DATAREST-521 - Excerpts now contain all links of the projection target.

Extended the serialization capabilities to explicitly treat projection proxies by wrapping them into a ProjectionResource and collecting links for the target backing the projection if the target is an exported resource.

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/PersistentEntityResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -43,7 +43,6 @@ public class PersistentEntityResource extends Resource<Object> {
 
 	private final PersistentEntity<?, ?> entity;
 	private final Resources<EmbeddedWrapper> embeddeds;
-	private final boolean enforceAssociationLinks;
 
 	/**
 	 * Creates a new {@link PersistentEntityResource} for the given {@link PersistentEntity}, content, embedded
@@ -52,11 +51,10 @@ public class PersistentEntityResource extends Resource<Object> {
 	 * @param entity must not be {@literal null}.
 	 * @param content must not be {@literal null}.
 	 * @param links must not be {@literal null}.
-	 * @param renderAllAssociations
 	 * @param embeddeds can be {@literal null}.
 	 */
 	private PersistentEntityResource(PersistentEntity<?, ?> entity, Object content, Iterable<Link> links,
-			boolean renderAllAssociations, Resources<EmbeddedWrapper> embeddeds) {
+			Resources<EmbeddedWrapper> embeddeds) {
 
 		super(content, links);
 
@@ -64,7 +62,6 @@ public class PersistentEntityResource extends Resource<Object> {
 
 		this.entity = entity;
 		this.embeddeds = embeddeds == null ? NO_EMBEDDEDS : embeddeds;
-		this.enforceAssociationLinks = renderAllAssociations;
 	}
 
 	/**
@@ -118,7 +115,6 @@ public class PersistentEntityResource extends Resource<Object> {
 		private final List<Link> links = new ArrayList<Link>();
 
 		private Resources<EmbeddedWrapper> embeddeds;
-		private boolean renderAllAssociationLinks = false;
 
 		/**
 		 * Creates a new {@link Builder} instance for the given content and {@link PersistentEntity}.
@@ -147,17 +143,6 @@ public class PersistentEntityResource extends Resource<Object> {
 			return this;
 		}
 
-		/**
-		 * Configures the builder to render all association links independently of the embedded resources added.
-		 * 
-		 * @return the builder
-		 */
-		public Builder renderAllAssociationLinks() {
-
-			this.renderAllAssociationLinks = true;
-			return this;
-		}
-
 		/**
 		 * Adds the given {@link Link} to the {@link PersistentEntityResource}.
 		 * 
@@ -178,7 +163,7 @@ public class PersistentEntityResource extends Resource<Object> {
 		 * @return
 		 */
 		public PersistentEntityResource build() {
-			return new PersistentEntityResource(entity, content, links, renderAllAssociationLinks, embeddeds);
+			return new PersistentEntityResource(entity, content, links, embeddeds);
 		}
 	}
 }

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/PersistentEntityResourceAssembler.java

@@ -32,7 +32,6 @@ import org.springframework.data.rest.webmvc.mapping.AssociationLinks;
 import org.springframework.data.rest.webmvc.support.Projector;
 import org.springframework.hateoas.EntityLinks;
 import org.springframework.hateoas.Link;
-import org.springframework.hateoas.Resource;
 import org.springframework.hateoas.ResourceAssembler;
 import org.springframework.hateoas.core.EmbeddedWrapper;
 import org.springframework.hateoas.core.EmbeddedWrappers;
@@ -81,9 +80,7 @@ public class PersistentEntityResourceAssembler implements ResourceAssembler<Obje
 	public PersistentEntityResource toResource(Object instance) {
 
 		Assert.notNull(instance, "Entity instance must not be null!");
-
 		return wrap(projector.projectExcerpt(instance), instance).build();
-
 	}
 
 	/**
@@ -95,8 +92,7 @@ public class PersistentEntityResourceAssembler implements ResourceAssembler<Obje
 	public PersistentEntityResource toFullResource(Object instance) {
 
