Remove BodyInserters.fromServerSentEvent variants

Removed superfluous `fromServerSentEvent` variants from `BodyInserters`,
as their functionality can also be obtained by passing a stream of
strings or POJOs (to be encoded as JSON) to
`fromPublisher(Publisher, Class)}`, and specifying a `text/event-stream`
Content-Type.

Issue: SPR-15826

spring-webflux/src/main/java/org/springframework/web/reactive/function/BodyInserters.java

@@ -149,6 +149,9 @@ public abstract class BodyInserters {
 
 	/**
 	 * Return a {@code BodyInserter} that writes the given {@code ServerSentEvent} publisher.
+	 * <p>Note that a SSE {@code BodyInserter} can also be obtained by passing a stream of strings
+	 * or POJOs (to be encoded as JSON) to {@link #fromPublisher(Publisher, Class)}, and specifying a
+	 * {@link MediaType#TEXT_EVENT_STREAM text/event-stream} Content-Type.
 	 * @param eventsPublisher the {@code ServerSentEvent} publisher to write to the response body
 	 * @param <T> the type of the elements contained in the {@link ServerSentEvent}
 	 * @return a {@code BodyInserter} that writes a {@code ServerSentEvent} publisher
@@ -173,66 +176,6 @@ public abstract class BodyInserters {
 		};
 	}
 
-	/**
-	 * Return a {@code BodyInserter} that writes the given {@code Publisher} publisher as
-	 * Server-Sent Events.
-	 * @param eventsPublisher the publisher to write to the response body as Server-Sent Events
-	 * @param eventClass the class of event contained in the publisher
-	 * @param <T> the type of the elements contained in the publisher
-	 * @return a {@code BodyInserter} that writes the given {@code Publisher} publisher as
-	 * Server-Sent Events
-	 * @see <a href="https://www.w3.org/TR/eventsource/">Server-Sent Events W3C recommendation</a>
-	 */
-	// Note that the returned BodyInserter is parameterized to ServerHttpResponse, not
-	// ReactiveHttpOutputMessage like other methods, since sending SSEs only typically happens on
-	// the server-side
-	public static <T, S extends Publisher<T>> BodyInserter<S, ServerHttpResponse> fromServerSentEvents(S eventsPublisher,
-			Class<T> eventClass) {
-
-		Assert.notNull(eventsPublisher, "'eventsPublisher' must not be null");
-		Assert.notNull(eventClass, "'eventClass' must not be null");
-		return fromServerSentEvents(eventsPublisher, ResolvableType.forClass(eventClass));
-	}
-
-	/**
-	 * Return a {@code BodyInserter} that writes the given {@code Publisher} publisher as
-	 * Server-Sent Events.
-	 * @param eventsPublisher the publisher to write to the response body as Server-Sent Events
-	 * @param typeReference the type of event contained in the publisher
-	 * @param <T> the type of the elements contained in the publisher
-	 * @return a {@code BodyInserter} that writes the given {@code Publisher} publisher as
-	 * Server-Sent Events
-	 * @see <a href="https://www.w3.org/TR/eventsource/">Server-Sent Events W3C recommendation</a>
-	 */
-	// Note that the returned BodyInserter is parameterized to ServerHttpResponse, not
-	// ReactiveHttpOutputMessage like other methods, since sending SSEs only typically happens on
-	// the server-side
-	public static <T, S extends Publisher<T>> BodyInserter<S, ServerHttpResponse> fromServerSentEvents(S eventsPublisher,
-			ParameterizedTypeReference<T> typeReference) {
-
-		Assert.notNull(eventsPublisher, "'eventsPublisher' must not be null");
-		Assert.notNull(typeReference, "'typeReference' must not be null");
-		return fromServerSentEvents(eventsPublisher,
-				ResolvableType.forType(typeReference.getType()));
-	}
-
-	static <T, S extends Publisher<T>> BodyInserter<S, ServerHttpResponse> fromServerSentEvents(S eventsPublisher,
-			ResolvableType eventType) {
-
-		Assert.notNull(eventsPublisher, "'eventsPublisher' must not be null");
-		Assert.notNull(eventType, "'eventType' must not be null");
-		return (serverResponse, context) -> {
-			HttpMessageWriter<T> messageWriter =
-					findMessageWriter(context, SERVER_SIDE_EVENT_TYPE, MediaType.TEXT_EVENT_STREAM);
-			return context.serverRequest()
-					.map(serverRequest -> messageWriter.write(eventsPublisher, eventType,
-							eventType, MediaType.TEXT_EVENT_STREAM, serverRequest,
-							serverResponse, context.hints()))
-					.orElseGet(() -> messageWriter.write(eventsPublisher, eventType,
-							MediaType.TEXT_EVENT_STREAM, serverResponse, context.hints()));
-		};
-	}
-
 	/**
 	 * Return a {@code BodyInserter} that writes the given {@code MultiValueMap} as URL-encoded
 	 * form data.
@@ -241,7 +184,7 @@ public abstract class BodyInserters {
 	 */
 	// Note that the returned BodyInserter is parameterized to ClientHttpRequest, not
 	// ReactiveHttpOutputMessage like other methods, since sending form data only typically happens
-	// on the server-side
+	// on the client-side
 	public static BodyInserter<MultiValueMap<String, String>, ClientHttpRequest> fromFormData(
 			MultiValueMap<String, String> formData) {
 
