Introduction To Generics | Generics

What are Generics?

Generics are a powerful feature in programming languages that allow you to define classes, interfaces, and functions with a placeholder for types. This allows for code reusability and type safety, as you can work with different data types while maintaining the same code structure.

Why Use Generics?

Generics offer several advantages:

Type Safety: Generics ensure that you work with the correct data types, reducing runtime errors.
Code Reusability: You can write a single method or class that works with different data types.
Improved Readability: Code using generics is often easier to read and understand.

Generic Classes

A generic class is defined with a type parameter. Here is how you can define a simple generic class in Kotlin:

class Box(var item: T)

In this example, T is a type parameter that can be replaced with any type when creating an instance of the Box class.

Using Generic Classes

You can create instances of a generic class with different types:

val intBox = Box(1)

val stringBox = Box("Hello")

Here, intBox holds an Int value, and stringBox holds a String value.

Generic Functions

Just like classes, functions can also be defined with generics. Here is an example of a generic function:

fun printItem(item: T) {

println(item)

}

This function takes a parameter of type T and prints it. You can call it with any type:

printItem(42)

printItem("Hello World")

Bounded Type Parameters

Sometimes, you may want to restrict the types that can be used as type parameters. This is done using bounded type parameters:

fun addNumbers(a: T, b: T): T {

return (a.toDouble() + b.toDouble()) as T

}

In this example, T is restricted to subclasses of Number.

Conclusion

Generics in Kotlin provide a robust way to create flexible, reusable, and type-safe code. By using generic classes and functions, developers can write code that works with any data type while ensuring that the program remains safe and efficient. Understanding and utilizing generics is essential for advanced Kotlin programming.

Introduction to Generics in Kotlin