Move response status processing in InvocableHandlerMethod

Prior to this commit, WebFlux would look at the handler method
annotations (`@ResponseStatus`) for each handler execution, even calling
the expensive `synthesizeAnnotation`.

This commit moves this logic to the InvocableHandlerMethod so that this
executed once at instantiation time and for all result handlers.

Issue: SPR-15227

spring-webflux/src/main/java/org/springframework/web/reactive/result/AbstractHandlerResultHandler.java

@@ -24,13 +24,10 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.function.Supplier;
 
-import org.springframework.core.MethodParameter;
 import org.springframework.core.Ordered;
 import org.springframework.core.ReactiveAdapterRegistry;
-import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.http.MediaType;
 import org.springframework.util.Assert;
-import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
 import org.springframework.web.server.ServerWebExchange;
@@ -158,17 +155,4 @@ public abstract class AbstractHandlerResultHandler implements Ordered {
 		return (comparator.compare(acceptable, producible) <= 0 ? acceptable : producible);
 	}
 
-	/**
-	 * Optionally set the response status using the information provided by {@code @ResponseStatus}.
-	 * @param methodParameter the controller method return parameter
-	 * @param exchange the server exchange being handled
-	 */
-	protected void updateResponseStatus(MethodParameter methodParameter, ServerWebExchange exchange) {
-		ResponseStatus annotation = methodParameter.getMethodAnnotation(ResponseStatus.class);
-		if (annotation != null) {
-			annotation = AnnotationUtils.synthesizeAnnotation(annotation, methodParameter.getMethod());
-			exchange.getResponse().setStatusCode(annotation.code());
-		}
-	}
-
 }

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/InvocableHandlerMethod.java

@@ -32,9 +32,12 @@ import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.GenericTypeResolver;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.http.HttpStatus;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
+import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.reactive.HandlerResult;
@@ -54,6 +57,8 @@ public class InvocableHandlerMethod extends HandlerMethod {
 
 	private static final Object NO_ARG_VALUE = new Object();
 
+	private HttpStatus responseStatus;
+
 
 	private List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>();
 
@@ -62,12 +67,23 @@ public class InvocableHandlerMethod extends HandlerMethod {
 
 	public InvocableHandlerMethod(HandlerMethod handlerMethod) {
 		super(handlerMethod);
+		initResponseStatus();
 	}
 
 	public InvocableHandlerMethod(Object bean, Method method) {
 		super(bean, method);
+		initResponseStatus();
 	}
 
+	private void initResponseStatus() {
+		ResponseStatus annotation = getMethodAnnotation(ResponseStatus.class);
+		if (annotation == null) {
+			annotation = AnnotatedElementUtils.findMergedAnnotation(getBeanType(), ResponseStatus.class);
+		}
+		if (annotation != null) {
+			this.responseStatus = annotation.code();
+		}
+	}
 
 	/**
 	 * Configure the argument resolvers to use to use for resolving method
@@ -102,6 +118,9 @@ public class InvocableHandlerMethod extends HandlerMethod {
 			try {
 				Object value = doInvoke(args);
 				HandlerResult result = new HandlerResult(this, value, getReturnType(), bindingContext);
+				if (this.responseStatus != null) {
+					exchange.getResponse().setStatusCode(this.responseStatus);
+				}
 				return Mono.just(result);
 			}
 			catch (InvocationTargetException ex) {
@@ -165,7 +184,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 			return resolver.resolveArgument(parameter, bindingContext, exchange)
 					.defaultIfEmpty(NO_ARG_VALUE)
 					.doOnError(cause -> {
-						if(logger.isDebugEnabled()) {
+						if (logger.isDebugEnabled()) {
 							logger.debug(getDetailedErrorMessage("Failed to resolve", parameter), cause);
 						}
 					});

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java

@@ -111,8 +111,7 @@ public abstract class AbstractMessageWriterResultHandler extends AbstractHandler
 		}
 
 		if (void.class == elementType.getRawClass() || Void.class == elementType.getRawClass()) {
-			return Mono.from((Publisher<Void>) publisher)
-					.doOnSubscribe(sub -> updateResponseStatus(bodyParameter, exchange));
+			return Mono.from((Publisher<Void>) publisher);
 		}
 
