DATACMNS-1322 - Generified PersistentPropertyAccessor API.

PersistentPropertyAccessor is now generic to be able to retain the type information about the object it was created for and the return type of ….getBean(). Adapted client APIs.

Author: odrotbohm

src/main/java/org/springframework/data/auditing/MappingAuditableBeanWrapperFactory.java

@@ -148,7 +148,7 @@ public boolean isAuditable() {
 	 */
 	static class MappingMetadataAuditableBeanWrapper<T> extends DateConvertingAuditableBeanWrapper<T> {
 
-		private final PersistentPropertyAccessor accessor;
+		private final PersistentPropertyAccessor<T> accessor;
 		private final MappingAuditingMetadata metadata;
 
 		/**
@@ -158,7 +158,8 @@ static class MappingMetadataAuditableBeanWrapper<T> extends DateConvertingAudita
 		 * @param accessor must not be {@literal null}.
 		 * @param metadata must not be {@literal null}.
 		 */
-		public MappingMetadataAuditableBeanWrapper(PersistentPropertyAccessor accessor, MappingAuditingMetadata metadata) {
+		public MappingMetadataAuditableBeanWrapper(PersistentPropertyAccessor<T> accessor,
+				MappingAuditingMetadata metadata) {
 
 			Assert.notNull(accessor, "PersistentPropertyAccessor must not be null!");
 			Assert.notNull(metadata, "Auditing metadata must not be null!");
@@ -224,9 +225,8 @@ public TemporalAccessor setLastModifiedDate(TemporalAccessor value) {
 		 * @see org.springframework.data.auditing.AuditableBeanWrapper#getBean()
 		 */
 		@Override
-		@SuppressWarnings("unchecked")
 		public T getBean() {
-			return (T) accessor.getBean();
+			return accessor.getBean();
 		}
 
 		private <S, P extends PersistentProperty<?>> S setProperty(

src/main/java/org/springframework/data/mapping/PersistentEntity.java

@@ -285,7 +285,7 @@ default <A extends Annotation> A getRequiredAnnotation(Class<A> annotationType)
 	 * @return new {@link PersistentPropertyAccessor}.
 	 * @since 1.10
 	 */
-	PersistentPropertyAccessor getPropertyAccessor(Object bean);
+	<B> PersistentPropertyAccessor<B> getPropertyAccessor(B bean);
 
 	/**
 	 * Returns the {@link IdentifierAccessor} for the given bean.

src/main/java/org/springframework/data/mapping/PersistentPropertyAccessor.java

@@ -33,7 +33,7 @@
  * @see PersistentEntity#getPropertyAccessor(Object)
  * @see ConvertingPropertyAccessor
  */
-public interface PersistentPropertyAccessor {
+public interface PersistentPropertyAccessor<T> {
 
 	/**
 	 * Sets the given {@link PersistentProperty} to the given value. Will do type conversion if a
@@ -71,7 +71,7 @@ default void setProperty(PersistentPropertyPath<? extends PersistentProperty<?>>
 					getBean().getClass().getName()));
 		}
 
-		PersistentPropertyAccessor accessor = parent == getBean() //
+		PersistentPropertyAccessor<?> accessor = parent == getBean() //
 				? this //
 				: leafProperty.getOwner().getPropertyAccessor(parent);
 
@@ -126,7 +126,7 @@ default Object getProperty(PersistentPropertyPath<? extends PersistentProperty<?
 			}
 
 			PersistentEntity<?, ? extends PersistentProperty<?>> entity = property.getOwner();
-			PersistentPropertyAccessor accessor = entity.getPropertyAccessor(current);
+			PersistentPropertyAccessor<Object> accessor = entity.getPropertyAccessor(current);
 
 			current = accessor.getProperty(property);
 		}
@@ -140,5 +140,5 @@ default Object getProperty(PersistentPropertyPath<? extends PersistentProperty<?
 	 *
 	 * @return will never be {@literal null}.
 	 */
-	Object getBean();
+	T getBean();
 }

