[Neo4j] Modeling Direction.BOTH Relationships with @RelatedToVia element classes on Neo4J

[Marcello de Sales]

Hi All,

I have posted this question at the SpringSource NoSQL forum...
http://forum.springsource.org/showthread.php?110318-Modeling-Direction.BOTH-Relationships-with-RelatedToVia-element-classes-on-Neo4J...
I decided to learn by modifying the my-restaurants-social example by adding
an RBAC implementation for applications...

----

I must say that the project is looking amazing!!! Congratulations Spring
team and Neo4J team to bring this together... I must say I was already in
love with NoSQL using MongoDB, but Graph Databases with Neo4J is just a
piece of art!!! After watching the presentation about Spring Data Graph, I
must say I was hooked after I saw the term "Polyglot Persistence" and I
decided to give this a try!!!

Suppose I have an RBAC model such that users are granted action permissions
to applications... The questions I'd like to answer about it is as follows:

1. Which permissions a user have been granted to a set of applications?
2. Which users have certain action permissions to an application?

User <---> Permission <---> Application

By reading the documentation, I thought I could use a @Direction.BOTH
implementation of a @RelationshipEntity using a @RelatedToVia aggregation on
my User @NodeEntity... Here's the code snippet for User...

Code:


@NodeEntity
public class User {

    @Indexed
    private String id;

    @Indexed
    private String username;

    @RelatedToVia(type = "grantedPermissions", Direction.BOTH,
elementClass = Permission.class)
    Iterable<Permission> permissions;

    public Iterable<Permission> getPermissions() {
        return this.permissions;
    }
    ...
    ...
}

The implementation of the Application @NodeEntity... At this point, I
decided to paste the same code, but with a different property name and same
"type" value for the annotation @RelatedToVia using @Direction.BOTH...

Code:


@NodeEntity
public class Application {

    @Indexed
    private String id;

    @Indexed
    private String name;

    ...
    ...
    @RelatedToVia(type = "grantedPermissions", Direction.BOTH,
elementClass = Permission.class)
    Iterable<Permission> permittedUsers;

    public Iterable<Permission> getPermittedUsers() {
        return this.permittedUsers;
    }
}

Now here are the questions for the implementation Permission as
@RelationshipEntity...

1. Can I express the @StartNode and the @EndNode in the same property on a
@RelationshipEntity?

2. Given the "public enum Action { CREATE, VIEW, EDIT, DELETE }", can I have
a set of ENUMs as a @RelationshipEntity property?

Here's the implementation of the @RelationshipEntity...

Code:


@RelationshipEntity
public class Permission {

    @StartNode
    @EndNode
    private User user;

    @EndNode
    @StartNode
    private Application application;

    private Set<Action> actions;

    public Permission() {

    }

    public void addAction(Action action) {
        this.actions.add(action);
    }

}

Would this work? I'm still setting up my environment and I'm adding this to
the my-restaurants-social application based on the Neo4J presentation...

Thanks
Marcello
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