 		ServerHttpRequest request = exchange.getRequest();
@@ -121,12 +120,11 @@ public abstract class AbstractMessageWriterResultHandler extends AbstractHandler
 		if (bestMediaType != null) {
 			for (HttpMessageWriter<?> messageWriter : getMessageWriters()) {
 				if (messageWriter.canWrite(elementType, bestMediaType)) {
-					Mono<Void> bodyWriter = (messageWriter instanceof ServerHttpMessageWriter ?
+					return (messageWriter instanceof ServerHttpMessageWriter ?
 							((ServerHttpMessageWriter<?>) messageWriter).write((Publisher) publisher,
 									valueType, elementType, bestMediaType, request, response, Collections.emptyMap()) :
 							messageWriter.write((Publisher) publisher, elementType,
 									bestMediaType, response, Collections.emptyMap()));
-					return bodyWriter.doOnSubscribe(sub -> updateResponseStatus(bodyParameter, exchange));
 				}
 			}
 		}

spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java

@@ -208,8 +208,6 @@ public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
 				.otherwiseIfEmpty(exchange.isNotModified() ? Mono.empty() : NO_VALUE_MONO)
 				.then(returnValue -> {
 
-					updateResponseStatus(result.getReturnTypeSource(), exchange);
-
 					Mono<List<View>> viewsMono;
 					Model model = result.getModel();
 

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/InvocableHandlerMethodTests.java

@@ -24,8 +24,10 @@ import org.junit.Test;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
+import org.springframework.http.HttpStatus;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.reactive.result.ResolvableMethod;
@@ -147,6 +149,15 @@ public class InvocableHandlerMethodTests {
 		}
 	}
 
+	@Test
+	public void invokeMethodWithResponseStatus() throws Exception {
+		InvocableHandlerMethod hm = handlerMethod("responseStatus");
+		Mono<HandlerResult> mono = hm.invoke(this.exchange, new BindingContext());
+
+		assertHandlerResultValue(mono, "created");
+		assertThat(this.exchange.getResponse().getStatusCode(), is(HttpStatus.CREATED));
+	}
+
 
 	private InvocableHandlerMethod handlerMethod(String name) throws Exception {
 		TestController controller = new TestController();
@@ -186,6 +197,11 @@ public class InvocableHandlerMethodTests {
 		public void exceptionMethod() {
 			throw new IllegalStateException("boo");
 		}
+
+		@ResponseStatus(HttpStatus.CREATED)
+		public String responseStatus() {
+			return "created";
+		}
 	}
 
 }

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java

@@ -23,13 +23,11 @@ import java.util.List;
 import org.junit.Before;
 import org.junit.Test;
 import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
 import rx.Completable;
 import rx.Single;
 
 import org.springframework.core.codec.ByteBufferEncoder;
 import org.springframework.core.codec.CharSequenceEncoder;
-import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
 import org.springframework.http.codec.HttpMessageWriter;
@@ -42,7 +40,6 @@ import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse
 import org.springframework.stereotype.Controller;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.bind.annotation.ResponseBody;
-import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.bind.annotation.RestController;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.reactive.HandlerResult;
@@ -119,24 +116,6 @@ public class ResponseBodyResultHandlerTests {
 		testSupports(controller, "handleToMonoResponseEntity", false);
 	}
 
-	@Test
-	public void writeResponseStatus() throws NoSuchMethodException {
-		Object controller = new TestRestController();
-		HandlerMethod hm = handlerMethod(controller, "handleToString");
-		HandlerResult handlerResult = new HandlerResult(hm, null, hm.getReturnType());
-
-		initExchange();
-		StepVerifier.create(this.resultHandler.handleResult(this.exchange, handlerResult)).expectComplete().verify();
-		assertEquals(HttpStatus.NO_CONTENT, this.response.getStatusCode());
-
-		hm = handlerMethod(controller, "handleToMonoVoid");
-		handlerResult = new HandlerResult(hm, null, hm.getReturnType());
-
-		initExchange();
-		StepVerifier.create(this.resultHandler.handleResult(this.exchange, handlerResult)).expectComplete().verify();
-		assertEquals(HttpStatus.CREATED, this.response.getStatusCode());
-	}
-
 	private void testSupports(Object controller, String method, boolean result) throws NoSuchMethodException {
 		HandlerMethod hm = handlerMethod(controller, method);
 		HandlerResult handlerResult = new HandlerResult(hm, null, hm.getReturnType());
@@ -157,10 +136,8 @@ public class ResponseBodyResultHandlerTests {
 	@RestController @SuppressWarnings("unused")
 	private static class TestRestController {
 
