Thanks for the reply!
I indeed used arrays to store it. I guess it will never change so it does not really matter that much.
(in case of future Google searches, my PHP solution
Code:
public static $classRoles = array(
self::CLASS_WARRIOR => array(self::ROLE_DPS, self::ROLE_TANK),
self::CLASS_PALADIN => array(self::ROLE_DPS, self::ROLE_TANK, self::ROLE_HEALING),
self::CLASS_HUNTER => array(self::ROLE_DPS),
self::CLASS_ROGUE => array(self::ROLE_DPS),
self::CLASS_PRIEST => array(self::ROLE_DPS, self::ROLE_HEALING),
self::CLASS_DEATHKNIGHT => array(self::ROLE_DPS, self::ROLE_TANK),
self::CLASS_SHAMAN => array(self::ROLE_DPS, self::ROLE_HEALING),
self::CLASS_MAGE => array(self::ROLE_DPS),
self::CLASS_WARLOCK => array(self::ROLE_DPS),
self::CLASS_MONK => array(self::ROLE_DPS, self::ROLE_TANK, self::ROLE_HEALING),
self::CLASS_DRUID => array(self::ROLE_DPS, self::ROLE_TANK, self::ROLE_HEALING),
);