Sequence Diagram Elements

See Also

The following table describes the elements that you can add to Sequence diagrams. The elements are grouped by Context Palette and Modeling Palette section.

Element Icon Description
Basic Section
Lifeline An individual participant in the Interaction. While Parts and structural features may have multiplicity greater than one, Lifelines represent only one interacting entity.
  • To re-order Lifelines, simply drag a timeline to a new location.
Actor A role played by users in your system.
Comment A Notepad notation. Use Comments to record information for an element or link in a diagram. This information is not included in generated code but is for information only. Each Comment can contain unlimited text, and can be numbered. You can also define a stereotype, and enter a noted element.
Context Palette
Synchronous Message A message that does not return to its sender until the target process completes.
Asynchronous Message A message that blocks the calling object. This kind of message is capable of creating a new object, creating a new thread, or communicating with an existing thread.
Create Message An element that enables the creation of a lifeline or instance. This is a constructor operation.
Message to Self A message intended for the calling object.
Destroy Lifeline The destruction of an object, located at the bottom of the object's lifeline. Objects can be designed to self-destruct, or you can use messages to trigger the destruction.
Link Comment The connection between the comment element and the associated element.
Control Section
Combined Fragment A combined fragment, which lets you specify UML conditions to messages between classes and/or actors. Combined Fragments are a new UML 2.0 convention. For more information, see Working With Sequence Diagram Elements.
See Also
About Sequence Diagrams
Diagram Elements

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