Architecting and designing : UML 2.5 : Diagram views : Sequence diagram
  
Sequence diagram
Type of diagram: Dynamic Model
A Sequence diagram is a dynamic behavioral diagram that shows interactions (collaborations) among distributed objects or services through sequences of messages exchanged, along with corresponding (optional) events. An Object is represented by a vertical ‘Lifeline’; messages passed between the objects are drawn as vectored lines between the lifelines.
The messages are drawn chronologically from the top of the diagram to the bottom; the horizontal placing or spacing of objects is arbitrary by default; however, you may place timings on the diagram.
A graphic depicting a Sequence diagram
Learn more about Sequence diagrams
Where applicable, click the following links to learn more about Sequence diagrams:
Lifelines on Sequence diagram
Messages on Sequence diagram
Generic Line on Sequence diagram
GeneralOrdering on Sequence diagram
Combined fragment on Sequence diagram
ConsiderIgnoreFragment on Sequence diagram
Constraints on Sequence diagram:
IntervalConstraint
TimeConstraint
DurationConstraint
InteractionConstraint
Continuation
Coregions on Sequence diagram
ExecutionSpecification on Sequence diagram:
Behaviorial ExecutionSpecification
Action ExecutionSpecification
Interaction on Sequence diagram
InteractionOperand on Sequence diagram
InteractionUse on Sequence diagram
Note PartDecomposition is a specialization of an InteractionUse.
Observation on Sequence diagram:
Duration Observation
Time Observation
State Invariant on Sequence diagram