CSC172 Class Design

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CSC172 Class Design

• Pepper

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Goals

• How to design classes
• How to think in terms of objects
• StarUML
• Code Generation

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How to Design Classes

• What objects to choose to solve a given problem?
• What classes will we need to implement a system
  that meets our requirements?
• What fields and methods will each class have?
• How will the classes interact with each other?

http//www.yyu.edu.tr/abis/admin/dosya/5637/files/
UML20TasarC4B1m.pdf
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Good Class Design

• Cohesive
• only one abstraction
• No unnecessary coupling
• No printing to a specific device such as screen
  scanner
• Related data in the same class

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Class UML Diagram

• Each class box
• Name / state / behavior
• Relations
• Has a
• Knows a
• Uses a
• Is a
• Great Explanation matched to code
• http//www.cse.buffalo.edu/faculty/adrienne/ClassR
  esources/ClassDiagramsInANutshell/

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CRC cards

• One per noun / entity / object
• Class Noun is the class name on the top
• Responsibility List responsibilities on the left
  
• Collaboration List collaborating objects on the
  right
• If a class is being used in a collaboration, its
  card will not show the collaboration the user
  shows the collaboration

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CRC Exercise

• 5 card draw
• List objects / entities
• Make one card for each
• Walk through the game
• Draw a UML diagram

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StarUML

• Card
• Deck
• Hand
• Players
• Dealer
• Game

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StarUML Code Generation

• UML diagram generates code
• Can reverse engineer
• Link to Diagram
• Link to Code

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Summary

• StarUML
• CRC Cards
• Good design principles
• Cohesive - one abstraction
• No unnecessary coupling
• Related data in the same class