-		@ResponseStatus(code = HttpStatus.CREATED)
 		public Mono<Void> handleToMonoVoid() { return null;}
 
-		@ResponseStatus(code = HttpStatus.NO_CONTENT)
 		public String handleToString() {
 			return null;
 		}

spring-webflux/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java

@@ -41,7 +41,6 @@ import org.springframework.core.Ordered;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DefaultDataBufferFactory;
-import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.reactive.ServerHttpResponse;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
@@ -49,7 +48,6 @@ import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse
 import org.springframework.ui.ConcurrentModel;
 import org.springframework.ui.Model;
 import org.springframework.web.bind.annotation.ModelAttribute;
-import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.reactive.accept.HeaderContentTypeResolver;
@@ -131,23 +129,19 @@ public class ViewResolutionResultHandlerTests {
 
 		returnType = forClass(View.class);
 		returnValue = new TestView("account");
-		ServerWebExchange exchange = testHandle("/path", returnType, returnValue, "account: {id=123}");
-		assertEquals(HttpStatus.NO_CONTENT, exchange.getResponse().getStatusCode());
+		testHandle("/path", returnType, returnValue, "account: {id=123}");
 
 		returnType = forClassWithGenerics(Mono.class, View.class);
 		returnValue = Mono.just(new TestView("account"));
-		exchange = testHandle("/path", returnType, returnValue, "account: {id=123}");
-		assertEquals(HttpStatus.SEE_OTHER, exchange.getResponse().getStatusCode());
+		testHandle("/path", returnType, returnValue, "account: {id=123}");
 
 		returnType = forClass(String.class);
 		returnValue = "account";
-		exchange = testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
-		assertEquals(HttpStatus.CREATED, exchange.getResponse().getStatusCode());
+		testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
 
 		returnType = forClassWithGenerics(Mono.class, String.class);
 		returnValue = Mono.just("account");
-		exchange = testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
-		assertEquals(HttpStatus.PARTIAL_CONTENT, exchange.getResponse().getStatusCode());
+		testHandle("/path", returnType, returnValue, "account: {id=123}", resolver);
 
 		returnType = forClass(Model.class);
 		returnValue = new ConcurrentModel().addAttribute("name", "Joe");
@@ -438,38 +432,61 @@ public class ViewResolutionResultHandlerTests {
 	@SuppressWarnings("unused")
 	private static class TestController {
 
-		@ResponseStatus(code = HttpStatus.CREATED)
-		String string() { return null; }
+		String string() {
+			return null;
+		}
 
-		@ResponseStatus(HttpStatus.NO_CONTENT)
-		View view() { return null; }
+		View view() {
+			return null;
+		}
 
-		@ResponseStatus(HttpStatus.PARTIAL_CONTENT)
-		Mono<String> monoString() { return null; }
+		Mono<String> monoString() {
+			return null;
+		}
 
-		@ResponseStatus(code = HttpStatus.SEE_OTHER)
-		Mono<View> monoView() { return null; }
+		Mono<View> monoView() {
+			return null;
+		}
 
-		Mono<Void> monoVoid() { return null; }
+		Mono<Void> monoVoid() {
+			return null;
+		}
 
-		void voidMethod() {}
+		void voidMethod() {
+		}
 
-		Single<String> singleString() { return null; }
+		Single<String> singleString() {
+			return null;
+		}
 
-		Single<View> singleView() { return null; }
+		Single<View> singleView() {
+			return null;
+		}
 
-		Completable completable() { return null; }
+		Completable completable() {
+			return null;
+		}
 
-		Model model() { return null; }
+		Model model() {
+			return null;
+		}
 
-		Map map() { return null; }
+		Map map() {
+			return null;
+		}
 
-		TestBean testBean() { return null; }
+		TestBean testBean() {
+			return null;
+		}
 
-		Integer integer() { return null; }
+		Integer integer() {
+			return null;
+		}
 
 		@ModelAttribute("num")
-		Long longAttribute() { return null; }
+		Long longAttribute() {
+			return null;
+		}
 	}
 
 }