[SOLVED] How to retrieve additional attribute on edge with Spring Data ArangoDB

How to retrieve additional attribute on edge with Spring Data ArangoDB

I just start implementing a hobby project with ArangoDB and its spring data library.

I have created two documents with names User and Post. And have created one edge with name Vote.

I have a custom attribute on Vote different then _from and _to. I can save that edge with that custom attribute and also can see it from ArangoDB ui. But I couldn't retrieve that attribute with my Java object.

My environment:

ArangoDB Version : 3.6.3
arangodb-spring-data Version : 3.1.0

My classes are these:

@Document("posts")
@Getter @Setter @NoArgsConstructor
public class Post {

  @Id
  String id;

  @Relations(edges = Vote.class, lazy = true, direction = Direction.INBOUND)
  Collection<Vote> votes;
  @Ref
  User writtenBy;

  String content;
  List<String> externalLinks;
  List<String> internalLinks;
  
  public Post(String content) {
    super();
    this.content = content;
  }
  
}


@Document("users")
@Getter @Setter @NoArgsConstructor
public class User {

  @Id
  String id;

  String name;
  String surname;
  String nick;
  String password;
  
  public User(String name, String surname, String nick) {
    super();
    this.name = name;
    this.surname = surname;
    this.nick = nick;
  }

}

@Edge
@Getter @Setter @NoArgsConstructor
@HashIndex(fields = { "user", "post" }, unique = true)
public class Vote {

  @Id
  String id;

  @From
  User user;

  @To
  Post post;

  Boolean upvoted;

  public Vote(User user, Post post, Boolean upvoted) {
    super();
    this.user = user;
    this.post = post;
    this.upvoted = upvoted;
  }

}

Solution

The @Relations annotation should be applied to a field representing the related vertexes (not edges). Eg. this should work:

  @Relations(edges = Vote.class, lazy = true, direction = Direction.INBOUND)
  Collection<User> usersWhoVoted;