1 Use Case Modeling Reference: RUP Doc

Use Case Example 2

3 Constructs  Mandatory elements Name: should be unique; describes what is achieved after the interaction with the actor. Example: withdraw cash. Brief description; example: this use case describes how Bank Customer uses the ATM to withdraw money from his bank account. Actor: the actor that participates in the use case. Example: Bank Customer. Flow of events: sequential interactions between the actor and the system.  Main (basic) flow of events  Alternate flows of events

4 Constructs  Optional elements Pre-conditions: the state of the system that must be present before the use case can be triggered. Example: The ATM has cash available Post-conditions: the state of the system after the use case has been run. Example: the Bank Customer’s account has been updated

5 Actors Persons who use, provide information to, or maintain the system. Other systems that use this system.

6 Basic Flow  The use case starts when the actor does something.  An actor always initiates the use cases.  The use case should describe what the actor does and what the system does in response.  It should be phrased in the form of a dialog between the actor and the system.  The use case should describe what happens inside the system, but not how or why.

7 Alternate Flows Optional situations in the use case. Odd cases (something goes wrong).

8 Refinement of Use Cases Extending a use case: exceptional or alternate event Bank Customer Withdraw Cash TimeOut > NoChange > OutOfOrder >

9 Refinement of Use Cases Including a use case: factored out for reuse, not because it is an alternate event. Bank Customer Withdraw Cash Transfer Funds > Validate User >