Update Year and UtcOffset to take advantage of Kotlin 1.4.30 features (…

…#168)

* Update Year and UtcOffset to take advantage of Kotlin 1.4.30 features

* Minor fixes

core/src/commonMain/kotlin/io/islandtime/OffsetDateTime.kt

@@ -24,10 +24,6 @@ class OffsetDateTime(
     val offset: UtcOffset
 ) : TimePoint<OffsetDateTime> {
 
-    init {
-        offset.validate()
-    }
-
     /**
      * Creates an [OffsetDateTime].
      * @throws DateTimeException if the offset is invalid
@@ -143,21 +139,24 @@ class OffsetDateTime(
         ReplaceWith("this.toYearMonth()"),
         DeprecationLevel.ERROR
     )
-    inline val yearMonth: YearMonth get() = toYearMonth()
+    inline val yearMonth: YearMonth
+        get() = toYearMonth()
 
     @Deprecated(
         "Use toOffsetTime() instead.",
         ReplaceWith("this.toOffsetTime()"),
         DeprecationLevel.ERROR
     )
-    inline val offsetTime: OffsetTime get() = toOffsetTime()
+    inline val offsetTime: OffsetTime
+        get() = toOffsetTime()
 
     @Deprecated(
         "Use toInstant() instead.",
         ReplaceWith("this.toInstant()"),
         DeprecationLevel.ERROR
     )
-    inline val instant: Instant get() = toInstant()
+    inline val instant: Instant
+        get() = toInstant()
 
     override val secondsSinceUnixEpoch: LongSeconds
         get() = dateTime.secondsSinceUnixEpochAt(offset)

core/src/commonMain/kotlin/io/islandtime/OffsetTime.kt

@@ -15,10 +15,6 @@ class OffsetTime(
     val offset: UtcOffset
 ) {
 
-    init {
-        offset.validate()
-    }
-
     /**
      * Creates an [OffsetTime].
      * @throws DateTimeException if the time or offset is invalid

core/src/commonMain/kotlin/io/islandtime/TimeZone.kt

@@ -152,10 +152,6 @@ sealed class TimeZone : Comparable<TimeZone> {
         val offset: UtcOffset
     ) : TimeZone() {
 
-        init {
-            offset.validate()
-        }
-
         override val id: String get() = offset.toString()
         override val isValid: Boolean get() = true
         override val rules: TimeZoneRules get() = FixedTimeZoneRules(offset)

core/src/commonMain/kotlin/io/islandtime/UtcOffset.kt

@@ -13,18 +13,16 @@ import kotlin.math.sign
 /**
  * The time shift between a local time and UTC.
  *
- * To ensure that the offset is within the valid supported range, you must explicitly call [validate] or [validated].
- *
  * @param totalSeconds the total number of seconds to offset by
- * @see validate
- * @see validated
+ * @throws DateTimeException if the offset is outside the supported range
  */
 inline class UtcOffset(val totalSeconds: IntSeconds) : Comparable<UtcOffset> {
 
-    /**
-     * Checks if this offset is within the supported range.
-     */
-    val isValid: Boolean get() = totalSeconds in MIN_TOTAL_SECONDS..MAX_TOTAL_SECONDS
+    init {
+        if (totalSeconds !in MIN_TOTAL_SECONDS..MAX_TOTAL_SECONDS) {
+            throw DateTimeException("'$totalSeconds' is outside the valid offset range of +/-18:00")
+        }
+    }
 
     /**
      * Checks if this is the UTC offset of +00:00.
@@ -66,31 +64,13 @@ inline class UtcOffset(val totalSeconds: IntSeconds) : Comparable<UtcOffset> {
         }
     }
 
