Consumer methods for WebHttpHandlerBuilder

Replace the more limited List-based methods to add filtes and exception
handlers with Consumer<List<?>> variants.

spring-test/src/main/java/org/springframework/test/web/reactive/server/AbstractMockServerSpec.java

@@ -51,23 +51,20 @@ abstract class AbstractMockServerSpec<B extends WebTestClient.MockServerSpec<B>>
 	@Override
 	public WebTestClient.Builder configureClient() {
 		WebHttpHandlerBuilder builder = initHttpHandlerBuilder();
-		filtersInReverse().forEach(builder::prependFilter);
+		builder.filters(currentFilters -> {
+			List<WebFilter> toPrepend = new ArrayList<>(this.filters);
+			Collections.reverse(toPrepend);
+			toPrepend.forEach(filter -> currentFilters.add(0, filter));
+		});
 		return new DefaultWebTestClientBuilder(builder.build());
 	}
 
 	/**
-	 * Sub-classes to create the {@code WebHttpHandlerBuilder} to use.
+	 * Sub-classes must create an {@code WebHttpHandlerBuilder} that will then
+	 * be used to create the HttpHandler for the mock server.
 	 */
 	protected abstract WebHttpHandlerBuilder initHttpHandlerBuilder();
 
-	/**
-	 * Return the filters in reverse order for pre-pending.
-	 */
-	private List<WebFilter> filtersInReverse() {
-		List<WebFilter> result = new ArrayList<>(this.filters);
-		Collections.reverse(result);
-		return result;
-	}
 
 	@Override
 	public WebTestClient build() {

spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultMockServerSpec.java

@@ -20,6 +20,8 @@ import org.springframework.web.server.WebHandler;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
 
 /**
+ * Simple extension of {@link AbstractMockServerSpec} that is given a target
+ * {@link WebHandler}.
  *
  * @author Rossen Stoyanchev
  * @since 5.0

spring-web/src/main/java/org/springframework/web/server/adapter/WebHttpHandlerBuilder.java

@@ -17,7 +17,9 @@ package org.springframework.web.server.adapter;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
+import java.util.function.Consumer;
 
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -133,8 +135,8 @@ public class WebHttpHandlerBuilder {
 
 		SortedBeanContainer container = new SortedBeanContainer();
 		context.getAutowireCapableBeanFactory().autowireBean(container);
-		builder.filters(container.getFilters());
-		builder.exceptionHandlers(container.getExceptionHandlers());
+		builder.filters(filters -> filters.addAll(container.getFilters()));
+		builder.exceptionHandlers(handlers -> handlers.addAll(container.getExceptionHandlers()));
 
 		try {
 			builder.sessionManager(
@@ -166,8 +168,8 @@ public class WebHttpHandlerBuilder {
 
 	/**
 	 * Add the given filter(s).
-	 * @param filters the filter(s) to add
-that's	 */
+	 * @param filters the filter(s) to add that's
+	 */
 	public WebHttpHandlerBuilder filter(WebFilter... filters) {
 		if (!ObjectUtils.isEmpty(filters)) {
 			this.filters.addAll(Arrays.asList(filters));
@@ -176,23 +178,11 @@ that's	 */
 	}
 
 	/**
-	 * Add the given filters.
-	 * @param filters the filters to add
-	 */
-	public WebHttpHandlerBuilder filters(List<? extends WebFilter> filters) {
-		if (!ObjectUtils.isEmpty(filters)) {
-			this.filters.addAll(filters);
-		}
-		return this;
-	}
-
-	/**
-	 * Insert the given filter before other configured filters.
-	 * @param filter the filters to insert
+	 * Manipulate the "live" list of currently configured filters.
+	 * @param consumer the consumer to use
 	 */
-	public WebHttpHandlerBuilder prependFilter(WebFilter filter) {
-		Assert.notNull(filter, "WebFilter is required");
-		this.filters.add(0, filter);
+	public WebHttpHandlerBuilder filters(Consumer<List<WebFilter>> consumer) {
+		consumer.accept(this.filters);
 		return this;
 	}
 
@@ -208,23 +198,11 @@ that's	 */
 	}
 
 	/**
-	 * Add the given exception handlers.
-	 * @param handlers the exception handlers
-	 */
-	public WebHttpHandlerBuilder exceptionHandlers(List<WebExceptionHandler> handlers) {
-		if (!ObjectUtils.isEmpty(handlers)) {
-			this.exceptionHandlers.addAll(handlers);
-		}
-		return this;
-	}
-
-	/**
-	 * Insert the given exception handler before other configured handlers.
-	 * @param handler the exception handler to insert
+	 * Manipulate the "live" list of currently configured exception handlers.
+	 * @param consumer the consumer to use
 	 */
-	public WebHttpHandlerBuilder prependExceptionHandler(WebExceptionHandler handler) {
-		Assert.notNull(handler, "WebExceptionHandler is required");
-		this.exceptionHandlers.add(0, handler);
+	public WebHttpHandlerBuilder exceptionHandlers(Consumer<List<WebExceptionHandler>> consumer) {
+		consumer.accept(this.exceptionHandlers);
 		return this;
 	}
 
@@ -288,9 +266,9 @@ that's	 */
 
 	private static class SortedBeanContainer {
 
-		private List<WebFilter> filters;
+		private List<WebFilter> filters = Collections.emptyList();
 
-		private List<WebExceptionHandler> exceptionHandlers;
+		private List<WebExceptionHandler> exceptionHandlers = Collections.emptyList();
 
 
 		@Autowired(required = false)

spring-web/src/test/java/org/springframework/web/server/adapter/WebHttpHandlerBuilderTests.java

@@ -36,8 +36,8 @@ import org.springframework.web.server.WebExceptionHandler;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebHandler;
 
-import static java.time.Duration.*;
-import static org.junit.Assert.*;
+import static java.time.Duration.ofMillis;
+import static org.junit.Assert.assertEquals;
 
 /**
  * Unit tests for {@link WebHttpHandlerBuilder}.

spring-web/src/test/java/org/springframework/web/server/handler/FilteringWebHandlerTests.java

@@ -119,8 +119,8 @@ public class FilteringWebHandlerTests {
 		TestExceptionHandler exceptionHandler = new TestExceptionHandler();
 
 		WebHttpHandlerBuilder.webHandler(new StubWebHandler())
-				.filters(Collections.singletonList(new ExceptionFilter()))
-				.exceptionHandlers(Collections.singletonList(exceptionHandler)).build()
+				.filter(new ExceptionFilter())
+				.exceptionHandler(exceptionHandler).build()
 				.handle(request, response)
 				.block();
 

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

@@ -197,8 +197,8 @@ public abstract class RouterFunctions {
 
 		WebHandler webHandler = toWebHandler(routerFunction, strategies);
 		return WebHttpHandlerBuilder.webHandler(webHandler)
-				.filters(strategies.webFilters())
-				.exceptionHandlers(strategies.exceptionHandlers())
+				.filters(filters -> filters.addAll(strategies.webFilters()))
+				.exceptionHandlers(handlers -> handlers.addAll(strategies.exceptionHandlers()))
 				.localeContextResolver(strategies.localeContextResolver())
 				.build();
 	}

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

@@ -63,7 +63,7 @@ public class SimpleUrlHandlerMappingIntegrationTests extends AbstractHttpHandler
 		wac.refresh();
 
 		return WebHttpHandlerBuilder.webHandler(new DispatcherHandler(wac))
-				.exceptionHandlers(Collections.singletonList(new ResponseStatusExceptionHandler()))
+				.exceptionHandler(new ResponseStatusExceptionHandler())
 				.build();
 	}