Spring Mvc RxJava integration.

README.adoc

@@ -139,7 +139,7 @@ or you will encounter compile problems. It also needs a specific version of mave
 enabled. Intellij 14.1+ requires some configuration to ensure these are setup properly.
 
  1. Click Preferences, Plugins. *Ensure Lombok is installed*
- 2. Click New, Project from Existing Sources, choose your spring-cloud-sleuth directory
+ 2. Click New, Project from Existing Sources, choose your spring-cloud project directory
  3. Choose Maven, and select Environment Settings. *Ensure you are using Maven 3.3.3*
  4. In the next screen, *Select the profile `spring`* click Next until Finish.
  5. Click Preferences, "Build, Execution, Deployment", Compiler, Annotation Processors. *Click Enable Annotation Processing*

docs/src/main/asciidoc/spring-cloud-netflix.adoc

@@ -1483,6 +1483,36 @@ info:
   url: https://github.com/spring-cloud-samples
 ----
 
+[[netflix-rxjava-springmvc]]
+== RxJava with Spring MVC
+Spring Cloud Netflix includes the https://github.com/ReactiveX/RxJava[RxJava].
+
+> RxJava is a Java VM implementation of http://reactivex.io/[Reactive Extensions]: a library for composing asynchronous and event-based programs by using observable sequences.
+
+Spring Cloud Netflix provides support for returning `rx.Single` objects from Spring MVC Controllers. It also supports using `rx.Observable` objects for https://en.wikipedia.org/wiki/Server-sent_events[Server-sent events (SSE)]. This can be very convenient if your internal APIs are already built using RxJava (see <<spring-cloud-feign-hystrix>> for examples).
+
+Here are some examples of using `rx.Single`:
+
+[source,java]
+----
+include::../../../../spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/SingleReturnValueHandlerTest.java[tags=rx_single,indent=0]
+----
+
+If you have an `Observable`, rather than a single, you can use `.toSingle()` or `.toList().toSingle()`. Here are some examples:
+
+[source,java]
+----
+include::../../../../spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableReturnValueHandlerTest.java[tags=rx_observable,indent=0]
+----
+
+If you have a streaming endpoint and client, SSE could be an option. To convert `rx.Observable` to a Spring `SseEmitter` use `RxResponse.sse()`. Here are some examples:
+
+[source,java]
+----
+include::../../../../spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableSseEmitterTest.java[tags=rx_observable_sse,indent=0]
+----
+
+[[netflix-metrics]]
 == Metrics: Spectator, Servo, and Atlas
 
 When used together, Spectator/Servo and Atlas provide a near real-time operational insight platform.
@@ -1545,6 +1575,7 @@ If Spring AOP is enabled and `org.aspectj:aspectjweaver` is present on your runt
 3. URI, sanitized for Atlas
 4. Client name
 
+[[netflix-metrics-spectator]]
 === Metrics Collection: Spectator
 
 To enable Spectator metrics, include a dependency on `spring-boot-starter-spectator`:
@@ -1626,6 +1657,7 @@ DistributionSummary ds = registry.distributionSummary("dsName", "tagKey1", "tagV
 ds.record(request.sizeInBytes());
 ----
 
+[[netflix-metrics-servo]]
 === Metrics Collection: Servo
 
 WARNING: If your code is compiled on Java 8, please use Spectator instead of Servo as Spectator is destined to replace Servo entirely in the long term.
@@ -1649,6 +1681,7 @@ Timer timer = new BasicTimer(config);
 monitorRegistry.register(timer);
 ----
 
+[[netflix-metrics-atlas]]
 === Metrics Backend: Atlas
 
 Atlas was developed by Netflix to manage dimensional time series data for near real-time operational insight. Atlas features in-memory data storage, allowing it to gather and report very large numbers of metrics, very quickly.

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/ObservableReturnValueHandler.java → spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/DeferredResultSubscriber.java

 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -16,60 +16,53 @@
 
 package org.springframework.cloud.netflix.rx;
 
-import org.springframework.core.MethodParameter;
-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.AsyncHandlerMethodReturnValueHandler;
-import org.springframework.web.method.support.ModelAndViewContainer;
 
 import rx.Observable;
-import rx.functions.Action1;
+import rx.Subscriber;
+import rx.Subscription;
 
