Liskov Substitution Principle (LSP) – Portfolio

Portfolio

Blog

My articles

Liskov Substitution Principle (LSP):

Description: Objects should be replaceable by their subtypes without affecting the correctness of the program.

Before LSP:

class Bird {
    public void fly() {
        // Fly
    }
}

class Penguin extends Bird {
    @Override
    public void fly() {
        throw new UnsupportedOperationException("Penguins cannot fly");
    }
}

After LSP:

interface Bird {
    void move();
}

class NormalBird implements Bird {
    @Override
    public void move() {
        // Fly
    }
}

class Penguin implements Bird {
    @Override
    public void move() {
        // Penguins walk, they don't fly
    }
}

Web Developer

© Michał Pieróg. All Rights Reserved.