Book Image

Programming Kotlin

Book Image

Programming Kotlin

Overview of this book

Quickly learn the fundamentals of the Kotlin language and see it in action on the web. Easy to follow and covering the full set of programming features, this book will get you fluent in Kotlin for Android.
Table of Contents (20 chapters)
Programming Kotlin
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Reflective functions and properties


Reflection doesn't stop with classes and objects. Most of the Kotlin system can be accessed, and that includes functions and properties. Let's start with a class that contains some member functions, an extension function for Double, and a couple of properties:

    class Rocket() { 
      var lat: Double = 0 
      var long: Double = 0 
 
      fun explode() { 
        println("Boom") 
      } 
 
      fun setCourse(lat: Double, long: Double) { 
        require(lat.isValid()) 
        require(long.isValid()) 
        this.lat = lat 
        this.long = long 
      } 
 
      fun Double.isValid() = Math.abs(this) <= 180 
    } 

The extension function is used to check that the Double parameter is a valid latitude or longitude whenever we invoke setCourse.

The next function is similar to the function for printing constructors from earlier, and prints out the names of each...