org.zkoss.zul
Interface RendererCtrl

public interface RendererCtrl

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

Though ListitemRenderer.render(org.zkoss.zul.Listitem, T, int) 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 redering, and doFinally() will be caleld 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.

Author:

tomyeh

Method Summary

void	doCatch(java.lang.Throwable ex) Called if any exception occurs when rendering items.
void	doFinally() Invoked after all rendering are done successfully or an exception occurs.
void	doTry() Called before rendering any item.

Method Detail

doTry

void doTry()

Called before rendering any item.

Example, you could start an transaction here.

doCatch

void doCatch(java.lang.Throwable ex)
             throws java.lang.Throwable

Called if any exception occurs when rendering items. Note: this method won't be called if exception occurs in doTry().

If this method doesn't throw exception, ex is 'eaten' though rendering is terminating. Thus, if you want to bubble up the exception, you could throw it again.

Example, you could roll back the transaction.

Throws:

java.lang.Throwable

doFinally

void doFinally()

Invoked after all rendering are done successfully or an exception occurs.

If an exception occurs, doCatch(java.lang.Throwable) will be invoked first and then doFinally().