-    /**
-     * Checks if the offset is valid and throws an exception if it isn't.
-     * @throws DateTimeException if the offset is outside the supported range
-     * @see isValid
-     */
-    fun validate() {
-        if (!isValid) {
-            throw DateTimeException("'$totalSeconds' is outside the valid offset range of +/-18:00")
-        }
-    }
-
-    /**
-     * Ensures that the offset is valid, throwing an exception if it isn't.
-     * @throws DateTimeException if the offset is outside the supported range
-     * @see isValid
-     */
-    fun validated(): UtcOffset = apply { validate() }
-
     companion object {
-        val MAX_TOTAL_SECONDS = 18.hours.inSecondsUnchecked
-        val MIN_TOTAL_SECONDS = (-18).hours.inSecondsUnchecked
+        val MAX_TOTAL_SECONDS: IntSeconds = 18.hours.inSecondsUnchecked
+        val MIN_TOTAL_SECONDS: IntSeconds = (-18).hours.inSecondsUnchecked
 
-        val MIN = UtcOffset(MIN_TOTAL_SECONDS)
-        val MAX = UtcOffset(MAX_TOTAL_SECONDS)
-        val ZERO = UtcOffset(0.seconds)
+        val MIN: UtcOffset = UtcOffset(MIN_TOTAL_SECONDS)
+        val MAX: UtcOffset = UtcOffset(MAX_TOTAL_SECONDS)
+        val ZERO: UtcOffset = UtcOffset(0.seconds)
     }
 }
 
@@ -100,7 +80,7 @@ inline class UtcOffset(val totalSeconds: IntSeconds) : Comparable<UtcOffset> {
  * @param hours hours to offset by, within +/-18
  * @param minutes minutes to offset by, within +/-59
  * @param seconds seconds to offset by, within +/-59
- * @throws DateTimeException if any of the individual components is outside the valid range
+ * @throws DateTimeException if the offset or any of its components are invalid
  * @return a [UtcOffset]
  */
 fun UtcOffset(
@@ -167,7 +147,7 @@ internal fun DateTimeParseResult.toUtcOffset(): UtcOffset? {
     val totalSeconds = fields[DateTimeField.UTC_OFFSET_TOTAL_SECONDS]
 
     if (totalSeconds != null) {
-        return UtcOffset(totalSeconds.toIntExact().seconds).validated()
+        return UtcOffset(totalSeconds.toIntExact().seconds)
     }
 
     val sign = fields[DateTimeField.UTC_OFFSET_SIGN]
@@ -178,9 +158,9 @@ internal fun DateTimeParseResult.toUtcOffset(): UtcOffset? {
         val seconds = (fields[DateTimeField.UTC_OFFSET_SECONDS]?.toIntExact() ?: 0).seconds
 
         return if (sign < 0L) {
-            UtcOffset(-hours, -minutes, -seconds).validated()
+            UtcOffset(-hours, -minutes, -seconds)
         } else {
-            UtcOffset(hours, minutes, seconds).validated()
+            UtcOffset(hours, minutes, seconds)
         }
     }
 
@@ -210,13 +190,13 @@ internal fun StringBuilder.appendUtcOffset(offset: UtcOffset): StringBuilder {
 
 private fun validateUtcOffsetComponents(hours: IntHours, minutes: IntMinutes, seconds: IntSeconds) {
     when {
-        hours.isPositive() -> if (minutes.isNegative() || seconds.isNegative()) {
+        hours.value > 0 -> if (minutes.value < 0 || seconds.value < 0) {
             throw DateTimeException("Time offset minutes and seconds must be positive when hours are positive")
         }
-        hours.isNegative() -> if (minutes.isPositive() || seconds.isPositive()) {
+        hours.value < 0 -> if (minutes.value > 0 || seconds.value > 0) {
             throw DateTimeException("Time offset minutes and seconds must be negative when hours are negative")
         }
-        else -> if ((minutes.isNegative() && seconds.isPositive()) || (minutes.isPositive() && seconds.isNegative())) {
+        else -> if ((minutes.value < 0 && seconds.value > 0) || (minutes.value > 0 && seconds.value < 0)) {
             throw DateTimeException("Time offset minutes and seconds must have the same sign")
         }
     }

core/src/commonMain/kotlin/io/islandtime/Year.kt

@@ -11,31 +11,36 @@ import kotlin.math.absoluteValue
  * A year as defined by ISO-8601.
  * @constructor Creates a [Year].
  * @param value the year
+ * @throws DateTimeException if the year is invalid
  * @property value The year value.
  */
 inline class Year(val value: Int) : Comparable<Year> {
 
