Mastering get() and set() in Kotlin: A Complete Guide 🚀

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Kotlin provides a powerful and concise way to define getter (get()) and setter (set()) functions for properties. These functions allow us to control access, modify values, and add custom logic while reading and writing properties.

In this article, we’ll explore get() and set() in Kotlin with detailed explanations and real-world examples. By the end, you’ll know when and how to use them efficiently in your Kotlin projects.

Mastering Sealed Class & Sealed Interface in Kotlin: The Ultimate Guide with Real-World Examples 🚀

What Are get() and set() in Kotlin?

In Kotlin, properties are more than just variables. They come with built-in getters and setters, making them smart and flexible.

• get() (Getter): Defines how to retrieve a property’s value.

set() (Setter): Defines how to update a property’s value. Syntax of get() and set()

class Person {
    var name: String = "John Doe"
        get() = field  // Custom getter (optional)
        set(value) {  // Custom setter
            field = value.uppercase() // Convert value to uppercase before setting
        }
}

fun main() {
    val person = Person()
    println(person.name) // Output: John Doe
    person.name = "alice"
    println(person.name) // Output: ALICE
}

Explanation:

• field is a backing field (used inside get() and set() to avoid infinite recursion).
• The get() function simply returns the value stored in field.
• The set() function modifies the value before storing it (converting it to uppercase).

Why Use get() and set()?

1. Validation & Constraints — Ensure only valid values are assigned.
2. Transformation — Modify values before setting them.
3. Logging & Debugging — Track property changes.
4. Lazy Evaluation — Compute values only…