Support ListenableFuture on @RequestMapping methods

Issue: SPR-11695

spring-test/src/test/java/org/springframework/test/web/servlet/samples/standalone/AsyncTests.java

@@ -34,6 +34,8 @@ import org.springframework.test.web.Person;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.test.web.servlet.MvcResult;
 import org.springframework.ui.Model;
+import org.springframework.util.concurrent.ListenableFuture;
+import org.springframework.util.concurrent.ListenableFutureTask;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.context.request.async.DeferredResult;
@@ -96,11 +98,29 @@ public class AsyncTests {
 				.andExpect(content().string("{\"name\":\"Joe\",\"someDouble\":0.0,\"someBoolean\":false}"));
 	}
 
+	@Test
+	public void testListenableFuture() throws Exception {
+		MvcResult mvcResult = this.mockMvc.perform(get("/1").param("listenableFuture", "true"))
+				.andExpect(request().asyncStarted())
+				.andReturn();
+
+		this.asyncController.onMessage("Joe");
+
+		this.mockMvc.perform(asyncDispatch(mvcResult))
+				.andExpect(status().isOk())
+				.andExpect(content().contentType(MediaType.APPLICATION_JSON))
+				.andExpect(content().string("{\"name\":\"Joe\",\"someDouble\":0.0,\"someBoolean\":false}"));
+	}
+
 
 	@Controller
 	private static class AsyncController {
 
-		private Collection<DeferredResult<Person>> deferredResults = new CopyOnWriteArrayList<DeferredResult<Person>>();
+		private Collection<DeferredResult<Person>> deferredResults =
+				new CopyOnWriteArrayList<DeferredResult<Person>>();
+
+		private Collection<ListenableFutureTask<Person>> futureTasks =
+				new CopyOnWriteArrayList<ListenableFutureTask<Person>>();
 
 
 		@RequestMapping(value="/{id}", params="callable", produces="application/json")
@@ -130,11 +150,28 @@ public class AsyncTests {
 			return deferredResult;
 		}
 
+		@RequestMapping(value="/{id}", params="listenableFuture", produces="application/json")
+		@ResponseBody
+		public ListenableFuture<Person> getListenableFuture() {
+			ListenableFutureTask<Person> futureTask = new ListenableFutureTask<Person>(new Callable<Person>() {
+				@Override
+				public Person call() throws Exception {
+					return new Person("Joe");
+				}
+			});
+			this.futureTasks.add(futureTask);
+			return futureTask;
+		}
+
 		public void onMessage(String name) {
 			for (DeferredResult<Person> deferredResult : this.deferredResults) {
 				deferredResult.setResult(new Person(name));
 				this.deferredResults.remove(deferredResult);
 			}
+			for (ListenableFutureTask<Person> futureTask : this.futureTasks) {
+				futureTask.run();
+				this.futureTasks.remove(futureTask);
+			}
 		}
 	}
 

spring-web/src/main/java/org/springframework/web/bind/annotation/RequestMapping.java

@@ -204,6 +204,9 @@ import java.util.concurrent.Callable;
  * <li>A {@link org.springframework.web.context.request.async.DeferredResult}
  * which the application uses to produce a return value in a separate
  * thread of its own choosing, as an alternative to returning a Callable.
+ * <li>A {@link org.springframework.util.concurrent.ListenableFuture}
+ * which the application uses to produce a return value in a separate
+ * thread of its own choosing, as an alternative to returning a Callable.
  * <li>{@code void} if the method handles the response itself (by
  * writing the response content directly, declaring an argument of type
  * {@link javax.servlet.ServletResponse} / {@link javax.servlet.http.HttpServletResponse}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ListenableFutureReturnValueHandler.java

+/*
+ * Copyright 2002-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.web.servlet.mvc.method.annotation;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.util.concurrent.ListenableFuture;
+import org.springframework.util.concurrent.ListenableFutureCallback;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.context.request.async.DeferredResult;
+import org.springframework.web.context.request.async.WebAsyncUtils;
+import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
+import org.springframework.web.method.support.ModelAndViewContainer;
+
+/**
+ * Handles return values of type
+ * {@link org.springframework.util.concurrent.ListenableFuture}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 4.1
+ */
+public class ListenableFutureReturnValueHandler implements HandlerMethodReturnValueHandler {
+
+	@Override
+	public boolean supportsReturnType(MethodParameter returnType) {
+		Class<?> paramType = returnType.getParameterType();
+		return ListenableFuture.class.isAssignableFrom(paramType);
+	}
+
+	@Override
+	public void handleReturnValue(Object returnValue,
+			MethodParameter returnType, ModelAndViewContainer mavContainer,
+			NativeWebRequest webRequest) throws Exception {
+
+		if (returnValue == null) {
+			mavContainer.setRequestHandled(true);
+			return;
+		}
+
+		DeferredResult<Object> deferredResult = new DeferredResult<Object>();
+		WebAsyncUtils.getAsyncManager(webRequest).startDeferredResultProcessing(deferredResult, mavContainer);
+
+		ListenableFuture<?> future = (ListenableFuture<?>) returnValue;
+		future.addCallback(new ListenableFutureCallback<Object>() {
+			@Override
+			public void onSuccess(Object result) {
+				deferredResult.setResult(result);
+			}
+			@Override
+			public void onFailure(Throwable ex) {
+				deferredResult.setErrorResult(ex);
+			}
+		});
+	}
+
+}

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerAdapter.java

@@ -588,6 +588,7 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter
 		handlers.add(new CallableMethodReturnValueHandler());
 		handlers.add(new DeferredResultMethodReturnValueHandler());
 		handlers.add(new AsyncTaskMethodReturnValueHandler(this.beanFactory));
+		handlers.add(new ListenableFutureReturnValueHandler());
 
 		// Annotation-based return value types
 		handlers.add(new ModelAttributeMethodProcessor(false));

src/asciidoc/index.adoc

@@ -29143,6 +29143,8 @@ The following are the supported return types:
   asynchronously in a thread managed by Spring MVC.
 * A `DeferredResult<?>` can be returned when the application wants to produce the return
   value from a thread of its own choosing.
+* A `ListenableFuture<?>` can be returned when the application wants to produce the return
+  value from a thread of its own choosing.
 * Any other return type is considered to be a single model attribute to be exposed to
   the view, using the attribute name specified through `@ModelAttribute` at the method
   level (or the default attribute name based on the return type class name). The model