DATAREST-521 - Re-added accidentally dropped existing links.

The LinkCollector introduced in previous commits accidentally dropped links already existing on the Resource.

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

@@ -594,27 +594,53 @@ public class PersistentEntityJackson2Module extends SimpleModule {
 
 			PersistentEntity<?, ?> entity = entities.getPersistentEntity(object.getClass());
 
-			Link selfLink = getSelfLink(object, entity, new Links(existingLinks));
+			Links links = new Links(existingLinks);
+			Link selfLink = createSelfLink(object, entity, links);
+
+			if (selfLink == null) {
+				return links;
+			}
+
 			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)));
+			List<Link> result = new ArrayList<Link>(existingLinks);
 			result.addAll(handler.getLinks());
 
-			return new Links(result);
+			return addSelfLinkIfNecessary(object, entity, result);
 		}
 
-		private Link getSelfLink(Object object, PersistentEntity<?, ?> entity, Links existing) {
+		private Links addSelfLinkIfNecessary(Object object, PersistentEntity<?, ?> entity, List<Link> existing) {
+
+			Links result = new Links(existing);
+
+			if (result.hasLink(Link.REL_SELF)) {
+				return result;
+			}
+
+			List<Link> list = new ArrayList<Link>();
+			list.add(createSelfLink(object, entity, result));
+			list.addAll(existing);
+
+			return new Links(list);
+		}
+
+		private Link createSelfLink(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();
+			Object identifier = accessor.getIdentifier();
+
+			if (identifier == null) {
+				return null;
+			}
+
+			return links.linkToSingleResource(entity.getType(), identifier).withSelfRel();
 		}
 	}
 

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

@@ -48,13 +48,15 @@ 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.mock.web.MockHttpServletRequest;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
+import org.springframework.web.context.request.RequestContextHolder;
+import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.util.UriTemplate;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
-import com.fasterxml.jackson.databind.SerializationFeature;
 import com.jayway.jsonpath.JsonPath;
 
 /**
@@ -82,6 +84,8 @@ public class PersistentEntitySerializationTests {
 	@Before
 	public void setUp() {
 
+		RequestContextHolder.setRequestAttributes(new ServletWebRequest(new MockHttpServletRequest()));
+
 		this.linkDiscoverer = new HalLinkDiscoverer();
 		this.projectionFactory = new SpelAwareProxyProjectionFactory();
 	}
@@ -234,9 +238,11 @@ public class PersistentEntitySerializationTests {
 	@Test
 	public void serializesLinksForExcerpts() throws Exception {
 
-		Person oliver = new Person("Oliver August", "Matthews");
-
 		Person dave = new Person("Dave", "Matthews");
+		dave.setId(1L);
+
+		Person oliver = new Person("Oliver August", "Matthews");
+		oliver.setId(2L);
 		oliver.setFather(dave);
 
 		UserExcerpt daveExcerpt = projectionFactory.createProjection(UserExcerpt.class, dave);
@@ -248,9 +254,27 @@ public class PersistentEntitySerializationTests {
 				withEmbedded(Arrays.asList(wrapper)).//
 				build();
 
-		mapper.enable(SerializationFeature.INDENT_OUTPUT);
 		String result = mapper.writeValueAsString(resource);
 
 		assertThat(JsonPath.read(result, "$_embedded.father[*]._links.self"), is(notNullValue()));
 	}
+
+	/**
+	 * @see DATAREST-521
+	 */
+	@Test
+	public void rendersAdditionalLinksRegisteredWithResource() throws Exception {
+
+		Person dave = new Person("Dave", "Matthews");
+
+		PersistentEntityResource resource = PersistentEntityResource.//
+				build(dave, repositories.getPersistentEntity(Person.class)).//
+				withLink(new Link("/people/1")).//
+				withLink(new Link("/aditional", "processed")).//
+				build();
+
+		String result = mapper.writeValueAsString(resource);
+
+		assertThat(JsonPath.read(result, "$_links.processed"), is(notNullValue()));
+	}
 }

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

@@ -15,13 +15,12 @@
  */
 package org.springframework.data.rest.webmvc.json;
 
-import static org.mockito.Matchers.*;
 import static org.mockito.Mockito.*;
 
+import java.util.Arrays;
 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;
@@ -38,13 +37,17 @@ import org.springframework.data.rest.webmvc.jpa.JpaRepositoryConfig;
 import org.springframework.data.rest.webmvc.jpa.Person;
 import org.springframework.data.rest.webmvc.jpa.PersonRepository;
 import org.springframework.data.rest.webmvc.mongodb.MongoDbRepositoryConfig;
+import org.springframework.data.rest.webmvc.spi.BackendIdConverter;
+import org.springframework.data.rest.webmvc.spi.BackendIdConverter.DefaultIdConverter;
+import org.springframework.data.rest.webmvc.support.PagingAndSortingTemplateVariables;
+import org.springframework.data.rest.webmvc.support.RepositoryEntityLinks;
 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;
+import org.springframework.plugin.core.OrderAwarePluginRegistry;
 
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.databind.DeserializationFeature;
@@ -101,12 +104,13 @@ public class RepositoryTestsConfig {
 	@Bean
 	public Module persistentEntityModule() {
 
-		EntityLinks entityLinks = mock(EntityLinks.class);
-		when(entityLinks.linkToSingleResource(Matchers.<Class<?>> any(), anyObject())).thenReturn(new Link("/mock/1"));
+		RepositoryResourceMappings mappings = new RepositoryResourceMappings(repositories(), persistentEntities());
+		EntityLinks entityLinks = new RepositoryEntityLinks(repositories(), mappings, config(),
+				mock(PagingAndSortingTemplateVariables.class),
+				OrderAwarePluginRegistry.<Class<?>, BackendIdConverter> create(Arrays.asList(DefaultIdConverter.INSTANCE)));
 
-		return new PersistentEntityJackson2Module(new RepositoryResourceMappings(repositories(), persistentEntities()),
-				persistentEntities(), config(), new UriToEntityConverter(persistentEntities(), defaultConversionService()),
-				entityLinks);
+		return new PersistentEntityJackson2Module(mappings, persistentEntities(), config(), new UriToEntityConverter(
+				persistentEntities(), defaultConversionService()), entityLinks);
 	}
 
 	@Bean