WCF .NET 4.0 Console Hosted Json Rest Secure HTTP Web Service with Authentication and Roles

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Principal;

namespace WtfService
{
    public class WtfPrincipal : IPrincipal
    {
        IIdentity _identity;
        string[] _roles;

        public WtfPrincipal(IIdentity identity)
        {
            _identity = identity;
            LoadUsersRoles();
        }
        
        /// <summary>
        /// we should load up the user's roles from the database here based on username
        /// </summary>
        private void LoadUsersRoles()
        {
            //run query using on db using _identity.Name
            //then put into _role
            _roles = new string[] { "WtfUser" };
        }


        public IIdentity Identity
        {
            get { return _identity; }
        }

        public bool IsInRole(string role)
        {
            if (_roles.Contains(role))
                return true;
            else
                return false;   
        }

        public string[] Roles
        {
            get { return _roles; }
        }

    }
}