Factory Object

Factory.php

<?php
/**
 * Sample Application
 *
 * @copyright  Copyright (C) WebSpark, Inc. All rights reserved.
 * @license    http://www.gnu.org/licenses/gpl-2.0.txt GNU General Public License Version 2 or Later
 */

namespace Sample;

use Joomla\DI\Container;

/**
 * Application Factory
 *
 * @since  1.0
 */
class Factory
{
	/**
	 * DI Container
	 *
	 * @var    Container
	 * @since  1.0
	 */
	private $container;

	/**
	 * Singleton Factory instance
	 *
	 * @var    Factory
	 * @since  1.0
	 */
	private static $instance;

	/**
	 * Constructor
	 *
	 * @param   Container  $container  DI Container
	 *
	 * @since   1.0
	 */
	public function __construct(Container $container)
	{
		$this->container = $container;
		self::$instance  = $this;
	}

	/**
	 * Fetch the DI container
	 *
	 * @return  Container
	 *
	 * @since   1.0
	 */
	public function getContainer()
	{
		return $this->container;
	}

	/**
	 * Retrieves a helper class
	 *
	 * @param   string  $helper  The helper object to retrieve
	 *
	 * @return  object
	 *
	 * @since   1.0
	 * @throws  \InvalidArgumentException
	 */
	private static function getHelper($helper)
	{
		$class = 'Sample\\Helper\\' . ucfirst(strtolower($helper)) . 'Helper';

		// Make sure the helper exists
		if (!class_exists($class))
		{
			/** @var \Joomla\Language\Text $text */
			$text = self::$instance->getContainer()->get('Joomla\\Language\\Text');

			throw new \InvalidArgumentException(sprintf('Helper class for "%s" not found.', $helper));
		}

		// If the helper already exists in the DI Container, fetch the existing object
		if (self::$instance->getContainer()->exists($class))
		{
			return self::$instance->getContainer()->get($class);
		}

		return self::$instance->getContainer()->buildObject($class);
	}

	/**
	 * Retrieves a model class
	 *
	 * @param   string  $model  The model object to retrieve
	 *
	 * @return  \Sample\Model\AbstractModel
	 *
	 * @since   1.0
	 */
	private static function getModel($model)
	{
		$class = 'Sample\\Model\\' . ucfirst(strtolower($model)) . 'Model';

		// If the requested model does not exist, revert to the application default
		if (!class_exists($class))
		{
			$class = 'Sample\\Model\\DefaultModel';
		}

		// If the model already exists in the DI Container, fetch the existing object
		if (self::$instance->getContainer()->exists($class))
		{
			return self::$instance->getContainer()->get($class);
		}

		return self::$instance->getContainer()->buildObject($class);
	}

	/**
	 * Retrieves the Repository object for the given entity
	 *
	 * @param   string  $entity  The fully qualified class name of the entity
	 *
	 * @return  \Sample\Entity\BaseRepository
	 *
	 * @since   1.0
	 */
	private static function getRepository($entity)
	{
		$entity = 'Sample:' . $entity;

		/** @var \Sample\Doctrine\ManagerRegistry $manager */
		$manager = self::get('doctrine');

		return $manager->getManager()->getRepository($entity);
	}

	/**
	 * Retrieves the active user
	 *
	 * @param   integer  $id  User ID to retrieve
	 *
	 * @return  \Sample\Entity\User
	 *
	 * @since   1.0
	 */
	private static function getUser($id = 0)
	{
		return self::$instance->getContainer()->get('app')->getUser($id);
	}

	/**
	 * Retrieve objects from the DI container
	 *
	 * @param   string  $key  Container lookup key
	 *
	 * @return  mixed
	 *
	 * @note    Method accepts additional params for special cases
	 * @since   1.0
	 */
	public static function get($key)
	{
		$args = func_get_args();

		switch ($key)
		{
			case 'helper' :
				return self::getHelper($args[1]);

			case 'model' :
				return self::getModel($args[1]);

			case 'repository' :
				return self::getRepository($args[1]);

			case 'user':
				$id = isset($args[1]) ? $args[1] : 0;

				return self::getUser($id);

			default :
				return self::$instance->getContainer()->get($key);
		}
	}
}