public List<String> getValidationErrors() {
        List<String> errors = new ArrayList<String>();       

        if (customerId == null || customerId.length() == 0) errors.add("Customer ID is required");
        if (username == null || username.length() == 0) errors.add("Customer username is required");
        
        if (errors.size() > 0) return errors;
        
        if (!customerId.matches("\\d*")) errors.add("Customer ID should be a number");
        if (username.matches(".*[<>\"&].*")) errors.add("Username may not contain angle brackets, quotes, greater, less or ampersan");
        return errors;
    }