Module org.omnifaces
Package org.omnifaces.taghandler

Class EnableRestorableView

java.lang.Object
jakarta.faces.view.facelets.TagHandler
org.omnifaces.taghandler.EnableRestorableView
All Implemented Interfaces:
FaceletHandler
public class EnableRestorableView extends TagHandler

The <o:enableRestorableView> taghandler instructs the view handler to recreate the entire view whenever the view has been expired, i.e. whenever ViewHandler.restoreView(FacesContext, String) returns null and the current request is a postback. This effectively prevents ViewExpiredException on the view. This tag needs to be placed in <f:metadata> of the view.

There are however technical design limitations: the recreated view is exactly the same as during the initial request. In other words, the view has lost its state. Any modifications which were made after the original initial request, either by taghandlers or (ajax) conditionally rendered components based on some view or even session scoped variables, are completely lost. Thus, the view should be designed that way that it can be used with a request scoped bean. You can use it with a view scoped bean, but then you should add a @PostConstruct which checks if the request is a postback and then fill the missing bean properties based on request parameters.

Usage

To enable the restorable view, just add the <enableRestorableView> to the view metadata. 

 <f:metadata>
     <o:enableRestorableView/>
 </f:metadata>

Mojarra's new stateless mode

Since Mojarra 2.1.19, about 2 months after OmniFaces introduced the <o:enableRestorableView>, it's possible to enable a stateless mode on the view by simply setting its transient attribute to true: 

 <f:view transient="true">
     ...
 </f:view>

This goes actually a step further than <o:enableRestorableView> as no state would be saved at all. However, on those kind of pages where <o:enableRestorableView> would work just fine, this statelessness should not form any problem at all. So, if you have at least Mojarra 2.1.19 at hands, use the transient="true" instead.

Since:
1.3
Author:
Bauke Scholtz
See Also:

  • Constructor Details

    • EnableRestorableView

      public EnableRestorableView(TagConfig config)
      The tag constructor.
      Parameters:
      config - The tag config.

  • Method Details