gistfile1.txt

var criteria = session.CreateCriteria<Location>()
    .Add(Expression.Eq("Heirarchy.Token", token))
    .SetFetchMode("Metadata", FetchMode.Eager)
    .SetFetchMode("Heirarchy.Children", FetchMode.Eager)
    .SetFetchMode("Heirarchy.Metadata", FetchMode.Eager)
    .SetResultTransformer(new DistinctRootEntityResultTransformer());

Heirarchy.cs

public class Heirarchy<T> where T : class
{
    public Heirarchy()
    {
        Children = new List<T>();
    }

    public virtual T Parent
    {
        get;
        private set;
    }

    public virtual IList<T> Children
    {
        get;
        private set;
    }

    public virtual bool IsRoot
    {
        get
        {
            return Parent == null;
        }
    }

    public virtual bool HasChildren
    {
        get
        {
            return Children.Count > 0;
        }
    }
}

Location.cs

public class Location : Entity
{
    public Location()
    {
        InitMembers();
    }

    private void InitMembers()
    {
        Heirarchy = new LocationHeirarchy();
        Metadata = new List<Metadata>();
    }

    public virtual string Name
    {
       get;
       set;
    }

    public virtual string Route
    {
        get;
        private set;
    }

    
    public virtual LocationHeirarchy Heirarchy
    {
        get;
        private set;
    }

    public virtual IList<Metadata> Metadata
    {
        get;
        private set;
    }
}

LocationHeirarchy.cs

public class LocationHeirarchy : Heirarchy<Location>
{
    private string _token;

    public virtual string Token
    {
        get
        {
            if (string.IsNullOrEmpty(_token))
            {
                var parent = this.Parent;
                var tokenString = string.Empty;

                while (parent != null)
                {
                    tokenString += parent.Route;

                    if (parent.Heirarchy.Parent == null)
                    {
                        tokenString += "/";
                    }

                    parent = parent.Heirarchy.Parent;
                }

                _token = EncyptionUtils.MD5Hash(tokenString);
            }

            return _token;
        }
        private set
        {
            _token = value;
        }
    }
}