src/main/java/org/springframework/data/mapping/model/BasicPersistentEntity.java

@@ -461,7 +461,7 @@ public void setPersistentPropertyAccessorFactory(PersistentPropertyAccessorFacto
 	 * @see org.springframework.data.mapping.PersistentEntity#getPropertyAccessor(java.lang.Object)
 	 */
 	@Override
-	public PersistentPropertyAccessor getPropertyAccessor(Object bean) {
+	public <B> PersistentPropertyAccessor<B> getPropertyAccessor(B bean) {
 
 		verifyBeanType(bean);
 

src/main/java/org/springframework/data/mapping/model/BeanWrapper.java

@@ -40,7 +40,7 @@
  * @author Oliver Gierke
  * @author Mark Paluch
  */
-class BeanWrapper<T> implements PersistentPropertyAccessor {
+class BeanWrapper<T> implements PersistentPropertyAccessor<T> {
 
 	private T bean;
 

src/main/java/org/springframework/data/mapping/model/BeanWrapperPropertyAccessorFactory.java

@@ -32,7 +32,7 @@ enum BeanWrapperPropertyAccessorFactory implements PersistentPropertyAccessorFac
 	 * @see org.springframework.data.mapping.model.PersistentPropertyAccessorFactory#getPropertyAccessor(org.springframework.data.mapping.PersistentEntity, java.lang.Object)
 	 */
 	@Override
-	public PersistentPropertyAccessor getPropertyAccessor(PersistentEntity<?, ?> entity, Object bean) {
+	public <T> PersistentPropertyAccessor<T> getPropertyAccessor(PersistentEntity<?, ?> entity, T bean) {
 		return new BeanWrapper<>(bean);
 	}
 

src/main/java/org/springframework/data/mapping/model/ClassGeneratingPropertyAccessorFactory.java

@@ -83,21 +83,21 @@ public class ClassGeneratingPropertyAccessorFactory implements PersistentPropert
 	private final ThreadLocal<Object[]> argumentCache = ThreadLocal.withInitial(() -> new Object[1]);
 
 	private volatile Map<PersistentEntity<?, ?>, Constructor<?>> constructorMap = new HashMap<>(32);
-	private volatile Map<TypeInformation<?>, Class<PersistentPropertyAccessor>> propertyAccessorClasses = new HashMap<>(
+	private volatile Map<TypeInformation<?>, Class<PersistentPropertyAccessor<?>>> propertyAccessorClasses = new HashMap<>(
 			32);
 
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mapping.model.PersistentPropertyAccessorFactory#getPropertyAccessor(org.springframework.data.mapping.PersistentEntity, java.lang.Object)
 	 */
 	@Override
-	public PersistentPropertyAccessor getPropertyAccessor(PersistentEntity<?, ?> entity, Object bean) {
+	public <T> PersistentPropertyAccessor<T> getPropertyAccessor(PersistentEntity<?, ?> entity, T bean) {
 
 		Constructor<?> constructor = constructorMap.get(entity);
 
 		if (constructor == null) {
 
-			Class<PersistentPropertyAccessor> accessorClass = potentiallyCreateAndRegisterPersistentPropertyAccessorClass(
+			Class<PersistentPropertyAccessor<?>> accessorClass = potentiallyCreateAndRegisterPersistentPropertyAccessorClass(
 					entity);
 			constructor = accessorClass.getConstructors()[0];
 
@@ -110,7 +110,7 @@ public PersistentPropertyAccessor getPropertyAccessor(PersistentEntity<?, ?> ent
 		args[0] = bean;
 
 		try {
-			return (PersistentPropertyAccessor) constructor.newInstance(args);
+			return (PersistentPropertyAccessor<T>) constructor.newInstance(args);
 		} catch (Exception e) {
 			throw new IllegalArgumentException(String.format("Cannot create persistent property accessor for %s", entity), e);
 		} finally {
@@ -177,11 +177,11 @@ private boolean hasUniquePropertyHashCodes(PersistentEntity<?, ?> entity) {
 	/**
 	 * @param entity must not be {@literal null}.
 	 */
-	private synchronized Class<PersistentPropertyAccessor> potentiallyCreateAndRegisterPersistentPropertyAccessorClass(
+	private synchronized Class<PersistentPropertyAccessor<?>> potentiallyCreateAndRegisterPersistentPropertyAccessorClass(
 			PersistentEntity<?, ?> entity) {
 
