Add support for JSON Collection media type

Author: gregturn

pom.xml

@@ -31,6 +31,16 @@
 			</roles>
 			<timezone>+1</timezone>
 		</developer>
+		<developer>
+			<id>gturnquist</id>
+			<name>Greg Turnquist</name>
+			<email>gturnquist(at)pivotal.io</email>
+			<organization>Pivotal, Inc.</organization>
+			<roles>
+				<role>Contributor</role>
+			</roles>
+			<timezone>-6</timezone>
+		</developer>
 	</developers>
 
 	<licenses>

src/main/java/org/springframework/hateoas/MediaTypes.java

@@ -22,6 +22,7 @@
  * 
  * @author Oliver Gierke
  * @author Przemek Nowak
+ * @author Greg Turnquist
  */
 public class MediaTypes {
 
@@ -34,4 +35,14 @@ public class MediaTypes {
 	 * Public constant media type for {@code application/hal+json}.
 	 */
 	public static final MediaType HAL_JSON = MediaType.valueOf(HAL_JSON_VALUE);
+
+	/**
+	 * A String equivalent of {@link MediaTypes#JSON_COLLECTION}.
+	 */
+	public static final String JSON_COLLECTION_VALUE = "application/vnd.collection+json";
+
+	/**
+	 * Public constant media type for {@code application/vnd.collection+json}.
+	 */
+	public static final MediaType JSON_COLLECTION = MediaType.valueOf(JSON_COLLECTION_VALUE);
 }

src/main/java/org/springframework/hateoas/Resource.java

@@ -29,6 +29,7 @@
  * A simple {@link Resource} wrapping a domain object and adding links to it.
  * 
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 @XmlRootElement
 public class Resource<T> extends ResourceSupport {
@@ -38,7 +39,7 @@ public class Resource<T> extends ResourceSupport {
 	/**
 	 * Creates an empty {@link Resource}.
 	 */
-	Resource() {
+	protected Resource() {
 		this.content = null;
 	}
 

src/main/java/org/springframework/hateoas/alps/Alps.java

@@ -15,11 +15,11 @@
  */
 package org.springframework.hateoas.alps;
 
+import java.util.List;
+
 import lombok.Builder;
 import lombok.Value;
 
-import java.util.List;
-
 import org.springframework.hateoas.alps.Descriptor.DescriptorBuilder;
 import org.springframework.hateoas.alps.Doc.DocBuilder;
 import org.springframework.hateoas.alps.Ext.ExtBuilder;

src/main/java/org/springframework/hateoas/config/EnableHypermediaSupport.java

@@ -39,6 +39,7 @@
  * @see LinkDiscoverer
  * @see EntityLinks
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
@@ -57,6 +58,7 @@
 	 * Hypermedia representation types supported.
 	 * 
 	 * @author Oliver Gierke
+	 * @author Greg Turnquist
 	 */
 	static enum HypermediaType {
 
@@ -66,6 +68,13 @@ static enum HypermediaType {
 		 * @see http://stateless.co/hal_specification.html
 		 * @see http://tools.ietf.org/html/draft-kelly-json-hal-05
 		 */
-		HAL;
+		HAL,
+
+		/**
+		 * JSON Collection
+		 *
+		 * @see http://amundsen.com/media-types/collection/format/
+		 */
+		JSON_COLLECTION;
 	}
 }

src/main/java/org/springframework/hateoas/config/HypermediaSupportBeanDefinitionRegistrar.java

@@ -55,6 +55,8 @@
 import org.springframework.hateoas.hal.CurieProvider;
 import org.springframework.hateoas.hal.HalLinkDiscoverer;
 import org.springframework.hateoas.hal.Jackson2HalModule;
+import org.springframework.hateoas.jsoncollection.Jackson2JsonCollectionModule;
+import org.springframework.hateoas.jsoncollection.JsonCollectionLinkDiscoverer;
 import org.springframework.hateoas.mvc.TypeConstrainedMappingJackson2HttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean;
@@ -75,12 +77,14 @@
  * activated as well).
  * 
  * @author Oliver Gierke
+ * @author Greg Turnquist
  */
 class HypermediaSupportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
 
 	private static final String DELEGATING_REL_PROVIDER_BEAN_NAME = "_relProvider";
 	private static final String LINK_DISCOVERER_REGISTRY_BEAN_NAME = "_linkDiscovererRegistry";
 	private static final String HAL_OBJECT_MAPPER_BEAN_NAME = "_halObjectMapper";
+	private static final String JSON_COLLECTION_OBJECT_MAPPER_BEAN_NAME = "_jsonCollectionObjectMapper";
 	private static final String MESSAGE_SOURCE_BEAN_NAME = "linkRelationMessageSource";
 
 	private static final boolean JACKSON2_PRESENT = ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper",
@@ -127,6 +131,21 @@ public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionR
 			}
 		}
 
+		if (types.contains(HypermediaType.JSON_COLLECTION)) {
+
+			if (JACKSON2_PRESENT) {
+
+				BeanDefinitionBuilder jsonCollectionQueryMapperBuilder = rootBeanDefinition(ObjectMapper.class);
+				registerSourcedBeanDefinition(jsonCollectionQueryMapperBuilder, metadata, registry, JSON_COLLECTION_OBJECT_MAPPER_BEAN_NAME);
+
+				BeanDefinitionBuilder customizerBeanDefinition = rootBeanDefinition(DefaultObjectMapperCustomizer.class);
+				registerSourcedBeanDefinition(customizerBeanDefinition, metadata, registry);
+
+				BeanDefinitionBuilder builder = rootBeanDefinition(Jackson2ModuleRegisteringBeanPostProcessor.class);
+				registerSourcedBeanDefinition(builder, metadata, registry);
+			}
+		}
+
 		if (!types.isEmpty()) {
 
