added missing Duration conversions from String and JavaDuration (by Claude)

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/convert.kt

@@ -78,8 +78,15 @@ import kotlin.reflect.KProperty
 import kotlin.reflect.KType
 import kotlin.reflect.full.isSubtypeOf
 import kotlin.reflect.typeOf
+import kotlin.time.Duration
 import kotlin.time.Instant as StdlibInstant
 import kotlinx.datetime.Instant as DeprecatedInstant
+import java.time.Instant as JavaInstant
+import java.time.Duration as JavaDuration
+import java.time.LocalDate as JavaLocalDate
+import java.time.LocalTime as JavaLocalTime
+import java.time.LocalDateTime as JavaLocalDateTime
+
 
 /**
  * See also [parse] — a specialized form of the [convert] operation that parses [String] columns
@@ -2917,6 +2924,132 @@ public fun <T> Convert<T, *>.toDateTimeComponents(): DataFrame<T> = asColumn { i
 
 // endregion
 
+// region toDuration
+
+/**
+ * Converts values in this [String] column to [Duration].
+ *
+ * Parses each string using [Duration.parse].
+ * Fails with an exception if a value cannot be parsed.
+ *
+ * @return A new [DataColumn] with the [Duration] values.
+ */
+@JvmName("convertToDurationFromString")
+public fun DataColumn<String>.convertToDuration(): DataColumn<Duration> = convertTo()
+
+/**
+ * Converts values in this [String] column to [Duration]. Preserves null values.
+ *
+ * Parses each string using [Duration.parse].
+ * Fails with an exception if a value cannot be parsed.
+ *
+ * @return A new [DataColumn] with the [Duration] nullable values.
+ */
+@JvmName("convertToDurationFromStringNullable")
+public fun DataColumn<String?>.convertToDuration(): DataColumn<Duration?> = convertTo()
+
+/**
+ * Converts values in this [JavaDuration] column to [Duration].
+ *
+ * @return A new [DataColumn] with the [Duration] values.
+ */
+@JvmName("convertToDurationFromJavaDuration")
+public fun DataColumn<JavaDuration>.convertToDuration(): DataColumn<Duration> = convertTo()
+
+/**
+ * Converts values in this [JavaDuration] column to [Duration]. Preserves null values.
+ *
+ * @return A new [DataColumn] with the [Duration] nullable values.
+ */
+@JvmName("convertToDurationFromJavaDurationNullable")
+public fun DataColumn<JavaDuration?>.convertToDuration(): DataColumn<Duration?> = convertTo()
+
+/**
+ * Converts values in the [String] columns previously selected with [convert] to [Duration],
+ * preserving their original names and positions within the [DataFrame].
+ * Preserves null values.
+ *
+ * Parses each string using [Duration.parse].
+ * Fails with an exception if a value cannot be parsed.
+ *
+ * For more information: {@include [DocumentationUrls.Convert]}
+ *
+ * ### Examples:
+ * ```kotlin
+ * df.convert { duration }.toDuration()
+ * ```
+ *
+ * @return A new [DataFrame] with the values converted to [Duration].
+ */
+@JvmName("toDurationFromStringNullable")
+@Refine
+@Converter(Duration::class, nullable = true)
+@Interpretable("ToSpecificType")
+public fun <T> Convert<T, String?>.toDuration(): DataFrame<T> = asColumn { it.convertToDuration() }
+
+/**
+ * Converts values in the [String] columns previously selected with [convert] to [Duration],
+ * preserving their original names and positions within the [DataFrame].
+ *
+ * Parses each string using [Duration.parse].
+ * Fails with an exception if a value cannot be parsed.
+ *
+ * For more information: {@include [DocumentationUrls.Convert]}
+ *
+ * ### Examples:
+ * ```kotlin
+ * df.convert { duration }.toDuration()
+ * ```
+ *
+ * @return A new [DataFrame] with the values converted to [Duration].
+ */
+@JvmName("toDurationFromString")
+@Refine
+@Converter(Duration::class, nullable = false)
+@Interpretable("ToSpecificType")
+public fun <T> Convert<T, String>.toDuration(): DataFrame<T> = asColumn { it.convertToDuration() }
+
+/**
+ * Converts values in the [JavaDuration] columns previously selected with [convert] to [Duration],
+ * preserving their original names and positions within the [DataFrame].
+ * Preserves null values.
+ *
+ * For more information: {@include [DocumentationUrls.Convert]}
+ *
+ * ### Examples:
+ * ```kotlin
+ * df.convert { duration }.toDuration()
+ * ```
+ *
+ * @return A new [DataFrame] with the values converted to [Duration].
+ */
+@JvmName("toDurationFromJavaDurationNullable")
+@Refine
+@Converter(Duration::class, nullable = true)
+@Interpretable("ToSpecificType")
+public fun <T> Convert<T, JavaDuration?>.toDuration(): DataFrame<T> = asColumn { it.convertToDuration() }
+
+/**
+ * Converts values in the [JavaDuration] columns previously selected with [convert] to [Duration],
+ * preserving their original names and positions within the [DataFrame].
+ *
+ * For more information: {@include [DocumentationUrls.Convert]}
+ *
+ * ### Examples:
+ * ```kotlin
+ * df.convert { duration }.toDuration()
+ * ```
+ *
+ * @return A new [DataFrame] with the values converted to [Duration].
+ */
+@JvmName("toDurationFromJavaDuration")
+@Refine
+@Converter(Duration::class, nullable = false)
+@Interpretable("ToSpecificType")
+public fun <T> Convert<T, JavaDuration>.toDuration(): DataFrame<T> = asColumn { it.convertToDuration() }
+
+// endregion
+
 /**
  * Converts values in the columns previously selected with [convert] to the [Int],
  * preserving their original names and positions within the [DataFrame].

