Queueable class

<?php
/**
 * A class that allows multiple method inheritance by queuing different implementations,
 * and running them one after another. Works only for static classes, but it's not really mandatory.
 */

abstract class Queueable
{
    protected static $_implementations = array();

    protected function __construct() {}

    /*
     * Example: Entries::register_method('list', 'Entries_Sortable');
     */
    public static function register_method($method_name, $class_name)
    {
        if(!isset(static::$_implementations[$method_name]))
        {
            static::$_implementations[$method_name] = array();
        }

        static::$_implementations[$method_name][] = $class_name;
    }

    protected static function call($method_name, $arguments)
    {
        if(isset(static::$_implementations[$method_name]))
        {
            foreach(static::$_implementations[$method_name] as $class)
            {
                call_user_func_array($class.'::'.$method_name, $arguments);
            }
        }
    }

    public static function __callStatic($name, $arguments)
    {
        return static::call($name, $arguments);
    }
}