A three level user access control without rbac.Yii framework

WebUser.php

<?php
/**
 * Created by JetBrains PhpStorm.
 * User: ubeergeek
 * Date: 9/12/12
 * Time: 12:34 PM
 * To change this template use File | Settings | File Templates.
 */
class WebUser extends CWebUser{
    private $_user;
    //is the user an admin ?
    function getIsAdmin(){
        return ( $this->user && $this->user->accessLevel == User::LEVEL_ADMIN );
    }
    //is the user a provider ?
    function getIsProvider(){
        return ( $this->user && $this->user->accessLevel == User::LEVEL_PROVIDER );
    }
    //is the user an Agent?
    function getIsAgent(){
        return ( $this->user && $this->user->accessLevel == User::LEVEL_AGENT );
    }
    //get the logged user
    function getUser(){
        if( $this->isGuest )
            return;
        if( $this->_user === null ){
            $this->_user = User::model()->findByPk( $this->id );
        }
        return $this->_user;
    }
}