DATAREST-1260 - Tweaked DomainObjectReader to support immutable entities.

DomainObjectReader now aborts the recursive merges in case it encounters an entity that's described as @Immutable (just introduced in Spring Data Commons).

Fixed some generics and removed DomainObjectMerger as it's unused.

Related ticket: DATACMNS-1322.

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

@@ -112,7 +112,7 @@ public class HttpHeadersPreparer {
 	 * @param source can be {@literal null}.
 	 * @return
 	 */
-	private Optional<AuditableBeanWrapper> getAuditableBeanWrapper(Object source) {
+	private Optional<AuditableBeanWrapper<Object>> getAuditableBeanWrapper(Object source) {
 		return auditableBeanWrapperFactory.getBeanWrapperFor(source);
 	}
 

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

@@ -71,7 +71,6 @@ import org.springframework.data.rest.core.mapping.RepositoryResourceMappings;
 import org.springframework.data.rest.core.mapping.ResourceDescription;
 import org.springframework.data.rest.core.mapping.ResourceMappings;
 import org.springframework.data.rest.core.support.DefaultSelfLinkProvider;
-import org.springframework.data.rest.core.support.DomainObjectMerger;
 import org.springframework.data.rest.core.support.EntityLookup;
 import org.springframework.data.rest.core.support.RepositoryRelProvider;
 import org.springframework.data.rest.core.support.SelfLinkProvider;
@@ -346,17 +345,6 @@ public class RepositoryRestMvcConfiguration extends HateoasAwareSpringDataWebCon
 		return new AnnotatedEventHandlerInvoker();
 	}
 
-	/**
-	 * For merging incoming objects materialized from JSON with existing domain objects loaded from the repository.
-	 *
-	 * @return
-	 * @throws Exception
-	 */
-	@Bean
-	public DomainObjectMerger domainObjectMerger() throws Exception {
-		return new DomainObjectMerger(repositories(), defaultConversionService());
-	}
-
 	/**
 	 * Turns an {@link javax.servlet.http.HttpServletRequest} into a
 	 * {@link org.springframework.http.server.ServerHttpRequest}.

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

@@ -138,20 +138,22 @@ public class DomainObjectReader {
 
 		Class<? extends Object> type = target.getClass();
 
-		return entities.getPersistentEntity(type).map(it -> {
+		return entities.getPersistentEntity(type) //
+				.filter(it -> !it.isImmutable()) //
+				.map(it -> {
 
-			MergingPropertyHandler propertyHandler = new MergingPropertyHandler(source, target, it, mapper);
+					MergingPropertyHandler propertyHandler = new MergingPropertyHandler(source, target, it, mapper);
 
-			it.doWithProperties(propertyHandler);
-			it.doWithAssociations(new LinkedAssociationSkippingAssociationHandler(associationLinks, propertyHandler));
+					it.doWithProperties(propertyHandler);
+					it.doWithAssociations(new LinkedAssociationSkippingAssociationHandler(associationLinks, propertyHandler));
 
-			// Need to copy unmapped properties as the PersistentProperty model currently does not contain any transient
-			// properties
-			copyRemainingProperties(propertyHandler.getProperties(), source, target);
+					// Need to copy unmapped properties as the PersistentProperty model currently does not contain any transient
+					// properties
+					copyRemainingProperties(propertyHandler.getProperties(), source, target);
 
-			return target;
+					return target;
 
-		}).orElse(source);
+				}).orElse(source);
 	}
 
 	/**
@@ -229,7 +231,7 @@ public class DomainObjectReader {
 			}
 
 			PersistentProperty<?> property = mappedProperties.getPersistentProperty(fieldName);
-			PersistentPropertyAccessor accessor = entity.getPropertyAccessor(target);
+			PersistentPropertyAccessor<?> accessor = entity.getPropertyAccessor(target);
 			Optional<Object> rawValue = Optional.ofNullable(accessor.getProperty(property));
 
 			if (!rawValue.isPresent() || associationLinks.isLinkableAssociation(property)) {
@@ -596,8 +598,8 @@ public class DomainObjectReader {
 	private class MergingPropertyHandler implements SimplePropertyHandler {
 
 		private final @Getter MappedProperties properties;
-		private final PersistentPropertyAccessor targetAccessor;
-		private final PersistentPropertyAccessor sourceAccessor;
+		private final PersistentPropertyAccessor<?> targetAccessor;
+		private final PersistentPropertyAccessor<?> sourceAccessor;
 		private final ObjectMapper mapper;
 
 		/**
@@ -617,7 +619,7 @@ public class DomainObjectReader {
 			Assert.notNull(mapper, "ObjectMapper must not be null!");
 
 			this.properties = MappedProperties.fromJacksonProperties(entity, mapper);
-			this.targetAccessor = new ConvertingPropertyAccessor(entity.getPropertyAccessor(target),
+			this.targetAccessor = new ConvertingPropertyAccessor<>(entity.getPropertyAccessor(target),
 					new DefaultConversionService());
 			this.sourceAccessor = entity.getPropertyAccessor(source);
 			this.mapper = mapper;
@@ -639,6 +641,12 @@ public class DomainObjectReader {
 			}
 
 			Optional<Object> sourceValue = Optional.ofNullable(sourceAccessor.getProperty(property));
+
+			if (property.isImmutable()) {
+				targetAccessor.setProperty(property, sourceValue.orElse(null));
+				return;
+			}
+
 			Optional<Object> targetValue = Optional.ofNullable(targetAccessor.getProperty(property));
 			Optional<?> result = Optional.empty();
 

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

@@ -23,6 +23,7 @@ import static org.mockito.Mockito.*;
 
 import lombok.AllArgsConstructor;
 import lombok.EqualsAndHashCode;
+import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.RequiredArgsConstructor;
 import lombok.Value;
@@ -51,6 +52,7 @@ import org.mockito.Mock;
 import org.mockito.junit.MockitoJUnitRunner;
 import org.springframework.data.annotation.CreatedDate;
 import org.springframework.data.annotation.Id;
+import org.springframework.data.annotation.Immutable;
 import org.springframework.data.annotation.ReadOnlyProperty;
 import org.springframework.data.annotation.Reference;
 import org.springframework.data.annotation.Transient;
@@ -734,11 +736,13 @@ public class DomainObjectReaderUnitTests {
 		List<SampleEnum> enums = new ArrayList<SampleEnum>();
 	}
 
-	@Value
+	@EqualsAndHashCode
+	@AllArgsConstructor
 	static class SampleWithReference {
-		@Reference List<Nested> nested;
+		private @Getter @Reference List<Nested> nested;
 	}
 
+	@Immutable
 	@Value
 	static class Nested {
 		int x, y;