/**
  * Validate that the record in the result set is indeed a record 
  * that matched the identity provided to this adapter.
  * 
  * 
  * @access protected
  * @param array $resultIdentities
  * @return Result
  */
 protected function validateResult($resultIdentities)
 {
     if (count($resultIdentities) < 1) {
         $this->_authenticateResultInfo['code'] = Result::FAILURE_IDENTITY_NOT_FOUND;
         $this->_authenticateResultInfo['messages'][] = 'A record with the supplied identity could not be found.';
         return $this->authenticateCreateAuthResult();
     } elseif (count($resultIdentities) > 1) {
         $this->_authenticateResultInfo['code'] = Result::FAILURE_IDENTITY_AMBIGUOUS;
         $this->_authenticateResultInfo['messages'][] = 'More than one record matches the supplied identity.';
         return $this->authenticateCreateAuthResult();
     } elseif (count($resultIdentities) == 1) {
         $resultIdentity = $resultIdentities[0];
         $password = $resultIdentity->{$this->_credentialColumn};
         if (!User::verifyPassword($this->_credential, $password)) {
             $this->_authenticateResultInfo['code'] = Result::FAILURE_CREDENTIAL_INVALID;
             $this->_authenticateResultInfo['messages'][] = 'Supplied credential is invalid.';
         } else {
             $this->_authenticateResultInfo['code'] = Result::SUCCESS;
             $this->_authenticateResultInfo['identity'] = $this->_identity;
             $this->_authenticateResultInfo['messages'][] = 'Authentication successful.';
         }
     } else {
         $this->_authenticateResultInfo['code'] = Result::FAILURE_UNCATEGORIZED;
     }
     return $this->authenticateCreateAuthResult();
 }