comparador de fecha con kotlin

compareDateTime.kt

import java.util.*
import java.util.concurrent.TimeUnit

fun main() {
    println("Hello, world!!!")
    
    compareDateTime()
}



fun compareDateTime() {

    val today = Calendar.getInstance()

    val yesterday = Calendar.getInstance()
    yesterday.add(Calendar.HOUR, -23)

    println("differenceOfDaysByDateAndTime - With Time component")
    println("%s - %s = %s days"
            .format(
                    today.time,
                    yesterday.time,
                    diffOfDaysByDateAndTime(today, yesterday)
            ))

    println()

    println("differenceOfDaysByDate - Ignore Time component")
    println("${today.time} - ${yesterday.time} = " +
            "${diffOfDaysByDate(today, yesterday)} days")
}

private fun diffOfDaysByDateAndTime( a: Calendar, b: Calendar ): Int {

    val duration = a.timeInMillis - b.timeInMillis
    return TimeUnit.MILLISECONDS.toDays(duration).toInt()
}

private fun diffOfDaysByDate( a: Calendar, b: Calendar ): Int {

    clearTimeComponent(a)
    clearTimeComponent(b)

    return diffOfDaysByDateAndTime(a, b)
}

private fun clearTimeComponent( date: Calendar ) {

    date.set(Calendar.HOUR_OF_DAY, 0)
    date.set(Calendar.MINUTE, 0)
    date.set(Calendar.SECOND, 0)
    date.set(Calendar.MILLISECOND, 0)
}