Neo4j RelationshipEntity and Spring JPA - neo4j

Question

I have the following nodes and relationships defined:
CarMaker and Models
A CarModel is made CarMaker in multiple years, and that is represented as a property of the MADE_IN relationship.
A CarModel is made by one CarMaker only.
A CarMaker can make multiple CarModels in multiple years.
I have defined the following Classes to represent the nodes: CarModel, CarMaker and the relationship MADE_IN
CarModel
#NodeEntity
public class CarModel {
private Long id;
private String name;
#Relationship (type="MADE_IN", direction = Relationship.UNDIRECTED)
private Set<MadeIn> madeIns = new HashSet<MadeIn>();
private Set<String> years = new HashSet<String>();
public CarModel() {
}
public Long getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void addMadeIn(MadeIn madeIn) {
System.out.println ("Found CarMaker: " + madeIn.getCarMaker());
this.madeIns.add(madeIn);
}
private Set<MadeIn> getMadeIn() {
return madeIns;
}
public Set<String> getYears() {
Iterator<MadeIn> itr = madeIns.iterator();
while (itr.hasNext()) {
years.add(((MadeIn) itr.next()).getYear());
}
Set<String> sortedYears = years.stream().collect(Collectors.toCollection(TreeSet::new));
return sortedYears;
}
}
CarMaker
public class CarMaker {
#GraphId private Long id;
private String name;
#Relationship (type="MADE_IN", direction = Relationship.UNDIRECTED)
private Set<CarModel> carModels = new HashSet<>();
public CarMaker() {
}
public Long getId() {
return id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Set<CarModel> getCarModels() {
return carModels;
}
public void setCarModels(CarModel carModel) {
carModels.add(carModel);
}
}
MADE_IN
#RelationshipEntity(type="MADE_IN")
public class MadeIn {
#GraphId private Long relationshipId;
#Property private String year;
#StartNode private CarMaker carMaker;
#EndNode private CarModel carModel;
public MadeIn() {
}
public MadeIn(CarMaker carMaker, CarModel carModel, String year) {
this.carMaker = carMaker;
this.carModel = carModel;
this.year = year;
}
public Long getRelationshipId() {
return relationshipId;
}
public void setCarMaker(CarMaker carMaker) {
this.carMaker = carMaker;
}
public CarMaker getCarMaker() {
return this.getCarMaker();
}
public void setCarModel(CarModel carModel) {
this.carModel = carModel;
}
public CarModel getCarModel() {
return this.getCarModel();
}
public String getYear() {
return year;
}
public void setYear(String year) {
this.year = year;
}
}
When I make a request to retrieve a CarModel, I receive a response with the details of that model and all years when it was manufactured:
{
"id": 260248,
"name": "Ulysse",
"years": [
"1994",
"1995",
"1996",
"1997",
"1998",
"1999",
"2000",
"2001",
"2004",
"2005",
"2006",
"2007",
"2008",
"2009",
"2010",
"2011",
"2012"
]
}
The problem is when I try to request the CarModels made by a CarMaker:
{
"id": 4152072,
"name": "BMW",
"carModels": []
}
I noticed that if I reverse the annotations #StartNode and #EndNode on the MadeIn class I get the information about the CarModels made by a CarMaker, however I will not longer get the information about the years when those models were made.
{
"id": 4152072,
"name": "BMW",
"carModels": [
{
"id": 260852,
"name": "120",
"years": []
},
{
"id": 261430,
"name": "Z18",
"years": []
},
{
"id": 262044,
"name": "L7",
"years": []
},
Any idea on what am I missing, or what I am doing wrong ?
Thanks in advance for any help.
--MD