Feature: allow embedded entities instead of resolvers (#270)

* refactor: expose specific owner for persistent properties

* [#269] allow return merged entities to be mapped directly

* revert change of deprecated usage

* remove unused import

* test enhancements

* test fix

---------

Co-authored-by: Michele Rastelli <[email protected]>

Author: aburmeis

src/main/java/com/arangodb/springframework/core/convert/DefaultArangoConverter.java

@@ -336,9 +336,13 @@ private Optional<Object> readReference(
 		final ArangoPersistentProperty property,
 		final Annotation annotation) {
 
+		if (source.isNone() || source.isNull()) {
+			return Optional.empty();
+		}
+
 		final Optional<ReferenceResolver<Annotation>> resolver = resolverFactory.getReferenceResolver(annotation);
 
-		if (!resolver.isPresent() || source.isNone()) {
+		if (!resolver.isPresent()) {
 			return Optional.empty();
 		}
 
@@ -353,6 +357,11 @@ else if (property.isCollectionLike()) {
 			return resolver.map(res -> res.resolveMultiple(ids, property.getTypeInformation(), annotation));
 		}
 
+		else if (source.isObject()) {
+			// source contains target
+			return Optional.of(readInternal(property.getTypeInformation(), source));
+		}
+
 		else {
 			if (!source.isString()) {
 				throw new MappingException(
@@ -370,6 +379,10 @@ private <A extends Annotation> Optional<Object> readRelation(
 		final ArangoPersistentProperty property,
 		final A annotation) {
 
+		if (source.isNull()) {
+			return Optional.empty();
+		}
+
 		final Class<? extends Annotation> collectionType = entity.findAnnotation(Edge.class) != null ? Edge.class
 				: Document.class;
 		final Optional<RelationResolver<Annotation>> resolver = resolverFactory.getRelationResolver(annotation,
@@ -383,16 +396,26 @@ private <A extends Annotation> Optional<Object> readRelation(
 		}
 
 		else if (property.isCollectionLike()) {
+			if (source.isArray()) {
+				// source contains target array
+				return Optional.of(readInternal(property.getTypeInformation(), source));
+			}
 			if (parentId == null) {
 				return Optional.empty();
 			}
 			return resolver.map(res -> res.resolveMultiple(parentId, property.getTypeInformation(), traversedTypes, annotation));
 		}
 
 		else if (source.isString()) {
+			// resolve from/to using target id
 			return resolver.map(res -> res.resolveOne(source.getAsString(), property.getTypeInformation(), traversedTypes, annotation));
 		}
 
+		else if (source.isObject()) {
+			// source contains target
+			return Optional.of(readInternal(property.getTypeInformation(), source));
+		}
+
 		else {
 			return resolver.map(res -> res.resolveOne(parentId, property.getTypeInformation(), traversedTypes, annotation));
 		}

src/main/java/com/arangodb/springframework/core/mapping/ArangoPersistentProperty.java

@@ -22,6 +22,7 @@
 
 import java.util.Optional;
 
+import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 
 import com.arangodb.springframework.annotation.From;
@@ -43,6 +44,9 @@ public interface ArangoPersistentProperty extends PersistentProperty<ArangoPersi
 
 	String getFieldName();
 
+	@Override
+	ArangoPersistentEntity<?> getOwner();
+
 	boolean isArangoIdProperty();
 
 	boolean isRevProperty();

src/main/java/com/arangodb/springframework/core/mapping/DefaultArangoPersistentProperty.java

@@ -22,6 +22,7 @@
 
 import java.util.Optional;
 
+import com.arangodb.entity.CollectionType;
 import org.springframework.data.mapping.Association;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.model.AnnotationBasedPersistentProperty;
@@ -55,13 +56,18 @@ public class DefaultArangoPersistentProperty extends AnnotationBasedPersistentPr
 	private final FieldNamingStrategy fieldNamingStrategy;
 
 	public DefaultArangoPersistentProperty(final Property property,
-		final PersistentEntity<?, ArangoPersistentProperty> owner, final SimpleTypeHolder simpleTypeHolder,
+		final ArangoPersistentEntity<?> owner, final SimpleTypeHolder simpleTypeHolder,
 		final FieldNamingStrategy fieldNamingStrategy) {
 		super(property, owner, simpleTypeHolder);
 		this.fieldNamingStrategy = fieldNamingStrategy != null ? fieldNamingStrategy
 				: PropertyNameFieldNamingStrategy.INSTANCE;
 	}
 
+	@Override
+	public ArangoPersistentEntity<?> getOwner() {
+		return (ArangoPersistentEntity<?>) super.getOwner();
+	}
+
 	@Override
 	protected Association<ArangoPersistentProperty> createAssociation() {
 		return new Association<>(this, null);
@@ -106,9 +112,9 @@ public String getFieldName() {
 			fieldName = "_key";
 		} else if (isRevProperty()) {
 			fieldName = "_rev";
-		} else if (getFrom().isPresent()) {
+		} else if (getFrom().isPresent() && getOwner().getCollectionOptions().getType() == CollectionType.EDGES) {
 			fieldName = "_from";
-		} else if (getTo().isPresent()) {
+		} else if (getTo().isPresent() && getOwner().getCollectionOptions().getType() == CollectionType.EDGES) {
 			fieldName = "_to";
 		} else {
 			fieldName = getAnnotatedFieldName().orElse(fieldNamingStrategy.getFieldName(this));