     /**
-     * Checks if this year is within the supported range.
+     * Creates a [Year].
+     * @param value the year
+     * @throws DateTimeException if the year is invalid
      */
-    val isValid: Boolean get() = value in MIN_VALUE..MAX_VALUE
+    constructor(value: Long) : this(checkValidYear(value))
+
+    init {
+        checkValidYear(value)
+    }
 
     /**
      * Checks if this is a leap year.
      */
-    val isLeap: Boolean
-        get() = value % 4 == 0 && (value % 100 != 0 || value % 400 == 0)
+    val isLeap: Boolean get() = isLeapYear(value)
 
     /**
      * The length of the year in days.
      */
-    val length: IntDays
-        get() = if (isLeap) 366.days else 365.days
+    val length: IntDays get() = lengthOfYear(value)
 
     /**
      * The last day of the year. This will be either `365` or `366` depending on whether this is a common or leap year.
      */
-    val lastDay: Int get() = length.value
+    val lastDay: Int get() = lastDayOfYear(value)
 
     /**
      * The day range of the year. This will be either `1..365` or `1.366` depending on whether this is a common or leap
@@ -59,11 +64,10 @@ inline class Year(val value: Int) : Comparable<Year> {
     val endDate: Date get() = Date(value, Month.DECEMBER, 31)
 
     operator fun plus(years: LongYears): Year {
-        val newValue = checkValidYear(value + years.value)
-        return Year(newValue)
+        return Year(value + years.value)
     }
 
-    operator fun plus(years: IntYears) = plus(years.toLongYears())
+    operator fun plus(years: IntYears): Year = plus(years.toLongYears())
 
     operator fun minus(years: LongYears): Year {
         return if (years.value == Long.MIN_VALUE) {
@@ -73,23 +77,11 @@ inline class Year(val value: Int) : Comparable<Year> {
         }
     }
 
-    operator fun minus(years: IntYears) = plus(years.toLongYears().negateUnchecked())
+    operator fun minus(years: IntYears): Year = plus(years.toLongYears().negateUnchecked())
 
     operator fun contains(yearMonth: YearMonth): Boolean = yearMonth.year == value
     operator fun contains(date: Date): Boolean = date.year == value
 
-    /**
-     * Ensures that this year is valid, throwing an exception if it isn't.
-     * @throws DateTimeException if the year is invalid
-     * @see isValid
-     */
-    fun validated(): Year {
-        if (!isValid) {
-            throw DateTimeException(getInvalidYearMessage(value.toLong()))
-        }
-        return this
-    }
-
     override fun compareTo(other: Year): Int = value - other.value
 
     /**
@@ -113,22 +105,22 @@ inline class Year(val value: Int) : Comparable<Year> {
         /**
          * The earliest supported year value.
          */
-        const val MIN_VALUE = -999_999_999
+        const val MIN_VALUE: Int = -999_999_999
 
         /**
          * The latest supported year value.
          */
-        const val MAX_VALUE = 999_999_999
+        const val MAX_VALUE: Int = 999_999_999
 
         /**
          * The earliest supported [Year], which can be used as a "far past" sentinel.
          */
-        val MIN = Year(MIN_VALUE)
+        val MIN: Year = Year(MIN_VALUE)
 
         /**
          * The latest supported [Year], which can be used as a "far future" sentinel.
          */
-        val MAX = Year(MAX_VALUE)
+        val MAX: Year = Year(MAX_VALUE)
     }
 }
 
