Apply "instanceof pattern matching" in spring-webflux

Closes gh-29635

spring-webflux/src/main/java/org/springframework/web/reactive/config/ResourceHandlerRegistry.java

@@ -148,8 +148,8 @@ public class ResourceHandlerRegistry {
 	private ResourceWebHandler getRequestHandler(ResourceHandlerRegistration registration) {
 		ResourceWebHandler handler = registration.getRequestHandler();
 		for (ResourceTransformer transformer : handler.getResourceTransformers()) {
-			if (transformer instanceof ResourceTransformerSupport) {
-				((ResourceTransformerSupport) transformer).setResourceUrlProvider(this.resourceUrlProvider);
+			if (transformer instanceof ResourceTransformerSupport resourceTransformerSupport) {
+				resourceTransformerSupport.setResourceUrlProvider(this.resourceUrlProvider);
 			}
 		}
 		try {

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

@@ -363,8 +363,8 @@ public abstract class BodyInserters {
 			M outputMessage, BodyInserter.Context context, Object body, ResolvableType bodyType, @Nullable ReactiveAdapter adapter) {
 
 		Publisher<?> publisher;
-		if (body instanceof Publisher) {
-			publisher = (Publisher<?>) body;
+		if (body instanceof Publisher<?> publisherBody) {
+			publisher = publisherBody;
 		}
 		else if (adapter != null) {
 			publisher = adapter.toPublisher(body);

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

@@ -133,11 +133,11 @@ class DefaultClientResponse implements ClientResponse {
 	public <T> T body(BodyExtractor<T, ? super ClientHttpResponse> extractor) {
 		T result = extractor.extract(this.response, this.bodyExtractorContext);
 		String description = "Body from " + this.requestDescription + " [DefaultClientResponse]";
-		if (result instanceof Mono) {
-			return (T) ((Mono<?>) result).checkpoint(description);
+		if (result instanceof Mono<?> monoResult) {
+			return (T) monoResult.checkpoint(description);
 		}
-		else if (result instanceof Flux) {
-			return (T) ((Flux<?>) result).checkpoint(description);
+		else if (result instanceof Flux<?> fluxResult) {
+			return (T) fluxResult.checkpoint(description);
 		}
 		else {
 			return result;

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

@@ -107,7 +107,7 @@ final class DefaultRenderingResponseBuilder implements RenderingResponse.Builder
 	@Override
 	public RenderingResponse.Builder modelAttribute(Object attribute) {
 		Assert.notNull(attribute, "Attribute must not be null");
-		if (attribute instanceof Collection && ((Collection<?>) attribute).isEmpty()) {
+		if (attribute instanceof Collection<?> attrCollection && attrCollection.isEmpty()) {
 			return this;
 		}
 		return modelAttribute(Conventions.getVariableName(attribute), attribute);

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

@@ -129,8 +129,8 @@ class PathResourceLookupFunction implements Function<ServerRequest, Mono<Resourc
 			resourcePath = resource.getURL().toExternalForm();
 			locationPath = StringUtils.cleanPath(this.location.getURL().toString());
 		}
-		else if (resource instanceof ClassPathResource) {
-			resourcePath = ((ClassPathResource) resource).getPath();
+		else if (resource instanceof ClassPathResource classPathResource) {
+			resourcePath = classPathResource.getPath();
 			locationPath = StringUtils.cleanPath(((ClassPathResource) this.location).getPath());
 		}
 		else {

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

@@ -795,11 +795,11 @@ public abstract class RequestPredicates {
 
 		@Override
 		public void changeParser(PathPatternParser parser) {
-			if (this.left instanceof ChangePathPatternParserVisitor.Target) {
-				((ChangePathPatternParserVisitor.Target) this.left).changeParser(parser);
+			if (this.left instanceof ChangePathPatternParserVisitor.Target leftTarget) {
+				leftTarget.changeParser(parser);
 			}
-			if (this.right instanceof ChangePathPatternParserVisitor.Target) {
-				((ChangePathPatternParserVisitor.Target) this.right).changeParser(parser);
+			if (this.right instanceof ChangePathPatternParserVisitor.Target rightTarget) {
+				rightTarget.changeParser(parser);
 			}
 		}
 
@@ -841,8 +841,8 @@ public abstract class RequestPredicates {
 
 		@Override
 		public void changeParser(PathPatternParser parser) {
-			if (this.delegate instanceof ChangePathPatternParserVisitor.Target) {
-				((ChangePathPatternParserVisitor.Target) this.delegate).changeParser(parser);
+			if (this.delegate instanceof ChangePathPatternParserVisitor.Target target) {
+				target.changeParser(parser);
 			}
 		}
 
