Comp 204 Final Project Fall 2002

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Comp 204 Final ProjectFall 2002

• Brad E. Hinson
• Alicia L. Wright

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Class Database

• Responsibilities
• Data storage
• Stores election results
• Login information
• Variables for voters, candidates and admins
• Issues
• Pattern has to allow undoable operations
• Should externalize data in case of system failure

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Class Database
Singleton
memento
Database
Memento
Caretaker
static getDatabase( )
return uniqueDatabase
GetState( )
setMemento(Memento m)
SetState( )
createMemento( )
uniqueDatabase
state
Memento
return new Memento(state)
state m ? GetState( )
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Class Security

• Responsibilities
• Prevents unauthorized access to the system
• Talks to the database to provide secure login
• Issues
• Do we need one Security object per user?

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Class Security
Singleton
Security
Database
static getSecurity( )
return uniqueDatabase
uniqueSecurity
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Class Election

• Responsibilities
• Holds variables pertaining to a particular
  election
• Issues
• Can we just use a single election flyweight?
• Allows admin to access and edit election variables

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Class Election
Visitor
Client
visitElection( )
Election
Accept(Visitor)
Visitor
Vote A
Vote B
Accept(Visitor)
Accept(Visitor)
v ? visitVoteB(this)
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Class DocumentHandler

• Responsibilities
• Handles document creation and deletion
• Allows user to view document
• Issues
• Should handle multiple languages (Interpreter?)
• One handler per user or one per document?

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Class DocumentHandler
Factory
DocumentHandler
loadDocument( )
displayDocument( )
EnglishHandler
SpanishHandler
ChineseHandler
DocHandlerCreator
FactoryMethod( )
return new DocumentHandler
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Class Session

• Responsibilities
• Acts as interface for logged in users
• Stores voter, candidate admin states to
  Database
• Issues
• Can we just use a single session flyweight?
• Election objects must be notified of new votes
• Should be able to grab data from the Database
• Session type determined at user login

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Class Session
Session
Mediator
Elections
Mediator
Candidate Session
Voter Session
Admin Session
SessionCreator
realSubject
Proxy
Database
FactoryMethod( )
return uniqueDatabase
Request( )
Request( )
Factory
Proxy
Database ? Request( )
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Class StatAnalysis

• Responsibilities
• Prepares reports from stored data
• Generates StatReport objects (later)
• Issues
• Able to step through elections collecting data
• Command vs. Strategy for actual computation

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Class StatAnalysis
Strategy
Elections
createIterator( )
Election Iterator
StatAnalysis
Iterator
Strategy
First( )
AlgorithmInterface( )
Next( )
isDone( )
Current( )
Computation A
Computation B
Iterator
AlgorithmInterface( )
AlgorithmInterface( )
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Class StatReport

• Responsibilities
• Stores and displays results from StatAnalysis
• Issues
• Created by StatAnalysis
• Should execute various commands (e.g. print, plot)

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Class StatReport
Command
StatAnalysis
StatReport
Command
Execute( )
Client
receiver
PrintCommand
PlotCommand
SaveCommand
Execute( )
Execute( )
Execute( )
Receiver
receiver ? Action( )
Action( )
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Class UserInterface

• Responsibilities
• Acts as the graphical user interface for a
  session
• Issues
• Alters itself based on current user permissions
• Should provide a single interface for inner
  workings

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Class UserInterface
Facade
UserInterface
Draw( )
Elections
Sessions

Security
Database

component
EmptyScreen
Decorator
component ? Draw( )
Draw( )
Draw( )
Decorator
Option
Choice
Button
Draw( )
Draw( )
Draw( )
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QUESTIONS?
Happy Holidays!