Use Case

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A Use Case is a UML modeling element that describes how a user of the proposed system interacts with the system to perform a discrete unit of work. It describes and signifies a single interaction over time that has meaning for the end user (person, machine or other system), and is required to leave the system in a complete state: the interaction either completed or rolled back to the initial state. A Use Case:

·Typically has requirements and constraints that describe the essential features and rules under which it operates
·Can have an associated Sequence diagram illustrating behavior over time; who does what to whom, and when
·Typically has scenarios associated with it that describe the work flow over time that produces the end result; alternative work flows (for example, to capture exceptions) are also enabled.

Tip: Use a Use Case diagram and model to build up the functional requirements and implementation details of the system.

The following is an example Use Case model:


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See Also

OMG UML Specification

The OMG UML specification (UML Superstructure Specification, v2.0, p. 17) states:

"The specification of a sequence of actions, including variants, that a system (or other entity) can perform, interacting with actors of the system."