Object Oriented Design Tools

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Object Oriented Design Tools

• Joe Komar

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Overview

• Object Characteristic
• How to determine initial objects/methods
• CRC Cards
• Use Case Diagrams
• Module Diagrams

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Object Oriented Design Characteristics

• Objects have small methods -- no more than eight
  lines of code
• Classes have no more than seven (plus or minus
  two) methods
• Applications should have few, if any, IF
  statements
• Objects are lazy -- they request information
  before doing it themselves
• There is a great deal of interaction among
  objects
• There is some form of User Interface (e.g., GUI)

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Determining Objects and Methods

• Collect scenarios -- descriptions of situations
  to be handled and how to handle them
• Nouns become candidates for objects
• Verbs become candidates for methods
• Relationships among objects become clearer

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A Class Responsibilities Collaborators (CRC) Card
Account
Responsibilities
Collaborators
Know account number
Know account balance
Deposit funds
Withdraw funds
Report Balance
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Another Example
Pizza
Know Customer
Customer
Determine Cooking Time
Crust, Toppings, Sauce
Determine Delivery Time
Compute its Price
Crust, Toppings, Sauce
Report Cooking Time and Price
GUI
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Use Case Diagrams
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Module Diagrams
Class
Inheritance
Collaboration
has a..
Is a kind of
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Module Diagram
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Object Oriented Design Tools

• There are a variety of tools used today
• No one set of tools seems to be dominant
• Need to learn what each specific organization
  prefers