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.
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