@@ -165,16 +157,28 @@ internal fun DateTimeParseResult.toYear(): Year? {
     val value = fields[DateTimeField.YEAR]
 
     return if (value != null) {
-        Year(checkValidYear(value))
+        Year(value)
     } else {
         null
     }
 }
 
-internal fun isLeapYear(year: Int) = Year(year).isLeap
-internal fun lengthOfYear(year: Int) = Year(year).length
-internal fun lastDayOfYear(year: Int): Int = Year(year).lastDay
-internal fun checkValidYear(year: Int) = Year(year).validated().value
+internal fun isLeapYear(year: Int): Boolean {
+    return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)
+}
+
+internal fun lengthOfYear(year: Int): IntDays {
+    return if (isLeapYear(year)) 366.days else 365.days
+}
+
+internal fun lastDayOfYear(year: Int): Int = lengthOfYear(year).value
+
+internal fun checkValidYear(year: Int): Int {
+    if (!isValidYear(year)) {
+        throw DateTimeException(getInvalidYearMessage(year.toLong()))
+    }
+    return year
+}
 
 internal fun checkValidYear(year: Long): Int {
     if (!isValidYear(year)) {
@@ -183,6 +187,10 @@ internal fun checkValidYear(year: Long): Int {
     return year.toInt()
 }
 
+internal fun isValidYear(year: Int): Boolean {
+    return year in Year.MIN_VALUE..Year.MAX_VALUE
+}
+
 internal fun isValidYear(year: Long): Boolean {
     return year in Year.MIN_VALUE..Year.MAX_VALUE
 }

core/src/commonTest/kotlin/io/islandtime/UtcOffsetTest.kt

@@ -67,34 +67,22 @@ class UtcOffsetTest : AbstractIslandTimeTest() {
         assertEquals(1.seconds, 1.seconds.asUtcOffset().totalSeconds)
     }
 
-    @Test
-    fun `isValid property returns true is offset is inside the valid range`() {
-        assertTrue { UtcOffset.MAX.isValid }
-        assertTrue { UtcOffset.MIN.isValid }
-    }
-
-    @Test
-    fun `isValid property returns false if offset is outside of +-18_00`() {
-        assertFalse { UtcOffset(UtcOffset.MAX_TOTAL_SECONDS + 1.seconds).isValid }
-        assertFalse { UtcOffset(UtcOffset.MIN_TOTAL_SECONDS - 1.seconds).isValid }
-    }
-
     @Test
     fun `isZero() returns true only when the offset is zero`() {
         assertTrue { UtcOffset(0.seconds).isZero() }
         assertFalse { UtcOffset((-1).seconds).isZero() }
     }
 
     @Test
-    fun `validated() returns the unmodified offset when within the valid range`() {
-        assertEquals(UtcOffset.MAX, UtcOffset.MAX.validated())
-        assertEquals(UtcOffset.MIN, UtcOffset.MIN.validated())
+    fun `construction succeeds when the offset is within the valid range`() {
+        assertEquals(UtcOffset.MAX_TOTAL_SECONDS, UtcOffset.MAX.totalSeconds)
+        assertEquals(UtcOffset.MIN_TOTAL_SECONDS, UtcOffset.MIN.totalSeconds)
     }
 
     @Test
-    fun `validated() throws an exception if the offset is outside the valid range`() {
-        assertFailsWith<DateTimeException> { UtcOffset(UtcOffset.MAX_TOTAL_SECONDS + 1.seconds).validated() }
-        assertFailsWith<DateTimeException> { UtcOffset(UtcOffset.MIN_TOTAL_SECONDS - 1.seconds).validated() }
+    fun `construction throws an exception if the offset is outside the valid range`() {
+        assertFailsWith<DateTimeException> { UtcOffset(UtcOffset.MAX_TOTAL_SECONDS + 1.seconds) }
+        assertFailsWith<DateTimeException> { UtcOffset(UtcOffset.MIN_TOTAL_SECONDS - 1.seconds) }
     }
 
     @Test