@@ -262,7 +205,7 @@ public abstract class BodyInserters {
 	 */
 	// Note that the returned BodyInserter is parameterized to ClientHttpRequest, not
 	// ReactiveHttpOutputMessage like other methods, since sending form data only typically happens
-	// on the server-side
+	// on the client-side
 	public static BodyInserter<MultiValueMap<String, ?>, ClientHttpRequest> fromMultipartData(
 			MultiValueMap<String, ?> multipartData) {
 

spring-webflux/src/test/java/org/springframework/web/reactive/function/BodyInsertersTests.java

@@ -247,17 +247,6 @@ public class BodyInsertersTests {
 		StepVerifier.create(result).expectNextCount(0).expectComplete().verify();
 	}
 
-	@Test
-	public void ofServerSentEventClass() throws Exception {
-		Flux<String> body = Flux.just("foo");
-		BodyInserter<Flux<String>, ServerHttpResponse> inserter =
-				BodyInserters.fromServerSentEvents(body, String.class);
-
-		MockServerHttpResponse response = new MockServerHttpResponse();
-		Mono<Void> result = inserter.insert(response, this.context);
-		StepVerifier.create(result).expectNextCount(0).expectComplete().verify();
-	}
-
 	@Test
 	public void ofFormData() throws Exception {
 		MultiValueMap<String, String> body = new LinkedMultiValueMap<>();

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/SseHandlerFunctionIntegrationTests.java

@@ -25,6 +25,7 @@ import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
 import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.MediaType;
 import org.springframework.http.codec.ServerSentEvent;
 import org.springframework.web.reactive.function.client.WebClient;
 
@@ -120,13 +121,17 @@ public class SseHandlerFunctionIntegrationTests extends AbstractRouterFunctionIn
 
 		public Mono<ServerResponse> string(ServerRequest request) {
 			Flux<String> flux = Flux.interval(Duration.ofMillis(100)).map(l -> "foo " + l).take(2);
-			return ServerResponse.ok().body(fromServerSentEvents(flux, String.class));
+			return ServerResponse.ok()
+					.contentType(MediaType.TEXT_EVENT_STREAM)
+					.body(flux, String.class);
 		}
 
 		public Mono<ServerResponse> person(ServerRequest request) {
 			Flux<Person> flux = Flux.interval(Duration.ofMillis(100))
 					.map(l -> new Person("foo " + l)).take(2);
-			return ServerResponse.ok().body(fromServerSentEvents(flux, Person.class));
+			return ServerResponse.ok()
+					.contentType(MediaType.TEXT_EVENT_STREAM)
+					.body(flux, Person.class);
 		}
 
 		public Mono<ServerResponse> sse(ServerRequest request) {