interfaceSegregationViolates.ts

/**
 * Interface Segregation Principle - VIOLATION Example
 *
 * The Interface Segregation Principle states that clients should not be forced
 * to depend on interfaces they do not use. In other words, it's better to have
 * multiple specific interfaces than one general-purpose interface.
 *
 * This example demonstrates a VIOLATION of ISP by forcing 2D shapes to implement
 * a volume() method that is not applicable to them.
 */

/**
 * Abstract Shape class that forces ALL shapes to implement both area() and volume()
 * PROBLEM: This violates ISP because 2D shapes (Square, Rectangle) don't have volume,
 * yet they are forced to implement the volume() method.
 */
abstract class Shape {
    abstract area():number;
    abstract volume():number;  // This method doesn't make sense for 2D shapes!
}

/**
 * Square is a 2D shape that should only need an area() method
 * VIOLATION: Forced to implement volume() even though it's not applicable
 */
class Square extends Shape {
    public area(): number {
        return 0
    }

    /**
     * This method should NOT exist for a 2D shape!
     * We're forced to throw an error because the Shape interface requires it.
     * This is a clear sign of Interface Segregation Principle violation.
     */
    public volume(): number {
        throw new Error("Square Does not have volume");
    }
}

/**
 * Rectangle is a 2D shape that should only need an area() method
 * VIOLATION: Forced to implement volume() even though it's not applicable
 */
class Rectangle extends Shape {
    public area(): number {
        return 0
    }

    /**
     * This method should NOT exist for a 2D shape!
     * We're forced to throw an error because the Shape interface requires it.
     * This is a clear sign of Interface Segregation Principle violation.
     */
    public volume(): number {
        throw new Error("Rectangle does not have volume")
    }
}

/**
 * Cube is a 3D shape that legitimately needs both area() and volume() methods
 * This class works fine with the current interface, but the interface design
 * is still problematic because it forces 2D shapes to implement volume().
 */
class Cube extends Shape {
    public area() : number {
        return 0
    }

    public volume(): number {
        return 0
    }
}