 /**
- * MVC handler for return values of type {@link rx.Observable}.
+ * A subscriber that sets the single value produced by the {@link Observable} on the {@link DeferredResult}.
  *
- * @author Spencer Gibb
+ * @author Jakub Narloch
+ * @see DeferredResult
  */
-public class ObservableReturnValueHandler
-		implements AsyncHandlerMethodReturnValueHandler {
+class DeferredResultSubscriber<T> extends Subscriber<T> implements Runnable {
 
-	@Override
-	public boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType) {
-		return returnValue != null && returnValue instanceof Observable;
-	}
+    private final DeferredResult<T> deferredResult;
 
-	@Override
-	public boolean supportsReturnType(MethodParameter returnType) {
-		return Observable.class.isAssignableFrom(returnType.getParameterType());
-	}
+    private final Subscription subscription;
 
-	@Override
-	public void handleReturnValue(Object returnValue, MethodParameter returnType,
-			ModelAndViewContainer mavContainer, NativeWebRequest webRequest)
-					throws Exception {
-		if (returnValue == null) {
-			mavContainer.setRequestHandled(true);
-			return;
-		}
+    private boolean completed;
 
-		Observable<?> observable = Observable.class.cast(returnValue);
+    public DeferredResultSubscriber(Observable<T> observable, DeferredResult<T> deferredResult) {
 
-		final DeferredResult<Object> deferredResult = new DeferredResult<>();
+        this.deferredResult = deferredResult;
+        this.deferredResult.onTimeout(this);
+        this.deferredResult.onCompletion(this);
+        this.subscription = observable.subscribe(this);
+    }
 
-		observable.subscribe(new Action1<Object>() {
-			@Override
-			public void call(Object o) {
-				deferredResult.setResult(o);
-			}
-		}, new Action1<Throwable>() {
-			@Override
-			public void call(Throwable throwable) {
-				deferredResult.setErrorResult(throwable);
-			}
-		});
+    @Override
+    public void onNext(T value) {
+        if (!completed) {
+            deferredResult.setResult(value);
+        }
+    }
 
-		WebAsyncUtils.getAsyncManager(webRequest)
-				.startDeferredResultProcessing(deferredResult, mavContainer);
-	}
+    @Override
+    public void onError(Throwable e) {
+        deferredResult.setErrorResult(e);
+    }
+
+    @Override
+    public void onCompleted() {
+        completed = true;
+    }
+
+    @Override
+    public void run() {
+        this.subscription.unsubscribe();
+    }
 }

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/ObservableSseEmitter.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+import rx.Observable;
+
+/**
+ * A specialized {@link SseEmitter} that handles {@link Observable} return types.
+ *
+ * @author Jakub Narloch
+ * @see SseEmitter
+ */
+class ObservableSseEmitter<T> extends SseEmitter {
+
+    private final ResponseBodyEmitterSubscriber<T> subscriber;
+
+    public ObservableSseEmitter(Observable<T> observable) {
+        this(null, observable);
+    }
+
+    public ObservableSseEmitter(MediaType mediaType, Observable<T> observable) {
+        this(null, mediaType, observable);
+    }
+
+    public ObservableSseEmitter(Long timeout, MediaType mediaType, Observable<T> observable) {
+        super(timeout);
+        this.subscriber = new ResponseBodyEmitterSubscriber<>(mediaType, observable, this);
+    }
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/ResponseBodyEmitterSubscriber.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import java.io.IOException;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyEmitter;
+
+import rx.Observable;
+import rx.Subscriber;
+import rx.Subscription;
+
+
+/**
+ * Subscriber that emits any value produced by the {@link Observable} into the delegated {@link ResponseBodyEmitter}.
+ *
+ * @author Jakub Narloch
+ */
+class ResponseBodyEmitterSubscriber<T> extends Subscriber<T> implements Runnable {
+
+    private final MediaType mediaType;
+
+    private final Subscription subscription;
+
+    private final ResponseBodyEmitter responseBodyEmitter;
+
+    private boolean completed;
+
+    /**
+     * Creates new instance of {@link ResponseBodyEmitterSubscriber} with response media type, observable and response
+     * emitter.
+     *
+     * @param mediaType the marshaled object media type
+     * @param observable the observable
+     * @param responseBodyEmitter the response emitter
+     */
+    public ResponseBodyEmitterSubscriber(MediaType mediaType, Observable<T> observable, ResponseBodyEmitter responseBodyEmitter) {
+
+        this.mediaType = mediaType;
+        this.responseBodyEmitter = responseBodyEmitter;
+        this.responseBodyEmitter.onTimeout(this);
+        this.responseBodyEmitter.onCompletion(this);
+        this.subscription = observable.subscribe(this);
+    }
+
+    @Override
+    public void onNext(T value) {
+
+        try {
+            if(!completed) {
+                responseBodyEmitter.send(value, mediaType);
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e.getMessage(), e);
+        }
+    }
+
+    @Override
+    public void onError(Throwable e) {
+        responseBodyEmitter.completeWithError(e);
+    }
+
+    @Override
+    public void onCompleted() {
+        if(!completed) {
+            completed = true;
+            responseBodyEmitter.complete();
+        }
+    }
+
+    @Override
+    public void run() {
+        subscription.unsubscribe();
+    }
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/RxJavaAutoConfiguration.java

