RendererCtrl (zk 10.0.0 API)

```
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 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.

Author:

tomyeh

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`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().