Resolve all persistent entities for a persistent property.

Original pull request: #2394.
Closes #2390.

Author: christophstrobl

src/main/java/org/springframework/data/mapping/context/AbstractMappingContext.java

@@ -34,7 +34,6 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.InitializingBean;
@@ -116,7 +115,8 @@ protected AbstractMappingContext() {
 		this.persistentPropertyPathFactory = new PersistentPropertyPathFactory<>(this);
 
 		EntityInstantiators instantiators = new EntityInstantiators();
-		PersistentPropertyAccessorFactory accessorFactory = NativeDetector.inNativeImage() ? BeanWrapperPropertyAccessorFactory.INSTANCE
+		PersistentPropertyAccessorFactory accessorFactory = NativeDetector.inNativeImage()
+				? BeanWrapperPropertyAccessorFactory.INSTANCE
 				: new ClassGeneratingPropertyAccessorFactory();
 
 		this.persistentPropertyAccessorFactory = new InstantiationAwarePropertyAccessorFactory(accessorFactory,
@@ -485,7 +485,8 @@ protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
 		if (simpleTypeHolder.isSimpleType(type.getType())) {
 			return false;
 		}
-		if(NullableWrapperConverters.supports(type.getType())) {
+
+		if (NullableWrapperConverters.supports(type.getType())) {
 			return false;
 		}
 
@@ -564,6 +565,7 @@ private void createAndRegisterProperty(Property input) {
 			if (shouldSkipOverrideProperty(property)) {
 				return;
 			}
+
 			entity.addPersistentProperty(property);
 
 			if (property.isAssociation()) {
@@ -574,18 +576,8 @@ private void createAndRegisterProperty(Property input) {
 				return;
 			}
 
-			StreamSupport.stream(property.getPersistentEntityTypes().spliterator(), false)
-					.map(it -> {
-						if(it.isNullableWrapper()) {
-							return it.getActualType();
-						}
-						return it;
-					})
-					.filter(it -> {
-
-						boolean shouldCreate = AbstractMappingContext.this.shouldCreatePersistentEntityFor(it);
-						return shouldCreate;
-					})
+			StreamSupport.stream(property.getPersistentEntityTypes().spliterator(), false) //
+					.filter(AbstractMappingContext.this::shouldCreatePersistentEntityFor) //
 					.forEach(AbstractMappingContext.this::addPersistentEntity);
 		}
 
@@ -668,7 +660,6 @@ private Class<?> getPropertyType(PersistentProperty<?> persistentProperty) {
 		}
 	}
 
-
 	/**
 	 * Filter rejecting static fields as well as artificially introduced ones. See
 	 * {@link PersistentPropertyFilter#UNMAPPED_PROPERTIES} for details.

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

@@ -18,11 +18,16 @@
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
+import java.util.Collection;
 import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.Supplier;
 
+import org.springframework.core.GenericTypeResolver;
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
@@ -64,6 +69,7 @@ public abstract class AbstractPersistentProperty<P extends PersistentProperty<P>
 
 	private final Lazy<Boolean> isAssociation;
 	private final Lazy<TypeInformation<?>> associationTargetType;
+	private final Lazy<Collection<TypeInformation<?>>> entityTypes;
 
 	private final Method getter;
 	private final Method setter;
@@ -111,6 +117,43 @@ public AbstractPersistentProperty(Property property, PersistentEntity<?, P> owne
 		} else {
 			this.immutable = false;
 		}
+
+		this.entityTypes = Lazy.of(() -> collectEntityTypes(simpleTypeHolder, information, new LinkedHashSet<>()));
+	}
+
+	protected Set<TypeInformation<?>> collectEntityTypes(SimpleTypeHolder simpleTypeHolder, @Nullable TypeInformation<?> typeInformation, Set<TypeInformation<?>> entityTypes) {
+
+		if(typeInformation == null || entityTypes.contains(typeInformation) || simpleTypeHolder.isSimpleType(typeInformation.getType())) {
+			return entityTypes;
+		}
+
+		if(typeInformation.isMap()) {
+
+			collectEntityTypes(simpleTypeHolder, typeInformation.getComponentType(), entityTypes);
+			collectEntityTypes(simpleTypeHolder, typeInformation.getMapValueType(), entityTypes);
+			return entityTypes;
+		}
+
+		if(typeInformation.isCollectionLike()) {
+
+			collectEntityTypes(simpleTypeHolder, typeInformation.getComponentType(), entityTypes);
+			return entityTypes;
+		}
+
+		if(typeInformation.isNullableWrapper()) {
+
+			collectEntityTypes(simpleTypeHolder, typeInformation.getActualType(), entityTypes);
+			return entityTypes;
+		}
+
+		if(ASSOCIATION_TYPE != null && ASSOCIATION_TYPE.isAssignableFrom(typeInformation.getType())) {
+
+			entityTypes.add(getAssociationOrActualType());
+			return entityTypes;
+		}
+
+		entityTypes.add(typeInformation);
+		return entityTypes;
 	}
 