 		Assert.notNull(instance, "Entity instance must not be null!");
-		return wrap(projector.project(instance), instance).//
-				renderAllAssociationLinks().build();
+		return wrap(projector.project(instance), instance).build();
 	}
 
 	private Builder wrap(Object instance, Object source) {
@@ -165,14 +161,14 @@ public class PersistentEntityResourceAssembler implements ResourceAssembler<Obje
 
 					for (Object element : collection) {
 						if (element != null) {
-							nestedCollection.add(getExcerptResource(element));
+							nestedCollection.add(projector.projectExcerpt(element));
 						}
 					}
 
 					associationProjections.add(wrappers.wrap(nestedCollection, rel));
 
 				} else {
-					associationProjections.add(wrappers.wrap(getExcerptResource(value), rel));
+					associationProjections.add(wrappers.wrap(projector.projectExcerpt(value), rel));
 				}
 			}
 		});
@@ -203,14 +199,4 @@ public class PersistentEntityResourceAssembler implements ResourceAssembler<Obje
 		Link resourceLink = entityLinks.linkToSingleResource(entity.getType(), id);
 		return new Link(resourceLink.getHref(), Link.REL_SELF);
 	}
-
-	/**
-	 * Returns a {@link Resource} instance for the excerpt of the given source entity.
-	 * 
-	 * @param entity must not be {@literal null}.
-	 * @return
-	 */
-	private Resource<Object> getExcerptResource(Object entity) {
-		return new Resource<Object>(projector.projectExcerpt(entity), getSelfLinkFor(entity));
-	}
 }

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/config/RepositoryRestMvcConfiguration.java

@@ -539,8 +539,8 @@ public class RepositoryRestMvcConfiguration extends HateoasAwareSpringDataWebCon
 
 		PersistentEntities entities = persistentEntities();
 
-		return new PersistentEntityJackson2Module(resourceMappings(), entities, config(),
-				uriToEntityConverter(defaultConversionService()));
+		return new PersistentEntityJackson2Module(
+				resourceMappings(), entities, config(), uriToEntityConverter(defaultConversionService()), entityLinks());
 	}
 
 	/**

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/json/PersistentEntityJackson2Module.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -18,6 +18,7 @@ package org.springframework.data.rest.webmvc.json;
 import java.io.IOException;
 import java.net.URI;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 
@@ -25,9 +26,11 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.data.mapping.IdentifierAccessor;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.context.PersistentEntities;
+import org.springframework.data.projection.TargetAware;
 import org.springframework.data.repository.support.Repositories;
 import org.springframework.data.rest.core.Path;
 import org.springframework.data.rest.core.UriToEntityConverter;
@@ -36,7 +39,9 @@ import org.springframework.data.rest.core.mapping.ResourceMappings;
 import org.springframework.data.rest.webmvc.PersistentEntityResource;
 import org.springframework.data.rest.webmvc.mapping.AssociationLinks;
 import org.springframework.data.rest.webmvc.mapping.LinkCollectingAssociationHandler;
+import org.springframework.hateoas.EntityLinks;
 import org.springframework.hateoas.Link;
+import org.springframework.hateoas.Links;
 import org.springframework.hateoas.Resource;
 import org.springframework.hateoas.Resources;
 import org.springframework.hateoas.UriTemplate;
@@ -68,6 +73,7 @@ import com.fasterxml.jackson.databind.ser.BeanSerializerBuilder;
 import com.fasterxml.jackson.databind.ser.BeanSerializerModifier;
 import com.fasterxml.jackson.databind.ser.std.StdSerializer;
 import com.fasterxml.jackson.databind.type.CollectionLikeType;
+import com.fasterxml.jackson.databind.util.NameTransformer;
 
 /**
  * Jackson 2 module to serialize and deserialize {@link PersistentEntityResource}s.
@@ -92,7 +98,7 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 	 * @param converter must not be {@literal null}.
 	 */
 	public PersistentEntityJackson2Module(ResourceMappings mappings, PersistentEntities entities,
-			RepositoryRestConfiguration config, UriToEntityConverter converter) {
+			RepositoryRestConfiguration config, UriToEntityConverter converter, EntityLinks entityLinks) {
 
 		super(new Version(2, 0, 0, null, "org.springframework.data.rest", "jackson-module"));
 