 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -28,6 +28,7 @@ import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
 
 import rx.Observable;
+import rx.Single;
 
 /**
  * @author Spencer Gibb
@@ -39,25 +40,25 @@ public class RxJavaAutoConfiguration {
 
 	@Configuration
 	@ConditionalOnClass(AsyncHandlerMethodReturnValueHandler.class)
-	protected static class ObservableReturnValueHandlerConfig {
+	protected static class RxJavaReturnValueHandlerConfig {
 		@Bean
-		public ObservableReturnValueHandler observableReturnValueHandler() {
-			return new ObservableReturnValueHandler();
+		public SingleReturnValueHandler singleReturnValueHandler() {
+			return new SingleReturnValueHandler();
 		}
 
 		@Bean
-		public WebMvcConfigurerAdapter observableMVCConfiguration() {
+		public WebMvcConfigurerAdapter observableMVCConfiguration(final SingleReturnValueHandler singleReturnValueHandler) {
 			return new WebMvcConfigurerAdapter() {
 				@Override
 				public void addReturnValueHandlers(List<HandlerMethodReturnValueHandler> returnValueHandlers) {
-					returnValueHandlers.add(observableReturnValueHandler());
+					returnValueHandlers.add(singleReturnValueHandler);
 				}
 			};
 		}
 
 		@Bean
 		public HasFeatures rxFeature() {
-			return HasFeatures.namedFeature("MVC Observable", Observable.class);
+			return HasFeatures.namedFeatures("MVC Observable", Observable.class, "MVC Single", Single.class);
 		}
 	}
 }

