/**
  * Validate the CSR user to ensure it is active and has a role assigned.
  *
  * @param Mage_Admin_Model_User $user
  * @throws EbayEnterprise_Eb2cCustomerService_Exception_Authentication
  * @return self
  */
 protected function _validateUser(Mage_Admin_Model_User $user)
 {
     if (!$user->getIsActive()) {
         throw new EbayEnterprise_Eb2cCustomerService_Exception_Authentication('This account is inactive.');
     }
     if (!$user->hasAssigned2Role($user->getId())) {
         throw new EbayEnterprise_Eb2cCustomerService_Exception_Authentication('Access denied.');
     }
     return $this;
 }