@@ -102,8 +108,12 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 		Assert.notNull(converter, "UriToEntityConverter must not be null!");
 
 		AssociationLinks associationLinks = new AssociationLinks(mappings);
+		LinkCollector collector = new LinkCollector(entities, entityLinks, associationLinks);
+
+		addSerializer(new PersistentEntityResourceSerializer(collector));
+		addSerializer(new ProjectionSerializer(collector, mappings));
+		addSerializer(new ProjectionResourceContentSerializer());
 
-		addSerializer(new PersistentEntityResourceSerializer(entities, associationLinks));
 		setSerializerModifier(new AssociationOmittingSerializerModifier(entities, associationLinks, config));
 		setDeserializerModifier(new AssociationUriResolvingDeserializerModifier(entities, converter, associationLinks));
 	}
@@ -114,10 +124,10 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 	 * 
 	 * @author Oliver Gierke
 	 */
+	@SuppressWarnings("serial")
 	private static class PersistentEntityResourceSerializer extends StdSerializer<PersistentEntityResource> {
 
-		private final PersistentEntities entities;
-		private final AssociationLinks associationLinks;
+		private final LinkCollector collector;
 
 		/**
 		 * Creates a new {@link PersistentEntityResourceSerializer} using the given {@link PersistentEntities} and
@@ -127,15 +137,11 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 		 * @param links must not be {@literal null}.
 		 */
 		@SuppressWarnings({ "unchecked", "rawtypes" })
-		private PersistentEntityResourceSerializer(PersistentEntities entities, AssociationLinks links) {
+		private PersistentEntityResourceSerializer(LinkCollector collector) {
 
 			super((Class) PersistentEntityResource.class);
 
-			Assert.notNull(entities, "PersistentEntities must not be null!");
-			Assert.notNull(links, "AssociationLinks must not be null!");
-
-			this.associationLinks = links;
-			this.entities = entities;
+			this.collector = collector;
 		}
 
 		/*
@@ -150,23 +156,17 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 				LOG.debug("Serializing PersistentEntity " + resource.getPersistentEntity());
 			}
 
-			final Link id = resource.getId();
+			Object content = resource.getContent();
 
-			if (id == null) {
-				throw new JsonGenerationException(String.format("No self link found resource %s!", resource));
+			if (TargetAware.class.isInstance(content)) {
+
+				TargetAware targetAware = (TargetAware) content;
+				Links links = collector.getLinksFor(targetAware.getTarget(), resource.getLinks());
+				provider.defaultSerializeValue(new ProjectionResource(targetAware, links), jgen);
+				return;
 			}
 
-			List<Link> links = new ArrayList<Link>();
-			links.addAll(resource.getLinks());
-
-			Path basePath = new Path(id.expand().getHref());
-			LinkCollectingAssociationHandler associationHandler = new LinkCollectingAssociationHandler(entities, basePath,
-					associationLinks);
-			resource.getPersistentEntity().doWithAssociations(associationHandler);
-
-			for (Link link : associationHandler.getLinks()) {
-				links.add(link);
-			}
+			Links links = collector.getLinksFor(resource.getContent(), resource.getLinks());
 
 			Resource<Object> resourceToRender = new Resource<Object>(resource.getContent(), links) {
 
@@ -237,6 +237,8 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 					continue;
 				}
 
+				// Is there a default projection?
+
 				if (associationLinks.isLinkableAssociation(persistentProperty)) {
 					continue;
 				}
@@ -400,6 +402,222 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 		}
 	}
 