 	protected abstract Association<P> createAssociation();
@@ -167,13 +210,15 @@ public TypeInformation<?> getTypeInformation() {
 	@Override
 	public Iterable<? extends TypeInformation<?>> getPersistentEntityTypes() {
 
+		if(isMap() || isCollectionLike()) {
+			return entityTypes.get();
+		}
+
 		if (!isEntity()) {
 			return Collections.emptySet();
 		}
 
-		TypeInformation<?> result = getAssociationTypeOr(() -> entityTypeInformation.getNullable());
-
-		return result != null ? Collections.singleton(result) : Collections.emptySet();
+		return entityTypes.get();
 	}
 
 	/*

src/main/java/org/springframework/data/util/TypeInformation.java

@@ -274,6 +274,11 @@ default boolean isSubTypeOf(Class<?> type) {
 		return !type.equals(getType()) && type.isAssignableFrom(getType());
 	}
 
+	/**
+	 * Returns whether the current type is considered a {@literal null} value wrapper or not.
+	 *
+	 * @return {@literal true} if the type is considered to be a {@literal null} value wrapper such as {@link java.util.Optional}.
+	 */
 	default boolean isNullableWrapper() {
 		return NullableWrapperConverters.supports(getType());
 	}

src/test/java/org/springframework/data/mapping/context/AbstractMappingContextUnitTests.java

@@ -26,11 +26,14 @@
 import lombok.Value;
 
 import java.time.LocalDateTime;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
+import java.util.Optional;
 import java.util.TreeMap;
 import java.util.function.Supplier;
 
@@ -272,6 +275,36 @@ void shouldIgnoreNonAssignableOverridePropertyInSuperClass() {
 		});
 	}
 
+	@Test // GH-2390
+	void shouldNotCreatePersistentEntityForOptionalButItsGenericTypeArgument() {
+
+		context.getPersistentEntity(WithOptionals.class);
+
+		assertThat(context.getPersistentEntities()).map(it -> (Class) it.getType())
+				.contains(WithOptionals.class, Person.class, Base.class)
+				.doesNotContain(Optional.class, List.class, ArrayList.class);
+	}
+
+	@Test // GH-2390
+	void shouldNotCreatePersistentEntityForListButItsGenericTypeArgument() {
+
+		context.getPersistentEntity(WithNestedLists.class);
+
+		assertThat(context.getPersistentEntities()).map(it -> (Class) it.getType())
+				.contains(Base.class)
+				.doesNotContain(List.class, ArrayList.class);
+	}
+
+	@Test // GH-2390
+	void shouldNotCreatePersistentEntityForMapButItsGenericTypeArguments() {
+
+		context.getPersistentEntity(WithMap.class);
+
+		assertThat(context.getPersistentEntities()).map(it -> (Class) it.getType())
+				.contains(Base.class, Person.class, MapKey.class)
+				.doesNotContain(List.class, Map.class, String.class, Integer.class);
+	}
+
 	private static void assertHasEntityFor(Class<?> type, SampleMappingContext context, boolean expected) {
 
 		boolean found = false;
@@ -432,4 +465,26 @@ static class ShadowingPropertyAssignable extends ShadowedPropertyAssignable {
 		}
 	}
 
+	class WithOptionals {
+
+		Optional<String> optionalOfString;
+		Optional<Person> optionalOfPerson;
+		List<Optional<Base>> listOfOptionalOfBase;
+	}
+
+	class WithNestedLists {
+		ArrayList<List<Base>> arrayListOfOptionalOfBase;
+	}
+
+	class MapKey {
+
+	}
+
+	class WithMap {
+
+		Map<String, List<Base>> mapOfStringToList;
+		Map<String, Person> mapOfStringToPerson;
+		Map<MapKey, Integer> mapOfKeyToPerson;
+	}
+
 }