Add Kotlin data mapping examples (BAEL-2247) (#5560)

core-kotlin/src/main/kotlin/com/baeldung/datamapping/User.kt

@@ -0,0 +1,10 @@
+package com.baeldung.datamapping
+
+data class User(
+        val firstName: String,
+        val lastName: String,
+        val street: String,
+        val houseNumber: String,
+        val phone: String,
+        val age: Int,
+        val password: String)

core-kotlin/src/main/kotlin/com/baeldung/datamapping/UserExtensions.kt

@@ -0,0 +1,22 @@
+package com.baeldung.datamapping
+
+import kotlin.reflect.full.memberProperties
+
+fun User.toUserView() = UserView(
+        name = "$firstName $lastName",
+        address = "$street $houseNumber",
+        telephone = phone,
+        age = age
+)
+
+fun User.toUserViewReflection() = with(::UserView) {
+    val propertiesByName = User::class.memberProperties.associateBy { it.name }
+    callBy(parameters.associate { parameter ->
+        parameter to when (parameter.name) {
+            UserView::name.name -> "$firstName $lastName"
+            UserView::address.name -> "$street $houseNumber"
+            UserView::telephone.name -> phone
+            else -> propertiesByName[parameter.name]?.get(this@toUserViewReflection)
+        }
+    })
+}

core-kotlin/src/main/kotlin/com/baeldung/datamapping/UserView.kt

@@ -0,0 +1,8 @@
+package com.baeldung.datamapping
+
+data class UserView(
+        val name: String,
+        val address: String,
+        val telephone: String,
+        val age: Int
+)