+	@SuppressWarnings("serial")
+	static class ProjectionSerializer extends StdSerializer<TargetAware> {
+
+		private final LinkCollector collector;
+		private final ResourceMappings mappings;
+		private boolean unwrapping;
+
+		/**
+		 * Creates a new {@link ProjectionSerializer} for the given {@link LinkCollector}.
+		 * 
+		 * @param collector
+		 */
+		public ProjectionSerializer(LinkCollector collector, ResourceMappings mappings) {
+
+			super(TargetAware.class);
+
+			this.collector = collector;
+			this.mappings = mappings;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.ser.std.StdSerializer#serialize(java.lang.Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)
+		 */
+		@Override
+		public void serialize(TargetAware value, JsonGenerator jgen, SerializerProvider provider) throws IOException,
+				JsonGenerationException {
+
+			Object target = value.getTarget();
+			Links links = mappings.getMetadataFor(value.getTargetClass()).isExported() ? collector.getLinksFor(target)
+					: new Links();
+
+			jgen.writeStartObject();
+
+			provider.//
+					findValueSerializer(ProjectionResource.class, null).//
+					unwrappingSerializer(null).//
+					serialize(new ProjectionResource(value, links), jgen, provider);
+
+			jgen.writeEndObject();
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.JsonSerializer#isUnwrappingSerializer()
+		 */
+		@Override
+		public boolean isUnwrappingSerializer() {
+			return unwrapping;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.JsonSerializer#unwrappingSerializer(com.fasterxml.jackson.databind.util.NameTransformer)
+		 */
+		@Override
+		public JsonSerializer<TargetAware> unwrappingSerializer(NameTransformer unwrapper) {
+			this.unwrapping = true;
+			return this;
+		}
+	}
+
+	static class ProjectionResource extends Resource<ProjectionResourceContent> {
+
+		ProjectionResource(TargetAware projection, Iterable<Link> links) {
+			super(new ProjectionResourceContent(projection, projection.getClass().getInterfaces()[0]), links);
+		}
+	}
+
+	static class ProjectionResourceContent {
+
+		private final Object projection;
+		private final Class<?> projectionInterface;
+
+		/**
+		 * @param projection
+		 * @param projectionInterface
+		 */
+		public ProjectionResourceContent(Object projection, Class<?> projectionInterface) {
+			this.projection = projection;
+			this.projectionInterface = projectionInterface;
+		}
+
+		public Object getProjection() {
+			return projection;
+		}
+
+		public Class<?> getProjectionInterface() {
+			return projectionInterface;
+		}
+	}
+
+	@SuppressWarnings("serial")
+	private static class ProjectionResourceContentSerializer extends StdSerializer<ProjectionResourceContent> {
+
+		private boolean unwrapping;
+
+		/**
+		 * Creates a new {@link ProjectionResourceContentSerializer}.
+		 */
+		public ProjectionResourceContentSerializer() {
+			super(ProjectionResourceContent.class);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.ser.std.StdSerializer#serialize(java.lang.Object, com.fasterxml.jackson.core.JsonGenerator, com.fasterxml.jackson.databind.SerializerProvider)
+		 */
+		@Override
+		public void serialize(ProjectionResourceContent value, JsonGenerator jgen, SerializerProvider provider)
+				throws IOException, JsonGenerationException {
+
+			provider.//
+					findValueSerializer(value.getProjectionInterface(), null).//
+					unwrappingSerializer(null).//
+					serialize(value.getProjection(), jgen, provider);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.JsonSerializer#isUnwrappingSerializer()
+		 */
+		@Override
+		public boolean isUnwrappingSerializer() {
+			return unwrapping;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see com.fasterxml.jackson.databind.JsonSerializer#unwrappingSerializer(com.fasterxml.jackson.databind.util.NameTransformer)
+		 */
+		@Override
+		public JsonSerializer<ProjectionResourceContent> unwrappingSerializer(NameTransformer unwrapper) {
+
+			this.unwrapping = true;
+			return this;
+		}
+	}
+
+	/**
+	 * A service to collect all standard links that need to be added to a certain object.
+	 *
+	 * @author Oliver Gierke
+	 */
+	private static class LinkCollector {
+
+		private final PersistentEntities entities;
+		private final AssociationLinks associationLinks;
+		private final EntityLinks links;
+
+		/**
+		 * Creates a new {@link PersistentEntities}, {@link EntityLinks} and {@link AssociationLinks}.
+		 * 
+		 * @param entities must not be {@literal null}.
+		 * @param entityLinks must not be {@literal null}.
+		 * @param associationLinks must not be {@literal null}.
+		 */
+		public LinkCollector(PersistentEntities entities, EntityLinks entityLinks, AssociationLinks associationLinks) {
+
+			Assert.notNull(entities, "PersistentEntities must not be null!");
+			Assert.notNull(entityLinks, "EntityLinks must not be null!");
+			Assert.notNull(associationLinks, "AssociationLinks must not be null!");
+
+			this.links = entityLinks;
+			this.entities = entities;
+			this.associationLinks = associationLinks;
+		}
+
+		/**
+		 * Returns all {@link Links} for the given object.
+		 * 
+		 * @param object must not be {@literal null}.
+		 * @return
+		 */
+		public Links getLinksFor(Object object) {
+			return getLinksFor(object, Collections.<Link> emptyList());
+		}
+
+		/**
+		 * Returns all {@link Links} for the given object and already existing {@link Link}.
+		 * 
+		 * @param object must not be {@literal null}.
+		 * @param existingLinks must not be {@literal null}.
+		 * @return
+		 */
+		public Links getLinksFor(Object object, List<Link> existingLinks) {
+
+			Assert.notNull(object, "Object must not be null!");
+			Assert.notNull(existingLinks, "Existing links must not be null!");
+
+			PersistentEntity<?, ?> entity = entities.getPersistentEntity(object.getClass());
+
+			Link selfLink = getSelfLink(object, entity, new Links(existingLinks));
+			Path path = new Path(selfLink.expand().getHref());
+
+			LinkCollectingAssociationHandler handler = new LinkCollectingAssociationHandler(entities, path, associationLinks);
+			entity.doWithAssociations(handler);
+
+			List<Link> result = new ArrayList<Link>();
+			result.add(getSelfLink(object, entity, new Links(existingLinks)));
+			result.addAll(handler.getLinks());
+
+			return new Links(result);
+		}
+
+		private Link getSelfLink(Object object, PersistentEntity<?, ?> entity, Links existing) {
+
+			if (existing.hasLink(Link.REL_SELF)) {
+				return existing.getLink(Link.REL_SELF);
+			}
+
+			IdentifierAccessor accessor = entity.getIdentifierAccessor(object);
+			return links.linkToSingleResource(entity.getType(), accessor.getIdentifier()).withSelfRel();
+		}
+	}
+
 	/**
 	 * {@link ValueInstantiator} to create collection or map instances based on the type of the configured
 	 * {@link PersistentProperty}.

