Depicting Event Impacts

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Depicting Event Impacts

• State Transition Diagram

2
Terminology

• State A set of values an object can have
• Transition an event causing a change to an
  objects set of values

3
Two Methods of STDs

• Mealy Model
• Define all state changes
• Associate each change with an event
• Moore Model
• Define all events
• Associate each event with a state

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Video Rental Example
Customer Request
R E T U R N
Close Rental
Open Rental
Mark Date of Return
Pay late fee Close rental
Process Customer video rental
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STD Example

• In more detail we analyze the states of the
  rental process
• Open, Video on rental
• Temporary, Create temporary rental until fees
  paid
• Unpaid, Returned rental may have late fees
• Paid, Returned and late fees paid if any
• Closed, All fees paid and return date saved

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Video Rental Detail
Create Open VOR
Customer Request
Return rental
All fees paid
Unpaid, Returned VOR
Paid, Returned VOR
Create Temp VOR
Rental out or Late fees owed
Return, No fees
Fees paid
Close Rental
Read Bar Code
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States

• Identified without regard to time

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States in HDS

• Vendor
• Event
• Player
• History
• Inventory
• Equipment
• HotDog (Food)

9
Practice