I'm trying to implement one of the documentation example: <div class="snippet-clip

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Can't retrieve Edge documents as an attribute about spring-data HOT 1 CLOSED

arangodb commented on May 30, 2024

Can't retrieve Edge documents as an attribute

from spring-data.

Comments (1)

mvollmary commented on May 30, 2024

Hi @dmartinpro,

First issue: Yes, your are right. The docs are wrong it has to be value.

Let me quickly write down your needed classes for your case:

Class A with a field annotated with @Id and the list of links annotated with @From (or @To depending on the direction of you edge). I highly suggest to set the param lazy to true otherwise you can easily run into infinity loops.

@Document
public class A {
  @Id private String id;
  @From(lazy = true) private List<Link> links;

  public A() {
    super();
  }
  public String getId() {
    return id;
  }
  public List<Link> getLinks() {
    return links;
  }
}

Class B only needs a field annotated with @Id.

@Document
public class B {
  @Id private String id;

  public B() {
    super();
  }
  public String getId() {
    return id;
  }
}

Class Link has to be annotated with @Edge and needs a field from type A annotated with @From and a field from type B annotated with @To. I also recommend here using lazy=true.

@Edge
public class Link {
  @Id private String id;
  @From(lazy = true) private final A a;
  @To(lazy = true) private final B b;

  public Link(final A a, final B b) {
    super();
    this.a = a;
    this.b = b;
  }
  public String getId() {
    return id;
  }
  public A getA() {
    return a;
  }
  public B getB() {
    return b;
  }
}

Usage (i.e. with ArangoOperations):

@Autowired
private ArangoOperations operations;

...

A a = new A();
operations.insert(a);

B b = new B();
operations.insert(b);

operations.insert(new Link(a, b));

Optional<A> find = operations.find(a.getId(), A.class);
find.ifPresent(e -> {
  e.getLinks();
  ...
});