public function setCustomerID($id)
    {
        if(preg_match('/[^A-Za-z0-9]/', $id))
        {
            throw new ErrorException('Customer ID has invalid characters');
        }
        elseif(strlen($id) > 8)
        {
            throw new ErrorException('Customer ID cannot be longer than eight (8) characters');
        }

        $this->customerID = $id;

        return $this;
    }