@@ -909,11 +909,11 @@ public abstract class RequestPredicates {
 
 		@Override
 		public void changeParser(PathPatternParser parser) {
-			if (this.left instanceof ChangePathPatternParserVisitor.Target) {
-				((ChangePathPatternParserVisitor.Target) this.left).changeParser(parser);
+			if (this.left instanceof ChangePathPatternParserVisitor.Target leftTarget) {
+				leftTarget.changeParser(parser);
 			}
-			if (this.right instanceof ChangePathPatternParserVisitor.Target) {
-				((ChangePathPatternParserVisitor.Target) this.right).changeParser(parser);
+			if (this.right instanceof ChangePathPatternParserVisitor.Target rightTarget) {
+				rightTarget.changeParser(parser);
 			}
 		}
 

spring-webflux/src/main/java/org/springframework/web/reactive/handler/AbstractHandlerMapping.java

@@ -233,8 +233,8 @@ public abstract class AbstractHandlerMapping extends ApplicationObjectSupport
 	 */
 	@Nullable
 	protected CorsConfiguration getCorsConfiguration(Object handler, ServerWebExchange exchange) {
-		if (handler instanceof CorsConfigurationSource) {
-			return ((CorsConfigurationSource) handler).getCorsConfiguration(exchange);
+		if (handler instanceof CorsConfigurationSource ccs) {
+			return ccs.getCorsConfiguration(exchange);
 		}
 		return null;
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/handler/SimpleUrlHandlerMapping.java

@@ -153,8 +153,8 @@ public class SimpleUrlHandlerMapping extends AbstractUrlHandlerMapping {
 					url = "/" + url;
 				}
 				// Remove whitespace from handler bean name.
-				if (handler instanceof String) {
-					handler = ((String) handler).trim();
+				if (handler instanceof String handlerName) {
+					handler = handlerName.trim();
 				}
 				registerHandler(url, handler);
 			}

spring-webflux/src/main/java/org/springframework/web/reactive/resource/EncodedResourceResolver.java

@@ -272,8 +272,8 @@ public class EncodedResourceResolver extends AbstractResourceResolver {
 		@Override
 		public HttpHeaders getResponseHeaders() {
 			HttpHeaders headers;
-			if (this.original instanceof HttpResource) {
-				headers = ((HttpResource) this.original).getResponseHeaders();
+			if (this.original instanceof HttpResource httpResource) {
+				headers = httpResource.getResponseHeaders();
 			}
 			else {
 				headers = new HttpHeaders();

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

@@ -247,7 +247,7 @@ public class ModelAttributeMethodArgumentResolver extends HandlerMethodArgumentR
 						}
 					}
 				}
-				value = (value instanceof List ? ((List<?>) value).toArray() : value);
+				value = (value instanceof List<?> valueList ? valueList.toArray() : value);
 				MethodParameter methodParam = new MethodParameter(ctor, i);
 				if (value == null && methodParam.isOptional()) {
 					args[i] = (methodParam.getParameterType() == Optional.class ? Optional.empty() : null);

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

@@ -177,8 +177,8 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	@Nullable
 	private RequestMappingInfo createRequestMappingInfo(AnnotatedElement element) {
 		RequestMapping requestMapping = AnnotatedElementUtils.findMergedAnnotation(element, RequestMapping.class);
-		RequestCondition<?> condition = (element instanceof Class ?
-				getCustomTypeCondition((Class<?>) element) : getCustomMethodCondition((Method) element));
+		RequestCondition<?> condition = (element instanceof Class<?> typeElement ?
+				getCustomTypeCondition(typeElement) : getCustomMethodCondition((Method) element));
 		return (requestMapping != null ? createRequestMappingInfo(requestMapping, condition) : null);
 	}
 

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

@@ -137,8 +137,8 @@ public class ResponseEntityResultHandler extends AbstractMessageWriterResultHand
 
 		return returnValueMono.flatMap(returnValue -> {
 			HttpEntity<?> httpEntity;
-			if (returnValue instanceof HttpEntity) {
-				httpEntity = (HttpEntity<?>) returnValue;
+			if (returnValue instanceof HttpEntity<?> he) {
+				httpEntity = he;
 			}
 			else if (returnValue instanceof ErrorResponse response) {
 				httpEntity = new ResponseEntity<>(response.getBody(), response.getHeaders(), response.getStatusCode());
@@ -146,8 +146,8 @@ public class ResponseEntityResultHandler extends AbstractMessageWriterResultHand
 			else if (returnValue instanceof ProblemDetail detail) {
 				httpEntity = ResponseEntity.of(detail).build();
 			}
-			else if (returnValue instanceof HttpHeaders) {
-				httpEntity = new ResponseEntity<>((HttpHeaders) returnValue, HttpStatus.OK);
+			else if (returnValue instanceof HttpHeaders headers) {
+				httpEntity = new ResponseEntity<>(headers, HttpStatus.OK);
 			}
 			else {
 				throw new IllegalArgumentException(

