KTLN-645: Nested Declarations in Annotations in Kotlin (#594)

Co-authored-by: Tapan Avasthi <[email protected]>

Author: tapankavasthi

core-kotlin-modules/core-kotlin-annotations/src/main/kotlin/com/baeldung/annotations/NestedDeclaration.kt

@@ -0,0 +1,14 @@
+package com.baeldung.annotations
+
+annotation class Parent(val type: Type) {
+    annotation class Child1(val prop1: String)
+    annotation class Child2(val prop2: Int)
+    enum class Type { TYPE1, TYPE2 }
+}
+
+@Parent(Parent.Type.TYPE1)
+@Parent.Child1("sample prop")
+@Parent.Child2(prop2 = 1)
+class ClassUsingNestedAnnotation {
+
+}

core-kotlin-modules/core-kotlin-annotations/src/test/kotlin/com/baeldung/annotations/NestedDeclarationUnitTest.kt

@@ -0,0 +1,27 @@
+package com.baeldung.annotations
+
+import org.junit.jupiter.api.Test
+import kotlin.reflect.full.findAnnotation
+import kotlin.test.assertEquals
+
+class NestedDeclarationUnitTest {
+
+
+    @Test
+    fun `given nested declarations in annotation, when check for parent-level member, should get expected result`() {
+        val parentAnnotation = ClassUsingNestedAnnotation::class.findAnnotation<Parent>()
+        assertEquals(Parent.Type.TYPE1, parentAnnotation?.type)
+    }
+
+    @Test
+    fun `given nested declarations in annotation, when check for child1 annotation, should get expected result`() {
+        val child1Annotation = ClassUsingNestedAnnotation::class.findAnnotation<Parent.Child1>()
+        assertEquals("sample prop", child1Annotation?.prop1)
+    }
+
+    @Test
+    fun `given nested declarations in annotation, when check for child2 annotation, should get expected result`() {
+        val child2Annotation = ClassUsingNestedAnnotation::class.findAnnotation<Parent.Child2>()
+        assertEquals(1, child2Annotation?.prop2)
+    }
+}