Kotlin reflection is a powerful feature that allows programs to examine, introspect, and modify their own structure and behavior at runtime. It provides a way to inspect classes, properties, and functions dynamically.
Reflection in Kotlin enables developers to:
In Kotlin, you can obtain a reference to a class using the ::class syntax. This provides access to the class's metadata.
val myClass = String::class
println(myClass.simpleName) // Outputs: String
For more details on class references, check out the Kotlin Class References guide.
Kotlin allows you to reflect on properties and functions of a class:
class Person(val name: String, var age: Int) {
fun sayHello() = println("Hello, I'm $name")
}
val person = Person("Alice", 30)
val nameProperty = Person::name
val ageProperty = Person::age
val sayHelloFunction = Person::sayHello
println(nameProperty.get(person)) // Outputs: Alice
ageProperty.set(person, 31)
sayHelloFunction.invoke(person) // Outputs: Hello, I'm Alice
Reflection in Kotlin has several practical uses:
While reflection is powerful, it comes with performance overhead. Use it judiciously, especially in performance-critical sections of your code.
Reflection should be used sparingly in production code, as it can impact performance and make your code harder to understand and maintain.
To deepen your understanding of Kotlin reflection, explore these related topics:
Kotlin reflection is a sophisticated feature that opens up new possibilities for dynamic programming. While powerful, it should be used thoughtfully, considering both its benefits and potential drawbacks in terms of performance and code clarity.