Remove object wrappers in Kotlin extensions

This commit also improve significantly Kotlin extensions
documentation.

Issue: SPR-15127

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/BodyExtractorsExtension.kt

@@ -1,40 +0,0 @@
-package org.springframework.web.reactive.function
-
-import org.springframework.http.ReactiveHttpInputMessage
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import kotlin.reflect.KClass
-
-/**
- * Extension for [BodyExtactors] providing [KClass] based API and avoiding specifying
- * a class parameter when possible thanks to Kotlin reified type parameters.
- *
- * @author Sebastien Deleuze
- * @since 5.0
- */
-object BodyExtractorsExtension {
-
-	/**
-	 * @see BodyExtactors.toMono
-	 */
-	inline fun <reified T : Any> toMono() : BodyExtractor<Mono<T>, ReactiveHttpInputMessage> =
-			BodyExtractors.toMono(T::class.java)
-
-	/**
-	 * @see BodyExtactors.toMono
-	 */
-	fun <T : Any> toMono(elementClass: KClass<T>) : BodyExtractor<Mono<T>, ReactiveHttpInputMessage> =
-			BodyExtractors.toMono(elementClass.java)
-
-	/**
-	 * @see BodyExtactors.toFlux
-	 */
-	inline fun <reified T : Any> toFlux() : BodyExtractor<Flux<T>, ReactiveHttpInputMessage> =
-			BodyExtractors.toFlux(T::class.java)
-
-	/**
-	 * @see BodyExtactors.toFlux
-	 */
-	fun <T : Any> toFlux(elementClass: KClass<T>) : BodyExtractor<Flux<T>, ReactiveHttpInputMessage> =
-			BodyExtractors.toFlux(elementClass.java)
-}

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/BodyExtractorsExtensions.kt

@@ -0,0 +1,42 @@
+package org.springframework.web.reactive.function
+
+import org.springframework.http.ReactiveHttpInputMessage
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import kotlin.reflect.KClass
+
+/**
+ * Function for providing a `toMono()` alternative to `BodyExtractors.toMono(Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+inline fun <reified T : Any> toMono() : BodyExtractor<Mono<T>, ReactiveHttpInputMessage> =
+		BodyExtractors.toMono(T::class.java)
+
+/**
+ * Function for providing a `toMono(Foo::class)` alternative to `BodyExtractors.toMono(Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> toMono(elementClass: KClass<T>) : BodyExtractor<Mono<T>, ReactiveHttpInputMessage> =
+		BodyExtractors.toMono(elementClass.java)
+
+/**
+ * Function for providing a `toFlux()` alternative to `BodyExtractors.toFlux(Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+inline fun <reified T : Any> toFlux() : BodyExtractor<Flux<T>, ReactiveHttpInputMessage> =
+		BodyExtractors.toFlux(T::class.java)
+
+/**
+ * Function for providing a `toFlux(Foo::class)` alternative to `BodyExtractors.toFlux(Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> toFlux(elementClass: KClass<T>) : BodyExtractor<Flux<T>, ReactiveHttpInputMessage> =
+		BodyExtractors.toFlux(elementClass.java)

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/BodyInsertersExtension.kt

@@ -1,27 +0,0 @@
-package org.springframework.web.reactive.function
-
-import org.reactivestreams.Publisher
-import org.springframework.http.ReactiveHttpOutputMessage
-import org.springframework.http.server.reactive.ServerHttpResponse
-
-/**
- * Extension for [BodyInserters] providing [KClass] based API and avoiding specifying
- * a class parameter when possible thanks to Kotlin reified type parameters.
- *
- * @author Sebastien Deleuze
- * @since 5.0
- */
-object BodyInsertersExtension {
-
-	/**
-	 * @see BodyInserters.fromPublisher
-	 */
-	inline fun <reified T : Publisher<S>, reified S : Any> fromPublisher(publisher: T) : BodyInserter<T, ReactiveHttpOutputMessage> =
-			BodyInserters.fromPublisher(publisher, S::class.java)
-
-	/**
-	 * @see BodyInserters.fromServerSentEvents
-	 */
-	inline fun <reified T : Publisher<S>, reified S : Any> fromServerSentEvents(publisher: T) : BodyInserter<T, ServerHttpResponse> =
-			BodyInserters.fromServerSentEvents(publisher, S::class.java)
-}

