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Add support for Kotlin value classes in BeanUtils

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This commit adds support for Kotlin value classes annotated
with @JvmInline to BeanUtils#findPrimaryConstructor.

This is only the first step, more refinements are expected
to be needed to achieve a comprehensive support of Kotlin
values classes in Spring Framework.

Closes gh-28638
This commit is contained in:
Sébastien Deleuze
2023-08-09 10:26:25 +02:00
parent dd76ed7a0a
commit 88c2a25f12
2 changed files with 65 additions and 1 deletions
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14
spring-beans/src/main/java/org/springframework/beans/BeanUtils.java
View File

@@ -31,8 +31,11 @@ import java.util.Map;
import java.util.Set;
import kotlin.jvm.JvmClassMappingKt;
import kotlin.jvm.JvmInline;
import kotlin.reflect.KClass;
import kotlin.reflect.KFunction;
import kotlin.reflect.KParameter;
import kotlin.reflect.full.KAnnotatedElements;
import kotlin.reflect.full.KClasses;
import kotlin.reflect.jvm.KCallablesJvm;
import kotlin.reflect.jvm.ReflectJvmMapping;
@@ -835,13 +838,22 @@ public abstract class BeanUtils {
* @see <a href="https://kotlinlang.org/docs/reference/classes.html#constructors">
* https://kotlinlang.org/docs/reference/classes.html#constructors</a>
*/
@SuppressWarnings("unchecked")
@Nullable
public static <T> Constructor<T> findPrimaryConstructor(Class<T> clazz) {
try {
KFunction<T> primaryCtor = KClasses.getPrimaryConstructor(JvmClassMappingKt.getKotlinClass(clazz));
KClass<T> kClass = JvmClassMappingKt.getKotlinClass(clazz);
KFunction<T> primaryCtor = KClasses.getPrimaryConstructor(kClass);
if (primaryCtor == null) {
return null;
}
if (kClass.isValue() && !KAnnotatedElements
.findAnnotations(kClass, JvmClassMappingKt.getKotlinClass(JvmInline.class)).isEmpty()) {
Constructor<?>[] constructors = clazz.getDeclaredConstructors();
Assert.state(constructors.length == 1,
"Kotlin value classes annotated with @JvmInline are expected to have a single JVM constructor");
return (Constructor<T>) constructors[0];
}
Constructor<T> constructor = ReflectJvmMapping.getJavaConstructor(primaryCtor);
if (constructor == null) {
throw new IllegalStateException(

52
spring-beans/src/test/kotlin/org/springframework/beans/BeanUtilsKotlinTests.kt
View File

@@ -90,6 +90,45 @@ class BeanUtilsKotlinTests {
BeanUtils.instantiateClass(PrivateClass::class.java.getDeclaredConstructor())
}
@Test
fun `Instantiate value class`() {
val constructor = BeanUtils.findPrimaryConstructor(ValueClass::class.java)!!
assertThat(constructor).isNotNull()
val value = "Hello value class!"
val instance = BeanUtils.instantiateClass(constructor, value)
assertThat(instance).isEqualTo(ValueClass(value))
}
@Test
fun `Instantiate value class with multiple constructors`() {
val constructor = BeanUtils.findPrimaryConstructor(ValueClassWithMultipleConstructors::class.java)!!
assertThat(constructor).isNotNull()
val value = "Hello value class!"
val instance = BeanUtils.instantiateClass(constructor, value)
assertThat(instance).isEqualTo(ValueClassWithMultipleConstructors(value))
}
@Test
fun `Instantiate class with value class parameter`() {
val constructor = BeanUtils.findPrimaryConstructor(OneConstructorWithValueClass::class.java)!!
assertThat(constructor).isNotNull()
val value = ValueClass("Hello value class!")
val instance = BeanUtils.instantiateClass(constructor, value)
assertThat(instance).isEqualTo(OneConstructorWithValueClass(value))
}
@Test
fun `Instantiate class with nullable value class parameter`() {
val constructor = BeanUtils.findPrimaryConstructor(OneConstructorWithNullableValueClass::class.java)!!
assertThat(constructor).isNotNull()
val value = ValueClass("Hello value class!")
var instance = BeanUtils.instantiateClass(constructor, value)
assertThat(instance).isEqualTo(OneConstructorWithNullableValueClass(value))
instance = BeanUtils.instantiateClass(constructor, null)
assertThat(instance).isEqualTo(OneConstructorWithNullableValueClass(null))
}
class Foo(val param1: String, val param2: Int)
class Bar(val param1: String, val param2: Int = 12)
@@ -128,4 +167,17 @@ class BeanUtilsKotlinTests {
private class PrivateClass
@JvmInline
value class ValueClass(private val value: String)
@JvmInline
value class ValueClassWithMultipleConstructors(private val value: String) {
constructor() : this("Fail")
constructor(part1: String, part2: String) : this("Fail")
}
data class OneConstructorWithValueClass(val value: ValueClass)
data class OneConstructorWithNullableValueClass(val value: ValueClass?)
}