(バージョン情報なし。おそらく SVN 版にしか存在しないでしょう)
Plugins allow for easy extensibility and customization of the framework.
Plugins are classes. The actual class definition will vary based on the component -- you may need to implement this interface, but the fact remains that the plugin is itself a class.
A plugin could be loaded into Yaf by using Yaf_Dispatcher::registerPlugin(), after registerd, All the methods which the plugin implemented according to this interface, will be called at the proper time.
$request
, Yaf_Response_Abstract $response
)