<?php
class Foo{
    public function call($call){
        call_user_func(array($this, $call));
    }
    static public function publicmethod(){
        echo __METHOD__;
    }
    static protected function protectedmethod(){
        echo __METHOD__;
    }
    static private function privatemethod(){
        echo __METHOD__;
    }
}

$foo = new Foo();
$foo->call('publicmethod');
$foo->call('protectedmethod');
$foo->call('privatemethod');