The Grant License use case from the City of Nirvana License and Tax System will be used as a comprehensive example. As you study this example, note how the essential events become a larger number of practical events and that for this use case, there are practical manual events and practical operator events.

Essential Use Case (Top)

The two main events in the Grant License essential use case are:

Event: Business Applies for License
Message Stimulus:	Receive License Application and Fee from Business.
Update Response:	Create entry in application pending log.
Message Response:	Send Fee to Treasurer.
Message Response:	Send License Application to Zoning.

Event: Zoning Approves License Application
Message Stimulus:	Receive License Application with complete approved attributes including zoning code.
Update Response:	Delete application from pending log.
Update Response:	Create new business Entity instance.
Update Response:	Create new Business instance with open state.
Update Response:	Create new owner Entity instance [if not already exist].
Update Response:	Create new Ownership instance.
Update Response:	Create new LicenseHist instance for current tax year with issued state.
Message Response:	Send License Certificate to Business.

Note that there is already a delegation pattern here because it is essential that the system delegate zoning approval to another actor.

System Architecture (Top)

The architectural choices are:

• Interfaces:
  
  • Business Applies for License
    About 14 per day. Application must be on paper because it must have a legal signature of the Owner.
    • Stimulus
      Accept paper application by mail or in person.
    • Message Responses
      Send paper applications in a batch to Zoning. Zoning response may be delayed. Send paper checks to Treasurer. Treasurer response may be delayed until 3:30 pm.
    This will lead to Multiple Practical Events and a Delayed Response Pattern.

  • Zoning Approves License Application
    About 14 per day.
    • Stimulus
      Applications arrive on paper in a batch about 9:00 am.
    • Message Responses
      License must be printed on a paper certificate and delivered by mail. License response may be delayed for up to seven days.
    This will lead to several Delayed Response Patterns.

• Partitions:
  
  • Business Applies for License
    The stimulus is delivered using a manual method. The two responses must be delivered using manual methods. The state (pending log) can be kept manually because there are only about fourteen applications received each day. This event is entirely in the Manual Partition.

  • Zoning Approves License Application
    The stimulus is delivered using a manual method. The response is also delivered using a manual method. But, the state must be kept in the automated partition to support high volume events for the Renew License and Collect Tax use cases. This event is Split between the Manual and Automated Partitions and will require a Delegation Pattern.

• Processing:
  
  • Business Applies for License
    In person delivery accepted on demand. Mail requests arrive in a batch about 9:00 am. Responses processed in a daily batch at about 2:30 pm.

  • Zoning Approves License Application
    Enter approved applications using daily batch processing with on line entry and on line update. Prepare and mail licenses in a weekly batch on Friday afternoon.

• Process Location Model
  Manual and automated partition located in same office. Use a client/server model with personal computer clients and a server for business logic and system state.

• State Location Model
  Almost all of the state will be located on the server in the automated partition. Some logs will be kept in the manual partition.

Manual Partition (Top)

The practical events in the manual partition are:

• Receive Application

  Event: Owner Mails Application and Fee
  Message Stimulus:	License Applications arrive in a batch in the mail.
  Business Rule:	Verify that application is signed and that a check is enclosed for the correct amount. Stamp all checks with for deposit only stamp.
  Update Response:	Put check for license fee in Treasurer's Inbox.
  Update Response:	Put License Application in Application Inbox.

  Event: Owner Delivers Application and Fee
  Message Stimulus:	Accept signed application and check for license fee from business representitive.
  Update Response:	Put check for license fee in Treasurer's Inbox.
  Update Response:	Put License Application in Application Inbox.

  Event: Zoning Expects Applications
  Temporal Stimulus:	It is about 3:30 pm.
  Update Response:	Add each License Application in Application Inbox to application pending log.
  Message Response:	Send License Applications to Zoning.

  Event: Treasurer Expects Fees
  Temporal Stimulus:	It is about 3:30 pm.
  Message Response:	Send License Fee Transmittal Form and checks for licence fees to Treasurer.

• Enter Application

  Event: Zoning Approves License Application
  Message Stimulus:	Receive approved License Applications from Zoning
  Update Response:	Mark application returned in pending log.
  Message Response:	Enter License Application into automated system.

  Event: Zoning Fails to Return License Application
  Temporal Stimulus:	It is 7 days since application was enter in pending log and it has not been marked as returned.
  Message Response:	Contact Zoning to check on status

  Event: Automated Partition Accepts Application
  Message Stimulus:	Automated system confirms Application entry
  Update Response:	Put approved application in Approved Bin (for later manual filing)

  Event: Automated Partition Fails to Accept Application

• Prepare License

  Event: Business Needs License Certificate

  Event: Automated Partition Prints License Certificates

  Event: Automated Partition Fails to Print License Certificates

Automated Partition (Top)

The practical events in the automated partition are:

• Enter Application

  Event: Operator Enters License Application
  Message Stimulus:	Operator clicks accept on Application Screen.
  Update Response:	If valid, create new business Entity instance.
  Update Response:	If valid, create new Business instance with open state.
  Update Response:	If valid, create new owner Entity instance [if not already exist].
  Update Response:	If valid, create new Ownership instance.
  Update Response:	If valid, create new LicenseHist instance for current tax year with accepted state.
  Message Response:	If valid, return Application accepted message.
  Message Response:	If invalid, return appropriate error message.

• Prepare License

  Event: Operator Requests License Certificates

Note that this event list does not include details for automated events such as Operator Selects Enter License Application or Operator Selects Print License Certificates which would be triggered by a selection from a main menu.