ObjectManager.php

<?php
/**
 * Magento object manager. Responsible for instantiating objects taking itno account:
 * - constructor arguments (using configured, and provided parameters)
 * - class instances life style (singleton, transient)
 * - interface preferences
 *
 * Intentionally contains multiple concerns for best performance
 *
 * 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.
 *
 * @copyright Copyright (c) 2014 X.commerce, Inc. (http://www.magentocommerce.com)
 * @license   http://opensource.org/licenses/osl-3.0.php  Open Software License (OSL 3.0)
 */
namespace Magento\Framework\ObjectManager;

class ObjectManager implements \Magento\Framework\ObjectManager
{
    /**
     * @var \Magento\Framework\ObjectManager\Factory
     */
    protected $_factory;

    /**
     * List of shared instances
     *
     * @var array
     */
    protected $_sharedInstances = array();

    /**
     * @var Config\Config
     */
    protected $_config;

    /**
     * @param Factory $factory
     * @param Config $config
     * @param array $sharedInstances
     */
    public function __construct(Factory $factory, Config $config, array $sharedInstances = array())
    {
        $this->_config = $config;
        $this->_factory = $factory;
        $this->_sharedInstances = $sharedInstances;
        $this->_sharedInstances['Magento\Framework\ObjectManager'] = $this;
    }

    /**
     * Create new object instance
     *
     * @param string $type
     * @param array $arguments
     * @return mixed
     */
    public function create($type, array $arguments = array())
    {
        return $this->_factory->create($this->_config->getPreference($type), $arguments);
    }

    /**
     * Retrieve cached object instance
     *
     * @param string $type
     * @return mixed
     */
    public function get($type)
    {
        $type = $this->_config->getPreference($type);
        if (!isset($this->_sharedInstances[$type])) {
            $this->_sharedInstances[$type] = $this->_factory->create($type);
        }
        return $this->_sharedInstances[$type];
    }

    /**
     * Configure di instance
     *
     * @param array $configuration
     * @return void
     */
    public function configure(array $configuration)
    {
        $this->_config->extend($configuration);
    }
}