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/RxResponse.java

+package org.springframework.cloud.netflix.rx;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+import rx.Observable;
+
+/**
+ * A convenient class allowing to wrap either the {@link Observable} into a response supported by the
+ * Spring MVC.
+ *
+ * @author Jakub Narloch
+ */
+public final class RxResponse {
+
+    private RxResponse() {
+
+    }
+
+    /**
+     * Wraps the {@link Observable} into a {@link SseEmitter}. Every value produced by the observable will be emitted
+     * as server side event.
+     *
+     * @param observable the observable instance
+     * @param <T> the result type
+     * @return the sse emitter
+     */
+    public static <T> SseEmitter sse(Observable<T> observable) {
+        return new ObservableSseEmitter<>(observable);
+    }
+
+    /**
+     * Wraps the {@link Observable} into a {@link SseEmitter}. Every value produced by the observable will be emitted
+     * as server side event.
+     *
+     * @param mediaType the media type of produced entry
+     * @param observable the observable instance
+     * @param <T> the result type
+     * @return the sse emitter
+     */
+    public static <T> SseEmitter sse(MediaType mediaType, Observable<T> observable) {
+        return new ObservableSseEmitter<>(mediaType, observable);
+    }
+
+    /**
+     * Wraps the {@link Observable} into a {@link SseEmitter}. Every value produced by the observable will be emitted
+     * as server side event.
+     *
+     * @param timeout the response timeout
+     * @param mediaType the media type of produced entry
+     * @param observable the observable instance
+     * @param <T> the result type
+     * @return the sse emitter
+     */
+    public static <T> SseEmitter sse(long timeout, MediaType mediaType, Observable<T> observable) {
+        return new ObservableSseEmitter<>(timeout, mediaType, observable);
+    }
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/SingleDeferredResult.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import org.springframework.util.Assert;
+import org.springframework.web.context.request.async.DeferredResult;
+
+import rx.Single;
+
+/**
+ * A specialized {@link DeferredResult} that handles {@link Single} return type.
+ *
+ * @author Jakub Narloch
+ * @see DeferredResult
+ */
+class SingleDeferredResult<T> extends DeferredResult<T> {
+
+    private static final Object EMPTY_RESULT = new Object();
+
+    private final DeferredResultSubscriber<T> subscriber;
+
+    public SingleDeferredResult(Single<T> single) {
+        this(null, EMPTY_RESULT, single);
+    }
+
+    public SingleDeferredResult(long timeout, Single<T> single) {
+        this(timeout, EMPTY_RESULT, single);
+    }
+
+    public SingleDeferredResult(Long timeout, Object timeoutResult, Single<T> single) {
+        super(timeout, timeoutResult);
+        Assert.notNull(single, "single can not be null");
+
+        subscriber = new DeferredResultSubscriber<>(single.toObservable(), this);
+    }
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/rx/SingleReturnValueHandler.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.core.ResolvableType;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+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.AsyncHandlerMethodReturnValueHandler;
+import org.springframework.web.method.support.ModelAndViewContainer;
+
+import rx.Single;
+import rx.functions.Func1;
+
+/**
+ * A specialized {@link AsyncHandlerMethodReturnValueHandler} that handles {@link Single} return types.
+ *
+ * @author Spencer Gibb
+ * @author Jakub Narloch
+ */
+public class SingleReturnValueHandler implements AsyncHandlerMethodReturnValueHandler {
+
+    @Override
+    public boolean isAsyncReturnValue(Object returnValue, MethodParameter returnType) {
+        return returnValue != null && supportsReturnType(returnType);
+    }
+
+    @Override
+    public boolean supportsReturnType(MethodParameter returnType) {
+        return Single.class.isAssignableFrom(returnType.getParameterType()) || isResponseEntity(returnType);
+    }
+
+	private boolean isResponseEntity(MethodParameter returnType) {
+		if(ResponseEntity.class.isAssignableFrom(returnType.getParameterType())) {
+			Class<?> bodyType = ResolvableType.forMethodParameter(returnType).getGeneric(0).resolve();
+			return bodyType != null && Single.class.isAssignableFrom(bodyType);
+		}
+		return false;
+	}
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public void handleReturnValue(Object returnValue, MethodParameter returnType, ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception {
+
+        if (returnValue == null) {
+            mavContainer.setRequestHandled(true);
+            return;
+        }
+
+		ResponseEntity<Single<?>> responseEntity = getResponseEntity(returnValue);
+		if(responseEntity != null) {
+			returnValue = responseEntity.getBody();
+			if (returnValue == null) {
+				mavContainer.setRequestHandled(true);
+				return;
+			}
+		}
+
+        final Single<?> single = Single.class.cast(returnValue);
+        WebAsyncUtils.getAsyncManager(webRequest)
+                .startDeferredResultProcessing(convertToDeferredResult(responseEntity, single), mavContainer);
+    }
+
+	@SuppressWarnings("unchecked")
+	private ResponseEntity<Single<?>> getResponseEntity(Object returnValue) {
+		if (ResponseEntity.class.isAssignableFrom(returnValue.getClass())) {
+			return (ResponseEntity<Single<?>>) returnValue;
+
+		}
+		return null;
+	}
+
+	protected DeferredResult<?> convertToDeferredResult(final ResponseEntity<Single<?>> responseEntity, Single<?> single) {
+
+		//TODO: fix when java8 :-)
+		Single<ResponseEntity> singleResponse = single.map(new Func1<Object, ResponseEntity>() {
+			@Override
+			public ResponseEntity call(Object object) {
+				return new ResponseEntity<>(object, getHttpHeaders(responseEntity), getHttpStatus(responseEntity));
+			}
+		});
+
+		return new SingleDeferredResult<>(singleResponse);
+	}
+
+	private HttpStatus getHttpStatus(ResponseEntity<?> responseEntity) {
+		if(responseEntity == null) {
+			return HttpStatus.OK;
+		}
+		return responseEntity.getStatusCode();
+	}
+
+	private HttpHeaders getHttpHeaders(ResponseEntity<?> responseEntity) {
+		if(responseEntity == null) {
+			return new HttpHeaders();
+		}
+		return responseEntity.getHeaders();
+	}
+}

