Allow dynamic projection for Neo4jTemplate::save

[Andy2003]

There are situations when you want to dynamically determine which fields of a domain object should actually be saved.

To achieve this it would be good to have a method similar to Neo4jTemplate::saveImpl available as a public API

spring-data-neo4j/src/main/java/org/springframework/data/neo4j/core/Neo4jTemplate.java

Lines 360 to 411 in ea7bfb7

	private <T> T saveImpl(T instance, @Nullable Map<PropertyPath, Boolean> includedProperties, @Nullable NestedRelationshipProcessingStateMachine stateMachine) {
	if (stateMachine != null && stateMachine.hasProcessedValue(instance)) {
	return instance;
	}
	Neo4jPersistentEntity<?> entityMetaData = neo4jMappingContext.getRequiredPersistentEntity(instance.getClass());
	boolean isEntityNew = entityMetaData.isNew(instance);
	T entityToBeSaved = eventSupport.maybeCallBeforeBind(instance);
	DynamicLabels dynamicLabels = determineDynamicLabels(entityToBeSaved, entityMetaData);
	@SuppressWarnings("unchecked") // Applies to retrieving the meta data
	TemplateSupport.FilteredBinderFunction<T> binderFunction = TemplateSupport.createAndApplyPropertyFilter(
	includedProperties, entityMetaData,
	neo4jMappingContext.getRequiredBinderFunctionFor((Class<T>) entityToBeSaved.getClass())
	);
	Optional<Entity> newOrUpdatedNode = neo4jClient
	.query(() -> renderer.render(cypherGenerator.prepareSaveOf(entityMetaData, dynamicLabels)))
	.bind(entityToBeSaved)
	.with(binderFunction)
	.fetchAs(Entity.class)
	.one();
	if (!newOrUpdatedNode.isPresent()) {
	if (entityMetaData.hasVersionProperty()) {
	throw new OptimisticLockingFailureException(OPTIMISTIC_LOCKING_ERROR_MESSAGE);
	}
	// defensive exception throwing
	throw new IllegalStateException("Could not retrieve an internal id while saving.");
	}
	Long internalId = newOrUpdatedNode.get().id();
	PersistentPropertyAccessor<T> propertyAccessor = entityMetaData.getPropertyAccessor(entityToBeSaved);
	if (entityMetaData.isUsingInternalIds()) {
	propertyAccessor.setProperty(entityMetaData.getRequiredIdProperty(), internalId);
	}
	TemplateSupport.updateVersionPropertyIfPossible(entityMetaData, propertyAccessor, newOrUpdatedNode.get());
	if (stateMachine == null) {
	stateMachine = new NestedRelationshipProcessingStateMachine(neo4jMappingContext, instance, internalId);
	}
	stateMachine.markValueAsProcessed(instance, internalId);
	processRelations(entityMetaData, propertyAccessor, isEntityNew, stateMachine, binderFunction.filter);
	T bean = propertyAccessor.getBean();
	stateMachine.markValueAsProcessedAs(instance, bean);
	return bean;
	}

[Andy2003]

Is there a possibility of downporting this to 6.2 so we don't have to wait for the next spring boot release?