Get set in Kotlin

In Kotlin, get/set is used to access the private fields of a class and to set or get their values.

Here's an example:

class Person() {
    private var name: String = ""
    
    // Getter method
    fun getName(): String {
        return name
    }
    
    // Setter method
    fun setName(newName: String) {
        name = newName
    }
}

Here, the name property is declared as private, which means it cannot be accessed from outside the class. To access the value of name from outside the class, we define a getter method getName() that returns the value of name. Similarly, to set the value of name from outside the class, we define a setter method setName() that takes a new value for name.

However, Kotlin provides a more concise way of defining getters and setters through properties.

class Person() {
    var name: String = ""
        get() = field
        set(value) {
            field = value
        }
}

In this example, we define the name property with its getter and setter methods. The field property inside the getter and setter is used to access the underlying field of the property, which is name in this case.

Now, we can access and modify the name property of an instance of the Person class as follows:

val person = Person()
person.name = "John"    // sets the value of name to "John"
println(person.name)   // prints "John"

We can also simplify the code further using the shorthand notation for getters and setters:

class Person() {
    var name: String = ""
        get() = field
        set(value) = run { field = value }
}

Here, we use the run function along with assignment to set the value of name. The shorthand notation can be used if the logic inside the getter and setter methods is simple enough.