This interface defines the methods components like Listbox use to notify the renderer for several circumstance.

Though ListitemRenderer.render(org.zkoss.zul.Listitem, java.lang.Object) is called one item a timer, a request might have several items to render. And, if the renderer implements this interface, doTry() will be called before any rendering, and doFinally() will be called after all rendering. If any exception occurs, doCatch(java.lang.Throwable) will be called.

A typical use is to start a transaction and use it for rendering all items from the same request.