Sample-Use-Case: Withdraw Money from ATM
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.. Description of a use case
.. The description must be formulated as seen from system (not: actors)
.. Describes those changes an (outside) actor can notice
.. Short and abstract as possible, as long as necessary.
.. Each use case must have at least one actor involved
.. Each use case must have a trigger and a result


Short Description
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An account holder is paid a requested amount of money and the account
is charged this amount.


Actor(s)
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Account holder, Accounting System


Trigger(s)
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The account holder puts a debit card into the ATM slot.


Result(s)
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The account holder got an amount of money. The account has been
charged. The account holder got back the debit card.


Incoming Data
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PIN, requested amount


Outgoing Data
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Data leaving the system _during_ use case. Includes only data not
existing any more after use-case has been finished. For instance
screen messages, etc.


Precondition(s)
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The ATM is ready to receive a debit card.


Postcondition(s)
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The ATM is ready to receive a debit card.


Invariant(s)
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Essential Steps
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* Authenticate account holder
* Get requested amount
* Check possibility to withdraw
* Charge account
* Pay amount


Open Issues
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Remarks
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.. raw:: latex

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