Migration to RX

Drivers & Stacks Spring Data Neo4j & Neo4j-OGM
1

I started the process of switching over to spring data neo4j rx. Right away, I noticed quite a few hurdles that we will need to overcome.

For starters, the missing support of @RelationshipEntity, @StartNode, @EndNode, @Index, @DateLong

We use RelationshipEntity a lot in our project, We have many relationship classes with @StartNode and @EndNode, and it is important to us to know which way the relationship -> points

Are there any suggestions as to how we can migrate. Here's an example of what I'm referring to:

@NoArgsConstructor
@AllArgsConstructor
@EqualsAndHashCode(exclude = {"startRoute", "endRoute"}, callSuper = false)
@ToString(exclude = {"startRoute", "endRoute"})
//@CompositeIndex(value = {"Route_ID", "Capture_Id"}, unique = true)

@RelationshipEntity(type = "CARRIED_BY")
public class CarriedBy {
    @Id @GeneratedValue
    private Long graphId;

    @Index
    @Property(name = "Route_ID")
    private String id;

    @Property(name = "Route_IsAEnd")
    private boolean aEndRouteId;

    @Property(name = "Date_NetworkExtract")
    @DateLong
    private Date networkExtract;

    @Index
    @Property(name = "Capture_Id")
    private Long captureId;

    @StartNode
    private RouteEntity startRoute;

    @EndNode
    private RouteEntity endRoute;
}

Thanks.
2

With the SDN 6.0 RC1 that has been released last Wednesday, there is a new API for mapping relationships with properties.

@RelationshipProperties
public class CarriedBy {

  @Property("Route_ID")
  private String id

// other properties

  @TargetNode
   private RouteEntity endRoute;
}

and in your RouteEntity something like:

@Relationship("CARRIED_BY")
private List<CarriedBy> carriedByRouteEntities;

will make SDN use those relationship properties classes.

For the raw conversion, you would need to define your own converter as described here: Spring Data Neo4j⚡️RX

Note: We are currently updating the documentation and examples for the new relationship properties and moving all to the official Spring Data reference docs.

4

Thank you Gerrit.

Another snag in the migration we run into is this. We use converters for embedded objects as shown below:

    @Convert(RouteStateConverter.class)
    private RouteState routeState;

And we wrote our own converters to go to/from the graph:

public class RouteStateConverter implements CompositeAttributeConverter<RouteState> {

    @Override
    public Map<String, ?> toGraphProperties(RouteState routeState) {
        // conversion code
    }

    @Override
    public RouteState toEntityAttribute(Map<String, ?> map) {
       // conversion code
    }
5

I hope that somebody already reached out to you on a different channel but for having a documented answer here: Add support for OGM's CompositeAttributeConverter. [DATAGRAPH-1393] · Issue #1954 · spring-projects/spring-data-neo4j · GitHub
We are working on this.

1 Like
6

Gerrit do you know when is going to be release?

7

It has already been released with SDN 6.0.0. To get some impression how it works and should be used I suggest to look into this test class spring-data-neo4j/ImperativeCompositePropertiesIT.java at main · spring-projects/spring-data-neo4j · GitHub