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

@@ -124,8 +124,8 @@ public class ServerWebExchangeMethodArgumentResolver extends HandlerMethodArgume
 	@Nullable
 	private TimeZone getTimeZone(LocaleContext localeContext) {
 		TimeZone timeZone = null;
-		if (localeContext instanceof TimeZoneAwareLocaleContext) {
-			timeZone = ((TimeZoneAwareLocaleContext) localeContext).getTimeZone();
+		if (localeContext instanceof TimeZoneAwareLocaleContext timeZoneAwareLocaleContext) {
+			timeZone = timeZoneAwareLocaleContext.getTimeZone();
 		}
 		return timeZone;
 	}

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

@@ -126,8 +126,8 @@ public class BindStatus {
 					this.objectErrors = this.errors.getFieldErrors(this.expression);
 					this.value = this.errors.getFieldValue(this.expression);
 					this.valueType = this.errors.getFieldType(this.expression);
-					if (this.errors instanceof BindingResult) {
-						this.bindingResult = (BindingResult) this.errors;
+					if (this.errors instanceof BindingResult bindingResultError) {
+						this.bindingResult = bindingResultError;
 						this.actualValue = this.bindingResult.getRawFieldValue(this.expression);
 						this.editor = this.bindingResult.findEditor(this.expression, null);
 					}
@@ -162,8 +162,8 @@ public class BindStatus {
 			this.errorMessages = new String[0];
 		}
 
-		if (htmlEscape && this.value instanceof String) {
-			this.value = HtmlUtils.htmlEscape((String) this.value);
+		if (htmlEscape && this.value instanceof String valueString) {
+			this.value = HtmlUtils.htmlEscape(valueString);
 		}
 	}
 
@@ -238,8 +238,8 @@ public class BindStatus {
 	 * will get HTML-escaped.
 	 */
 	public String getDisplayValue() {
-		if (this.value instanceof String) {
-			return (String) this.value;
+		if (this.value instanceof String stringValue) {
+			return stringValue;
 		}
 		if (this.value != null) {
 			return (this.htmlEscape ?

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

@@ -324,8 +324,8 @@ public class UrlBasedViewResolver extends ViewResolverSupport
 		ApplicationContext context = getApplicationContext();
 		if (context != null) {
 			Object initialized = context.getAutowireCapableBeanFactory().initializeBean(view, viewName);
-			if (initialized instanceof View) {
-				return (View) initialized;
+			if (initialized instanceof View initializedView) {
+				return initializedView;
 			}
 		}
 		return view;

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

@@ -223,7 +223,7 @@ public class ViewResolutionResultHandler extends HandlerResultHandlerSupport imp
 						if (view == null) {
 							view = getDefaultViewName(exchange);
 						}
-						viewsMono = (view instanceof String ? resolveViews((String) view, locale) :
+						viewsMono = (view instanceof String stringView? resolveViews(stringView, locale) :
 								Mono.just(Collections.singletonList((View) view)));
 					}
 					else if (Model.class.isAssignableFrom(clazz)) {

spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketService.java

@@ -164,8 +164,8 @@ public class HandshakeWebSocketService implements WebSocketService, Lifecycle {
 	}
 
 	protected void doStart() {
-		if (getUpgradeStrategy() instanceof Lifecycle) {
-			((Lifecycle) getUpgradeStrategy()).start();
+		if (getUpgradeStrategy() instanceof Lifecycle lifecycle) {
+			lifecycle.start();
 		}
 	}
 
@@ -178,8 +178,8 @@ public class HandshakeWebSocketService implements WebSocketService, Lifecycle {
 	}
 
 	protected void doStop() {
-		if (getUpgradeStrategy() instanceof Lifecycle) {
-			((Lifecycle) getUpgradeStrategy()).stop();
+		if (getUpgradeStrategy() instanceof Lifecycle lifecycle) {
+			lifecycle.stop();
 		}
 	}
 

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

@@ -84,8 +84,8 @@ class WebClientDataBufferAllocatingTests extends AbstractDataBufferAllocatingTes
 	private ReactorClientHttpConnector initConnector() {
 		assertThat(super.bufferFactory).isNotNull();
 
