Add Kotlin extensions for bean registration and retrieval

Issue: SPR-15048

spring-beans/src/main/kotlin/org/springframework/beans/factory/BeanFactoryExtension.kt

@@ -0,0 +1,29 @@
+package org.springframework.beans.factory
+
+import kotlin.reflect.KClass
+
+/**
+ * Extension for [BeanFactory] providing [KClass] based API.
+ *
+ * @since 5.0
+ */
+object BeanFactoryExtension {
+
+	/**
+	 * @see BeanFactory.getBean(Class<T>)
+	 */
+	fun <T : Any> BeanFactory.getBean(requiredType: KClass<T>) = getBean(requiredType.java)
+
+	/**
+	 * @see BeanFactory.getBean(String, Class<T>)
+	 */
+	fun <T : Any> BeanFactory.getBean(name: String, requiredType: KClass<T>) =
+			getBean(name, requiredType.java)
+
+	/**
+	 * @see BeanFactory.getBean(Class<T>, Object...)
+	 */
+	fun <T : Any> BeanFactory.getBean(requiredType: KClass<T>, vararg args:Any) =
+			getBean(requiredType.java, *args)
+
+}

spring-beans/src/main/kotlin/org/springframework/beans/factory/ListableBeanFactoryExtension.kt

@@ -0,0 +1,56 @@
+package org.springframework.beans.factory
+
+import kotlin.reflect.KClass
+
+/**
+ * Extension for [ListableBeanFactory] providing [KClass] based API.
+ *
+ * @since 5.0
+ */
+object ListableBeanFactoryExtension {
+
+	/**
+	 * @see ListableBeanFactory.getBeanNamesForType(Class<?>)
+	 */
+	fun <T : Any> ListableBeanFactory.getBeanNamesForType(type: KClass<T>) =
+			getBeanNamesForType(type.java)
+
+	/**
+	 * @see ListableBeanFactory.getBeanNamesForType(Class<?>, boolean, boolean)
+	 */
+	fun <T : Any> ListableBeanFactory.getBeanNamesForType(type: KClass<T>,
+			includeNonSingletons: Boolean, allowEagerInit: Boolean) =
+					getBeanNamesForType(type.java, includeNonSingletons, allowEagerInit)
+
+	/**
+	 * @see ListableBeanFactory.getBeansOfType(Class<T>)
+	 */
+	fun <T : Any> ListableBeanFactory.getBeansOfType(type: KClass<T>) =
+			getBeansOfType(type.java)
+
+	/**
+	 * @see ListableBeanFactory.getBeansOfType(Class<T>, boolean, boolean)
+	 */
+	fun <T : Any> ListableBeanFactory.getBeansOfType(type: KClass<T>,
+			includeNonSingletons: Boolean, allowEagerInit: Boolean) =
+					getBeansOfType(type.java, includeNonSingletons, allowEagerInit)
+
+	/**
+	 * @see ListableBeanFactory.getBeanNamesForAnnotation
+	 */
+	fun <T : Annotation> ListableBeanFactory.getBeanNamesForAnnotation(type: KClass<T>) =
+			getBeanNamesForAnnotation(type.java)
+
+	/**
+	 * @see ListableBeanFactory.getBeansWithAnnotation
+	 */
+	fun <T : Annotation> ListableBeanFactory.getBeansWithAnnotation(type: KClass<T>) =
+			getBeansWithAnnotation(type.java)
+
+	/**
+	 * @see ListableBeanFactoryExtension.findAnnotationOnBean
+	 */
+	fun <T : Annotation> ListableBeanFactory.findAnnotationOnBean(beanName:String, type: KClass<T>) =
+			findAnnotationOnBean(beanName, type.java)
+
+}