-		Map<TypeInformation<?>, Class<PersistentPropertyAccessor>> map = this.propertyAccessorClasses;
-		Class<PersistentPropertyAccessor> propertyAccessorClass = map.get(entity.getTypeInformation());
+		Map<TypeInformation<?>, Class<PersistentPropertyAccessor<?>>> map = this.propertyAccessorClasses;
+		Class<PersistentPropertyAccessor<?>> propertyAccessorClass = map.get(entity.getTypeInformation());
 
 		if (propertyAccessorClass != null) {
 			return propertyAccessorClass;
@@ -198,10 +198,10 @@ private synchronized Class<PersistentPropertyAccessor> potentiallyCreateAndRegis
 	}
 
 	@SuppressWarnings("unchecked")
-	private Class<PersistentPropertyAccessor> createAccessorClass(PersistentEntity<?, ?> entity) {
+	private Class<PersistentPropertyAccessor<?>> createAccessorClass(PersistentEntity<?, ?> entity) {
 
 		try {
-			return (Class<PersistentPropertyAccessor>) PropertyAccessorClassGenerator.generateCustomAccessorClass(entity);
+			return (Class<PersistentPropertyAccessor<?>>) PropertyAccessorClassGenerator.generateCustomAccessorClass(entity);
 		} catch (Exception e) {
 			throw new RuntimeException(e);
 		}

src/main/java/org/springframework/data/mapping/model/ConvertingPropertyAccessor.java

@@ -30,9 +30,9 @@
  * @author Oliver Gierke
  * @author Mark Paluch
  */
-public class ConvertingPropertyAccessor implements PersistentPropertyAccessor {
+public class ConvertingPropertyAccessor<T> implements PersistentPropertyAccessor<T> {
 
-	private final PersistentPropertyAccessor accessor;
+	private final PersistentPropertyAccessor<T> accessor;
 	private final ConversionService conversionService;
 
 	/**
@@ -42,7 +42,7 @@ public class ConvertingPropertyAccessor implements PersistentPropertyAccessor {
 	 * @param accessor must not be {@literal null}.
 	 * @param conversionService must not be {@literal null}.
 	 */
-	public ConvertingPropertyAccessor(PersistentPropertyAccessor accessor, ConversionService conversionService) {
+	public ConvertingPropertyAccessor(PersistentPropertyAccessor<T> accessor, ConversionService conversionService) {
 
 		Assert.notNull(accessor, "PersistentPropertyAccessor must not be null!");
 		Assert.notNull(conversionService, "ConversionService must not be null!");
@@ -78,7 +78,7 @@ public Object getProperty(PersistentProperty<?> property) {
 	 * @return
 	 */
 	@Nullable
-	public <T> T getProperty(PersistentProperty<?> property, Class<T> targetType) {
+	public <S> S getProperty(PersistentProperty<?> property, Class<S> targetType) {
 
 		Assert.notNull(property, "PersistentProperty must not be null!");
 		Assert.notNull(targetType, "Target type must not be null!");
@@ -91,7 +91,7 @@ public <T> T getProperty(PersistentProperty<?> property, Class<T> targetType) {
 	 * @see org.springframework.data.mapping.PersistentPropertyAccessor#getBean()
 	 */
 	@Override
-	public Object getBean() {
+	public T getBean() {
 		return accessor.getBean();
 	}
 
@@ -105,8 +105,8 @@ public Object getBean() {
 	 */
 	@Nullable
 	@SuppressWarnings("unchecked")
-	private <T> T convertIfNecessary(@Nullable Object source, Class<T> type) {
-		return (T) (source == null ? null
+	private <S> S convertIfNecessary(@Nullable Object source, Class<S> type) {
+		return (S) (source == null ? null
 				: type.isAssignableFrom(source.getClass()) ? source : conversionService.convert(source, type));
 	}
 }

src/main/java/org/springframework/data/mapping/model/IdPropertyIdentifierAccessor.java