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableReturnValueHandlerTest.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Ignore;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.IntegrationTest;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.boot.test.TestRestTemplate;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+import rx.Observable;
+import rx.Single;
+import rx.functions.Func1;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
+
+/**
+ * Tests the demonstrate using {@link Observable} with {@link SingleReturnValueHandler} class.
+ *
+ * @author Spencer Gibb
+ * @author Jakub Narloch
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = ObservableReturnValueHandlerTest.Application.class)
+@WebAppConfiguration
+@IntegrationTest({"server.port=0"})
+@DirtiesContext
+public class ObservableReturnValueHandlerTest {
+
+    @Value("${local.server.port}")
+    private int port = 0;
+
+    private TestRestTemplate restTemplate = new TestRestTemplate();
+
+    @Configuration
+    @EnableAutoConfiguration
+    @RestController
+    protected static class Application {
+
+		// tag::rx_observable[]
+        @RequestMapping(method = RequestMethod.GET, value = "/single")
+        public Single<String> single() {
+            return Observable.just("single value").toSingle();
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/multiple")
+        public Single<List<String>> multiple() {
+            return Observable.just("multiple", "values").toList().toSingle();
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/responseWithObservable")
+        public ResponseEntity<Single<String>> responseWithObservable() {
+
+            Observable<String> observable = Observable.just("single value");
+            HttpHeaders headers = new HttpHeaders();
+            headers.setContentType(APPLICATION_JSON_UTF8);
+            return new ResponseEntity<>(observable.toSingle(), headers, HttpStatus.CREATED);
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/timeout")
+        public Observable<String> timeout() {
+            return Observable.timer(1, TimeUnit.MINUTES).map(new Func1<Long, String>() {
+                @Override
+                public String call(Long aLong) {
+                    return "single value";
+                }
+            });
+        }
+		// end::rx_observable[]
+
+		@RequestMapping(method = RequestMethod.GET, value = "/throw")
+		public Single<Object> error() {
+			return Observable.error(new RuntimeException("Unexpected")).toSingle();
+		}
+    }
+
+    @Test
+    public void shouldRetrieveSingleValue() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/single"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals("single value", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveMultipleValues() {
+
+        // when
+        ResponseEntity<List> response = restTemplate.getForEntity(path("/multiple"), List.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals(Arrays.asList("multiple", "values"), response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveSingleValueWithStatusCodeAndCustomHeader() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/responseWithObservable"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.CREATED, response.getStatusCode());
+        assertEquals(MediaType.APPLICATION_JSON_UTF8, response.getHeaders().getContentType());
+        assertEquals("single value", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveErrorResponse() {
+
+        // when
+        ResponseEntity<Object> response = restTemplate.getForEntity(path("/throw"), Object.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, response.getStatusCode());
+    }
+
+    @Test
+	@Ignore("adds 30s to build")
+    public void shouldTimeoutOnConnection() {
+
+        // when
+        ResponseEntity<Object> response = restTemplate.getForEntity(path("/timeout"), Object.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, response.getStatusCode());
+    }
+
+    private String path(String context) {
+        return String.format("http://localhost:%d%s", port, context);
+    }
+}
\ No newline at end of file

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableSseEmitterTest.java

+/*
+ * Copyright 2013-2016 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.cloud.netflix.rx;
+
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.TimeZone;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.IntegrationTest;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.boot.test.TestRestTemplate;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.web.WebAppConfiguration;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+import rx.Observable;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.springframework.http.MediaType.APPLICATION_JSON_UTF8;
+
+/**
+ * Tests the {@link ObservableSseEmitter} class.
+ *
+ * @author Spencer Gibb
+ * @author Jakub Narloch
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = ObservableSseEmitterTest.Application.class)
+@WebAppConfiguration
+@IntegrationTest({"server.port=0"})
+@DirtiesContext
+public class ObservableSseEmitterTest {
+
+    @Value("${local.server.port}")
+    private int port = 0;
+
+    private TestRestTemplate restTemplate = new TestRestTemplate();
+
+    @Configuration
+    @EnableAutoConfiguration
+    @RestController
+    protected static class Application {
+
+		// tag::rx_observable_sse[]
+        @RequestMapping(method = RequestMethod.GET, value = "/sse")
+        public SseEmitter single() {
+            return RxResponse.sse(Observable.just("single value"));
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/messages")
+        public SseEmitter messages() {
+            return RxResponse.sse(Observable.just("message 1", "message 2", "message 3"));
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/events")
+        public SseEmitter event() {
+            return RxResponse.sse(APPLICATION_JSON_UTF8, Observable.just(
+                    new EventDto("Spring io", getDate(2016, 5, 19)),
+                    new EventDto("SpringOnePlatform", getDate(2016, 8, 1))
+            ));
+        }
+		// end::rx_observable_sse[]
+    }
+
+    @Test
+    public void shouldRetrieveSse() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/sse"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals("data:single value\n\n", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveSseWithMultipleMessages() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/messages"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals("data:message 1\n\ndata:message 2\n\ndata:message 3\n\n", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveJsonOverSseWithMultipleMessages() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/events"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals("data:{\"name\":\"Spring io\",\"date\":1466337600000}\n\ndata:{\"name\":\"SpringOnePlatform\",\"date\":1472731200000}\n\n", response.getBody());
+    }
+
+    private String path(String context) {
+        return String.format("http://localhost:%d%s", port, context);
+    }
+
+    private static Date getDate(int year, int month, int day) {
+        GregorianCalendar calendar = new GregorianCalendar(year, month, day, 12, 0, 0);
+        calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
+        return calendar.getTime();
+    }
+
+	/**
+	 * A simple DTO used for testing purpose.
+	 *
+	 * @author Jakub Narloch
+	 */
+	static class EventDto {
+
+		private final String name;
+
+		private final Date date;
+
+		@JsonCreator
+		public EventDto(@JsonProperty("name") String name, @JsonProperty("date") Date date) {
+			this.name = name;
+			this.date = date;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public Date getDate() {
+			return date;
+		}
+	}
+}
\ No newline at end of file

