toutpratique/Adapter/Adapter_Configuration.php

<?php
/**
 * 2007-2015 PrestaShop
 *
 * 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@prestashop.com so we can send you a copy immediately.
 *
 * DISCLAIMER
 *
 * Do not edit or add to this file if you wish to upgrade PrestaShop to newer
 * versions in the future. If you wish to customize PrestaShop for your
 * needs please refer to http://www.prestashop.com for more information.
 *
 *  @author 	PrestaShop SA <contact@prestashop.com>
 *  @copyright  2007-2015 PrestaShop SA
 *  @license    http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 *  International Registered Trademark & Property of PrestaShop SA
 */

class Adapter_Configuration implements Core_Business_ConfigurationInterface
{
    /**
     * Returns constant defined by given $key if exists or check directly into PrestaShop
     * Configuration
     * @param $key
     * @return mixed
     */
    public function get($key)
    {
        if (defined($key)) {
            return constant($key);
        } else {
            return Configuration::get($key);
        }
    }
}