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/jpa/UserExcerpt.java

@@ -0,0 +1,25 @@
+/*
+ * 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.data.rest.webmvc.jpa;
+
+/**
+ * @author Oliver Gierke
+ * @soundtrack Elen - Sink like a stone (Elen)
+ */
+public interface UserExcerpt {
+
+	UserExcerpt getFather();
+}

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/json/PersistentEntitySerializationTests.java

@@ -28,6 +28,8 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.mapping.PersistentEntity;
+import org.springframework.data.projection.ProjectionFactory;
+import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
 import org.springframework.data.repository.support.Repositories;
 import org.springframework.data.rest.webmvc.PersistentEntityResource;
 import org.springframework.data.rest.webmvc.jpa.LineItem;
@@ -35,6 +37,7 @@ import org.springframework.data.rest.webmvc.jpa.Order;
 import org.springframework.data.rest.webmvc.jpa.OrderRepository;
 import org.springframework.data.rest.webmvc.jpa.Person;
 import org.springframework.data.rest.webmvc.jpa.PersonRepository;
+import org.springframework.data.rest.webmvc.jpa.UserExcerpt;
 import org.springframework.data.rest.webmvc.mongodb.Address;
 import org.springframework.data.rest.webmvc.mongodb.User;
 import org.springframework.data.rest.webmvc.util.TestUtils;
@@ -42,6 +45,8 @@ import org.springframework.hateoas.Link;
 import org.springframework.hateoas.LinkDiscoverer;
 import org.springframework.hateoas.PagedResources;
 import org.springframework.hateoas.PagedResources.PageMetadata;
+import org.springframework.hateoas.core.EmbeddedWrapper;
+import org.springframework.hateoas.core.EmbeddedWrappers;
 import org.springframework.hateoas.hal.HalLinkDiscoverer;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@@ -49,6 +54,7 @@ import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.util.UriTemplate;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import com.jayway.jsonpath.JsonPath;
 
