Method getInstance

/**
 * Method to get a singleton controller instance.
 *
 * @param   string  $prefix  The prefix for the controller.
 * @param   array   $config  An array of optional constructor options.
 *
 * @return  static
 *
 * @since       3.0
 * @deprecated  5.0 Get the controller through the MVCFactory instead
 * @throws      \Exception if the controller cannot be loaded.
 */
public static function getInstance($prefix, $config = array())
{
    if (\is_object(self::$instance)) {
        return self::$instance;
    }
    @trigger_error(sprintf('%1$s::getInstance() is deprecated. Load it through the MVC factory.', self::class), E_USER_DEPRECATED);
    $app = Factory::getApplication();
    $input = $app->input;
    // Get the environment configuration.
    $basePath = \array_key_exists('base_path', $config) ? $config['base_path'] : JPATH_COMPONENT;
    $format = $input->getWord('format');
    $command = $input->get('task', 'display');
    // Check for array format.
    $filter = InputFilter::getInstance();
    if (\is_array($command)) {
        $keys = array_keys($command);
        $command = $filter->clean(array_pop($keys), 'cmd');
    } else {
        $command = $filter->clean($command, 'cmd');
    }
    // Check for a controller.task command.
    if (strpos($command, '.') !== false) {
        // Explode the controller.task command.
        list($type, $task) = explode('.', $command);
        // Define the controller filename and path.
        $file = self::createFileName('controller', array('name' => $type, 'format' => $format));
        $path = $basePath . '/controllers/' . $file;
        $backuppath = $basePath . '/controller/' . $file;
        // Reset the task without the controller context.
        $input->set('task', $task);
    } else {
        // Base controller.
        $type = '';
        // Define the controller filename and path.
        $file = self::createFileName('controller', array('name' => 'controller', 'format' => $format));
        $path = $basePath . '/' . $file;
        $backupfile = self::createFileName('controller', array('name' => 'controller'));
        $backuppath = $basePath . '/' . $backupfile;
    }
    // Get the controller class name.
    $class = ucfirst($prefix) . 'Controller' . ucfirst($type);
    // Include the class if not present.
    if (!class_exists($class)) {
        // If the controller file path exists, include it.
        if (is_file($path)) {
            require_once $path;
        } elseif (isset($backuppath) && is_file($backuppath)) {
            require_once $backuppath;
        } else {
            throw new \InvalidArgumentException(Text::sprintf('JLIB_APPLICATION_ERROR_INVALID_CONTROLLER', $type, $format));
        }
    }
    // Instantiate the class.
    if (!class_exists($class)) {
        throw new \InvalidArgumentException(Text::sprintf('JLIB_APPLICATION_ERROR_INVALID_CONTROLLER_CLASS', $class));
    }
    // Check for a possible service from the container otherwise manually instantiate the class
    if (Factory::getContainer()->has($class)) {
        self::$instance = Factory::getContainer()->get($class);
    } else {
        self::$instance = new $class($config, null, $app, $input);
    }
    return self::$instance;
}