 			BeanDefinitionBuilder linkDiscoverersRegistryBuilder = BeanDefinitionBuilder
@@ -188,6 +207,9 @@ private AbstractBeanDefinition getLinkDiscovererBeanDefinition(HypermediaType ty
 			case HAL:
 				definition = new RootBeanDefinition(HalLinkDiscoverer.class);
 				break;
+			case JSON_COLLECTION:
+				definition = new RootBeanDefinition(JsonCollectionLinkDiscoverer.class);
+				break;
 			default:
 				throw new IllegalStateException(String.format("Unsupported hypermedia type %s!", type));
 		}
@@ -289,21 +311,43 @@ private List<HttpMessageConverter<?>> potentiallyRegisterModule(List<HttpMessage
 
 			CurieProvider curieProvider = getCurieProvider(beanFactory);
 			RelProvider relProvider = beanFactory.getBean(DELEGATING_REL_PROVIDER_BEAN_NAME, RelProvider.class);
-			ObjectMapper halObjectMapper = beanFactory.getBean(HAL_OBJECT_MAPPER_BEAN_NAME, ObjectMapper.class);
-			MessageSourceAccessor linkRelationMessageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME,
-					MessageSourceAccessor.class);
 
-			halObjectMapper.registerModule(new Jackson2HalModule());
-			halObjectMapper.setHandlerInstantiator(new Jackson2HalModule.HalHandlerInstantiator(relProvider, curieProvider,
-					linkRelationMessageSource, beanFactory));
+			List<HttpMessageConverter<?>> result = new ArrayList<HttpMessageConverter<?>>(converters.size());
 
-			MappingJackson2HttpMessageConverter halConverter = new TypeConstrainedMappingJackson2HttpMessageConverter(
-					ResourceSupport.class);
-			halConverter.setSupportedMediaTypes(Arrays.asList(HAL_JSON));
-			halConverter.setObjectMapper(halObjectMapper);
+			if (beanFactory.containsBean(HAL_OBJECT_MAPPER_BEAN_NAME)) {
+
+				ObjectMapper halObjectMapper = beanFactory.getBean(HAL_OBJECT_MAPPER_BEAN_NAME, ObjectMapper.class);
+				MessageSourceAccessor linkRelationMessageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME,
+						MessageSourceAccessor.class);
+
+				halObjectMapper.registerModule(new Jackson2HalModule());
+				halObjectMapper.setHandlerInstantiator(
+						new Jackson2HalModule.HalHandlerInstantiator(relProvider, curieProvider, linkRelationMessageSource, beanFactory));
+
+				MappingJackson2HttpMessageConverter halConverter = new TypeConstrainedMappingJackson2HttpMessageConverter(
+						ResourceSupport.class);
+				halConverter.setSupportedMediaTypes(Arrays.asList(HAL_JSON));
+				halConverter.setObjectMapper(halObjectMapper);
+				result.add(halConverter);
+			}
+
+			if (beanFactory.containsBean(JSON_COLLECTION_OBJECT_MAPPER_BEAN_NAME)) {
+
+				ObjectMapper jsonCollectionObjectMapper = beanFactory.getBean(JSON_COLLECTION_OBJECT_MAPPER_BEAN_NAME, ObjectMapper.class);
+				MessageSourceAccessor linkRelationMessageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME,
+						MessageSourceAccessor.class);
+
+				jsonCollectionObjectMapper.registerModule(new Jackson2JsonCollectionModule());
+				jsonCollectionObjectMapper.setHandlerInstantiator(
+						new Jackson2JsonCollectionModule.JsonCollectionHandlerInstantiator(linkRelationMessageSource));
+
+				MappingJackson2HttpMessageConverter jsonCollectionConverter = new TypeConstrainedMappingJackson2HttpMessageConverter(
+						ResourceSupport.class);
+				jsonCollectionConverter.setSupportedMediaTypes(Arrays.asList(JSON_COLLECTION));
+				jsonCollectionConverter.setObjectMapper(jsonCollectionObjectMapper);
+				result.add(jsonCollectionConverter);
+			}
 
-			List<HttpMessageConverter<?>> result = new ArrayList<HttpMessageConverter<?>>(converters.size());
-			result.add(halConverter);
 			result.addAll(converters);
 			return result;
 		}

src/main/java/org/springframework/hateoas/jsoncollection/Item.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2015 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.hateoas.jsoncollection;
+
+import java.util.List;
+
+import lombok.Builder;
+import lombok.Data;
+import lombok.Singular;
+import lombok.Value;
+
+import org.springframework.hateoas.Link;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+/**
+ * Representation of an item in a JSON Collection.
+ *
+ * @author Greg Turnquist
+ */
+@Data
+@Value
+@Builder
+public class Item<T> {
+
+	private final String href;
+	@Singular("data") private final List<T> data;
+	private final List<Link> links;
+
+	@JsonCreator
+	public Item(@JsonProperty("href") String href, @JsonProperty("data") List<T> data,
+				@JsonProperty("links") List<Link> links) {
+
+		this.href = href;
+		this.data = data;
+		this.links = links;
+	}
+
+}