Question

Is this code a good fit for the strategy pattern?

public function isValidEmail($email, $organization)
{   
    switch ($organization) {
        case 'USAF':
        case 'Army':
        case 'USMC':
        case 'Navy':
        case 'SOCOM':
            return (preg_match('/[.]mil$/i', $email) === 1);
            break;

        case 'Federal Gov.':
            return (preg_match('/[.]gov$/i', $email) === 1);
            break;

        case 'State/Local Gov.':
            $regionCollection = Mage::getModel('directory/region')
                ->getResourceCollection()
                ->addCountryFilter(array('US'))
                ->load();

            $stateAbbr = array();

            // Cycle through state abbreviations for match
            foreach ($regionCollection as $region) {
                $stateAbbr[] = strtolower($region->getCode());
            }
            $states = implode('|', $stateAbbr);

            return (preg_match("/[\.|@]{1}($states){1}\.us$/i", $email) ===
            break;

        case 'USCG':
        case 'DOD':
        case 'Defense Industry':
            return true;
            break;

        default:
            return false;
            break;
    }
    // It got past somehow?
    return false;
}

I was assuming you could have a simple interface to define a validate method but I’m slightly confused on how to handle the two odd ball cases in the switch statement that return true/false w/ no email logic.

interface ValidInterface
{
    public function isValid($email);
}

Answer 1

You’re on the right track with your validator interface (I would name it something more meaningful like EmailValidator). You can then create a mapping of organizations to validators and look this up when performing the validation:

private $validators = array(
  'USAF' => new MilitaryEmailValidator(),
  'Army' => new MilitaryEmailValidator(),
  ...
  'Defense Industry' => new TrueEmailValidator()
);

public function isValidEmail($email, $organization) {
  if (isset($this->validators[$organization]))
    return $this->validators[$organization])->isValid($email);

  // default return
  return false;
}