Add a factory method for RoleHierarchyImpl

[making]

Currenctly Hierarchical Roles requires the setter method to define the hierarchy.

RoleHierarchyImpl hierarchy = new RoleHierarchyImpl();
hierarchy.setHierarchy("...");

This PR adds a factory method for this use case to make it easier

RoleHierarchyImpl hierarchy = RoleHierarchyImpl.of("...");

[jzheaux]

@making, I like this idea; however, I'd prefer that it not be on the implementation.

Usually, this is addressed in Spring Security with a factory class like RoleHierarchies. The nice thing about that is that we could do the following:

public final class RoleHierarchies {
    public static RoleHierarchy of(String hierarchy) { ... }
    public static RoleHierarchy of(Map<String, List<String>> hierarchy) { ... }
}

Are you able to change the PR along these lines?

[making]

I’ll do it

[making]

The reason I created this factory method in the impl class is because the format of the string representation is highly dependent on RoleHierarchyImpl.
If I don't have to care about it I'll move to RoleHierarchies.

[making]

Map<String, List<String>> hierarchy

Is this a map where directly assigned authority is the key and reachable authorities is the value?
And is this intended to be a factory method for a different implementation class than RoleHierarchyImpl?

[jzheaux]

@making Good points.

The reason I created this factory method in the impl class is because the format of the string representation is highly dependent on RoleHierarchyImpl.

Good point. Maybe instead what we do is deprecate the setHierarchy method as well as add the factory method. My concern is that it's confusing to have a setter and a constructor that do the same thing in the same class.

And is this intended to be a factory method for a different implementation class than RoleHierarchyImpl?

No, I was thinking for the same implementation. It could use RoleHierarchyUtils to adapt, for example.

That said, a builder is probably better than taking a map, so instead let's just add the factory method to RoleHierarchyImpl, as you originally proposed, and also deprecate setHierarchy. I'll create separate ticket to look at a more fluent way to describe a hierarchy. Will that work?

[jzheaux]

Thanks again for your submission, @making! This is now merged into main. I added a polish in 9ffa54d.