Relationships breaking with spring-data-neo4j 4.0.0

Question

I've got something weird in my project and I can't see if it's may fault or not.

I'm using Spring with spring-data-neo4j (v4.0.0).

This code in my controller breaks relationships.

@RequestMapping("/initialize")
public Object initialize() {
    Organization orga = new Organization();
    orga.setName("WEAVERS");
    this.organizationRepository.save(orga);

    User user = new User();
    user.setEmail("[email protected]");
    user.setFirst_name("Thierno");
    user.setLast_name("Rignoux");
    user.setLogin("317");
    user.setOrganization(orga);
    this.userRepository.save(user);

    User user2 = new User();
    user2.setEmail("[email protected]");
    user2.setFirst_name("Eléonore");
    user2.setLast_name("Klein");
    user2.setLogin("nessie");
    user2.setOrganization(orga);
    this.userRepository.save(user2);

    Project project = new Project();
    project.setName("PROJET 1");
    project.setOrganization(orga);
    project.setUser(user);
    this.projectRepository.save(project);

    Project project2 = new Project();
    project2.setName("PROJET 2");
    project2.setOrganization(orga);
    project2.setUser(user2);
    this.projectRepository.save(project2);

    return orga;
}

As you can see on this graph:

The relation between ORGANIZATION and USER1 has been severed when I created USER2.

Broken relationships is something I see everywhere in my application... I don't understand!

neo4j configuration

@EnableTransactionManagement
@Import(RepositoryRestMvcConfiguration.class)
@EnableScheduling
@EnableAutoConfiguration
@ComponentScan(basePackages = {"fr.weavers.loom"})
@Configuration
@EnableNeo4jRepositories(basePackages = "fr.weavers.loom.repositories")
public class LoomNeo4jConfiguration extends Neo4jConfiguration {

    public static final String URL = System.getenv("NEO4J_URL") != null ? System.getenv("NEO4J_URL") : "http://localhost:7474";

    @Override
    public Neo4jServer neo4jServer() {
        return new RemoteServer(URL,"neo4j","loomREST2016");
    }

    @Override
    public SessionFactory getSessionFactory() {
        return new SessionFactory("fr.weavers.loom.domain");
    }
}

Organization Domain :

public class Organization extends Node {
@GraphId
Long id;

String name;

@Relationship(type = "SET_UP", direction = Relationship.OUTGOING)
Set<SET_UP> projects;

@Relationship(type = "WORK_FOR", direction = Relationship.INCOMING)
Set<WORK_FOR> users;

[...]

WORK_FOR Domain :

public class WORK_FOR extends Relationship {

    @GraphId
    private Long relationshipId;

    @StartNode
    public User user;

    @EndNode
    public Organization organization;

    public WORK_FOR() {
        super();
    }

}

User Domain:

public class User extends Node {

@GraphId
Long id;

String login;

@JsonIgnore
String password;

String first_name;

String last_name;

String email;

@Relationship(type = "WORK_FOR")
WORK_FOR workFor;

I looked everywhere and I can't find anything to help me...

Thank you

Vince Vince · Accepted Answer · 2016-01-12T15:16:57

In your initialisation request you make several repository calls to construct the database. Each of these calls will construct a new Session, effectively clearing out information from the previous one because the Spring config defaults to Session-per-request. This is most likely the reason existing relationships are being deleted.

If you add the following bean definition to your config, I believe the problem should be resolved.

@Override
@Bean
@Scope(value = "session", proxyMode = ScopedProxyMode.TARGET_CLASS)
public Session getSession() throws Exception {
    return super.getSession();
}

Please refer to the documentation here for more information about Session scope.

Relationships breaking with spring-data-neo4j 4.0.0

2 Answers