protected function setNextState($current_state, $executed)
	{
		try
		{
			$next_state = $current_state->getNextState();
		}
		catch(ClassNotFoundException $e)
		{
			Session::put('Errors', new MessageBag( array("Class" => "Class not found") ) );
			return false;
		}

		if($executed)
		{
			// append next state
			$this->append($next_state);
		}
		else
		{
			// replace current state
			$this->replaceCurrent($next_state);
		}

		return true;
	}