DATACMNS-1391 - Use prefered constructors to discover Kotlin's copy method.

We now use the primary constructor of Kotlin classes to discover the copy method. We use the primary constructor args to compare signatures and only use the copy method that takes all parameters in the constructor args order. This allows to find the appropriate copy method in case the class declares multiple copy methods.

We now also cache the copy method (KCallable) to reduce lookups in BeanWrapper.

Original pull request: #312.

src/test/kotlin/org/springframework/data/mapping/model/DataClasses.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mapping.model
+
+import java.util.*
+
+/**
+ * @author Mark Paluch
+ */
+data class DataClassKt(val id: String) {
+}
+
+data class ExtendedDataClassKt(val id: Long, val name: String) {
+	fun copy(name: String, id: Long): ExtendedDataClassKt {
+		throw UnsupportedOperationException("Wrong copy method")
+	}
+}
+
+data class SingleSettableProperty constructor(val id: UUID = UUID.randomUUID()) {
+	val version: Int? = null
+}

src/test/kotlin/org/springframework/data/mapping/model/UnusedCustomCopy.kt

@@ -13,13 +13,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.springframework.data.mapping.model
+package org.springframework.data.mapping.model;
+
+import java.sql.Timestamp
 
 /**
  * @author Mark Paluch
  */
-data class DataClassKt(val id: String) {
-}
+data class UnusedCustomCopy internal constructor(val date: Timestamp) {
 
-data class ExtendedDataClassKt(val id: String, val name: String) {
+	fun copy(date: Long): UnusedCustomCopy {
+		return UnusedCustomCopy(Timestamp(date))
+	}
 }