This document provides an overview of the SOLID principles of object-oriented design: Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion. Each principle is defined in 1-2 sentences. Examples are given to illustrate correct and incorrect implementations related to the Liskov Substitution and Interface Segregation principles. The conclusion states that following these five SOLID principles results in code that is reusable, maintainable, scalable, and testable. References for further reading on SOLID are also included.

1. SOLID Principles
Presented by,
Aayushi Shah
Janvi Shah
Kaushik Sathvara
Anil Soni
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2. Introduction
Philosophy
Don’t repeat yourself
Keep it simple and stupid
You aren’t gonna need it
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3. Single Responsibility
Do you expect, your ide will code for you?
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4. Open-Closed
Operating System
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5. What is Liskov substitution principle?
Child classes should not break the parent
class's type definitions.
Liskov SubstitutionPrinciple
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6. What is breaking the rule of Liskov principle?
In below class diagram we cannot withdraw from kids account and that will create an exception in
superclass withdrawal method. That is a breach in Liskov Substitution Principle.
❌ Withdraw method in the kids account class is a breach
of LSP
✔️ Handling Non withdrawable behaviour by introducing two
new classes inheriting base class.
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7. Interface-segregation principle (ISP) states that :
“Client should not be forced to depend on methods it does not use.”
Why ISP is needed?
● Fat Interface
Interface Segregation Principle
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8. What ISP suggests?
● Role Interfaces
Advantages :
● Small, highly cohesive and
“Solid” classes
● increases readability and maintainability
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9. Dependency Inversion Principle
Dependency Inversion Principle states that:
“Entities must depend on abstractions not on concretions”
What does it says?
● High level modules
● Low level modules
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10. Example:
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11. Conclusion:
By applying these 5 principles that make the SOLID acronym, we get to benefit from a
reusable, maintainable, scalable and easy testable codebase.
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12. References
● https://scotch.io/bar-talk/s-o-l-i-d-the-first-five-principles-of-object-oriented-design
● https://medium.com/@trekhleb/solid-principles-around-you-6db2f0e12139
● https://fi.ort.edu.uy/innovaportal/file/2032/1/design_principles.pdf(4-16)
● https://blog.bitsrc.io/solid-principles-every-developer-should-know-b3bfa96bb688
● https://itnext.io/solid-principles-explanation-and-examples-715b975dcad4
● https://docs.google.com/a/cleancoder.com/viewer?a=v&pid=explorer&chrome=true&srcid=0BwhCYaYDn8E
gOTViYjJhYzMtMzYxMC00MzFjLWJjMzYtOGJiMDc5N2JkYmJi&hl=en
● https://www.baeldung.com/solid-principles
● https://hackernoon.com/solid-principles-simple-and-easy-explanation-f57d86c47a7f
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13. THANK YOU
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