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/ObservableReturnValueHandlerTests.java → spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/rx/SingleReturnValueHandlerTest.java

 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -16,9 +16,6 @@
 
 package org.springframework.cloud.netflix.rx;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
-
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Value;
@@ -36,36 +33,88 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
-import rx.Observable;
+import rx.Single;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 
 /**
+ * Tests the {@link SingleReturnValueHandler} class.
+ *
  * @author Spencer Gibb
+ * @author Jakub Narloch
  */
 @RunWith(SpringJUnit4ClassRunner.class)
-@SpringApplicationConfiguration(classes = ObservableReturnValueHandlerTests.Application.class)
+@SpringApplicationConfiguration(classes = SingleReturnValueHandlerTest.Application.class)
 @WebAppConfiguration
-@IntegrationTest({ "server.port=0" })
+@IntegrationTest({"server.port=0"})
 @DirtiesContext
-public class ObservableReturnValueHandlerTests {
-
-	@Value("${local.server.port}")
-	private int port = 0;
-
-	@Configuration
-	@EnableAutoConfiguration
-	@RestController
-	protected static class Application {
-		@RequestMapping(method = RequestMethod.GET, value = "/")
-		public Observable<String> hi() {
-			return Observable.just("hello world");
-		}
-	}
+public class SingleReturnValueHandlerTest {
+
+    @Value("${local.server.port}")
+    private int port = 0;
+
+    private TestRestTemplate restTemplate = new TestRestTemplate();
+
+    @Configuration
+    @EnableAutoConfiguration
+    @RestController
+    protected static class Application {
+
+		// tag::rx_single[]
+        @RequestMapping(method = RequestMethod.GET, value = "/single")
+        public Single<String> single() {
+            return Single.just("single value");
+        }
 
-	@Test
-	public void observableReturns() {
-		ResponseEntity<String> response = new TestRestTemplate().getForEntity("http://localhost:" + port, String.class);
-		assertNotNull("response was null", response);
-		assertEquals("response code was wrong", HttpStatus.OK, response.getStatusCode());
-		assertEquals("response was wrong", "hello world", response.getBody());
+        @RequestMapping(method = RequestMethod.GET, value = "/singleWithResponse")
+        public ResponseEntity<Single<String>> singleWithResponse() {
+            return new ResponseEntity<>(Single.just("single value"), HttpStatus.NOT_FOUND);
+        }
+
+        @RequestMapping(method = RequestMethod.GET, value = "/throw")
+        public Single<Object> error() {
+            return Single.error(new RuntimeException("Unexpected"));
+        }
+		// end::rx_single[]
 	}
-}
+
+    @Test
+    public void shouldRetrieveSingleValue() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/single"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.OK, response.getStatusCode());
+        assertEquals("single value", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveSingleValueWithStatusCode() {
+
+        // when
+        ResponseEntity<String> response = restTemplate.getForEntity(path("/singleWithResponse"), String.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.NOT_FOUND, response.getStatusCode());
+        assertEquals("single value", response.getBody());
+    }
+
+    @Test
+    public void shouldRetrieveErrorResponse() {
+
+        // when
+        ResponseEntity<Object> response = restTemplate.getForEntity(path("/throw"), Object.class);
+
+        // then
+        assertNotNull(response);
+        assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, response.getStatusCode());
+    }
+
+    private String path(String context) {
+        return String.format("http://localhost:%d%s", port, context);
+    }
+}
\ No newline at end of file