Four Design Rules

Talk about Kent Becks four Design Rules:

- Passes the tests
- Reveals intention
- No duplication
- Fewest elements

Transcript

1. Four
   Design
   Rules
   Four Design Rules
   

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2. Four
   Design
   Rules
   • Java, Microservices, Cloud
   • @AltamuraClaudio
   • claudioaltamura
   Claudio Altamura
   

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3. Claudio Altamura
   Four
   Design
   Rules
   Kent Becks Design Rules
   • Passes the tests
   • Reveals intention
   • No duplication
   • Fewest elements
   

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4. Claudio Altamura
   Four
   Design
   Rules
   What's so special about it?
   • easy to remember
   • improves code in every language
   • helps to keep the design simple
   • leads to a good design
   

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5. Claudio Altamura
   Four
   Design
   Rules
   What is a good design?
   • high cohesive
   • loosely coupled
   • expressive names
   

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6. Claudio Altamura
   Four
   Design
   Rules
   Passes the Tests
   • the code must work
   • tests help to communicate the design
   • tests make refactoring safe
   

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7. Claudio Altamura
   Four
   Design
   Rules
   Reveals Intention
   • code as easy as possible
   • expresses every idea
   • meaningful names
   • brings clarity
   • maximizes cohesion
   

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8. Claudio Altamura
   Four
   Design
   Rules
   No Duplication
   • DRY
   • SPOT
   • everything should be said once
   • leads to a good design
   • minimize coupling
   

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9. Claudio Altamura
   Four
   Design
   Rules
   Fewest Elements
   • what is not useful should be removed
   • fewest possible classes and methods
   • don't add code for future requirements
   • complexity makes code harder to modify
   

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10. Claudio Altamura
    Four
    Design
    Rules
    Priority
    Reveals Intention
    Priority
    No Duplication
    Passes the Tests
    Fewest Elements
    

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11. Claudio Altamura
    Four
    Design
    Rules
    Intention vs Duplication
    • doesn't matter which comes first
    • both rules help to redefine the code
    • these rules lead to a simple design
    • most problems are naming problems
    

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