laravel/laravel/cache/manager.php

<?php namespace Laravel\Cache;

use Laravel\IoC;

class Manager {

	/**
	 * All of the active cache drivers.
	 *
	 * @var array
	 */
	protected static $drivers = array();

	/**
	 * Get a cache driver instance.
	 *
	 * If no driver name is specified, the default cache driver will be returned
	 * as defined in the cache configuration file.
	 *
	 * @param  string        $driver
	 * @return Cache\Driver
	 */
	public static function driver($driver = null)
	{
		if (is_null($driver)) $driver = Config::get('cache.default');

		if ( ! array_key_exists($driver, static::$drivers))
		{
			if ( ! IoC::container()->registered('laravel.cache.'.$driver))
			{
				throw new \Exception("Cache driver [$driver] is not supported.");
			}

			return static::$drivers[$driver] = IoC::container()->resolve('laravel.cache.'.$driver);
		}

		return static::$drivers[$driver];
	}

	/**
	 * Pass all other methods to the default cache driver.
	 *
	 * Passing method calls to the driver instance provides a convenient API for the developer
	 * when always using the default cache driver.
	 */
	public static function __callStatic($method, $parameters)
	{
		return call_user_func_array(array(static::driver(), $method), $parameters);
	}

}