notations
Class roles describe the way an object will behave in context. Use the UML object symbol to illustrate class roles, but don't list object attributes.
Learn how to edit text on a symbol.
Activation boxes represent the time an object needs to complete a task.
Messages are arrows that represent communication between objects. Use half-arrowed lines to represent asynchronous messages. Asynchronous messages are sent from an object that will not wait for a response from the receiver before continuing its tasks.
Various message types for Sequence and Collaboration diagrams
Learn how to draw messages.
Lifelines are vertical dashed lines that indicate the object's presence over time.
Learn how to attach activation boxes to lifelines.
Objects can be terminated early using an arrow labeled "<< destroy >>" that points to an X.
A repetition or loop within a sequence diagram is depicted as a rectangle. Place the condition for exiting the loop at
the bottom left corner in square brackets [ ].
Learn how to arrange objects on a page.