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/api/convert.kt

@@ -58,9 +58,13 @@ import kotlin.reflect.full.primaryConstructor
 import kotlin.reflect.full.withNullability
 import kotlin.reflect.jvm.jvmErasure
 import kotlin.reflect.typeOf
+import kotlin.time.Duration
+import kotlin.time.toJavaDuration
 import kotlin.time.toJavaInstant
+import kotlin.time.toKotlinDuration
 import kotlin.time.toKotlinInstant
 import kotlin.toBigDecimal
+import java.time.Duration as JavaDuration
 import java.time.Instant as JavaInstant
 import java.time.LocalDate as JavaLocalDate
 import java.time.LocalDateTime as JavaLocalDateTime
@@ -264,6 +268,17 @@ internal fun createConverter(from: KType, to: KType, options: ParserOptions? = n
     return when {
         fromClass == toClass -> TypeConverterIdentity
 
+        // kotlin.time.Duration is a value class,
+        // so it must be handled before the generic toClass.isValue / fromClass.isValue branches.
+        toClass == Duration::class -> when (fromClass) {
+            String::class -> Parsers.getAsConverterOrNull(to, options)!!
+            JavaDuration::class -> convert<JavaDuration> { it.toKotlinDuration() }
+            else -> null
+        }
+
+        fromClass == Duration::class && toClass == JavaDuration::class ->
+            convert<Duration> { it.toJavaDuration() }
+
         toClass.isValue -> {
             val constructor =
                 toClass.primaryConstructor ?: error("Value type $toClass doesn't have primary constructor")

core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/convert.kt

@@ -26,7 +26,11 @@ import kotlin.math.roundToLong
 import kotlin.random.Random
 import kotlin.reflect.full.starProjectedType
 import kotlin.reflect.typeOf
+import kotlin.time.Duration
 import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.toKotlinDuration
+import java.time.Duration as JavaDuration
 import java.time.LocalTime as JavaLocalTime
 
 class ConvertTests {
@@ -342,6 +346,62 @@ class ConvertTests {
         }
     }
 
+    @Test
+    fun `convertToDuration from String`() {
+        val col = columnOf("1h", "30m")
+        col.convertToDuration() shouldBe columnOf(1.hours, 30.minutes)
+    }
+
+    @Test
+    fun `convertToDuration from nullable String`() {
+        val col = columnOf("1h", null)
+        col.convertToDuration() shouldBe columnOf(1.hours, null)
+    }
+
+    @Test
+    fun `convertToDuration from JavaDuration`() {
+        val javaDuration = JavaDuration.ofHours(1)
+        val col = columnOf(javaDuration)
+        col.convertToDuration() shouldBe columnOf(javaDuration.toKotlinDuration())
+    }
+
+    @Test
+    fun `convertToDuration from nullable JavaDuration`() {
+        val javaDuration = JavaDuration.ofMinutes(30)
+        val col = columnOf(javaDuration, null)
+        col.convertToDuration() shouldBe columnOf(javaDuration.toKotlinDuration(), null)
+    }
+
+    @Test
+    fun `toDuration from String column`() {
+        val duration by columnOf("1h", "30m")
+        val df = duration.toDataFrame()
+        df.convert { duration }.toDuration()[{ "duration"<Duration>() }][0] shouldBe 1.hours
+    }
+
+    @Test
+    fun `toDuration from nullable String column`() {
+        val duration by columnOf("1h", null)
+        val df = duration.toDataFrame()
+        df.convert { duration }.toDuration()[{ "duration"<Duration?>() }].hasNulls shouldBe true
+    }
+
+    @Test
+    fun `toDuration from JavaDuration column`() {
+        val javaDuration = JavaDuration.ofHours(2)
+        val duration by columnOf(javaDuration)
+        val df = duration.toDataFrame()
+        df.convert { duration }.toDuration()[{ "duration"<Duration>() }][0] shouldBe javaDuration.toKotlinDuration()
+    }
+
+    @Test
+    fun `toDuration from nullable JavaDuration column`() {
+        val javaDuration = JavaDuration.ofMinutes(45)
+        val duration by columnOf(javaDuration, null)
+        val df = duration.toDataFrame()
+        df.convert { duration }.toDuration()[{ "duration"<Duration?>() }][0] shouldBe javaDuration.toKotlinDuration()
+    }
+
     private interface Marker
 
     private val ColumnsContainer<Marker>.a get() = this["a"] as DataColumn<String>