-		if (super.bufferFactory instanceof NettyDataBufferFactory) {
-			ByteBufAllocator allocator = ((NettyDataBufferFactory) super.bufferFactory).getByteBufAllocator();
+		if (super.bufferFactory instanceof NettyDataBufferFactory nettyDataBufferFactory) {
+			ByteBufAllocator allocator = nettyDataBufferFactory.getByteBufAllocator();
 			return new ReactorClientHttpConnector(this.factory,
 					client -> client.option(ChannelOption.ALLOCATOR, allocator));
 		}

spring-webflux/src/test/java/org/springframework/web/reactive/protobuf/Msg.java

@@ -144,8 +144,8 @@ public  final class Msg extends
    */
   public String getFoo() {
     Object ref = foo_;
-    if (ref instanceof String) {
-      return (String) ref;
+    if (ref instanceof String stringRef) {
+      return stringRef;
     } else {
       com.google.protobuf.ByteString bs =
           (com.google.protobuf.ByteString) ref;
@@ -162,10 +162,9 @@ public  final class Msg extends
   public com.google.protobuf.ByteString
       getFooBytes() {
     Object ref = foo_;
-    if (ref instanceof String) {
+    if (ref instanceof String stringRef) {
       com.google.protobuf.ByteString b =
-          com.google.protobuf.ByteString.copyFromUtf8(
-              (String) ref);
+          com.google.protobuf.ByteString.copyFromUtf8(stringRef);
       foo_ = b;
       return b;
     } else {
@@ -405,8 +404,8 @@ public  final class Msg extends
     }
 
     public Builder mergeFrom(com.google.protobuf.Message other) {
-      if (other instanceof Msg) {
-        return mergeFrom((Msg)other);
+      if (other instanceof Msg msg) {
+        return mergeFrom(msg);
       } else {
         super.mergeFrom(other);
         return this;
@@ -463,13 +462,13 @@ public  final class Msg extends
      */
     public String getFoo() {
       Object ref = foo_;
-      if (!(ref instanceof String)) {
+      if (!(ref instanceof String stringRef)) {
         String s = ((com.google.protobuf.ByteString) ref)
             .toStringUtf8();
         foo_ = s;
         return s;
       } else {
-        return (String) ref;
+        return stringRef;
       }
     }
     /**
@@ -478,10 +477,9 @@ public  final class Msg extends
     public com.google.protobuf.ByteString
         getFooBytes() {
       Object ref = foo_;
-      if (ref instanceof String) {
+      if (ref instanceof String stringRef) {
         com.google.protobuf.ByteString b =
-            com.google.protobuf.ByteString.copyFromUtf8(
-                (String) ref);
+            com.google.protobuf.ByteString.copyFromUtf8(stringRef);
         foo_ = b;
         return b;
       } else {

spring-webflux/src/test/java/org/springframework/web/reactive/protobuf/SecondMsg.java

@@ -304,8 +304,8 @@ public  final class SecondMsg extends
     }
 
     public Builder mergeFrom(com.google.protobuf.Message other) {
-      if (other instanceof SecondMsg) {
-        return mergeFrom((SecondMsg)other);
+      if (other instanceof SecondMsg secondMsg) {
+        return mergeFrom(secondMsg);
       } else {
         super.mergeFrom(other);
         return this;

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

@@ -354,7 +354,7 @@ class MultipartIntegrationTests extends AbstractHttpHandlerIntegrationTests {
 	}
 
 	private static String partDescription(Part part) {
-		return part instanceof FilePart ? part.name() + ":" + ((FilePart) part).filename() : part.name();
+		return part instanceof FilePart filePart? part.name() + ":" + filePart.filename() : part.name();
 	}
 
 	static class FormBean {

spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractReactiveWebSocketIntegrationTests.java

@@ -142,15 +142,15 @@ abstract class AbstractReactiveWebSocketIntegrationTests {
 		// Set dynamically chosen port
 		this.port = this.server.getPort();
 
-		if (this.client instanceof Lifecycle) {
-			((Lifecycle) this.client).start();
+		if (this.client instanceof Lifecycle lifecycle) {
+			lifecycle.start();
 		}
 	}
 
 	@AfterEach
 	void stopServer() {
-		if (this.client instanceof Lifecycle) {
-			((Lifecycle) this.client).stop();
+		if (this.client instanceof Lifecycle lifecycle) {
+			lifecycle.stop();
 		}
 		this.server.stop();
 	}