Idiomatic way of logging in Kotlin

Question

Kotlin doesn\'t have the same notion of static fields as used in Java. In Java, the generally accepted way of doing logging is:

public class Foo {
    privat         


        

Answer 1

You can simply build your own "library" of utilities. You don't need a large library for this task which will make your project heavier and complex.

For instance, you can use Kotlin Reflection to get the name, type and value of any class property.

First of all, make sure you have the meta-dependency settled in your build.gradle:

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
}

Afterwards, you can simply copy and paste this code into your project:

import kotlin.reflect.full.declaredMemberProperties

class LogUtil {
    companion object {
        /**
         * Receives an [instance] of a class.
         * @return the name and value of any member property.
         */
        fun classToString(instance: Any): String {
            val sb = StringBuilder()

            val clazz = instance.javaClass.kotlin
            clazz.declaredMemberProperties.forEach {
                sb.append("${it.name}: (${it.returnType}) ${it.get(instance)}, ")
            }

            return marshalObj(sb)
        }

        private fun marshalObj(sb: StringBuilder): String {
            sb.insert(0, "{ ")
            sb.setLength(sb.length - 2)
            sb.append(" }")

            return sb.toString()
        }
    }
}

Example of usage:

data class Actor(val id: Int, val name: String) {
    override fun toString(): String {
        return classToString(this)
    }
}