<?php
/**
 * Magento
 *
 * NOTICE OF LICENSE
 *
 * This source file is subject to the Open Software License (OSL 3.0)
 * that is bundled with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://opensource.org/licenses/osl-3.0.php
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@magentocommerce.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade Magento to newer
 * versions in the future. If you wish to customize Magento for your
 * needs please refer to http://www.magentocommerce.com for more information.
 *
 * @category    Mage
 * @package     Mage_Adminhtml
 * @copyright   Copyright (c) 2012 Magento Inc. (http://www.magentocommerce.com)
 * @license     http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */

class Mage_Adminhtml_Model_System_Config_Source_Customer_Group_Multiselect
{
    /**
     * Customer groups options array
     *
     * @var null|array
     */
    protected $_options;

    /**
     * Retrieve customer groups as array
     *
     * @return array
     */
    public function toOptionArray()
    {
        if (!$this->_options) {
            $this->_options = Mage::getResourceModel('customer/group_collection')
                ->setRealGroupsFilter()
                ->loadData()->toOptionArray();
        }
        return $this->_options;
    }
}