@@ -32,7 +32,7 @@
  */
 public class IdPropertyIdentifierAccessor extends TargetAwareIdentifierAccessor {
 
-	private final PersistentPropertyAccessor accessor;
+	private final PersistentPropertyAccessor<?> accessor;
 	private final PersistentProperty<?> idProperty;
 
 	/**

src/main/java/org/springframework/data/mapping/model/PersistentPropertyAccessorFactory.java

@@ -34,7 +34,7 @@ public interface PersistentPropertyAccessorFactory {
 	 * @param bean must not be {@literal null}.
 	 * @return will never be {@literal null}.
 	 */
-	PersistentPropertyAccessor getPropertyAccessor(PersistentEntity<?, ?> entity, Object bean);
+	<T> PersistentPropertyAccessor<T> getPropertyAccessor(PersistentEntity<?, ?> entity, T bean);
 
 	/**
 	 * Returns whether given {@link PersistentEntity} is supported by this {@link PersistentPropertyAccessorFactory}.

src/test/java/org/springframework/data/mapping/model/BasicPersistentEntityUnitTests.java

@@ -193,7 +193,7 @@ public void returnsBeanWrapperForPropertyAccessor() {
 		PersistentEntity<Object, SamplePersistentProperty> entity = context.getRequiredPersistentEntity(Entity.class);
 
 		Entity value = new Entity();
-		PersistentPropertyAccessor accessor = entity.getPropertyAccessor(value);
+		PersistentPropertyAccessor<Entity> accessor = entity.getPropertyAccessor(value);
 
 		assertThat(accessor).isInstanceOf(BeanWrapper.class);
 		assertThat(accessor.getBean()).isEqualTo(value);

src/test/java/org/springframework/data/mapping/model/PersistentPropertyAccessorTests.java

@@ -42,11 +42,11 @@
 @RunWith(Parameterized.class)
 public class PersistentPropertyAccessorTests {
 
-	private final static SampleMappingContext mappingContext = new SampleMappingContext();
+	private final static SampleMappingContext MAPPING_CONTEXT = new SampleMappingContext();
 
-	private final Function<Object, PersistentPropertyAccessor> propertyAccessorFunction;
+	private final Function<Object, PersistentPropertyAccessor<?>> propertyAccessorFunction;
 
-	public PersistentPropertyAccessorTests(Function<Object, PersistentPropertyAccessor> propertyAccessor,
+	public PersistentPropertyAccessorTests(Function<Object, PersistentPropertyAccessor<?>> propertyAccessor,
 			String displayName) {
 
 		this.propertyAccessorFunction = propertyAccessor;
@@ -60,9 +60,9 @@ public static List<Object[]> parameters() {
 
 		ClassGeneratingPropertyAccessorFactory factory = new ClassGeneratingPropertyAccessorFactory();
 
-		Function<Object, PersistentPropertyAccessor> beanWrapper = BeanWrapper::new;
-		Function<Object, PersistentPropertyAccessor> classGenerating = it -> factory
-				.getPropertyAccessor(mappingContext.getRequiredPersistentEntity(it.getClass()), it);
+		Function<Object, PersistentPropertyAccessor<?>> beanWrapper = BeanWrapper::new;
+		Function<Object, PersistentPropertyAccessor<?>> classGenerating = it -> factory
+				.getPropertyAccessor(MAPPING_CONTEXT.getRequiredPersistentEntity(it.getClass()), it);
 
 		parameters.add(new Object[] { beanWrapper, "BeanWrapper" });
 		parameters.add(new Object[] { classGenerating, "ClassGeneratingPropertyAccessorFactory" });
@@ -147,8 +147,7 @@ public void shouldRejectImmutableKotlinClassPropertyUpdate() {
 	}
 
 	private static SamplePersistentProperty getProperty(Object bean, String propertyName) {
-
-		return mappingContext.getRequiredPersistentEntity(bean.getClass()).getRequiredPersistentProperty(propertyName);
+		return MAPPING_CONTEXT.getRequiredPersistentEntity(bean.getClass()).getRequiredPersistentProperty(propertyName);
 	}
 
 	@Data