Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Kotlin Date Iterator
class TestingClass {
fun testingFunction() {
for (everyday in this year 2017) {
// Do something with everyday
println(everyday.toString())
}
}
private infix fun year(year: Int): DateRange {
return Date(year, 1, 1)..Date(year, 12, 31)
}
}
data class Date (private val year: Int, private val month: Int, private val day: Int)
: Comparable<Date> {
companion object {
const val MONTHS_IN_A_YEAR = 12
}
init {
if (month > MONTHS_IN_A_YEAR || month < 0) {
throw IllegalStateException("Month must between 1 - $MONTHS_IN_A_YEAR")
}
if (day > daysInMonth(month, year)) {
throw IllegalStateException("Day $day not valid in month $month of year $year")
}
}
override operator fun compareTo(other: Date): Int {
if (this.year > other.year) return 1
if (this.year < other.year) return -1
if (this.month > other.month) return 1
if (this.month < other.month) return -1
if (this.day > other.day) return 1
if (this.day < other.day) return -1
return 0
}
operator fun inc(): Date {
return when {
(day < daysInMonth(month, year))
-> Date(year, month, day+1)
(month < MONTHS_IN_A_YEAR)
-> Date(year, month + 1, 1)
else -> Date(year + 1, 1, 1)
}
}
private fun daysInMonth(month: Int, year: Int): Int {
return when (month) {
4, 6, 9, 11 -> 30
2 -> if (leapYear(year)) 29 else 28
else -> 31
}
}
private fun leapYear(year: Int): Boolean {
return when {
year % 400 == 0 -> true
year % 100 == 0 -> false
else -> year % 4 == 0
}
}
operator fun rangeTo(that: Date) = DateRange(this, that)
}
class DateRange(override val start: Date, override val endInclusive: Date)
: ClosedRange<Date>, Iterable<Date> {
override fun iterator(): Iterator<Date> {
return DateIterator(start, endInclusive)
}
}
class DateIterator(start: Date, private val endInclusive: Date) : Iterator<Date> {
private var current = start
override fun hasNext(): Boolean {
return current <= endInclusive
}
override fun next(): Date {
return current++
}
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.