 /**
@@ -71,10 +77,13 @@ public class PersistentEntitySerializationTests {
 	@Autowired OrderRepository orders;
 
 	LinkDiscoverer linkDiscoverer;
+	ProjectionFactory projectionFactory;
 
 	@Before
 	public void setUp() {
-		linkDiscoverer = new HalLinkDiscoverer();
+
+		this.linkDiscoverer = new HalLinkDiscoverer();
+		this.projectionFactory = new SpelAwareProxyProjectionFactory();
 	}
 
 	@Test
@@ -191,6 +200,8 @@ public class PersistentEntitySerializationTests {
 
 		String result = mapper.writeValueAsString(persistentEntityResource);
 
+		System.out.println(result);
+
 		assertThat(JsonPath.read(result, "$_embedded.users[*].address"), is(notNullValue()));
 	}
 
@@ -218,4 +229,30 @@ public class PersistentEntitySerializationTests {
 
 		assertThat(JsonPath.read(result, "$_embedded.orders[*].lineItems"), is(notNullValue()));
 	}
+
+	/**
+	 * @see DATAREST-521
+	 */
+	@Test
+	public void serializesLinksForExcerpts() throws Exception {
+
+		Person oliver = new Person("Oliver August", "Matthews");
+
+		Person dave = new Person("Dave", "Matthews");
+		oliver.setFather(dave);
+
+		UserExcerpt daveExcerpt = projectionFactory.createProjection(UserExcerpt.class, dave);
+		EmbeddedWrapper wrapper = new EmbeddedWrappers(false).wrap(daveExcerpt, "father");
+
+		PersistentEntityResource resource = PersistentEntityResource.//
+				build(oliver, repositories.getPersistentEntity(Person.class)).//
+				withLink(new Link("/people/1")).//
+				withEmbedded(Arrays.asList(wrapper)).//
+				build();
+
+		mapper.enable(SerializationFeature.INDENT_OUTPUT);
+		String result = mapper.writeValueAsString(resource);
+
+		assertThat(JsonPath.read(result, "$_embedded.father[*]._links.self"), is(notNullValue()));
+	}
 }

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/json/RepositoryTestsConfig.java

@@ -15,9 +15,13 @@
  */
 package org.springframework.data.rest.webmvc.json;
 
+import static org.mockito.Matchers.*;
+import static org.mockito.Mockito.*;
+
 import java.util.Collections;
 import java.util.List;
 
+import org.mockito.Matchers;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -36,6 +40,8 @@ import org.springframework.data.rest.webmvc.jpa.PersonRepository;
 import org.springframework.data.rest.webmvc.mongodb.MongoDbRepositoryConfig;
 import org.springframework.format.support.DefaultFormattingConversionService;
 import org.springframework.format.support.FormattingConversionService;
+import org.springframework.hateoas.EntityLinks;
+import org.springframework.hateoas.Link;
 import org.springframework.hateoas.RelProvider;
 import org.springframework.hateoas.core.EvoInflectorRelProvider;
 import org.springframework.hateoas.hal.Jackson2HalModule;
@@ -94,8 +100,13 @@ public class RepositoryTestsConfig {
 
 	@Bean
 	public Module persistentEntityModule() {
+
+		EntityLinks entityLinks = mock(EntityLinks.class);
+		when(entityLinks.linkToSingleResource(Matchers.<Class<?>> any(), anyObject())).thenReturn(new Link("/mock/1"));
+
 		return new PersistentEntityJackson2Module(new RepositoryResourceMappings(repositories(), persistentEntities()),
-				persistentEntities(), config(), new UriToEntityConverter(persistentEntities(), defaultConversionService()));
+				persistentEntities(), config(), new UriToEntityConverter(persistentEntities(), defaultConversionService()),
+				entityLinks);
 	}
 
 	@Bean