ObjectOriented Design Notation

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Object-OrientedDesign Notation

• CS 123/CS 231

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References

• Main Reference UML Distilled, by Martin Fowler
• Chapters 3, 4, 6, and 8
• Supplementary References
• Chapter 14 of Sommerville
• Chapter 22 of Pressman

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Component Design and Detailed Design

• Component Design
• For each subsystem determine components, and
  services/interface per component
• OO Design components are classes
• Detailed Design
• Determine attributes of classes and relationships
  between the classes
• Determine functionality of each class and
  interactions between classes

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Object-Oriented Modeling

• UML Unified Modeling Language
• OO Modeling Standard
• Booch, Jacobson, Rumbaugh
• What is depicted?
• Class details and static relationships
• System functionality
• Object interaction
• State transition within an object

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Some UML Modeling Techniques

• Class Diagrams
• Use Cases/Use Case Diagrams
• Interaction Diagrams
• State Diagrams

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ExampleClass Diagram
FastFoodCounter totalcash totalorders
PriceChecker getPrice()
pc
counters
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FastFood (Restaurant)
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ExampleUse Case Diagram
LIBRARY SYSTEM
Facilitate Checkout
Search for Book
Borrower
Librarian
Facilitate Return
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ExampleInteraction Diagram
2 checkIfAvailable()
Checkout Screen
Book
1 checkIfDelinquent() 3 borrowBook()
4 setBorrower()
Borrower
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ExampleState Diagram (Book)
start
Reserved
Borrowed
New
Librarian activates book as available
Borrower returns book
Available
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Object-Oriented Design Models

• Static Model
• Class Diagrams
• Dynamic Model
• Use Cases, Interaction Diagrams, State Diagrams,
  others

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OO Static Model

• Classes and Class Diagrams
• Relationships
• Association
• Aggregation/Composition
• Inheritance
• Dependencies
• Attribute and Method names

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OO Dynamic Model

• Goal Represent
• Object behavior
• Object interaction
• Traditional/Procedural Dynamic Modeling
• Data Flow Diagrams (DFDs)
• Problem Processes separate from data
• Need modeling notation that highlight tight
  relationship between data processes

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DFD Example(Inventory Management)
Accept and Post Delivery
Delivery info
Transaction
Item Master
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OO CounterpartObject Interaction
new (delivery info)
Encoder
Transaction
post (item count)
Item Master
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Building anOO Dynamic Model

• Identify use cases
• Describe each use case through an interaction
  diagram
• For more complex objects, provide a state diagram
  per class
• Derive implied methods (and attributes)

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Whats Next?

• Need to understand the notation
• Make sure it helps the software development
  process
• When to use the UML techniques
• Primarily when specifying OO design
• Formal means of communication across the
  different software development stages