Профи обосрались - 2. Partial classes, base functions extending

цепочка обязанностей нужна

<?php
abstract class FO_Base_Sefurls extends FormObject_Plugin
{
	public function __construct()
	{
		$slug = new FOField_Textbox("slug", "URL");
		$slug->addValidator(new FOValidator_NoEmpty());
		$this->addField($slug, "SEO");

		$this->addField(new FOField_Textbox("meta_keywords", "Meta Keywords"), "SEO");
		$this->addField(new FOField_Textbox("meta_description", "Meta Description"), "SEO");
	}

	public abstract function getLinkId($id);

	public function getItemTable()
	{
		return "sefurls";
	}

	public function getItem($id)
	{
		return $this->getDb()->get($this->getItemTable(), array(
				"url" => $this->getLinkId($id)
		));
	}

	public function onAfterEdit($data, $id, $form)
	{
		$this->updateLink($data, $id);
	}

	public function onAfterNew($data, $id, $form)
	{
		$this->updateLink($data, $id);
	}

	public function onAfterDelete($data, $id, $form)
	{
		$this->getDb()->delete($this->getItemTable(), array(
				"url" => $this->getLinkId($id)
		));
	}

	protected function updateLink($data, $id)
	{
		$url = $this->getLinkId($id);

		$r = $this->getDb()->get($this->getItemTable(), array("url" => $url));
		if(!$r)
		{
			$data['url'] = $url;

			$this->getDb()->insert($this->getItemTable(), $data);
		}
		else
		{
			$this->getDb()->update($this->getItemTable(), $data, array(
					"url" => $url
			));
		}
	}
}

<?php
require_once 'FO_Base.part.Sefurls.php';

class FO_Hotels_Sefurls extends FO_Base_Sefurls
{
	public function getLinkId($id)
	{
		return "hotels/$id";
	}
}