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/BodyInsertersExtensions.kt

@@ -0,0 +1,23 @@
+package org.springframework.web.reactive.function
+
+import org.reactivestreams.Publisher
+import org.springframework.http.ReactiveHttpOutputMessage
+import org.springframework.http.server.reactive.ServerHttpResponse
+
+/**
+ * Function for providing a `fromPublisher(publisher)` alternative to `BodyInserters.fromPublisher(publisher, Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+inline fun <reified T : Publisher<S>, reified S : Any> fromPublisher(publisher: T) : BodyInserter<T, ReactiveHttpOutputMessage> =
+		BodyInserters.fromPublisher(publisher, S::class.java)
+
+/**
+ * Function for providing a `fromServerSentEvents(publisher)` alternative to `BodyInserters.fromServerSentEvents(publisher, Foo::class.java)`.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+inline fun <reified T : Publisher<S>, reified S : Any> fromServerSentEvents(publisher: T) : BodyInserter<T, ServerHttpResponse> =
+		BodyInserters.fromServerSentEvents(publisher, S::class.java)

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/client/ClientResponseExtension.kt

@@ -1,24 +0,0 @@
-package org.springframework.web.reactive.function.client
-
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import kotlin.reflect.KClass
-
-/**
- * Extension for [ClientResponse] providing [KClass] based API.
- *
- * @author Sebastien Deleuze
- * @since 5.0
- */
-object ClientResponseExtension {
-
-	/**
-	 * @see ClientResponse.bodyToFlux
-	 */
-	fun <T : Any> ClientResponse.bodyToFlux(type: KClass<T>) : Flux<T> = bodyToFlux(type.java)
-
-	/**
-	 * @see ClientResponse.bodyToMono
-	 */
-	fun <T : Any> ClientResponse.bodyToMono(type: KClass<T>) : Mono<T> = bodyToMono(type.java)
-}

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/client/ClientResponseExtensions.kt

@@ -0,0 +1,24 @@
+package org.springframework.web.reactive.function.client
+
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+import kotlin.reflect.KClass
+
+
+/**
+ * Extension for [ClientResponse.bodyToMono] providing a [KClass] based variant.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> ClientResponse.bodyToMono(type: KClass<T>) : Mono<T> = bodyToMono(type.java)
+
+/**
+ * Extension for [ClientResponse.bodyToFlux] providing a [KClass] based variant.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> ClientResponse.bodyToFlux(type: KClass<T>) : Flux<T> = bodyToFlux(type.java)
+
+

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/server/ServerRequestExtension.kt

@@ -1,22 +0,0 @@
-package org.springframework.web.reactive.function.server
-
-import kotlin.reflect.KClass
-
-/**
- * Extension for [ServerRequest] providing [KClass] based API.
- *
- * @author Sebastien Deleuze
- * @since 5.0
- */
-object ServerRequestExtension {
-
-	/**
-	 * @see ServerRequest.bodyToMono
-	 */
-	fun <T : Any> ServerRequest.bodyToMono(type: KClass<T>) = bodyToMono(type.java)
-
-	/**
-	 * @see ServerRequest.bodyToFlux
-	 */
-	fun <T : Any> ServerRequest.bodyToFlux(type: KClass<T>) = bodyToFlux(type.java)
-}

spring-web-reactive/src/main/kotlin/org/springframework/web/reactive/function/server/ServerRequestExtensions.kt

@@ -0,0 +1,20 @@
+package org.springframework.web.reactive.function.server
+
+import kotlin.reflect.KClass
+
+
+/**
+ * Extension for [ServerRequest.bodyToMono] providing a [KClass] based variant.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> ServerRequest.bodyToMono(type: KClass<T>) = bodyToMono(type.java)
+
+/**
+ * Extension for [ServerRequest.bodyToFlux] providing a [KClass] based variant.
+ *
+ * @author Sebastien Deleuze
+ * @since 5.0
+ */
+fun <T : Any> ServerRequest.bodyToFlux(type: KClass<T>) = bodyToFlux(type.java)